Manufacturing method of peeled fruits and vegetables

Abstract

To provide a method for producing peeled fruits and vegetables, which can peel a larger number of fruit and vegetables and can produce peeled fruits and vegetables of excellent quality more simply and efficiently. [Solution] A method for producing peeled fruits and vegetables in which the outer pericarp is removed from the fruits and vegetables, comprising a first step of forming a carbonized layer on at least the surface of the outer pericarp, a second step of contacting the fruits and vegetables after the first step with an outer pericarp disintegrating agent, and a third step of removing the outer pericarp from the fruits and vegetables after the second step.

Description

[Technical Field]

[0001] The present disclosure relates to a method for producing peeled fruits and vegetables. [Background technology]

[0002] Conventionally, peeling of fruits and vegetables has been done manually using a blade such as a knife at processing sites of fruits and vegetables, which required a lot of labor. On the other hand, techniques for peeling fruits and vegetables by enzymatic treatment have been disclosed with the aim of improving the efficiency of peeling work (see, for example, Patent Documents 1 to 4).

[0003] Patent Document 1 discloses a technique in which persimmon fruits are exposed to a flame as a pretreatment for enzyme treatment, thereby generating cracks in the cuticle of the persimmon fruits.

[0004] Patent Document 2 discloses a technique for pre-treatment of the exocarp disintegration process, in which a surface treatment is performed by colliding an abrasive material with the surface of fruits or vegetables, and an inlet for introducing an exocarp disintegrating agent into the exocarp of the fruits or vegetables. Patent Document 3 discloses a technique for pre-treatment of the enzyme treatment, in which fruits or vegetables are immersed in surfactant-containing water at 20°C or below that contains 0.05% by mass or more of a polyglycerol fatty acid ester for at least 15 hours. Patent Document 4 discloses a technique for pre-treatment of the enzyme treatment, in which holes are drilled on the surface of citrus fruits with the exocarp attached, and then the citrus fruits are immersed in an enzyme solution and impregnated under reduced pressure (reduced pressure impregnation).

[0005] However, the technology described in Patent Document 1 is limited to persimmon fruit and is susceptible to inter-varietal, inter-individual, and intra-individual differences. Therefore, proper peeling may not be possible depending on the ripeness of each individual persimmon fruit and the location within each individual fruit, making it difficult to consistently peel a wide variety of persimmon fruit. The technology described in Patent Document 2 is applicable to a wide range of persimmon fruit, including potatoes, vegetables, and fruits. However, it requires a blasting device for surface treatment as a pretreatment, and a blasting device suitable for food processing is required. The technology described in Patent Document 3 is limited to grapes, whose outer peel is primarily composed of cuticle, and cannot be applied to citrus fruits and persimmons, which are major fruits. Furthermore, it cannot be applied to persimmons whose outer peel is primarily composed of cork, making it difficult to peel a wide variety of persimmon fruit. The technology described in Patent Document 4 is limited to citrus fruits and is not intended for peeling a wide variety of products, and furthermore, in order to peel citrus fruits in a short time, a pressure-reducing device and a sealed container are required for vacuum impregnation treatment as a pretreatment, and the costs for installing the pressure-reducing device and sealed container must be borne. As described above, all of the technologies described in Patent Documents 1 to 4 have at least one of the following problems: low versatility in terms of the range of products and varieties to which they can be applied, and the need to install devices and equipment for pretreatment before enzyme treatment. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-046030 [Patent Document 2] Japanese Patent Application Publication No. 2020-000218 [Patent Document 3] Japanese Patent Publication No. 2022-100582 [Patent Document 4] Japanese Patent Application Laid-Open No. 2015-188419 Summary of the Invention [Problem to be solved by the invention]

[0007] The present disclosure aims to solve the above-mentioned problems and provide a method for producing peeled fruits and vegetables that can peel a larger number of types of fruits and vegetables and can produce peeled fruits and vegetables of higher quality more simply and efficiently. [Means for solving the problem]

[0008] In order to solve the above problems, the inventors conducted extensive research and found that by heating the surface of fruits and vegetables to form a carbonized layer on the outermost layer of the fruits and vegetables, an exocarp disintegrant such as an enzyme can be appropriately introduced into the exocarp through the numerous pores formed in the carbonized layer, thereby enabling the fruits and vegetables to be efficiently peeled. Based on this finding, the inventors have completed the present disclosure.

[0009] That is, the present disclosure is as shown in the following (1) to (16). (1) A method for producing peeled fruits and vegetables by removing the outer skin from the fruits and vegetables, A first step of forming a carbonized layer on at least the surface of the epicarp; a second step of contacting the fruits and vegetables after the first step with an exocarp disintegrating agent; a third step of removing the outer skin of the fruit or vegetable after the second step; The method for producing peeled fruits and vegetables is characterized by comprising the steps of: (2) The method for producing peeled fruits and vegetables described in (1) above, wherein the first step includes a heat treatment of heating the surface of the fruits and vegetables so that the surface temperature is at least 200°C or higher, and the heat treatment is carried out until the outer skin is burned. (3) In the method for producing peeled fruits and vegetables described in (2), the heat treatment is carried out until the transpiration conductance of the surface of the fruits and vegetables after heating increases compared to before heating, until the weight of the fruits and vegetables after heating decreases compared to before heating, or until the color of the outer skin turns brown or black. (4) The method for producing peeled fruits and vegetables according to (3) above, wherein the heat treatment is carried out until the transpiration conductance after heating increases by 1.5 to 26 times compared to before heating. (5) In the method for producing peeled fruits or vegetables according to any one of (1) to (4), the second step includes a step of introducing the exocarp disintegrating agent into the exocarp or into the exocarp and an area adjacent to the exocarp, using countless pores formed in the carbonized layer as introduction paths. (6) The method for producing peeled fruits or vegetables according to any one of (1) to (5) above, wherein the second step is carried out under atmospheric pressure. (7) The method for producing peeled fruits and vegetables according to any one of (1) to (6), wherein the fruits and vegetables are fruits and vegetables whose outer skin has a cork layer, and the first step is a step of carbonizing the cork layer. (8) The method for producing peeled fruits and vegetables according to any one of (1) to (7), wherein the fruits and vegetables are fruits and vegetables whose outer skin has a cuticle layer, and the first step is a step of carbonizing the cuticle layer. (9) The method for producing peeled fruits and vegetables according to any one of (1) to (8), wherein the fruits and vegetables are any of root vegetables (excluding potatoes), potatoes, fruit vegetables, leafy vegetables, and fruits. (10) The method for producing peeled fruits or vegetables according to any one of (1) to (9), wherein the fruits or vegetables are lotus rhizomes or citrus fruits. (11) The method for producing peeled fruits or vegetables according to any one of (1) to (10) above, wherein the exocarp disintegrating agent used in the second step is an enzyme agent. (12) The method for producing peeled fruits and vegetables according to (11), wherein the enzyme preparation contains a carbohydrate-degrading enzyme. (13) The method for producing peeled fruits and vegetables according to (11), wherein the enzyme preparation is an enzyme preparation containing at least one carbohydrate-degrading enzyme selected from the group consisting of pectinase-based enzyme preparations, hemicellulase-based enzyme preparations, and cellulase-based enzyme preparations. (14) The method for producing peeled fruits or vegetables according to any one of (1) to (10) above, wherein the exocarp disintegrating agent used in the second step is an acidic substance or a basic substance. (15) The method for producing peeled fruits or vegetables according to (14) above, wherein the acidic substance is at least one selected from the group consisting of hydrochloric acid, sulfuric acid, citric acid, ascorbic acid, and acetic acid, and the basic substance is at least one selected from the group consisting of sodium hydroxide, sodium carbonate, and sodium bicarbonate. (16) The method for producing peeled fruits or vegetables according to (14), wherein the second step comprises sequentially carrying out a contact treatment of contacting the fruit or vegetables with the acidic substance and a contact treatment of contacting the fruit or vegetables with the basic substance. [Effects of the Invention]

[0010] According to the present disclosure, by simply forming a carbonized layer on the outermost layer of the epicarp of fruits and vegetables, it is possible to appropriately introduce an epicarp disintegrating agent into the epicarp of fruits and vegetables through the carbonized layer while avoiding damage to the flesh of the fruits and vegetables. As a result, the present disclosure makes it possible to peel more types of fruits and vegetables and to more simply and efficiently produce peeled fruits and vegetables of high quality. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a photographic image of the appearance of the lotus rhizome of Example 1 after the first step is completed and after the second and third steps are completed. [Figure 2] 10A and 10B are photographs of the appearance of the lotus root of Example 2 during thermal image measurement after the first step is completed, and after the second and third steps are completed. [Figure 3] FIG. 1 is a photographic image of a thermal image of the lotus rhizome of Example 2 during thermal image measurement after the first step is completed. [Figure 4] This is a photographic image of a thermal image of the lotus rhizome of Example 2 during thermal image measurement after the first step is completed. [Figure 5] FIG. 1 is a photographic image of the appearance of each lemon of Examples 3a, 3b, 3c and the control during measurement of weight change after completion of the first step. [Figure 6]1 is a graph showing the weight change of each individual animal of Examples 3a, 3b, 3c and the control after the carbonized layer formation treatment. [Figure 7] Photographs of the appearance of the lotus rhizome of Example 4a after the first step is completed and after the second and third steps are completed. [Figure 8] Photographs of the appearance of the lotus rhizome of Example 4b after the first step is completed and after the second and third steps are completed. [Figure 9] 1 is a photographic image of the appearance of the burdock root of Example 5 after the first step is completed and after the second and third steps are completed. [Figure 10] Photographs of the appearance of sweet potato roots in Example 6 after the first step is completed and after the second and third steps are completed. [Figure 11] This is a photographic image of the appearance of the taro rhizomes of Examples 7a, 7b and the control after completion of the first step, and after completion of the second and third steps. [Figure 12] FIG. 1 is a photographic image of the appearance of the potato rhizomes of Example 8 after the first step is completed and after the second and third steps are completed. [Figure 13] This is a photographic image of the appearance of the pumpkin fruit of Example 9 after completion of the first step, and after completion of the second and third steps. [Figure 14] FIG. 1 is a photographic image of the appearance of the asparagus of Example 10 after the first step is completed and after the second and third steps are completed. [Figure 15] FIG. 1 is a photographic image of the appearance of grapefruit fruit of Example 11 after the first step is completed, and after the second and third steps are completed. [Figure 16] FIG. 1 is a photographic image of the appearance of lemon fruits of Example 12 and the control after the first step is completed, and after the second step is completed and during the third step. [Figure 17] FIG. 1 is a photographic image of the appearance of lemon fruit of Example 12 and the control after completion of the third step. [Figure 18] This is a photographic image of the appearance of the sudachi fruit of Example 13 after completion of the first step and after completion of the second and third steps. [Figure 19] This is a photographic image of the appearance of the pomelo fruit of Example 14 after completion of the first step and after completion of the second and third steps. [Figure 20] 1 is a photographic image of the appearance of the pear fruit of Example 15 after the first step is completed and after the second and third steps are completed. [Figure 21] This is a photographic image of the appearance of the persimmon fruit of Example 16 after completion of the first step and after completion of the second and third steps. [Figure 22] Photographs of the appearance of grape berries of Example 17 after the first step and after the second step. [Figure 23] FIG. 1 is a photographic image of the appearance of grape berries of Example 17 after completion of the third step. [Figure 24] Photographs of the appearance of the kiwifruit of Example 18 after the first step and after the second step. [Figure 25] FIG. 1 is a photographic image of the appearance of the kiwifruit of Example 18 after the third step is completed. [Figure 26] Photographs of the appearance of lotus rhizomes of Examples 19a and 19b after the first step and after the second and third steps are completed. [Figure 27] Photographs of the appearance of lotus rhizomes of Examples 19c and 19d after the first step and after the second and third steps are completed. [Figure 28] Photographs of the appearance of the lotus rhizomes of Examples 19e and 19f after the first step and after the second and third steps are completed. [Figure 29] This is a photographic image of the appearance of the lotus rhizomes of Examples 19g and 19h after the first step has been completed and after the second and third steps have been completed. [Figure 30] Photographs of the appearance of the lotus rhizome of Example 20 after the first step is completed and after the second and third steps are completed. [Figure 31] Photographs of the appearance of the lotus rhizome of Example 21 after the first step is completed and after the second and third steps are completed. [Figure 32] Photographs of the appearance of lemon fruits of Examples 22a and 22b after the first step and after the second and third steps. [Figure 33] Photographs of the appearance of lemon fruits of Examples 22c and 22d after the first step and after the second and third steps. [Figure 34] Photographs of the appearance of lemon fruits of Examples 22e and 22f after the first step and after the second and third steps are completed. [Figure 35] Photographs of the appearance of lemon fruit of Example 23 after the first step is completed and after the second and third steps are completed. [Figure 36] FIG. 1 is a photographic image of the appearance of lemon fruit in Reference Experimental Example 1 after the first step is completed. [Figure 37] Photographs of the appearance of the lotus rhizome of Example 24 after the first step is completed and after the second and third steps are completed. [Figure 38] This is a photographic image of the appearance of the lotus rhizome of Example 25 after completion of the first step and after completion of the second and third steps. [Figure 39] This is a photographic image of the appearance of the lotus rhizome of Example 26 after completion of the first step and after completion of the second and third steps. [Figure 40] Photographs of the appearance of the lotus rhizome of Example 27a after the first step is completed and after the second and third steps are completed. [Figure 41] Photographs of the appearance of the lotus rhizome of Example 27b after the first step is completed and after the second and third steps are completed. [Figure 42] This is a photographic image of the appearance of the lotus rhizome of Example 27c after completion of the first step and after completion of the second and third steps. [Figure 43] Photographs of the appearance of the lotus rhizome of Example 28a after the first step is completed and after the second and third steps are completed. [Figure 44] This is a photographic image of the appearance of the lotus rhizome of Example 28b after completion of the first step and after completion of the second and third steps. [Figure 45] Photographs of the appearance of the lotus rhizome of Example 29a after the first step is completed and after the second and third steps are completed. [Figure 46] This is a photographic image of the appearance of the lotus rhizome of Example 29a after the completion of the fourth step. [Figure 47] This is a photographic image of the appearance of the lotus rhizome of Example 29b after completion of the first step and after completion of the second and third steps. [Figure 48]This is a photographic image of the appearance of the lotus rhizome of Example 29b after the fourth step is completed. [Figure 49] Photographs of the appearance of grapefruit of Example 30a after the first step is completed, after the second step is completed, and during the third step. [Figure 50] FIG. 1 is a photographic image of the appearance of grapefruit of Example 30a after completion of the third step. [Figure 51] 1 is a photographic image of the appearance of grapefruit of Example 30b after completion of the first step and after completion of the second step. [Figure 52] FIG. 1 is a photographic image of the appearance of grapefruit of Example 30b after completion of the third step. [Figure 53] 1 is a photographic image of the appearance of the grapefruit of Example 30c after the first step is completed, and after the second and third steps are completed. DETAILED DESCRIPTION OF THE INVENTION

[0012] An embodiment of the present disclosure will be described in detail below. The method for producing peeled fruits and vegetables in this embodiment is a method for producing peeled fruits and vegetables in which the epicarp is removed from the fruits and vegetables, and includes a first step of forming a carbonized layer on at least the surface of the epicarp, a second step of contacting the fruits and vegetables after the first step with an exocarp disintegrating agent, and a third step of removing the epicarp from the fruits and vegetables after the second step.

[0013] Moreover, the peeled fruits and vegetables according to this embodiment are peeled fruits and vegetables from which the outer pericarp has been removed, which are obtained by the method for producing peeled fruits and vegetables according to this embodiment. In other words, the peeled fruits and vegetables of this embodiment are peeled fruits and vegetables having a structure in which the epicarp has been removed, which are obtained by forming a carbonized layer on at least the surface of the epicarp, contacting the fruits and vegetables after the carbonized layer has been formed with an exocarp disintegrating agent, and then removing the exocarp.

[0014] In the peeled fruits and vegetables of this embodiment obtained by the method for producing peeled fruits and vegetables of this embodiment, when a carbonized layer is formed on at least the surface of the epicarp in the first step described below, the inside of the pulp is not heated. This avoids or reduces a decrease in the hardness of the peeled pulp, a change in aroma, and other quality deterioration, and also suppresses the formation of unnecessary irregularities on the surface of the peeled pulp, resulting in a smooth finish, allowing for the production of peeled fruits and vegetables of high quality. Furthermore, since the amount of pulp removed along with the epicarp can be reduced when removing the epicarp, the yield of peeled fruits and vegetables relative to the raw fruits and vegetables can be maintained at a high level.

[0015] However, it is impossible to directly identify the characteristics of such distinctive peeled fruits and vegetables based on the structure or properties of the object. That is, fruits and vegetables vary in physical properties such as firmness, as well as chemical properties such as the composition and content of nutrients, aroma compounds, and other chemical substances, depending on conditions such as variety, place of origin, harvest time, and maturity, and therefore the state of the peeled fruits and vegetables according to the present embodiment also varies. In light of the fact that structures and associated characteristics vary depending on conditions such as variety, place of origin, harvest time, and maturity, it is impossible to identify the peeled fruits and vegetables according to the present embodiment by, for example, the measured value of firmness, or the composition and content of nutrients and aroma compounds. Furthermore, there are no other terms that clearly identify the above characteristics in terms of structure or properties. Therefore, the peeled fruits and vegetables of this embodiment are specified as peeled fruits and vegetables from which the outer pericarp has been removed, which are obtained by a method for producing peeled fruits and vegetables.

[0016] The fruits and vegetables to be peeled in the peeled fruit and vegetable manufacturing method according to the present embodiment are those whose surfaces are covered with a skin (epicarum). Suitable examples of such fruits and vegetables include vegetables and fruits. Vegetables can be divided into three categories: root vegetables, fruit vegetables, and leafy vegetables, depending on the part of the plant consumed by humans. Among root vegetables, those that utilize enlarged, hard, starchy roots, tubers, corms, or rhizomes are sometimes referred to as potatoes. Leafy vegetables are sometimes referred to as stem and leafy vegetables. With the exception of some leafy vegetables that are generally eaten without peeling (e.g., Chinese cabbage and lettuce), all three categories of root vegetables, fruit vegetables, and leafy vegetables are suitable.

[0017] The method for producing peeled fruits and vegetables of this embodiment is also suitable for peeling fruits and vegetables whose epicarp has a cuticle layer to obtain peeled fruits and vegetables. The method for producing peeled fruits and vegetables of this embodiment is also suitable for peeling fruits and vegetables whose epicarp has a cork layer to obtain peeled fruits and vegetables. Furthermore, the method for producing peeled fruits and vegetables of this embodiment is also suitable for peeling fruits and vegetables whose epicarp has a cuticle layer and a cork layer to obtain peeled fruits and vegetables. Among these, the method for producing peeled fruits and vegetables of this embodiment is particularly suitable for peeling fruits and vegetables whose epicarp has a cork layer to obtain peeled fruits and vegetables, because it can easily peel even fruits and vegetables whose epicarp has a cork layer. Furthermore, the method for producing peeled fruits and vegetables of this embodiment is also suitable for peeling fruits and vegetables that are normally difficult to peel without using a blade or the like, and fruits and vegetables such as citrus fruits that conventionally required reduced pressure impregnation treatment when brought into contact with an exocarp disintegrating agent, to obtain peeled fruits and vegetables.

[0018] In this specification, vegetables are divided into three categories: root vegetables, fruit vegetables, and leafy vegetables, and root vegetables are further divided into root vegetables (excluding potatoes) and tubers. Suitable examples of root vegetables (excluding potatoes) include carrots, radishes, lotus rhizomes (hereinafter sometimes referred to as "lotus root"), turnips, burdock, ginger, etc. Suitable examples of tubers include potatoes, sweet potatoes, taro, Chinese yams, and Chinese yams. Suitable examples of fruit vegetables include pumpkins, eggplants, cucumbers, etc. Suitable examples of leafy vegetables include asparagus, burdock, and butterbur, etc.

[0019] Among root vegetables, there is a high demand for peeled lotus root for use in processed products, and it is desirable to be able to peel it easily and efficiently. Furthermore, some varieties have an elongated, flat shape, making it difficult to peel mechanically using a drum peeler or the like. Furthermore, many lotus roots used for processing cannot be shipped as fresh produce due to scratches or poor shape, making peeling even more difficult. Even such lotus roots can be easily peeled by applying the method for producing peeled fresh produce of the present embodiment. Therefore, the method for producing peeled fresh produce of the present embodiment is most effective for peeling lotus root and obtaining peeled lotus root. Specific examples of lotus roots with an elongated, flat shape include, but are not limited to, "Bicchu" and "Lotus (Lotus White)," which are representative varieties of lotus root produced in Tokushima Prefecture (more specifically, Naruto lotus root). According to the method for producing peeled fruits and vegetables of this embodiment, the lotus root can be peeled while maintaining its shape, making peeling much easier, resulting in a high pulp yield and peeled lotus roots that maintain their characteristic shapes, such as a flat shape that functions as a symbol of place of origin and quality, and internal holes that have aesthetic value.

[0020] Suitable examples of fruits include citrus fruits, persimmons, grapes, pears, kiwifruit, avocados, and the like. The market for peeled, ready-to-eat cut fruits has continued to expand in recent years, and the method for producing peeled fruits and vegetables of the present embodiment is effective for peeling fruits and obtaining peeled fruits. Among citrus fruits, grapefruit, pomelo, and lemon are particularly difficult to peel, and require mechanical peeling using a blade or vacuum impregnation treatment, as in the technique described in Patent Document 4. In contrast, the method for producing peeled fruits and vegetables of the present embodiment does not require the use of a blade or vacuum impregnation treatment, and is therefore particularly effective for peeling citrus fruits and obtaining peeled citrus fruits.

[0021] Here, the "pericarp" of fruits consists of the "epicarp," "mesocarp," and "endocarp." In many fruit varieties, the "epicarp" is the part that is peeled off as the "skin," while the "mesocarp" and "endocarp" are the parts that are eaten as the "flesh." In citrus fruits, the exocarp is the outermost layer of the fruit (flavedo), which is colored orange, yellow, green, etc., and the mesocarp is the white, cotton-like part (albedo) inside the exocarp. Inside these exocarp and mesocarp are a collection of bag-like "segments," and the inside of each "segment" is the "flesh" part called a "segment," and each "segment" is a collection of granular "segments." In contrast, in the case of vegetables, the outer part that is peeled off as the "skin" is called the "epiderm," and the edible inner part other than the "epiderm" is sometimes called the "fruit" or "flesh," etc.

[0022] In this specification, regardless of the type of fruit or vegetable, the surface part of the fruit or vegetable that is generally called the "skin" is referred to as the "epicopeum." The inner part covered by the epipicopeum that is primarily edible is referred to as the "flesh." Note that "flesh" includes cases where seeds and other substances that are not primarily edible are present. Furthermore, "edible" includes industrial uses such as use as a brewing ingredient or starch raw material.

[0023] The cuticle layer on the surface of fruits and vegetables is glossy and smooth to the touch. Examples of fruits and vegetables having a cuticle layer on the exocarp include, but are not limited to, fruits and vegetables. The cuticle is the component that constitutes the outermost layer of the exocarp of these fruits and vegetables. The main components of the cuticle are organic compounds, wax and cutin. Wax is a fat-soluble compound, and as the main component of the outer layer of the cuticle, it contributes to the water repellency and gloss of the cuticle. Cutin is a polymer compound formed by the polymerization of hydroxy fatty acids through ester bonds, and as the main component that forms the skeleton of the cuticle, it contributes to the physical strength of the cuticle. The cuticle is composed of a single layer of epidermal cells in which wax and cutin accumulate.

[0024] The cork layer on the surface of fruits and vegetables is not glossy and feels rough to the touch. Fruits and vegetables having a cork layer on the outer skin include, but are not limited to, root vegetables (excluding potatoes) and potatoes. The outermost layer of the outer skin of these fruits and vegetables, such as root vegetables (excluding potatoes) and potatoes, is cork. The main components of cork are the organic compounds suberin and lignin. Suberin is the main component that turns plant cell walls into cork and makes them thicker, contributing to the cork layer's water and air permeability and elasticity. Suberin is the main component that turns plant cell walls into lignification and hardening, contributing to the cork layer's physical strength. The cork layer is made up of two or more layers of dead cells in which suberin and lignin have accumulated.

[0025] Both the cuticle and cork layers have hydrophobic properties and anti-evaporation properties, and thus play an important role in protecting the flesh by preventing the invasion of pathogens from the outside and the loss of water from the inside. Comparing the cuticle and cork layers, the cork layer is thicker and stronger than the cuticle. Furthermore, the main components of cork are more chemically stable than the main components of the cuticle, and are difficult to dissolve in organic solvents or decompose into low-molecular-weight compounds by alkali treatment. For this reason, peeling fruits and vegetables having a cork layer on the exocarp has been more difficult than peeling fruits and vegetables having a cuticle layer on the exocarp. The peeled fruits and vegetables manufacturing method of the present embodiment allows for easy peeling of fruits and vegetables having a cork layer on the exocarp and is effective for obtaining peeled fruits and vegetables having a cork layer on the exocarp.

[0026] Each step of the method for producing peeled fruits and vegetables according to this embodiment will be described in detail below.

[0027] <First step> The first step is a carbonized layer formation treatment step (carbonized layer formation treatment step) for forming a carbonized layer on at least the surface of the epicarp. The first step includes a heat treatment for heating the surface of the fruits and vegetables. Even if some dirt or the like is attached to the surface of the fruits and vegetables, the heat treatment carbonizes the dirt and the like, so the first step can be performed on the harvested fruits and vegetables immediately. However, to perform the carbonized layer formation treatment more uniformly, the dirt on the surface of the fruits and vegetables can be removed in advance prior to the first step by brushing, immersion in a water bath, a water jet, or the like. For example, the dirt can be removed by manual washing with water or brushing, or by automatic cleaning using a water conveyor or the like. If the fruits and vegetables become wet prior to the first step, a water-removing step, such as wiping the water off the surface with a soft cloth or blowing it away with a gas jet such as air, can be performed before the first step to improve energy efficiency during heating and prevent unevenness and delays in the carbonized layer formation treatment.

[0028] The carbonized layer is also called "char." "Carbonization" refers to the transformation of organic matter into a carbon-rich substance by the action of heat or the like. As used herein, "carbonization" refers to the process of heat-treating the surface of fruits and vegetables, resulting in the denaturation of organic compounds (carbon-containing compounds) in the epicarp through a pyrolysis reaction and the transformation into a carbon-rich substance. The carbonized layer is formed on the outermost layer of the fruits and vegetables, as long as it is formed on at least the surface of the epicarp. Alternatively, the carbonized layer may be formed by carbonizing the entire epicarp, or may be formed by carbonizing a portion of the epicarp and a portion adjacent to the epicarp. Among these, it is more preferable for the entire epicarp to be carbonized to form a carbonized layer, which allows for more appropriate peeling of the fruits and vegetables by more appropriately performing the second and third steps described below, thereby maintaining a high yield.

[0029] The heat treatment in the first step is carried out using an appropriate heating method. The heat treatment is carried out until a charred layer is formed on at least the surface of the outer pericarp. It is more preferable to heat the surface of the fruit or vegetable to a surface temperature of 200°C or higher and continue until the outer pericarp is charred. When it is undesirable to increase the temperature of the pulp inside the fruit or vegetable, the heat treatment is carried out so as to minimize the temperature increase in the pulp inside the fruit or vegetable. That is, by rapidly heating the surface of the fruit or vegetable to a surface temperature of 200°C or higher, more preferably 300°C or higher, a charred layer is formed on the outermost layer of the fruit or vegetable while appropriately suppressing the temperature increase in the pulp. To minimize the temperature increase in the pulp due to heating, the fruit or vegetable can be cooled in advance of the heat treatment or rapidly cooled after the first step is completed. In this case, cooling can be carried out by contacting the fruit or vegetable with a liquid such as water or a gas such as air. The temperature of the liquid or gas used for cooling is generally within the range of 0°C to 16°C, which is suitable for preserving the fruit or vegetable. However, in order to achieve rapid cooling in a short period of time, the temperature of the liquid or gas used for cooling can be set below 0°C. Also, when targeting items that are sensitive to low temperatures, the temperature of the liquid or gas used for cooling can be set higher than 16°C, but from the perspective of preservation, an upper limit of around 40°C is desirable. Cooling after the completion of heat treatment and the associated blocking of combustion-supporting substances are also useful for extinguishing fires that may occur in fruits and vegetables due to heat treatment.

[0030] The carbonized layer contains countless pores (microscopic gaps) invisible to the naked eye. These pores are classified into three types according to the International Union of Pure and Applied Chemistry (IUPAC) classification. Pores with a diameter of more than 50 nm are classified as "macropores," and pores with a diameter of less than 2 nm are classified as "micropores." Pores between "macropores" and "micropores," i.e., pores with a diameter of more than 2 nm but not greater than 50 nm, are called "mesopores." The pores disclosed herein include all "macropores," "mesopores," and "micropores," but it is desirable that they be large enough to allow the exocarp disintegrating agent to pass through without hindrance.

[0031] Therefore, it becomes easy to introduce the exocarp disintegrating agent into the skin tissue from the outside of the fruit or vegetable through the carbonized layer formed on the outermost layer of the fruit or vegetable, more specifically through the countless pores in the carbonized layer.

[0032] The heating method is not particularly limited, and any heating method can be used as long as it can rapidly heat the surface of the fruit or vegetable to a temperature at which a carbonized layer is formed on the outermost layer of the fruit or vegetable. Suitable heating methods include, for example, a heating method by conduction, a heating method by propagation, a heating method by radiation, and a heating method that is a combination of these.

[0033] The method of heating by conduction is not particularly limited, but a suitable example is a method of bringing the outermost layer of fruit or vegetable into contact with a high-temperature solid (e.g., sand, charcoal or coke that is burning or has just been burned, a hot iron, etc.). Heat transfer from a part of the outermost layer of fruit or vegetable whose temperature has been increased by any heating means to a relatively low-temperature part (e.g., a part surrounding the part that is being heated) is by conduction.

[0034] Heating by convection is a method of heating the surface of fruits or vegetables by contacting the outermost layer of the fruit or vegetable with a heat transfer medium heated to a high temperature by any heating means while flowing. The heat transfer method is not particularly limited, but suitable examples include contact with a high-temperature flowing gas (e.g., air, steam, etc.) i.e., hot air, contact with a high-temperature flowing liquid (e.g., oil, molten salt, etc.), and contact with a high-temperature flowing solid (e.g., sand fluidized by a fluidizing gas). Among these, contact with hot air is more suitable as a heat transfer method because it is less likely to cause adhesion of the heat transfer medium to the outermost layer of the fruit or vegetable and therefore less likely to interfere with subsequent processes. The heat transfer gas and the means for heating the heat transfer medium are not particularly limited, but suitable examples include high-temperature combustion gas (burned gas) generated by burning a mixture of fuel and air (oxygen), hot air generated by electrically heating air using an electric fan, and hot air consisting of superheated steam generated by heating water electrically or by other means or by burning hydrogen gas. Among these, combustion gases (burned gases) and inert gases with oxygen concentrations lower than that of air, and superheated steam that does not contain oxygen molecules are more suitable, as using gases with lower oxygen concentrations allows the surface of fruits and vegetables to be carbonized more efficiently.

[0035] The method of heating by radiation is not particularly limited, but suitable examples include methods using radiation emitted by charcoal, coke, electric wire heaters, laser light sources, halogen lamps, xenon lamps, and LEDs. Among these, methods using laser light emitted by a laser light source are more suitable when it is necessary to precisely control the irradiation target area, irradiation intensity, and irradiation time to form a carbonized layer in a selective manner. The radiation may be continuous or pulsed. For example, pulsed irradiation using a light source such as a xenon lamp can rapidly heat only the outermost layer of fruits and vegetables in a short period of time, making it more suitable when it is desired to avoid the heating affecting the interior of the fruits and vegetables.

[0036] The combined heating method is not particularly limited, but a preferred example is a method using a flame, which is a combination of conduction and radiation. The means for generating the flame, both in terms of fuel and combustion equipment, are not particularly limited, but preferred examples include gas burners that use liquefied petroleum gas (LP gas, LPG) containing propane or butane as the main component, gas burners that use city gas containing methane as the main component, gas burners that use hydrogen gas, and oil burners that use fuel oil. Among these, gas burners that use city gas or liquefied petroleum gas are more preferred because they are widely used in general cooking, the fuel and combustion equipment are readily available, and they are less likely to impart unpleasant odors to fruits and vegetables.

[0037] It is most preferable that the carbonized layer formation process in this first step is carried out so that the entire area of ​​the surface of the fruit or vegetable to be peeled is charred, but this is not limited to this, and it is sufficient that the exocarp disintegrating agent is properly infiltrated into the exocarp through the carbonized layer, and it is also possible that some of the surface area to be peeled is not charred, but rather has scattered charred areas. The carbonized layer formation process is preferably carried out so that the carbonized layer is formed over an area of ​​at least 90%, more preferably at least 95%, even more preferably at least 98%, and most preferably 100% of the surface area of ​​the fruit or vegetable to be peeled. The term "area on the surface of a fruit or vegetable to be peeled" refers to an area on the surface of the fruit or vegetable that is to be intentionally and selectively peeled. The first step may be applied to only a portion of the surface of the fruit or vegetable, and the remaining portion may not be subjected to the first step. This allows some of the outer peel to be intentionally left on the fruit or vegetable for the purpose of functionality and convenience when using the peeled fruit or vegetable, for example, to prevent the fingers holding the peeled fruit or vegetable from getting dirty with fruit juice or the like when eating. Furthermore, some of the outer peel may be intentionally left on the fruit or vegetable for aesthetic purposes, for example, to express shapes, letters, etc.

[0038] Fruits and vegetables vary in physical properties such as hardness, and chemical properties such as the composition and content of nutrients, aroma components, and other chemical substances, depending on conditions such as variety, place of origin, harvest time, and maturity, and therefore the state of peeled fruits and vegetables according to this embodiment also varies. For this reason, an appropriate heating method can be selected from the above heating methods depending on the state of the fruit or vegetable, and an appropriate area of ​​the surface of the fruit or vegetable can be charred.

[0039] The heating time in the heat treatment varies depending on the type and output of the heating device, the energy source, the type and condition of the fruit or vegetable, the distance between the heating device and the fruit or vegetable, etc., and is not particularly limited. However, it can be the time until a carbonized layer is formed on at least the surface of the epicarp, more preferably until the epicarp is charred. The heating time is preferably as short as possible as long as the epicarp is charred. More specifically, for example, when the fruit or vegetable is heated with a gas burner, the heating time can be 10 seconds or less, preferably 5 seconds or less, and more preferably 2 seconds or less. The lower limit of the heating time may be more than 0 seconds, and more realistically can be 0.1 seconds or more, but is not limited to this.

[0040] Furthermore, the heat treatment is preferably carried out until the transpiration conductance after heating increases compared to before heating, until the rate of weight loss of the fruits or vegetables after heating increases compared to before heating, until the color of the epicarp turns brown or black, or until the combustion of the oils and fats contained in the epicarp is complete. By carrying out the heat treatment until such changes occur, a carbonized layer is formed in the outermost layer of the fruits or vegetables, which connects the inside and outside of the fruits or vegetables and has countless pores for introducing an epicarp disintegrating agent into the epicarp. In other words, an increase in the transpiration conductance of the surface of the fruits or vegetables, a weight loss of the fruits or vegetables, a change in the color of the surface of the fruits or vegetables, and the completion of the combustion of the oils and fats contained in the epicarp are preferably used as indicators for determining the completion of the heat treatment. These indicators can also be used in combination as needed. When the transpiration conductance or transpiration rate is used as an indicator, the heat treatment is more preferably carried out until the transpiration conductance or transpiration rate after heating increases by 1.5 to 26 times compared to before heating. An increase in transpiration conductance or transpiration rate of less than 1.5 times is undesirable because it becomes difficult to clearly identify the completion of formation of the carbonized layer. The increase in transpiration conductance or transpiration rate may exceed 26 times, but an excessive increase may cause rapid dehydration (evaporation) from the fruit or vegetable, requiring measures to suppress this, so the upper limit is preferably about 26 times. By increasing the transpiration conductance or transpiration rate within the above range, it is possible to form a carbonized layer with countless pores that connect the inside and outside of the fruit or vegetable and allow for more appropriate introduction of the exocarp disintegrating agent.

[0041] (1) When the increase in transpiration conductance is used as an index Plants develop epidermal tissue as a barrier to prevent the loss of water, which is essential for survival, and by forming cuticle and cork layers, they reduce the permeability to water and water vapor. Therefore, an increase in transpiration conductance, which is an index of water vapor permeability (also called "surface permeability") of the plant surface, indicates that this barrier has been damaged and a new route for water vapor diffusion has been formed from inside the plant to the atmosphere.

[0042] In Example 1 described below, it was shown that the first step increased the transpiration conductance after heating compared to a control that was not heated, and that in the subsequent second step, the epicarp disintegration treatment step, the effect of the epicarp disintegrating agent was appropriately exerted inside the epicarp and in the area adjacent to the epicarp. The "area adjacent to the epicarp" refers to the area other than the epicarp that is in contact with, close to, or continuous with the epicarp, and mainly includes the surface of the flesh that is adjacent to the epicarp. This shows that the carbonized layer formed by the carbonized layer formation treatment has countless pores that are large enough for the epicarp disintegrating agent to pass through and that connect the inside and outside of the fruit or vegetable, i.e., paths for water vapor diffusion. From the above, an increase in transpiration conductance on the surface of fruits or vegetables due to heating is an effective indicator of the completion of the carbonized layer formation process, i.e., the formation of numerous pores that connect the inside and outside of the fruits or vegetables and allow the pericarp disintegrating agent to pass through. Note that transpiration conductance is the reciprocal of the diffusion resistance of water vapor. Furthermore, when the vapor pressure difference between the evaporative surface inside the fruits or vegetables and the atmosphere is constant, the transpiration conductance and the transpiration rate are directly proportional, except when there is no vapor pressure difference between the evaporative surface inside the fruits or vegetables and the atmosphere. Therefore, changes in transpiration conductance can be detected using a device capable of measuring at least one of the transpiration conductance, the diffusion resistance of water vapor, and the transpiration rate, such as a transpiration measuring device. Note that an increase in transpiration conductance, accompanied by an increase in the transpiration rate, causes a decrease in surface temperature due to latent heat dissipation. Therefore, an increase in transpiration conductance can also be indirectly detected by a decrease in surface temperature. This change in surface temperature can be detected using, for example, a transpiration measuring device or a thermography device.

[0043] (2) When the increase in the rate of weight loss is used as an indicator The change in weight of fruits and vegetables before and after heating can also be used as an indicator of the water vapor permeability (surface permeability) of the plant surface (see Example 3 below). Fruits and vegetables generally lose moisture gradually over time due to transpiration from the surface, resulting in a decrease in weight. When the cuticle or cork layer, which acts as a barrier to prevent moisture loss, is damaged, forming a new pathway for water vapor diffusion from the fruit and vegetable to the atmosphere, i.e., when the transpiration conductance increases, the amount of moisture lost per unit time increases in the damaged fruit and vegetable compared to undamaged fruit and vegetable under the same environmental conditions, except when there is no vapor pressure difference between the evaporative surface inside the fruit and vegetable and the atmosphere, resulting in an increased weight loss rate. Therefore, an increase in the weight loss rate in heated fruits and vegetables compared to unheated or unheated control fruits and vegetables is an effective indicator of the completion of the carbonized layer formation process, i.e., the formation of numerous pores that connect the inside and outside of the fruit and vegetable and allow the passage of an exocarp disintegrating agent.

[0044] (3) When color change is used as an indicator When a plant is carbonized, its apparent color changes from its original color to brown or black (browning or blackening). Therefore, when the surface of a fruit or vegetable turns brown or black due to heat treatment, it indicates that a carbonized layer has formed on the outermost layer of the fruit or vegetable. Therefore, the color change on the surface of the fruit or vegetable is an effective indicator of the completion of the carbonized layer formation process, i.e., the formation of countless pores that connect the inside and outside of the fruit or vegetable and allow the exocarp disintegrant to pass through. Note that the color change here is not limited to changes in reflectance, transmittance, or absorbance of light in the human visible wavelength range, but also includes changes in reflectance, transmittance, or absorbance of light outside the visible wavelength range, such as ultraviolet and infrared. The color change can be detected visually or using equipment such as a camera or spectrophotometer that is sensitive to the wavelength range being used as an indicator.

[0045] (4) When the end of the burning of the oil contained in the peel is used as an indicator In citrus fruits, oil spots or oil sacs containing oils such as limonene are scattered throughout the epicarp. When heated, these oils ignite and produce flames. The flames associated with the combustion of these oils originate near the epicarp, which is different from the flame used as a heating means, making them clearly distinguishable visually. Furthermore, while the combustion of these oils may produce sporadic popping sounds (e.g., "chili chili" or "crackling"), heating means that generally produce sound (e.g., hot air or a burner) produce continuous fluid sounds (e.g., "gurgling" or "whoosh"), making the two clearly distinguishable auditorily. Since the oils contained in the epicarp are hydrophobic and therefore interfere with the introduction of a hydrophilic epicarp disintegrating agent, it is preferable to remove the oils by burning them. Therefore, the completion of the combustion of the oils and fats contained in the citrus peel is an effective indicator for determining that the hydrophobicity of the peel has decreased and the peel is in a suitable state for the introduction of a hydrophilic peel disintegrating agent.

[0046] The judgment using the above-mentioned increase in transpiration conductance on the surface of fruits and vegetables, the increase in the rate of weight loss of fruits and vegetables, the change in surface color of fruits and vegetables, and the completion of combustion of oils and fats contained in the outer peel as indicators for judging the completion of heat treatment does not necessarily have to be made for all individuals, when targeting a population of fruits and vegetables that can be considered homogeneous to the extent that it does not interfere with achieving the purpose of step 1. In other words, the purpose can be achieved even if the judgment is simplified or omitted by making judgments for a portion of individuals appropriately extracted from the population, establishing a treatment process by appropriately adjusting it, and then applying the process established by such adjustments to the treatment of the remainder of the population.

[0047] By carrying out the first step (carbonized layer forming treatment step) as described above, countless pores for introducing the exocarp disintegrating agent into the exocarp can be easily and appropriately formed on the surface of the fruit or vegetable without using sharp tools such as blades or forming cracks.

[0048] The first step (carbonized layer forming treatment step) described above is also effective in cleaning the surface of fruits and vegetables. Heating the surface of fruits and vegetables to 200°C or higher causes changes such as thermal denaturation, thermal decomposition, and shedding of living or non-living substances that are undesirable when using the fruits and vegetables, which is expected to reduce the density and harmfulness of these living or non-living substances.

[0049] Here, the difference between the carbonized layer formation process, which is the first process in this embodiment, and the crack formation process described in Patent Document 1, in which a flame is radiated onto a persimmon fruit to form cracks in the cuticle, is explained as follows.

[0050] The scientific principle of the crack formation treatment process described in Patent Document 1 is "physical destruction of the epicarp structure." That is, by heating the surface of a persimmon fruit, the cuticle (a cuticular membrane (also called the "cuticular layer"), the outermost layer of the epicarp, whose main component is the cuticle) is unable to maintain its membrane structure due to thermal expansion, and is torn and destroyed (cracked). As a result, a certain number of cracks visible to the naked eye are formed in the outermost layer of the epicarp of the persimmon fruit. Paragraph 0026 of Patent Document 1 also defines "crack" as "a long, thin cut that is formed over a certain length, such as a fissure, a crack, or a cleft."

[0051] In contrast, the scientific principle behind the carbonized layer forming treatment step of this embodiment is "chemical denaturation of the components of the epicarp." That is, by heating the surface of fruits or vegetables, the organic compounds (compounds containing carbon) in the outermost layer of the epicarp are denatured by a pyrolysis reaction, and are transformed into carbon-rich substances (carbonized state). As a result, countless pores (microscopic voids) invisible to the naked eye are formed in the outermost layer of the epicarp of fruits or vegetables. Therefore, the crack formation process in Patent Document 1, which forms "cracks" by "physical destruction of the epicarp structure," and the carbonized layer formation process in this embodiment, which forms "pores" by "chemically modifying the components of the epicarp," are based on completely different scientific principles.

[0052] <Second process> The second step is an exocarp disintegration step (exocarp disintegration step) in which the fruits and vegetables after the first step are brought into contact with an exocarp disintegrating agent to soften or disintegrate the exocarp. Following the first step, the second step brings the exocarp disintegrating agent into contact with the surface of the fruits and vegetables, allowing the exocarp disintegrating agent to be effectively introduced into the exocarp through the numerous pores in the carbonized layer formed in the first step, softening or disintegrating the exocarp. As a result, the next third step (exocarp removal step) can be easily carried out.

[0053] The second step, the exocarp disintegration step, consists of a contact treatment (hereinafter referred to as "contact treatment") in which an exocarp disintegrating agent is brought into contact with the fruit or vegetable, and a hydrolysis treatment (hereinafter referred to as "hydrolysis treatment") in which the components of the exocarp are hydrolyzed by the action of the exocarp disintegrating agent. Furthermore, the exocarp disintegrating agent used in the second step, the exocarp disintegration treatment step, may be an enzyme agent (hereinafter referred to as "enzyme agent") that enzymatically hydrolyzes the components of the exocarp, or it may be an acidic or basic substance that non-enzymatically and chemically hydrolyzes the components of the exocarp. That is, the second step, the exocarp disintegration step, may be a step in which the components of the exocarp are enzymatically hydrolyzed by the action of an exocarp disintegrating agent (hereinafter referred to as the "enzymatic treatment step"), or a step in which the components of the exocarp are non-enzymatically and chemically hydrolyzed by the action of an exocarp disintegrating agent (hereinafter referred to as the "chemical treatment step").

[0054] The exocarp disintegrating agent used in the second step, the exocarp disintegration treatment step, may be a solid such as a powder, granules, or tablet containing a component that has the effect of disintegrating the exocarp, or it may be a liquid in which a component that has the effect of disintegrating the exocarp is dissolved or dispersed. The exocarp disintegrating agent may be an agent consisting solely of a substance having exocarp disintegrating activity, or an agent containing at least a substance having exocarp disintegrating activity and exhibiting exocarp disintegrating activity. The enzymatic agent may be an agent consisting solely of a substance (protein) having enzymatic activity, or an agent containing at least a substance (protein) having enzymatic activity and exhibiting enzymatic activity. The acidic substance may be an agent consisting solely of an acidic substance, or an agent containing at least an acidic substance and exhibiting acidity. The basic substance may be an agent consisting solely of a basic substance, or an agent containing at least a basic substance and exhibiting basicity.

[0055] [Enzyme treatment process] Hereinafter, a case where the second step is an enzyme treatment step in which enzymatic hydrolysis is carried out will be described. In the enzyme treatment process, the enzyme agent is not particularly limited as long as it has the activity of hydrolyzing the components of the epicarp, but an enzyme agent having the activity of hydrolyzing the carbohydrates that are components of the epicarp, i.e., an enzyme agent containing a carbohydrate-degrading enzyme, is preferred.

[0056] One example of such carbohydrates is the polysaccharides that make up the cell walls of the exocarp cells. These polysaccharides can be classified into acid-soluble and alkali-soluble pectins, acid- and alkali-soluble hemicelluloses, and acid- and alkali-insoluble celluloses.

[0057] Therefore, in the enzyme treatment step, an enzyme agent having at least one of pectin-decomposing activity (pectinase activity), hemicellulose-decomposing activity (hemicellulase activity), and cellulose-decomposing activity (cellulase activity) can be suitably used. That is, in the enzyme treatment step, pectinase-based enzyme preparations mainly having pectin-degrading activity (pectinase activity), hemicellulase-based enzyme preparations mainly having hemicellulose-degrading activity (hemicellulase activity), and cellulase-based enzyme preparations mainly having cellulose-degrading activity (cellulase activity) can be suitably used. In addition, in the enzyme treatment step, a composite enzyme preparation having two or three activities selected from pectin-degrading activity (pectinase activity), hemicellulose-degrading activity (hemicellulase activity), and cellulose-degrading activity (cellulase activity) can also be suitably used.

[0058] When the fresh produce is a fruit such as a citrus fruit, an enzyme preparation having activity to decompose pectin, which is a cell wall component of the outer pericarp cells, can be suitably used. Commercially available enzyme preparations include not only pectinase-based enzyme preparations mainly having pectinase activity, but also complex enzyme preparations containing cellulase activity in addition to pectinase activity, and these enzyme preparations may also be used.

[0059] That is, in the enzyme treatment step, not only a pectinase-based enzyme preparation mainly having pectinase activity but also a composite enzyme preparation containing cellulase activity in addition to pectinase activity may be used. Therefore, as the enzyme preparation used in the enzyme treatment step, a pectinase-based enzyme preparation mainly having pectinase activity and a composite enzyme preparation containing pectinase activity and cellulase activity are preferred.

[0060] A suitable example of a pectinase-based enzyme preparation having pectinase activity as the main component is "Sucrase N" manufactured by Mitsubishi Chemical Corporation. A suitable example of a composite enzyme preparation containing pectinase activity and cellulase activity is "Acremocellulase KM" manufactured by Kyowa Kasei Co., Ltd.

[0061] Pectinase is a general term for enzymes that have the activity of degrading pectin. Pectinases can be classified by microorganism, including protopectinases derived from yeasts such as Trichosporon penicillatum, polygalacturonases derived from koji molds such as Aspergillus niger and Aspergillus awamori, and polymethoxypolygalacturonases derived from yeasts such as Trichosporon penicillatum.

[0062] Among these, polygalacturonases derived from koji molds such as Aspergillus niger and Aspergillus awamori are preferred. A suitable example of a pectinase-based enzyme preparation containing polygalacturonases is "Sucrase N" manufactured by Mitsubishi Chemical Corporation.

[0063] In the enzyme treatment step, the enzyme agent may be liquid or solid. When the enzyme agent is liquid, the stock solution may be used as is, or a diluted solution obtained by diluting the stock solution with water or a buffer solution may be used. When the enzyme agent is solid, an aqueous solution obtained by dissolving the solid in water or a buffer solution may be used, or a suspension obtained by dispersing the solid in water or a buffer solution may be used. For example, a suspension obtained by dispersing a dried powder enzyme agent as fine particles in water may be used. Note that any water can be used as the water, such as tap water, distilled water, deionized water, or water with high hardness, but distilled water is most preferred from the viewpoint of not affecting enzymatic hydrolysis. As a buffer solution, one that does not inhibit enzymatic hydrolysis is preferred. The temperature of the water or buffer solution is preferably room temperature.

[0064] In the enzyme treatment process, the concentration of the enzyme contained in the stock solution and dilution solution when the enzyme preparation is a liquid, and in the aqueous solution and suspension when the enzyme preparation is a solid (hereinafter referred to as the "enzyme solution") is not particularly limited and can be any known concentration. Here, an example is shown for a powdered enzyme preparation containing pectinase activity and cellulase activity. Note that one unit of enzyme activity is defined as the amount of enzyme that can convert 1 micromole of substrate per minute under optimal conditions.

[0065] In the enzyme treatment step, when the activity of the enzyme solution is 8,000 to 10,000 units / g for pectinase activity and 2,000 to 6,000 units / g for cellulase activity, the concentration of the enzyme in the enzyme solution is preferably 0.001 to 2.0%, more preferably 0.005 to 1.0%, even more preferably 0.01 to 0.5%, and most preferably 0.05 to 0.2%. Note that in this specification, the numerical value of % may be either % by mass or % by volume, and the same activity effect will be obtained.

[0066] In the enzyme treatment step, the temperature of the enzyme treatment may be within a range from a temperature at which the enzyme solution does not freeze to a temperature at which the enzyme, which is a protein, is thermally inactivated. That is, the enzyme treatment step can be either a high-temperature short-time treatment or a low-temperature long-time treatment. More specifically, for example, a temperature of 5 to 55°C is preferred, and room temperature is more preferred. In this specification, room temperature is defined as 5 to 35°C.

[0067] In the enzyme treatment step, contact treatment may be performed in various ways, including immersing the fruits or vegetables after the first step in an enzyme solution for a certain period of time (immersion treatment), immersing the fruits or vegetables in an enzyme solution for a very short period of time (soaking treatment), spraying the fruits or vegetables with the enzyme solution (spray treatment such as shower spray or mist spray), applying the enzyme solution to the fruits or vegetables with a brush-like tool (coating treatment), or wrapping the fruits or vegetables in a cloth, sponge, cushioning material, or the like impregnated with the enzyme solution (embedding treatment). From the viewpoint of uniform treatment, immersion treatment is the most preferable. In view of the above, immersion treatment is the most preferable, in which the fruits or vegetables after the first step are immersed in an enzyme solution at room temperature for a certain period of time (immersion treatment). When the enzyme agent is a solid, it is also possible to contact the surface of the fruits or vegetables with the enzyme agent in the form of a powder, granules, or tablet, and dissolve the enzyme agent in the liquid exuded from the fruits or vegetables. For example, it is also possible to coat the surface of the fruits or vegetables with a dry powder of the enzyme agent. Furthermore, in the method for producing peeled fruits and vegetables of this embodiment, the enzyme solution can be appropriately introduced into the outer pericarp through the numerous pores in the carbonized layer, so even when immersing in the enzyme solution, it is not necessary to apply a pressurized treatment or a reduced-pressure impregnation treatment during immersion. That is, the enzyme treatment step (second step) can be carried out under atmospheric pressure. However, to promote the introduction of the enzyme solution into the outer pericarp, a pressurized treatment or a reduced-pressure impregnation treatment can also be applied during immersion. Note that, in this specification, atmospheric pressure includes standard atmospheric pressure (1013.25 hPa) and pressures in the vicinity thereof, as well as pressures within the range of normal weather and altitude changes. For example, the atmospheric pressure in this specification is 80% or more and 120% or less of standard atmospheric pressure.

[0068] In the enzyme treatment step, the pH of the enzyme solution may or may not be adjusted. That is, the second step can be performed without adjusting the pH of the enzyme solution (no pH adjustment). Alternatively, the enzyme solution can be adjusted to an optimal pH to maximize the enzyme activity. The pH of the enzyme solution can be adjusted by adding a buffer solution or buffering agent with a buffering effect to the enzyme solution.

[0069] In the enzyme treatment step, the time for the enzyme treatment is not particularly limited, but is preferably 2 to 48 hours, more preferably 4 to 24 hours, even more preferably 12 to 20 hours, and most preferably 14 to 18 hours, under atmospheric conditions at 15 to 25°C without pH adjustment. In this case, the treatment time can be adjusted to be shortened or extended as appropriate depending on the concentration of the enzyme in the enzyme solution.

[0070] By carrying out an enzyme treatment step as the epicarp disintegration treatment step in the second step, an enzyme solution as an epicarp disintegrant can be introduced into the epicarp through the countless pores in the carbonized layer formed in the first step (pathways formed in the epicarp of fruits and vegetables for introducing the enzyme solution into the epicarp in the enzyme treatment in the second step), thereby bringing the epicarp into a disintegrated state. Note that in this specification, the disintegrated state of the epicarp (disintegrated state) also includes a softened state of the epicarp (softened state).

[0071] [Chemical treatment process] The case where the second step is a chemical treatment step will be described below. In the chemical treatment step, the acidic or basic substance is not particularly limited as long as it is an acidic or basic substance that has the effect of hydrolyzing the components of the epicarp. Suitable examples of the acidic substance include strong inorganic acids such as hydrochloric acid, weak inorganic acids such as carbonic acid, and weak organic acids such as citric acid, ascorbic acid, and acetic acid. Suitable examples of basic substances include strong bases such as sodium hydroxide, and weak bases such as sodium carbonate and sodium hydrogen carbonate.

[0072] In the chemical treatment step, the acidic or basic substance may be liquid or solid. When the acidic or basic substance is liquid, the stock solution may be used as is, or a diluted solution obtained by diluting the stock solution with water may be used. When the acidic or basic substance is solid, an aqueous solution obtained by dissolving the solid in water may be used. Note that any water can be used, such as tap water, distilled water, deionized water, or water with high hardness, but distilled water is most preferred from the viewpoint of not affecting chemical hydrolysis.

[0073] In the chemical treatment step, the concentrations of the acidic or basic substance contained in the undiluted solution and diluted solution when the acidic or basic substance is a liquid, and in the aqueous solution when the acidic or basic substance is a solid, are not particularly limited and can be any known concentration.

[0074] In the chemical treatment step, it is preferable to use an aqueous solution containing an acidic or basic substance, and among these, it is more preferable to use an aqueous solution containing at least one selected from the group consisting of hydrochloric acid, sulfuric acid, citric acid, sodium hydroxide, sodium carbonate, and sodium hydrogencarbonate.

[0075] In the chemical treatment step, the time for the chemical treatment is preferably short, particularly when the treatment is performed in a temperature range higher than room temperature, and specifically, for example, 5 to 60 minutes. In the chemical treatment step, the time for the chemical treatment is preferably long, particularly when the treatment is performed at room temperature or a temperature range lower than room temperature, depending on the strength of the treatment and the degree of effect of the treatment, and specifically, for example, 1 to 30 hours.

[0076] Furthermore, in the chemical treatment step, contact treatment modes include immersing the fruits and vegetables after the first step in an aqueous solution containing an acidic or basic substance for a certain period of time (immersion treatment), immersing the fruits and vegetables in the aqueous solution for a very short period of time (soaking treatment), spraying the aqueous solution onto the fruits and vegetables (spraying treatment such as shower spray or mist spray), applying the aqueous solution to the fruits and vegetables with a brush-like tool or the like (application treatment), and wrapping the fruits and vegetables in a cloth, sponge, cushioning material, or the like soaked in the aqueous solution (embedding treatment).From the viewpoint of uniform treatment, immersion treatment is the most preferred.

[0077] In the second step, the exocarp disintegration treatment step, a chemical treatment step is carried out using an aqueous solution containing an acidic or basic substance, which allows the aqueous solution to be introduced into the exocarp through the countless pores in the carbonized layer formed in the first step (the introduction paths formed in the exocarp of fruits and vegetables for introducing the aqueous solution into the exocarp in the chemical treatment in the second step), thereby bringing the exocarp into a disintegrated state.

[0078] <Third process> The third step is a step of performing an exocarp removal process (exocarp removal process) to remove the exocarp of the fruits and vegetables after the second step has been performed. By performing this third step (exocarp removal process), the exocarp that has been broken down by the second step (exocarp breaking process) can be removed from the surface of the fruits and vegetables after the second step has been performed.

[0079] The epicarp removal means used in the third step (epicocarp removal treatment step) is not particularly limited as long as it can remove the epicarp that has been disintegrated by the second step (epicocarp disintegration treatment step) from the surface of the fruit or vegetable after the second step has been performed. Examples of the epicarp removal means include rubbing with the hand, rubbing with gloves, using a brush, or a combination of these with running water, using a jet of liquid such as water or a jet of gas such as air, and using a known epicarp removal device. Among these, rubbing the epicarp by hand under running water or removing the epicarp with a brush under running water is most preferred, as it requires less time and effort and does not damage the surface of the fruit or vegetable after the epicarp has been removed. By performing the epicarp removal treatment under running water, the epicarp disintegrating agent (i.e., enzyme agent, acidic substance, basic substance) can also be washed away. Note that undesirable phenomena such as a decrease in pulp hardness due to the action of the epicarp disintegrating agent remaining in the peeled pulp on the pulp can be avoided by thoroughly performing the washing and removal.

[0080] In the method for producing peeled fruits and vegetables of this embodiment, the above-mentioned first to third steps must be performed in order, and the objective cannot be achieved unless they are performed in this order. For example, the objective cannot be achieved even if the first step (carbonized layer forming treatment step) is performed after the second step (epicocarp disintegration treatment step). However, if peeling is incomplete even after steps 1 to 3 have been performed, steps 1 to 3 or steps 2 to 3 can be repeated as necessary to achieve more complete peeling. Furthermore, in the method for producing peeled fruits and vegetables of this embodiment, the first step can be performed without using sharp tools such as blades, and further, the series of steps from the first step to the third step can be performed without using sharp tools.

[0081] Therefore, in the method for producing peeled fruits and vegetables of this embodiment, by performing steps 1 to 3 as described above, it is possible to peel fruits and vegetables more easily and efficiently and obtain peeled fruits and vegetables. The peeled fruits and vegetables of the present disclosure obtained in this manner have a carbonized layer formed on the outermost layer of the fruits and vegetables by the carbonized layer forming process, but the inside of the flesh is not heated, so that a decrease in the hardness of the peeled flesh, changes in aroma, and other quality deterioration are avoided or reduced, resulting in fruits and vegetables of excellent quality. Therefore, items that are generally eaten raw can be provided as food as they are. For example, fruits can be provided as ready-to-eat cut fruits or fruit salads. On the other hand, items that are not generally eaten raw can be provided as ingredients for cooking and processing. For example, vegetables can be provided as cut fruits and vegetables such as cut vegetables that can be cooked immediately after being taken out of the bag. Furthermore, peeled lotus roots that maintain their whole shape can be obtained, and in particular, lotus roots with characteristic shapes such as the flat lotus roots produced in Tokushima Prefecture can be provided as lotus roots for cooking that can be cooked immediately after being taken out of the bag, as they can maintain their characteristic shape and have a high pulp yield. Furthermore, even lotus roots that are misshapen or damaged can be provided as peeled lotus roots with a high pulp yield, so there is increasing demand for peeled lotus roots for processing.

[0082] The peeled fruits and vegetables of this embodiment can be used in ways other than eating them raw. For example, the peeled fruits and vegetables can be used as ingredients for secondary processing such as sweets and dishes. Furthermore, after a drying process, they can be used as dried fruits and vegetables, such as dried fruits and vegetables, and after a freezing process, they can be used as frozen fruits and vegetables, such as frozen fruits and vegetables. Furthermore, the peeled fruits and vegetables can be subjected to a preservation process and then distributed.

[0083] Therefore, the method for producing peeled fruits and vegetables of the present disclosure may, if necessary, include a fourth step in which the peeled fruits and vegetables from which the outer pericarp has been removed in the third step are subjected to a preservation treatment step, a color restoration step, a secondary processing step, etc. Hereinafter, an example of the fourth step will be described as another different embodiment of the present disclosure.

[0084] <Fourth step> The fourth step is a step in which the peeled fruits and vegetables from which the outer skin has been removed in the third step (outer skin removal process) are subjected to preservation treatment, color restoration process, secondary processing, etc. to improve their shelf life and product quality.

[0085] When the fourth step is a preservation step, the peeled fruits and vegetables obtained in the third step are sterilized by a conventional method and hermetically packaged in a synthetic resin film with gas barrier properties. For example, the peeled fruits and vegetables obtained in the third step are sequentially subjected to three steps: washing with running water for food production, sterilization with a chemical, and washing away the chemical with running water for food production. The peeled fruits and vegetables are then hermetically packaged in a synthetic resin film with gas barrier properties.

[0086] Examples of such agents include sodium hypochlorite solution, or chlorous acid water having a similar bactericidal effect, sodium chlorite solution, peracetic acid preparation, hypochlorous acid water, and organic acid solutions that can be used as food additives.

[0087] The above-described sterilization and packaging of peeled fruits and vegetables suppresses quality deterioration such as spoilage caused by microorganisms such as mold and bacteria, and oxidation caused by oxygen in the air. This improves the shelf life of peeled fruits and vegetables, allowing them to be stored for long periods (e.g., several weeks). Peeled fruits and vegetables can be distributed to the market either frozen or thawed, or cut into bite-sized pieces and distributed to the market as cut fruits, cut vegetables, salads, etc.

[0088] Steps 1 through 3 can be collectively referred to as the primary processing step, followed by a fourth step, the secondary processing step. For example, peeled fruits and vegetables obtained through the primary processing step can be appropriately subjected to conventional secondary processing to produce various foods. Examples of foods obtained through secondary processing include, for fruit, cut fruit, jelly with fruit pulp, fruit cake, fruit preserved in syrup, yokan (sweet bean jelly), and other Japanese and Western confectioneries; and for vegetables, cut vegetables, salads, side dishes, pickles, soups, sauces, and other cooked and processed products. The color restoration step is a step in which the peeled fruits or vegetables after the completion of the third step are brought into contact with a substance having a color restoration effect. For example, even if discoloration occurs in the peeled fruits or vegetables due to contact with the basic substance in the second step, the degree of discoloration can be reduced by immersing the peeled fruits or vegetables in a solution of an acidic substance such as hydrochloric acid.

[0089] Suitable secondary processing steps include conventional drying, boiling, freezing, etc. Dried processed foods obtained by carrying out the secondary processing steps include various dried fruits, dried persimmons, dried persimmons, dried sweet potatoes, freeze-dried fruits and vegetables, etc. Boiled processed foods obtained by carrying out the secondary processing steps include boiled sliced ​​lotus root, boiled shredded burdock, etc. Frozen processed foods obtained by carrying out the secondary processing steps include frozen fruits, frozen vegetables, etc.

[0090] When the secondary processing step is the production of alcoholic beverages, the peeled fruits and vegetables obtained by the primary processing step can be used as raw materials for fruit wines and other brewed alcoholic beverages, shochu and other distilled alcoholic beverages, liqueurs and other mixed alcoholic beverages, and happoshu and other sparkling alcoholic beverages.

[0091] As described above, the peeled fruit and vegetable manufacturing method of this embodiment can peel a wide variety of vegetables (root vegetables, fruit vegetables, leafy vegetables) and fruits. Furthermore, the peeled fruit and vegetable manufacturing method of this embodiment can peel both cuticle-type fruits, whose outer skin has a cuticle layer, and cork-type fruits, whose outer skin has a cork layer. Therefore, the peeled fruit and vegetable manufacturing method of this embodiment is applicable to a wide range of products and is a highly versatile method.

[0092] Furthermore, according to the method for producing peeled fruits and vegetables of this embodiment, it is possible to easily secure numerous pores as introduction paths for introducing an epicarp disintegrating agent into the epicarp simply by forming a carbonized layer on at least the surface of the epicarp in the first step. As a result, according to the method for producing peeled fruits and vegetables of this embodiment, it is possible to uniformly and satisfactorily introduce an epicarp disintegrating agent into the epicarp without being affected by differences between varieties, between individuals, or within individuals, and it is possible to uniformly and stably peel the entire epicarp of fruits and vegetables.

[0093] Furthermore, the method for producing peeled fruits and vegetables of this embodiment eliminates the need for conventional pretreatments for the outer peel disintegration process, such as crack formation treatment using flames and surface treatment using abrasives, and in particular for citrus fruits, reduces the need for vacuum impregnation treatment, eliminating the need for the costs of introducing the devices and equipment required for each pretreatment.

[0094] Furthermore, the first step of the peeled fruit and vegetable manufacturing method of this embodiment includes a heat treatment in which the surface of the fruit and vegetable is heated to a surface temperature of 200°C or higher, and this heat treatment is carried out at least until the outer skin is charred. This heat treatment can be carried out using existing heating equipment for food processing (e.g., an existing automatic broiler or salamander). Therefore, there is no need to develop and manufacture new equipment to perform the first step (carbonized layer forming treatment step), and the cost burden for introducing the equipment and materials required for the first step (carbonized layer forming treatment step) can be significantly reduced. Therefore, the peeled fruit and vegetable manufacturing method of this embodiment can easily be mechanized or automated. By mechanizing or automating the manufacturing steps related to the peeled fruit and vegetable manufacturing method of this embodiment, increased production and mass processing of peeled fruit and vegetable becomes possible, and improved production efficiency of peeled fruit and vegetable can be expected.

[0095] Furthermore, in the peeled fruits and vegetables obtained by the peeled fruit and vegetable manufacturing method of this embodiment, when a carbonized layer is formed on at least the surface of the epicarp in the first step, the pulp is not heated to the inside. This avoids or reduces a decrease in the hardness of the peeled pulp, a change in aroma, and other quality deterioration, and also suppresses the formation of unnecessary irregularities on the surface of the peeled pulp, resulting in a smooth finish, allowing for the production of peeled fruits and vegetables of high quality. Furthermore, since the amount of pulp removed along with the epicarp can be reduced when removing the epicarp, the yield of peeled fruits and vegetables relative to the raw fruits and vegetables can be maintained at a high level. [Example]

[0096] The present disclosure will be described in more detail below with reference to examples, but the scope of the present disclosure is not limited to these examples in any way.

[0097] Example 1 A method for producing peeled fruits and vegetables according to Example 1 of the present disclosure is described below with reference to Fig. 1. In Example 1, in order to verify the effectiveness of using a change in transpiration conductance as an index for determining the completion of the first step, which is the carbonized layer forming treatment step, the transpiration conductance of the fruits and vegetables after the first step was measured using a measurement method described below.

[0098] Fruits and vegetables: Lotus (Nelumbo nucifera) rhizome (lotus root) Variety: "Lotus" (produced in Naruto City, Tokushima Prefecture) 1 section (1) First step (carbonized layer forming treatment step) (a) Treatment level Outermost layer carbonization (carbonized layer formation process using flame) The heating equipment used was a gas burner, "Power Torch RZ-840" manufactured by Shinfuji Burner Co., Ltd., equipped with the commercial "Power Gas Pro RZ-860" (a mixture of butane and propane gas). The flame power control knob and air control knob were fully open. The maximum flame temperature was 1400°C to 1600°C. Control (non-carbonized) No heating (b) Processing Procedures One section of lotus root was cut into approximately two equal parts in the longitudinal direction as shown in Figure 1(A), and the right half was heated with a gas burner under the above conditions to form a carbonized layer (outermost layer carbonized). The left half of the lotus root was left unheated (no carbonized layer formed) and used as a control (non-carbonized). A photograph of the appearance of the lotus root after the first step is shown in Figure 1(A). In Figure 1(A), "carbonized outermost layer" indicates the area where a carbonized layer was formed by the carbonized layer formation treatment, and "control (uncarbonized)" indicates the unheated area where no carbonized layer formation treatment was performed. The same applies to the following examples. When the results of the carbonized layer formation treatment were evaluated, blackening was observed on the surface of the epicarp (right half) of the area that had been subjected to the carbonized layer formation treatment, as shown in the photographic image in Figure 1(A).

[0099] <Measurement of transpiration conductance after completion of the first step> (a)Measurement method After completing the first step, the lotus root was immersed in water to cool, then wiped with a paper towel to remove surface moisture, and then left to stand in a room to equilibrate to the ambient temperature. Using this lotus root as the measurement subject, the water vapor diffusion resistance in the epidermis was measured using a transpiration measuring device ("SC-1 Leaf Porometer" manufactured by Decagon Devices) as follows. The reciprocal of the diffusion resistance was defined as the transpiration conductance. Ten measurement points were randomly selected in the carbonized layer formation area and the control (non-carbonized) area by the carbonized layer formation treatment, and the water vapor transpiration conductance was measured. Measurements were conducted in the "first half period" and "second half period" depending on the time elapsed after dewetting. In the "first half period," measurements were conducted at five points in each area, and in the "second half period," measurements were conducted at five points in each area. Each measurement point was within a circle with a diameter of 7 mm. The "first half period" is from 5 to 36 minutes after the lotus root is removed from the wet state, and the "second half period" is from 39 to 84 minutes after the lotus root is removed from the wet state. The reason for using "after wetting removal" as the starting point is that when the fruit or vegetable is wet, evaporation from the surface of the water that adheres to the fruit or vegetable is dominant, and the water inside the fruit or vegetable is not lost. "Wetting removal" marks the start of the process of water loss inside the fruit or vegetable.

[0100] (b) Measurement results The measurement results are shown in Table 1 below. As shown in Table 1, in the measurements for the first half of the period, the average transpiration conductance in the area where a carbonized layer had formed was higher than that of the control (non-carbonized) area, with a Welch t-test showing a significant difference at the 0.1% level, and the ratio of transpiration conductance in the area where a carbonized layer had formed to that in the control (non-carbonized) area was 4.54:1. In measurements taken during the latter period, the mean transpiration conductance of the carbonized area was higher than that of the control (non-carbonized) area, with a significant difference at the 1% level determined by Welch's t-test. The ratio of transpiration conductance of the carbonized area to that of the control (non-carbonized) area was 2.72:1. The transpiration conductance of the control (non-carbonized) area did not change much between the average transpiration conductance measured in the first half of the period and the average transpiration conductance measured in the second half of the period. In contrast, the average transpiration conductance in the carbonized layer formed region was lower in the latter half of the measurement period than in the first half.

[0101] [Table 1]

[0102] From the above results, it is thought that the main reason why the ratio of transpiration conductance in the carbonized layer area to the control (non-carbonized) area decreased during measurements in the latter half of the period compared to measurements in the first half was a decrease in transpiration conductance over time due to dehydration in the carbonized layer area. In other words, the carbonized layer formation process increased the transpiration conductance from the inside to the outside of the lotus root, and even after the carbonized layer formation process, no path through which the flesh could be seen from the outside was created. This suggests that the carbonized layer formation process created tiny gaps (pores) in the outer pericarp that connect the inside and outside of the lotus root. Therefore, it is clear that an increase in transpiration conductance is an effective indicator for determining the completion of the first step.

[0103] (2) Second step (enzyme treatment step) After the first step was completed and the transpiration conductance was measured, the lotus root was subjected to the enzyme treatment in the second step. The enzyme agent used was "Acremocellulase KM" manufactured by Kyowa Kasei Co., Ltd., and was mixed with water to prepare an enzyme solution with a concentration of 0.5% by mass / volume. The pH of the enzyme solution was not adjusted. "Acremocellulase KM" is a powdered enzyme preparation that has pectinase and cellulase activities. The whole lotus root was immersed in the enzyme solution prepared as described above for 17 hours at an average treatment temperature of 18°C ​​for enzyme treatment.

[0104] (3) Third step (outer pericarp removal step) The lotus roots that had been subjected to the enzyme treatment were taken out, and the outer skin was rubbed off by hand and washed with water, thereby removing the collapsed outer skin of the lotus roots.

[0105] (4) Results As shown in Figure 1(B) in Example 1, the part where the outermost layer of the epicarp was carbonized in the first step softened and crumbled after the second step, and the epicarp could be easily removed in the third step, exposing the flesh (edible part). In contrast, in the areas where a carbonized layer was not formed in the first step, the epicarp did not soften and disintegrate even after the second step, and the epicarp could not be removed in the third step. Therefore, according to Example 1, it was found that by performing the first step of the carbonized layer formation treatment on lotus root until the transpiration conductance changes (increases), the subsequent second and third steps can be carried out properly, and the outer pericarp of the lotus root can be properly peeled to obtain peeled lotus root.

[0106] <Example 2> Example 2 of the method for producing peeled fruits and vegetables of the present disclosure will be described below with reference to Figures 2 to 4. In Example 2, in order to verify the effectiveness of using a change in transpiration conductance as an index for determining the completion of the first step, which is the carbonized layer forming treatment step, the surface temperature of the fruits and vegetables after the first step was performed was measured using the measurement method described below.

[0107] Fruits and vegetables: Lotus (Nelumbo nucifera) rhizome (lotus root) Variety: "Lotus" (produced in Naruto City, Tokushima Prefecture) 1 section (1) First step (carbonized layer forming treatment step) (a) Treatment level Outermost layer carbonization (carbonized layer formation process using flame) The same heating equipment and heating conditions as in Example 1 were used. Control (non-carbonized) No heating (b) Processing Procedures A section of lotus root was cut into approximately two equal parts in the longitudinal direction as shown in Figure 2(A), and the right half was heated with a gas burner under the above conditions to form a carbonized layer (outermost layer carbonized). The left half of the lotus root was not heated (no carbonized layer formed) and served as a control (non-carbonized). A photograph of the appearance of the lotus root after the first step is completed is shown in FIG. 2(A). When the results of the carbonized layer formation treatment were evaluated, blackening was observed on the surface of the epicarp (right half) of the area that had been subjected to the carbonized layer formation treatment, as shown in the photographic image in Figure 2(A).

[0108] <Measurement of surface temperature after completion of the first process> (a)Measurement method After completing the first step, the lotus root was soaked in water to cool, then wiped with a paper towel to remove any surface moisture, and then left to stand in a room to equilibrate with the ambient temperature. This lotus root was used as the measurement subject, and an infrared thermography device (NEC Avio Infrared Technologies Corporation's "H2640" equipped with a standard lens "TH92-422") was used to capture a thermal image by averaging two scans with an emissivity of 0.96. The environmental conditions at this time were a room temperature of 25.1°C and a relative humidity of 51%. The wind speed was set to two conditions: 0.21 m / s and 0.05 m / s, which were generated by an electric fan. The wind speed was measured using a hot wire anemometer ("V-01-AND2N" manufactured by Ai Denshi Giken Co., Ltd.) at a position 5 mm above the highest part of the lotus root (the part with the largest outer diameter). A rectangular area measuring 173 pixels long and 170 pixels wide was set in each of the carbonized layer formation area and the control (non-carbonized) area, and the average surface temperature in each rectangular area was calculated.

[0109] (b) Measurement results Figures 3 and 4 are photographs of thermal images of lotus root during thermal image measurement after the first process was completed. Thermal images are images that show the distribution of surface temperature (thermography). Figure 3 is a thermal image taken at a wind speed of 0.21 m / s, and Figure 4 is a thermal image taken at a wind speed of 0.05 m / s. As shown in Figures 3 and 4, the surface temperature of the carbonized region, where the outermost layer of the epicarp was carbonized in the first step, was lower than that of the control (uncarbonized) region. It is thought that the surface temperature of the carbonized region decreased due to latent heat dissipation caused by increased transpiration conductance. The rectangular area set as the control (non-carbonized) area is designated as A, and the rectangular area set as the carbonized layer formed area is designated as B. According to the thermal image 1 of lotus root in Figure 3 where the wind speed was 0.21 m / s, the average surface temperature of rectangular area A was 21.52°C, the average surface temperature B of rectangular area B was 19.52°C, and the average surface temperature difference (shown as "AB" in the figure) was 2.00°C. According to thermal image 2 of lotus root in Figure 4 where the wind speed was 0.05 m / s, the average surface temperature of rectangular area A in the control (non-carbonized) area was 21.12°C, the average surface temperature of rectangular area B in the carbonized layer formation area was 19.66°C, and the average surface temperature difference AB was 1.46°C. Therefore, in addition to the change in color tone and the increase in transpiration conductance, the completion of the first step can also be detected by the difference in surface temperature that occurs depending on whether or not a carbonized layer is present. Therefore, the change in surface temperature before and after the first step can also be used as an indicator for determining the completion of the first step. Furthermore, the average surface temperature difference AB was larger when the wind speed was high (0.21 m / s) than when the wind speed was low (0.05 m / s). This is thought to be the result of the transpiration rate increasing due to the high wind speed. From this, it is thought that by controlling the environment so that evaporation is increased, it will be possible to clearly detect the difference in average surface temperature between the carbonized layer formed area and the control (non-carbonized) area. Therefore, in view of these measurement results, it is clear that it is effective to use the change in transpiration conductance as an index for determining whether the first step has been completed.

[0110] (2) Second step (enzyme treatment step) After the first step was completed and thermal images were taken, the lotus root was subjected to the enzyme treatment in the second step. The whole lotus root was immersed in an enzyme solution containing 0.5% by mass / volume of "Acremocellulase KM" manufactured by Kyowa Kasei Co., Ltd., prepared in the same manner as in Example 1, for 20 hours at an average treatment temperature of 7°C, for enzyme treatment.

[0111] (3) Third step (outer pericarp removal step) The lotus roots that had been subjected to the enzyme treatment were taken out, and the outer skin was rubbed off by hand and washed with water, thereby removing the collapsed outer skin of the lotus roots.

[0112] (4) Results As shown in Figure 2(B), the outermost layer of the exocarp in the area where it was carbonized in the first step softened and collapsed in the second step, and in the third step the exocarp could be easily removed, exposing the flesh. In contrast, in the areas where a carbonized layer was not formed in the first step, the epicarp did not soften and disintegrate even after the second step, and the epicarp could not be removed in the third step. Therefore, Example 2 also showed that by performing the first step of the carbonized layer formation process on lotus root until the transpiration conductance changes (increases), the subsequent second and third steps can be carried out properly, the outer pericarp of the lotus root can be properly peeled, and peeled lotus root can be obtained.

[0113] Example 3 The method for producing peeled fruits and vegetables according to Example 3 of the present disclosure is described below with reference to Fig. 5. In Example 3, in order to verify the effectiveness of the first step, which is the carbonized layer forming treatment step, the water vapor permeability of the fruits and vegetables after the first step was evaluated using the evaluation method described below.

[0114] Fruits and vegetables: lemon (Citrus limon) fruit 6 from Shizuoka Prefecture (3 allocated to each of the 2 processing levels in the first process) (1) First step (carbonized layer forming treatment step) (a) Treatment level Outermost layer carbonization (carbonized layer formation process using flame) The same heating equipment and heating conditions as in Example 1 were used. Control (non-carbonized) No heating (b) Processing Procedures FIG. 5 is a photographic image of lemons from Example 3 (individual 1: Example 3a, individual 3: Example 3b, individual 5: Example 3c) and controls (individuals 2, 4, and 6) during measurement of weight change after the first step was completed. The numbers "1" to "6" shown in the photographic image in FIG. 5 represent "individual 1" to "individual 6." When carrying out the first step, these six lemons were arranged in two rows of three lemons each, in descending order of weight, from the upper left to the lower right of the page in FIG. 5. "Outermost layer carbonization treatment" and "control (untreated)" shown in FIG. 5 indicate the treatment levels. "Outermost layer carbonization treatment" refers to an individual (Example 3) that was subjected to the first step, which is the carbonized layer formation treatment, and "control (untreated)" refers to an individual (comparative example) that was not subjected to the same step. Individual 1 (Example 3a) was the "outermost layer carbonized treatment", individual 2 was the "control (untreated)", individual 3 (Example 3b) was the "outermost layer carbonized treatment", individual 4 was the "control (untreated)", individual 5 (Example 3c) was the "outermost layer carbonized treatment", and individual 6 was the "control (untreated)". In Example 3, the entire surface of three lemons that had been "carbonized at the outermost layer" (Individual 1: Example 3a, Individual 3: Example 3b, Individual 5: Example 3c) was subjected to a carbonized layer formation process, forming a carbonized layer on the entire surface of the outer peel of each lemon.

[0115] <Evaluation of water vapor permeability after completion of the first step> (a) Evaluation method The weight of each fruit was measured immediately after the carbonization treatment and up to 25 hours later, and the water vapor permeability from the inside of the fruit through the outer skin was evaluated. The fruits were left at room temperature. (b) Evaluation results FIG. 6 is a graph showing the weight change of each individual animal of Example 3 and the control after the carbonized layer formation treatment. The evaluation results of water vapor permeability are shown in Table 2. For the "outermost layer carbonized" specimens, the weights shown in Table 2 are relative weights at each elapsed time, with the weight immediately after the carbonized layer formation treatment set to 1, and for the "control (untreated)" specimens, the weights are relative weights at each elapsed time, with the weight before leaving set to 1.

[0116] [Table 2]

[0117] Table 3 below shows the surface area etc. when each individual is approximated as a spheroid. Table 4 below shows the transpiration rate (mg / cm) for each measurement interval (time elapsed after the carbonized layer formation treatment) for each individual. 2 The transpiration rate is calculated by approximating the weight loss of each individual plant at each measurement interval to the surface area (cm) of a spheroid based on the measured polar and equatorial radii of each individual plant shown in Table 3. 2 ) by the elapsed time (h) of the measurement section.

[0118] [Table 3]

[0119] [Table 4]

[0120] According to Figure 6 and Table 4, the transpiration rate from immediately after the carbonized layer formation treatment in the first step until one hour later was 26 times higher in the carbonized layer formation treatment population in Example 3 than in the control (non-carbonized) population. A significant difference was observed in the mean values ​​between treatments at the 5% level using Welch's t-test. The transpiration rate from 1 to 2 hours after the carbonized layer formation treatment was 6 times higher in the carbonized layer formation treatment group of Example 3 than in the control (non-carbonized) group, and the difference between the treatments was smaller than the transpiration rate from immediately after the carbonized layer formation treatment to 1 hour later. A Welch's t-test showed a significant difference at the 0.1% level between the mean values ​​of the treatments.

[0121] Although the transpiration rate from two hours after the carbonized layer formation treatment varied depending on the measurement section in the ratio of the outermost carbonized layer to the control, it was clearly lower than the measurement section from immediately after the carbonized layer formation treatment to one hour later. In each section, a significant difference was observed in the average values ​​between treatments at the 0.1% level using Welch's t-test. The transpiration rate from 1 hour to 25 hours after the carbonization treatment was 9 times higher in the carbonized plant compared to the control (non-carbonized) plant. A significant difference was observed between the mean values ​​at the 1% level using Welch's t-test.

[0122] The reason for the above results is that the carbonized layer formation process increased the rate of transpiration from the inside to the outside of the fruit (lemon), and since no path through which the flesh could be seen from the outside was created even after the carbonized layer formation process, it is thought that the carbonized layer formation process created minute voids in the outer skin that connected the inside and outside of the fruit.

[0123] Example 4 Example 4 (Example 4a, Example 4b) of the method for producing peeled fruits and vegetables of the present disclosure will be described below with reference to FIGS. 7 and 8. Fruits and vegetables: Lotus (Nelumbo nucifera) rhizome (lotus root) Variety: "Lotus" (produced in Naruto City, Tokushima Prefecture) 2 sections (1) First step (carbonized layer forming treatment step) (a) Treatment level Outermost layer carbonization (carbonized layer formation process using flame) The heating equipment used was a gas burner, "Power Torch RZ-811" manufactured by Shinfuji Burner Co., Ltd., equipped with a commercial-grade "Power Gas Pro RZ-860." The flame power adjustment knob and air adjustment knob were fully open. The maximum flame temperature was 1400°C to 1600°C. Control (non-carbonized) No heating (b) Processing Procedures Example 4a: One section of lotus root was cut into approximately two equal parts in the longitudinal direction as shown in Figure 7(A), and the right half was heated with the flame of a gas burner under the heating conditions described above to form a carbonized layer (outermost layer carbonized). The left half of the lotus root was left unheated and uncarbonized, and served as a control (uncarbonized). Example 4b: The entire surface of one section of the lotus root to be treated was heated by a gas burner under the above heating conditions as shown in FIG. 8(A), to form a carbonized layer on the entire surface. Blackening was observed on the surface of the epicarp in the area that had been subjected to the carbonized layer formation treatment.

[0124] (2) Second step (enzyme treatment step) After the first step was completed, each lotus root was subjected to the enzyme treatment in the second step. The whole lotus root was immersed in an enzyme solution containing 0.5% by mass / volume of "Acremocellulase KM" manufactured by Kyowa Kasei Co., Ltd., prepared in the same manner as in Example 1, for 19 hours at an average treatment temperature of 17°C, for enzyme treatment.

[0125] (3) Third step (outer pericarp removal step) The lotus roots that had been subjected to the enzyme treatment were taken out, and the outer skin was rubbed off by hand and washed with water, thereby removing the collapsed outer skin of the lotus roots.

[0126] (4) Results As shown in Figures 7(B) and 8(B), in the areas of each lotus root where the epicarp was carbonized in the first step, the epicarp softened and crumbled after the second step, and in the third step the epicarp could be easily removed, exposing the flesh. In contrast, in the areas where the epicarp was not carbonized in the first step, the epicarp did not soften or disintegrate even after the second step, and the epicarp could not be removed in the third step.

[0127] <Example 5> Example 5 of the method for producing peeled fruits and vegetables of the present disclosure is described below with reference to FIG.

[0128] Fruits and vegetables: Burdock (Arctium lappa) root 1 cut product from Ibaraki Prefecture (1) First step (carbonized layer forming treatment step) (a) Treatment level Outermost layer carbonization (carbonized layer formation process using flame) The same heating equipment ("Power Torch RZ-811") and heating conditions as in Example 4 were used. Control (non-carbonized) No heating (b) Processing Procedures The burdock root was cut into approximately two equal parts in the longitudinal direction as shown in Figure 9(A), and the right half was heated with a gas burner under the above conditions to form a carbonized layer (outermost layer carbonization). The left half of the burdock root was not heated and served as a control (non-carbonized). Blackening or browning of the epicarp surface was observed in the area that had been subjected to the carbonized layer formation treatment. The target (non-carbonized) part was not heated, but the area near the boundary of the carbonized layer formation treatment was discolored due to the heat associated with the carbonized layer formation treatment.

[0129] (2) Second step (enzyme treatment step) After the first step was completed, the burdock root was subjected to the enzyme treatment in the second step. The whole burdock root was immersed in an enzyme solution of "Acremocellulase KM" manufactured by Kyowa Kasei Co., Ltd., prepared in the same manner as in Example 1, at a concentration of 0.5% by volume, at room temperature for 12 hours to carry out enzyme treatment.

[0130] (3) Third step (outer pericarp removal step) The burdock roots that had been subjected to the enzyme treatment were taken out, and the epicarp was rubbed off by hand and washed with water, thereby removing and separating the collapsed epicarp from the burdock roots.

[0131] (4) Results As shown in Figure 9(B), the right half of the burdock root, whose epicarp was carbonized in the first step, underwent the second step, during which the epicarp softened and collapsed. In the third step, the epicarp could be easily removed, exposing the flesh. In contrast, the left half of the fruit, where the epicarp was not carbonized in the first step, did not soften or disintegrate even after the second step, and the epicarp could not be removed in the third step.

[0132] Example 6 Example 6 of the method for producing peeled fruits and vegetables of the present disclosure is described below with reference to FIG.

[0133] Fruits and vegetables: Sweet potato (Ipomoea batatas) root (tuberous root) Variety: "Beniharuka" (Kasumigaura City, Ibaraki Prefecture) 2 pieces (1) First step (carbonized layer forming treatment step) (a) Treatment level Outermost layer carbonization (carbonized layer formation process using hot air) The heating equipment used was a heat gun, Makita Corporation's "HG6031VK," equipped with a "concentrated nozzle (round) part number A67262." The temperature adjustment dial was set to "9," and the switch was set to "2" (setting for a blowout temperature of 550°C). Control (non-carbonized) No heating (b) Processing Procedures A single sweet potato root was cut into approximately two equal parts along its length as shown in Figure 10(A), and the right half was heated with hot air under the above conditions to form a carbonized layer (outermost layer carbonization). The left half of the sweet potato root was not heated and served as a control (non-carbonized). Blackening was observed on the surface of the epicarp in the area that had been subjected to the carbonized layer formation treatment.

[0134] (2) Second step (enzyme treatment step) After the first step was completed, the sweet potato roots were subjected to the second step of enzyme treatment. Enzyme treatment was carried out by immersing the whole sweet potato root in an enzyme solution containing 0.5% by mass / volume of "Acremocellulase KM" manufactured by Kyowa Kasei Co., Ltd., prepared in the same manner as in Example 1, at room temperature for 11 hours.

[0135] (3) Third step (outer pericarp removal step) The sweet potato roots that had been subjected to the enzyme treatment were taken out, and the epicarp was rubbed off by hand and washed with water, thereby detaching and removing the collapsed epicarp of the sweet potato roots.

[0136] (4) Results As shown in Figure 10(B), the right half of the sweet potato root, whose exocarp was carbonized in the first step, underwent the second step, during which the exocarp softened and collapsed. In the third step, the exocarp could be easily removed, exposing the flesh. In contrast, the left half of the fruit, where the epicarp was not carbonized in the first step, did not soften or disintegrate even after the second step, and the epicarp could not be removed in the third step.

[0137] Example 7 Example 7 (Examples 7a and 7b) of the method for producing peeled fruits and vegetables of the present disclosure is described below with reference to FIG.

[0138] Vegetables: Taro (Colocasia esculenta) underground stem (corm) 6 pieces from Tsuchiura City, Ibaraki Prefecture (2 pieces assigned to each of the 3 processing levels in the first process) (1) First step (carbonized layer forming treatment step) (a) Treatment level Outermost layer carbonization 1 (carbonized layer formation process using hot air) The same heating equipment ("heat gun HG6031VK") and heating conditions as in Example 6 were used. Outermost layer carbonization 2 (carbonized layer formation process using flame) The same heating equipment ("Power Torch RZ-811") and heating conditions as in Example 4 were used. Control (non-carbonized) No heating (b) Processing Procedures Example 7a: The entire surface of two taro rhizomes was heated with hot air from a heat gun to form a carbonized layer on the entire surface (outermost layer carbonization). The left side of Figure 11(A) is a photographic image of the appearance of the taro rhizomes after heating with hot air. Example 7b: The entire surface of the other two taro rhizomes was heated with a flame from a gas burner to form a carbonized layer on the entire surface (outermost layer carbonization). The center of Figure 11(A) is a photographic image of the appearance of the taro rhizomes after heating with a flame. Control (non-carbonized): The remaining two taro rhizomes were not heated and served as a control (non-carbonized). The right side of Figure 11(A) is a photograph of the appearance of the control (non-carbonized) taro rhizomes. Blackening was observed on the surface of the epicarp in the area that had been subjected to the carbonized layer formation treatment.

[0139] (2) Second step (enzyme treatment step) After the first step was completed, the four taro rhizomes and the two control (non-carbonized) taro rhizomes were subjected to the enzyme treatment in the second step. The entire taro rhizome was immersed in an enzyme solution of "Acremocellulase KM" manufactured by Kyowa Kasei Co., Ltd., prepared in the same manner as in Example 1, at a concentration of 0.5% by volume, at room temperature for 12.5 hours to perform enzyme treatment.

[0140] (3) Third step (outer pericarp removal step) The taro rhizomes that had been subjected to the enzyme treatment were taken out, and the epicarp was rubbed off by hand and washed with water, thereby detaching and removing the collapsed epicarp of the taro rhizomes.

[0141] (4) Results As shown in Figure 11(B), the taro rhizomes of Examples 7a and 7b, in which the exocarp was carbonized in the first step, underwent a second step in which the exocarp softened and collapsed, and in the third step the exocarp could be easily removed, exposing the flesh. In contrast, the epicarp of the control taro rhizomes, whose epicarp was not carbonized in the first step, did not soften or disintegrate even after undergoing the second step, and the epicarp could not be removed in the third step.

[0142] Example 8 Example 8 of the method for producing peeled fruits and vegetables of the present disclosure is described as follows with reference to FIG.

[0143] Vegetables: Potato (Solanum tuberosum) rhizome (tuber) Variety: "Danshaku potato" (Hokkaido) 2 pieces (1) First step (carbonized layer forming treatment step) (a) Treatment level Outermost layer carbonization (carbonized layer formation process using flame) The same heating equipment ("Power Torch RZ-840") and heating conditions as in Example 1 were used. Control (non-carbonized) No heating (b) Processing Procedures The entire potato rhizome shown on the right side of Figure 12(A) was heated with a gas burner flame under the above heating conditions to form a carbonized layer (outermost layer carbonization). The potato rhizome on the left side of Figure 12(A) was left unheated and uncarbonized as a control (non-carbonized). Blackening was observed on the surface of the epicarp in the area that had been subjected to the carbonized layer formation treatment.

[0144] (2) Second step (enzyme treatment step) After the first step was completed, the two potato rhizomes were subjected to the enzyme treatment in the second step. Potato rhizomes were immersed in an enzyme solution containing 0.5% by mass / volume of "Acremocellulase KM" manufactured by Kyowa Kasei Co., Ltd., prepared in the same manner as in Example 1, for 6 hours at an average treatment temperature of 16°C, for enzyme treatment.

[0145] (3) Third step (outer pericarp removal step) The potato rhizomes that had been subjected to the enzyme treatment were taken out, and the epicarp was rubbed off by hand and washed with water, thereby detaching and removing the collapsed epicarp of the potato rhizomes.

[0146] (4) Results As shown in Figures 12(B) and 12(C), the potato rhizomes of Example 8, in which the epicarp was carbonized in the first step, underwent the second step, during which the epicarp softened and collapsed, and in the third step the epicarp could be easily removed, exposing the flesh. In contrast, the epicarp of the control potato rhizomes, whose epicarp was not carbonized in the first step, did not soften or disintegrate even after undergoing the second step, and the epicarp could not be removed in the third step.

[0147] Example 9 Example 9 of the method for producing peeled fruits and vegetables of the present disclosure is described below with reference to FIG.

[0148] Fruits and vegetables: pumpkin (Cucurbita maxima) fruit 1 piece from Chiba Prefecture (1) First step (carbonized layer forming treatment step) (a) Treatment level Outermost layer carbonization (carbonized layer formation process using flame) The same heating equipment ("Power Torch RZ-840") and heating conditions as in Example 1 were used. Control (non-carbonized) No heating (b) Processing Procedures A roughly oblate ellipsoid-shaped pumpkin fruit was virtually divided into two equal halves along a plane that roughly included the rotation axis. As shown in Figure 13(A), one half of the divided area was heated with a gas burner flame under the above heating conditions to form a carbonized layer (carbonized outermost layer). The remaining half was left unheated and uncarbonized, serving as a control (uncarbonized). The photographs on the left and right of Figure 13(A) are photographs of the pumpkin fruit viewed from different angles, and the same is true for Figure 13(B). Blackening was observed on the surface of the epicarp in the area that had been subjected to the carbonized layer formation treatment.

[0149] (2) Second step (enzyme treatment step) After the first step was completed, the pumpkin fruits were subjected to the second step of enzyme treatment. Pumpkin fruits were immersed in an enzyme solution containing 0.5% by mass / volume of "Acremocellulase KM" manufactured by Kyowa Kasei Co., Ltd., prepared in the same manner as in Example 1, for 3 hours at an average treatment temperature of 25°C, and enzyme treatment was performed.

[0150] (3) Third step (outer pericarp removal step) The pumpkin fruit that had been subjected to the enzyme treatment was taken out, and the outer skin was rubbed off by hand and washed with water, thereby detaching and removing the collapsed outer skin of the pumpkin fruit.

[0151] (4) Results As shown in Figure 13(B), half of a pumpkin fruit, whose exocarp was carbonized in the first step, went through the second step, where the exocarp softened and crumbled, and in the third step the exocarp could be easily removed, exposing the yellow flesh. In contrast, the half of the fruit where the epicarp was not carbonized in the first step did not soften or disintegrate even after the second step, and the epicarp could not be removed in the third step.

[0152] Example 10 Example 10 of the method for producing peeled fruits and vegetables of the present disclosure is described below with reference to FIG.

[0153] Fruits and vegetables: Asparagus (Asparagus officinalis) sprouts 2 bottles from Tsukuba City, Ibaraki Prefecture (1) First step (carbonized layer forming treatment step) (a) Treatment level Outermost layer carbonization (carbonized layer formation process using flame) The same heating equipment ("Power Torch RZ-840") and heating conditions as in Example 1 were used. Control (non-carbonized) No heating (b) Processing Procedures As shown in the upper photograph of Figure 14(A), one asparagus stalk was virtually divided longitudinally into three sections, starting from the tip, namely, the tip, the center, and the rear end. The center of this asparagus was heated with the flame of a gas burner under the heating conditions described above to form a carbonized layer (outermost carbonized layer). The tip and rear ends were left unheated and uncarbonized, serving as controls (uncarbonized). The other asparagus stalk shown in the photograph at the bottom of Figure 14(B) was left unheated and uncarbonized, serving as a control (uncarbonized). Blackening was observed on the surface of the epicarp in the area that had been subjected to the carbonized layer formation treatment. The control (uncarbonized) part of the first asparagus was not heated, but the area near the boundary of the carbonized layer formation treatment showed discoloration due to the heat associated with the carbonized layer formation treatment.

[0154] (2) Second step (enzyme treatment step) After the first step was completed, the two asparagus stalks were subjected to the enzyme treatment in the second step. Asparagus was immersed in an enzyme solution containing Acremo Cellulase KM (manufactured by Kyowa Kasei Co., Ltd.) at a concentration of 0.5% by mass / volume, prepared in the same manner as in Example 1, for 2 hours at room temperature for enzyme treatment. The first asparagus, which had been subjected to a carbonized layer formation treatment in the center, had its center and rear end excluding the tip immersed in the enzyme solution.

[0155] (3) Third step (outer pericarp removal step) The asparagus that had been subjected to the enzyme treatment was taken out, the outer skin was rubbed off by hand, and washed with water, thereby removing the broken outer skin of the asparagus.

[0156] (4) Results As shown in Figure 14(B), the center of the first asparagus, whose epicarp was carbonized in the first step, went through the second step, where the epicarp softened and crumbled, and in the third step the epicarp could be easily removed, exposing the flesh. In contrast, the tip and rear ends of the first asparagus, whose epicarp was not carbonized in the first step, and the entire second asparagus, did not have their epicarp softened or broken down even after undergoing the second step, and the epicarp could not be removed in the third step.

[0157] Example 11 Example 11 of the method for producing peeled fruits and vegetables of the present disclosure is described below with reference to FIG.

[0158] Fruits and vegetables: Grapefruit (Citrus x paradisi) 1 piece from the United States (1) First step (carbonized layer forming treatment step) (a) Treatment level Outermost layer carbonization (carbonized layer formation process using flame) The same heating equipment ("Power Torch RZ-811") and heating conditions as in Example 4 were used. Control (non-carbonized) No heating (b) Processing Procedures A roughly spherical grapefruit was virtually divided into two halves along a plane roughly including the core, as shown in Figure 15(A). The right half was heated with a gas burner flame under the above heating conditions to form a carbonized layer (outermost layer carbonized). The left half was left unheated and uncarbonized, serving as a control (non-carbonized). Blackening was observed on the surface of the epicarp in the area that had been subjected to the carbonized layer formation treatment. The target (non-carbonized) part was not heated, but the area near the boundary of the carbonized layer formation treatment was discolored due to the heat associated with the carbonized layer formation treatment.

[0159] (2) Second step (enzyme treatment step) After the first step was completed, the grapefruit fruit was subjected to the second step of enzyme treatment. Enzyme treatment was carried out by immersing whole grapefruit fruits in an enzyme solution containing 0.5% by mass / volume of "Acremocellulase KM" manufactured by Kyowa Kasei Co., Ltd., prepared in the same manner as in Example 1, at room temperature for 11 hours.

[0160] (3) Third step (outer pericarp removal step) The grapefruit fruit that had been subjected to the enzyme treatment was taken out, and the outer skin was rubbed off by hand and washed with water, thereby detaching and removing the broken outer skin of the grapefruit fruit.

[0161] (4) Results As shown in Figure 15(B), half of a grapefruit fruit, the epicarp of which was carbonized in the first step, went through the second step, where the epicarp and mesocarp softened and collapsed, and in the third step, the epicarp and mesocarp could be easily removed, exposing the flesh. In contrast, in the half of the fruit where the epicarp was not carbonized in the first step, the epicarp and mesocarp did not soften and disintegrate even after the second step, and the epicarp and mesocarp could not be removed in the third step.

[0162] Example 12 Example 12 of the method for producing peeled fruits and vegetables of the present disclosure will be described below with reference to Figures 16 and 17.

[0163] Fruits and vegetables: lemon (Citrus limon) fruit 2 pieces from the Republic of Chile (1 piece assigned to each of the 2 processing levels in the first process) (1) First step (carbonized layer forming treatment step) (a) Treatment level Outermost layer carbonization (carbonized layer formation process using flame) The same heating equipment ("Power Torch RZ-840") and heating conditions as in Example 1 were used. Control (non-carbonized) No heating (b) Processing Procedures The entire lemon fruit shown on the right side of Figure 16(A) was heated with the flame of a gas burner under the above heating conditions to form a carbonized layer (carbonized outermost layer). The lemon fruit on the left side of Figure 16(A) was left unheated and uncarbonized, serving as a control (uncarbonized). Blackening was observed on the surface of the outer peel of lemon fruits that had been subjected to the carbonized layer formation treatment.

[0164] (2) Second step (enzyme treatment step) After the first step was completed, the lemon fruit of Example 12 and the control (non-carbonized) lemon fruit were subjected to the second enzyme treatment step. Enzyme treatment was performed by immersing the whole lemon fruit in an enzyme solution containing 0.5% by mass / volume of "Acremocellulase KM" manufactured by Kyowa Kasei Co., Ltd., prepared in the same manner as in Example 1, for 8.5 hours at an average treatment temperature of 17°C.

[0165] (3) Third step (outer pericarp removal step) The lemon fruit that had been subjected to the enzyme treatment was taken out, and the outer peel was rubbed off by hand and washed with water, thereby detaching and removing the broken outer peel from the lemon fruit.

[0166] (4) Results As shown in Figures 16(B) and 17, the lemon fruit of Example 12, in which the epicarp was carbonized in the first step, underwent the second step, during which the epicarp and mesocarp softened and collapsed, and in the third step the epicarp and mesocarp could be easily removed, exposing the flesh. In contrast, in the control lemon fruit in which the exocarp was not carbonized in the first step, the exocarp and mesocarp did not soften or disintegrate even after the second step, and the exocarp and mesocarp could not be removed in the third step.

[0167] Example 13 Example 13 of the method for producing peeled fruits and vegetables of the present disclosure is described below with reference to FIG.

[0168] Fruits and vegetables: Sudachi (Citrus aurantium Sour Orange Group, syn. Citrus sudachi) fruit 8 pieces from Tokushima Prefecture (4 pieces allocated to each of the two processing levels in the first process) (1) First step (carbonized layer forming treatment step) (a) Treatment level Outermost layer carbonization (carbonized layer formation process using flame) The same heating equipment ("Power Torch RZ-840") and heating conditions as in Example 1 were used. Control (non-carbonized) No heating (b) Processing Procedures The four sudachi fruits on the right side of Figure 18(A) were heated in their entirety with the flame of a gas burner under the above heating conditions to form a carbonized layer (carbonized outermost layer). The four sudachi fruits on the left side of Figure 18(A) were left unheated and uncarbonized as controls (uncarbonized). Blackening of the outer pericarp surface of sudachi fruits treated with the carbonized layer formation method was observed.

[0169] (2) Second step (enzyme treatment step) The sudachi fruits after the first step and the control (non-carbonized) sudachi fruits were subjected to the second step of enzyme treatment. Enzyme treatment was performed by immersing the entire sudachi fruit in an enzyme solution containing 0.5% by mass / volume of "Acremocellulase KM" manufactured by Kyowa Kasei Co., Ltd., prepared in the same manner as in Example 1, at an average treatment temperature of 16°C for 11.5 hours.

[0170] (3) Third step (outer pericarp removal step) The sudachi fruit that had been subjected to the enzyme treatment was taken out, and the outer skin was rubbed off by hand and washed with water, thereby detaching and removing the broken outer skin of the sudachi fruit.

[0171] (4) Results As shown in Figure 18(B), the lemon fruit of Example 12, in which the exocarp was carbonized in the first step, underwent the second step, during which the exocarp and mesocarp softened and collapsed, and in the third step the exocarp and mesocarp were easily removed, exposing the flesh. In contrast, in the control sudachi fruit, the epicarp and mesocarp did not soften or break down even after the second step, and the epicarp and mesocarp could not be removed in the third step.

[0172] Example 14 Example 15 of the method for producing peeled fruits and vegetables of the present disclosure is described below with reference to FIG.

[0173] Fruits and vegetables: Pomelo (Citrus maxima) fruit 1 piece from Kochi Prefecture (1) First step (carbonized layer forming treatment step) (a) Treatment level Outermost layer carbonization (carbonized layer formation process using flame) The same heating equipment ("Power Torch RZ-840") and heating conditions as in Example 1 were used. (b) Processing Procedures As shown in FIG. 18(A), the entire pomelo fruit was heated by the flame of a gas burner under the above heating conditions to form a carbonized layer (carbonized outermost layer). Blackening of the outer skin surface of pomelo fruits treated with the carbonized layer formation treatment was observed.

[0174] (2) Second step (enzyme treatment step) After the first step was completed, the pomelo fruit was subjected to the second step of enzyme treatment. The enzyme preparations used were "Acremocellulase KM" manufactured by Kyowa Kasei Co., Ltd. and "Hemicellulase "Amano" 90" manufactured by Amano Enzyme Co., Ltd. (main activity: xylanase, source: Aspergillus niger), and were mixed with water to a concentration of 0.5% by mass to prepare an enzyme solution. The pH of the enzyme solution was not adjusted. "Hemicellulase "Amano" 90" is a powdered enzyme preparation with hemicellulase activity. The whole pomelo fruit was immersed in the enzyme solution prepared as described above for 11 hours at an average treatment temperature of 17°C for enzyme treatment.

[0175] (3) Third step (outer pericarp removal step) The pomelo fruit that had been subjected to the enzyme treatment was taken out, and the outer skin was rubbed off by hand and washed with water, thereby removing and removing the broken outer skin of the pomelo fruit.

[0176] (4) Results As shown in Figure 19(B), the pomelo fruit of Example 14, in which the exocarp was carbonized in the first step, underwent the second step, during which the exocarp and mesocarp softened and collapsed throughout the entire exocarp, and in the third step the exocarp and mesocarp could be easily removed, exposing the flesh enclosed in the endocarp. For pomelo fruit, no control experiment was conducted in which the epicarp was not carbonized in step 1. However, since the epicarp of pomelo fruit is as hard as that of grapefruit fruit and thicker than that of grapefruit, lemon fruit, and sudachi fruit, it is naturally predicted from Examples 11, 12, and 13, which were conducted on the same citrus fruits, that the epicarp and mesocarp would not soften and disintegrate even if step 2 was performed without performing step 1, and that the epicarp and mesocarp could not be removed in step 3.

[0177] Example 15 Example 15 of the method for producing peeled fruits and vegetables of the present disclosure is described as follows with reference to FIG.

[0178] Fruits and vegetables: European pear (Pyrus communis) fruit Variety: "La France" (Aomori Prefecture) 1 piece (1) First step (carbonized layer forming treatment step) (a) Treatment level Outermost layer carbonization (carbonized layer formation process using flame) The same heating equipment ("Power Torch RZ-811") and heating conditions as in Example 4 were used. Control (non-carbonized) No heating (b) Processing Procedures A pear fruit, roughly shaped like a solid of revolution, was virtually divided into two halves along a plane roughly including the axis of rotation, as shown in Figure 20(A). The right half was heated with a gas burner flame under the above heating conditions to form a carbonized layer (outermost layer carbonized). The left half was left unheated and uncarbonized, serving as a control (non-carbonized). Blackening was observed on the surface of the epicarp in the area that had been subjected to the carbonized layer formation treatment. The target (non-carbonized) part was not heated, but the area near the boundary of the carbonized layer formation treatment was discolored due to the heat associated with the carbonized layer formation treatment.

[0179] (2) Second step (enzyme treatment step) After the first step was completed, the pear fruits were subjected to the second enzymatic treatment step. Enzyme treatment was carried out by immersing the whole pear fruit in an enzyme solution containing 0.5% by mass / volume of "Acremocellulase KM" manufactured by Kyowa Kasei Co., Ltd., prepared in the same manner as in Example 1, at room temperature for 12.5 hours.

[0180] (3) Third step (outer pericarp removal step) The pear fruit that had been subjected to the enzyme treatment was taken out, and the outer skin was rubbed off by hand and washed with water, thereby detaching and removing the broken outer skin of the pear fruit.

[0181] (4) Results As shown in Figure 20(B), half of a pear fruit, whose epicarp was carbonized in the first step, went through the second step, where the epicarp softened and collapsed, and in the third step the epicarp could be easily removed, exposing the flesh. In contrast, the half of the fruit where the epicarp was not carbonized in the first step did not soften or disintegrate even after the second step, and the epicarp could not be removed in the third step.

[0182] Example 16 Example 16 of the method for producing peeled fruits and vegetables of the present disclosure is described as follows with reference to Figure 21. Figure 21 is a photographic image of the appearance of a persimmon fruit when viewed from the stalk side.

[0183] Fruits and vegetables: Persimmon (Diospyros kaki) fruit (persimmon fruit) Variety: "Fuyu" (produced in Nara Prefecture) 2 pieces (1) First step (carbonized layer forming treatment step) (a) Treatment level Outermost layer carbonization (carbonized layer formation process using flame) The same heating equipment ("Power Torch RZ-840") and heating conditions as in Example 1 were used. Control (non-carbonized) No heating (b) Processing Procedures As shown in Figure 21(A), a roughly spherical persimmon fruit was virtually divided into two halves along a plane roughly including the core. The right half was heated with a gas burner flame under the above heating conditions to form a carbonized layer (outermost layer carbonization). The left half was left unheated and uncarbonized, serving as a control (non-carbonized). Blackening was observed on the surface of the epicarp in the area that had been subjected to the carbonized layer formation treatment. The target (non-carbonized) part was not heated, but the area near the boundary of the carbonized layer formation treatment was discolored due to the heat associated with the carbonized layer formation treatment.

[0184] (2) Second step (enzyme treatment step) After the first step was completed, the persimmon fruits were subjected to the second step of enzyme treatment. The whole persimmon fruit was immersed in an enzyme solution containing 0.5% by mass / volume of "Acremocellulase KM" manufactured by Kyowa Kasei Co., Ltd., prepared in the same manner as in Example 1, for 13 hours at an average treatment temperature of 17°C, and enzyme treatment was performed.

[0185] (3) Third step (outer pericarp removal step) The enzyme-treated persimmon fruits were taken out, the outer skin was rubbed off by hand, and washed with water, whereby the collapsed outer skin of the persimmon fruits was detached and removed.

[0186] (4) Results As shown in Figure 21(B), half of the persimmon fruit, whose exocarp was carbonized in the first step, underwent the second step, during which the exocarp softened and collapsed, and in the third step the exocarp could be easily removed, exposing the flesh. In contrast, the half of the fruit where the epicarp was not carbonized in the first step did not soften or disintegrate even after the second step, and the epicarp could not be removed in the third step. "Fuyu" is a variety of persimmon fruit that is most difficult to peel, but according to the manufacturing method of Example 16, it was possible to peel even the most difficult part of this "Fuyu" fruit, the "stalk side."

[0187] Example 17 Example 17 of the method for producing peeled fruits and vegetables of the present disclosure will be described below with reference to Figures 22 and 23.

[0188] Fruits and vegetables: Grapes (Vitis vinifera) Variety: "Thompson Seedless" (Chile) 6 pieces (3 pieces assigned to each of the two processing levels in the first step) (1) First step (carbonized layer forming treatment step) (a) Treatment level Outermost layer carbonization (carbonized layer formation process using flame) The same heating equipment ("Power Torch RZ-811") and heating conditions as in Example 4 were used. Control (non-carbonized) No heating (b) Processing Procedures The grape berry shown on the right side of Figure 22(A) was heated in its entirety with the flame of a gas burner under the above heating conditions to form a carbonized layer (carbonized outermost layer). The grape berry on the left side of Figure 22(A) was left unheated and uncarbonized, serving as a control (uncarbonized). Blackening was observed on the surface of the outer skin of grape berries that had been treated with the carbonized layer formation process.

[0189] (2) Second step (enzyme treatment step) After the first step was completed, the grape berries of Example 17 and the control (non-carbonized) grape berries were subjected to the second enzyme treatment step. Enzyme treatment was performed by immersing the entire grape berries in an enzyme solution containing 0.5% by mass / volume of "Acremocellulase KM" manufactured by Kyowa Kasei Co., Ltd., prepared in the same manner as in Example 1, for 9.5 hours at an average treatment temperature of 9°C.

[0190] (3) Third step (outer pericarp removal step) The grape berries that had been subjected to the enzyme treatment were taken out, and the outer skin was rubbed off by hand and washed with water, thereby detaching and removing the broken outer skin of the grape berries.

[0191] (4) Results As shown in Figures 22(B) and 23, the grape berries of Example 17, in which the epicarp was carbonized in the first step, underwent the second step, during which the epicarp softened and collapsed, and in the third step the epicarp was easily removed, exposing the flesh. In contrast, the skin of the control grape berries, which had not been carbonized in the first step, did not soften or break down even after the second step, and the skin could not be removed in the third step.

[0192] Example 18 Example 18 of the method for producing peeled fruits and vegetables of the present disclosure will be described below with reference to Figures 24 and 25.

[0193] Fruits and vegetables: Kiwifruit (Actinidia deliciosa) fruit Variety: "Hayward" (New Zealand) 2 units (1 unit assigned to each of the 2 processing levels in the first process) (1) First step (carbonized layer forming treatment step) (a) Treatment level Outermost layer carbonization (carbonized layer formation process using flame) The same heating equipment ("Power Torch RZ-811") and heating conditions as in Example 4 were used. Control (non-carbonized) No heating (b) Processing Procedures The whole kiwifruit shown on the right side of Figure 24(A) was heated with the flame of a gas burner under the above heating conditions to form a carbonized layer (carbonized outermost layer). The kiwifruit on the left side of Figure 24(A) was left unheated and uncarbonized as a control (uncarbonized). Blackening of the outer skin surface of kiwifruit treated with the carbonized layer formation treatment was observed.

[0194] (2) Second step (enzyme treatment step) After the first step was completed, the kiwifruit of Example 18 and the control (non-carbonized) kiwifruit were subjected to the second step of enzyme treatment. Enzyme treatment was performed by immersing the entire kiwifruit in an enzyme solution containing 0.5% by mass / volume of "Acremocellulase KM" manufactured by Kyowa Kasei Co., Ltd., prepared in the same manner as in Example 1, at an average treatment temperature of 9°C for 11.5 hours.

[0195] (3) Third step (outer pericarp removal step) The enzyme-treated kiwifruit was taken out, the outer skin was rubbed off by hand, and washed with water, whereby the broken outer skin of the kiwifruit was detached and removed.

[0196] (4) Results As shown in Figures 24(B) and 25, the kiwifruit of Example 18, in which the epicarp was carbonized in the first step, underwent a second step in which the epicarp softened and collapsed, and in the third step the epicarp could be easily removed, exposing the flesh. In contrast, the control kiwifruit, whose epicarp was not carbonized in the first step, did not have its epicarp softened or broken down even after the second step, and the epicarp could not be removed in the third step.

[0197] Example 19 Example 19 of the method for producing peeled fruits and vegetables of the present disclosure will be described as follows with reference to Figures 26 to 29. In Example 19, the surface temperature of the fruits and vegetables during heat treatment with hot air was measured, and the surface temperature appropriate for forming a carbonized layer was verified. Fruits and vegetables: Lotus (Nelumbo nucifera) rhizome (lotus root) Variety: "Lotus" (produced in Naruto City, Tokushima Prefecture) 4 sections (1) First step (carbonized layer forming treatment step) In Example 19, the first step was carried out at various temperatures (surface temperatures of lotus root) by changing the heating conditions. (a) Treatment level Outermost layer carbonization (carbonized layer formation process using hot air) The heating equipment used was a heat gun, Makita Corporation's "HG6031VK," equipped with a "concentrated nozzle (round) part number A67262." The switch was set to "2" (setting for a blowout temperature of 550°C). The temperature adjustment dial was set to eight levels from "2" to "9." Control (non-carbonized) No heating (b) Processing Procedures Four sections of lotus root were heated at two locations on the surface thereof under different heating conditions (temperatures) using the switch settings and temperature control dial settings shown in FIGS. For each lotus root, two locations on the surface of the outer pericarp within a circle of approximately 20 mm in diameter were heated with hot air from a heat gun under different heating conditions to form a carbonized layer (outermost layer carbonization). The outer pericarp of each lotus root that was not subjected to the heat treatment (the part other than the part where the carbonized layer was formed) was used as a control (non-carbonized). As shown in Figure 26(A), in Example 19a, the left portion of the exocarp was heat-treated with the switch set to "2" and the temperature control dial set to "2", and in Example 19b, the right portion of the exocarp was heat-treated with the switch set to "2" and the temperature control dial set to "3". Similarly, in Examples 19c to 19h, lotus root was heated with the switch settings and temperature control dial settings shown in Figure 27(A), Figure 28(A) and Figure 29(A). (c) Temperature measurement The surface temperature of the area subjected to the carbonized layer forming treatment was measured as follows. A K-type thermocouple probe (1 mm diameter x 200 mm length) in a stainless steel protective tube was brought into contact with the surface of the epicarp at the center of the area to be heat-treated, and the maximum temperature reached during the heat treatment was measured.

[0198] (2) Second step (enzyme treatment step) After the first step was completed, each lotus root was subjected to the enzyme treatment in the second step. The whole lotus root was immersed in an enzyme solution containing 0.5% by mass / volume of "Acremocellulase KM" manufactured by Kyowa Kasei Co., Ltd., prepared in the same manner as in Example 1, for 26 hours at an average treatment temperature of 7°C, for enzyme treatment.

[0199] (3) Third step (outer pericarp removal step) The lotus roots that had been subjected to the enzyme treatment were taken out, and the outer skin was rubbed off by hand and washed with water, thereby removing the collapsed outer skin of the lotus roots.

[0200] (4) Results Table 5 below shows the switch settings and temperature control dial settings, measurement repetition number, maximum temperature, state of the outer skin after heat treatment, and peeling results for the heat-treated areas after the second and third steps. For each combination of switch settings and temperature control dial settings, the lotus root was heated in a non-overlapping area, distinguished by the measurement repetition number, as the heating target area. Regarding the peeling results, "x" indicates that peeling was not possible (could not be done), and "o" indicates that peeling was easily completed and the flesh was exposed. The same applies to Tables 6 and 7 described below.

[0201] [Table 5]

[0202] According to Figures 26(B), 27(B), 28(B), 29(B) and Table 5, in Examples 19d to 19h, in which heat treatment was performed in the first step to achieve a surface temperature of 229.7°C or higher, the heated area was partially or completely carbonized, the epicarp softened and collapsed after the second step, and the epicarp could be easily removed in the third step, exposing the flesh. In contrast, in Examples 19a to 19h, the areas where the epicarp was not carbonized in the first step and the heated areas (non-carbonized areas) in Examples 19a to 19c, which were heated to a surface temperature of 171.3°C or below, did not soften or disintegrate even after the second step, and the epicarp could not be removed in the third step. Therefore, a carbonized layer can be appropriately formed on the surface of the lotus root by heating the lotus root with hot air so that the surface temperature reaches 200°C or higher. As a result, it was found that the method for producing peeled fruits and vegetables of the present disclosure is suitable for producing peeled lotus root, particularly flat lotus root produced in Tokushima Prefecture.

[0203] Example 20 Example 20 of the method for producing peeled fruits and vegetables of the present disclosure will be described as follows with reference to Figure 30. In Example 20, the surface temperature of fruits and vegetables during heat treatment with a flame was measured. Fruits and vegetables: Lotus (Nelumbo nucifera) rhizome (lotus root) Variety: "Lotus" (produced in Naruto City, Tokushima Prefecture) 1 section (1) First step (carbonized layer forming treatment step) (a) Treatment level Outermost layer carbonization (carbonized layer formation process using flame) The same heating equipment ("Power Torch RZ-840") and heating conditions as in Example 1 were used. (b) Processing Procedures The surface of the epicarp within a circle of approximately 40 mm in diameter on one node of lotus root was heated with the flame of a gas burner under the above heating conditions. This heating process was repeated 18 times while changing the heating location, until the entire surface of the epicarp was carbonized and a carbonized layer was formed (outermost layer carbonization). (c) Temperature measurement The surface temperature of the area subjected to the carbonized layer formation treatment was measured by contacting a K-type thermocouple probe (diameter 1 mm × length 200 mm) in a stainless steel protective tube with the surface of the epicarp in the center of the area to be heat-treated, as in Example 19. This measured the maximum temperature reached during the heat treatment.

[0204] (2) Second step (enzyme treatment step) After the first step was completed, each lotus root was subjected to the enzyme treatment in the second step. The whole lotus root was immersed in an enzyme solution containing 0.5% by mass / volume of "Acremocellulase KM" manufactured by Kyowa Kasei Co., Ltd., prepared in the same manner as in Example 1, for 26 hours at an average treatment temperature of 7°C, for enzyme treatment.

[0205] (3) Third step (outer pericarp removal step) The lotus roots that had been subjected to the enzyme treatment were taken out, and the outer skin was rubbed off by hand and washed with water, thereby removing the collapsed outer skin of the lotus roots.

[0206] (4) Results Table 6 below shows the repetition number, the maximum temperature, the state of the outer skin after heat treatment, and the peeling results of the heat-treated areas after the second and third steps.

[0207] [Table 6]

[0208] According to Figure 30(B) and Table 6, when heated with a gas burner flame in the first step, the lotus root surface temperature reached 316.1°C to 1021.0°C (average 707.7°C), and the entire epicarp was carbonized, forming a carbonized layer. Then, after the second step, the entire epicarp softened and crumbled, and in the third step, the epicarp could be easily removed, exposing the flesh. Therefore, it was found that even in a heat treatment using a flame, a carbonized layer can be appropriately formed on the surface of lotus root by heating to a surface temperature of 200° C. or higher, preferably 300° C. or higher. As a result, lotus root can be peeled more easily and efficiently, and peeled lotus root of excellent quality can be obtained. Therefore, it was found that the method for producing peeled fruits and vegetables of the present disclosure is suitable for producing lotus root, particularly peeled lotus root using flat lotus roots produced in Tokushima Prefecture.

[0209] <Example 21> Example 21 of the method for producing peeled fruits and vegetables of the present disclosure will be described as follows with reference to Figure 31. In Example 21, the surface temperature of the fruits and vegetables at the start of carbonization with hot air was measured. Fruits and vegetables: Lotus (Nelumbo nucifera) rhizome (lotus root) Variety: "Lotus" (produced in Naruto City, Tokushima Prefecture) 1 section (1) First step (carbonized layer forming treatment step) (a) Treatment level Outermost layer carbonization (carbonized layer formation process using hot air) The heating equipment used was a heat gun, Makita Corporation's "HG6031VK," equipped with a "concentrated nozzle (round) part number A67262." The temperature adjustment dial was set to "5," and the switch was set to "2" (setting for a blowout temperature of 550°C). Control (non-carbonized) No heating (b) Processing Procedures Ten locations on the surface of the epicarp within a circle of approximately 20 mm in diameter on one node of lotus root were heated with hot air under the above heating conditions. The hot air outlet of the heat gun was gradually brought closer to the treatment target (lotus root) from a distance, more specifically, from a distance of 30 cm, until carbonization occurred and one heating treatment (one location) was terminated. This resulted in the formation of a carbonized layer in ten locations on the lotus root epicarp (outermost layer carbonization). The outer pericarp of the lotus root that was not subjected to the heat treatment (the part other than the part where the carbonized layer was formed) was used as a control (non-carbonized). (c) Temperature measurement The surface temperature of the area subjected to the carbonized layer formation treatment was measured by contacting a K-type thermocouple probe (diameter 1 mm × length 200 mm) in a stainless steel protective tube with the surface of the epicarp in the center of the area to be heat-treated, as in Example 19. This measured the maximum temperature reached during the heat treatment.

[0210] (2) Second step (enzyme treatment step) After the first step was completed, each lotus root was subjected to the enzyme treatment in the second step. The whole lotus root was immersed in an enzyme solution containing 0.5% by mass / volume of "Acremocellulase KM" manufactured by Kyowa Kasei Co., Ltd., prepared in the same manner as in Example 1, for 11.5 hours at an average treatment temperature of 17°C, for enzyme treatment.

[0211] (3) Third step (outer pericarp removal step) The lotus roots that had been subjected to the enzyme treatment were taken out, and the outer skin was rubbed off by hand and washed with water, thereby removing the collapsed outer skin of the lotus roots.

[0212] (4) Results Table 7 below shows the maximum temperature of the epicarp surface during the heat treatment, the state of the epicarp after the heat treatment, and the peeling results of the heat-treated areas after the second and third steps.

[0213] [Table 7]

[0214] According to Figure 31(B) and Table 7, when the epicarp began to carbonize after heating with hot air in the first step, the surface temperature of the lotus root reached 191.7°C to 244.6°C (average 217.1°C). After the second step, the entire epicarp softened and collapsed in the carbonized area, and in the third step, the epicarp could be easily removed, exposing the flesh. In contrast, in areas where the epicarp was not carbonized in the first step, the epicarp did not soften or disintegrate even after the second step, and the epicarp could not be removed in the third step. Therefore, in the heat treatment with hot air, by heating so that the surface temperature at the start of carbonization is 190°C or higher, preferably 200°C or higher, a suitable carbonized layer can be formed on the surface of the lotus root, the lotus root can be peeled more easily and efficiently, and peeled lotus root of excellent quality can be obtained. From these results, it was found that the method for producing peeled fruits and vegetables of the present disclosure is suitable for producing peeled lotus root, particularly peeled lotus root using flat lotus roots produced in Tokushima Prefecture.

[0215] <Example 22> Example 22 of the method for producing peeled fruits and vegetables of the present disclosure will be described as follows with reference to Figures 32 to 34. In Example 22, fruits and vegetables (lemon fruit) different from those in Example 19 were used to measure the surface temperature of the fruits and vegetables during heat treatment with hot air, and to verify the appropriate surface temperature for forming a carbonized layer. Fruits and vegetables: lemon (Citrus limon) fruit 6 pieces from Shizuoka Prefecture (1) First step (carbonized layer forming treatment step) In Example 22, the first step was carried out at various temperatures (surface temperatures of lotus root) by changing the heating conditions. (a) Treatment level Outermost layer carbonization (carbonized layer formation process using hot air) The heating equipment used was a heat gun, Makita Corporation's "HG6031VK," equipped with a "concentrated nozzle (round) part number A67262." The switch setting was "2" (setting for a blowout temperature of 550°C). The temperature adjustment dial setting was changed to six levels from "4" to "9." Control (non-carbonized) No heating (b) Processing Procedures Six lemon fruits were heated at two locations on the surface of each fruit under different heating conditions (temperatures) using the switch settings and temperature control dial settings shown in Figures 32(A), 33(A), and 34(A). One spot on the surface of the outer peel of each lemon fruit within a circle of approximately 20 mm in diameter was heated with hot air from a heat gun under different heating conditions to form a carbonized layer (outermost layer carbonization). The outer pericarp of each lotus root that was not subjected to the heat treatment (the part other than the part where the carbonized layer was formed) was used as a control (non-carbonized). (c) Temperature measurement The surface temperature of the area subjected to the carbonized layer forming treatment was measured as follows. A K-type thermocouple probe (1 mm diameter x 200 mm length) in a stainless steel protective tube was brought into contact with the surface of the epicarp at the center of the area to be heat-treated, and the maximum temperature reached during the heat treatment was measured.

[0216] (2) Second step (enzyme treatment step) After the first step was completed, each lemon fruit was subjected to the second step of enzyme treatment. Enzyme treatment was performed by immersing the whole lemon fruit in an enzyme solution containing 0.5% by mass / volume of "Acremocellulase KM" manufactured by Kyowa Kasei Co., Ltd., prepared in the same manner as in Example 1, at an average treatment temperature of 6°C for 27.5 hours.

[0217] (3) Third step (outer pericarp removal step) The lemon fruit that had been subjected to the enzyme treatment was taken out, and the outer peel was rubbed off by hand and washed with water, thereby detaching and removing the broken outer peel from the lemon fruit.

[0218] (4) Results Table 8 below shows the repetition number, the maximum temperature, the state of the outer skin after heat treatment, and the peeling results of the heat-treated areas after the second and third steps.

[0219] [Table 8]

[0220] According to Figures 32(B), 33(B), and 34(B) and Table 8, in Examples 22b to 22f, which were heated in the first step to a surface temperature of 200°C or higher, the heated areas were carbonized, and after the second step the epicarp and endocarp softened and collapsed, and in the third step the epicarp and endocarp could be easily removed, exposing the flesh. In contrast, in Examples 22a to 22f, in the areas where the epicarp was not carbonized in the first step and in the heated area (non-carbonized area) of Example 22a where heat treatment was performed so that the surface temperature was less than 200°C, the epicarp and mesocarp did not soften and disintegrate even after the second step, and the epicarp and mesocarp could not be removed in the third step. Therefore, it was found that a carbonized layer can be appropriately formed on the surface of lemon fruit by heating with hot air so that the surface temperature reaches 200° C. As a result, it is possible to peel lemon fruit more simply and efficiently without the need for reduced pressure impregnation treatment, and peeled lemon fruit of excellent quality can be obtained, and therefore it was found that the method for producing peeled fruits and vegetables of the present disclosure is suitable for producing peeled lemon fruit.

[0221] Example 23 Example 23 of the method for producing peeled fruits and vegetables of the present disclosure will be described as follows with reference to Figure 35. In Example 23, the surface temperature of the fruits and vegetables during heat treatment with a flame was measured. Fruits and vegetables: lemon (Citrus limon) fruit 2 pieces from Shizuoka Prefecture (1) First step (carbonized layer forming treatment step) (a) Treatment level Outermost layer carbonization (carbonized layer formation process using flame) The same heating equipment ("Power Torch RZ-840") and heating conditions as in Example 1 were used. (b) Processing Procedures For each lemon fruit, the surface of the outer peel within a circle of approximately 40 mm in diameter was heated using the flame of a gas burner under the above heating conditions. This heating process was repeated 18 times while changing the heating location, until the entire surface of the outer peel was carbonized and a carbonized layer was formed (outermost layer carbonization). (c) Temperature measurement The surface temperature of the area subjected to the carbonized layer formation treatment was measured by contacting a K-type thermocouple probe (diameter 1 mm × length 200 mm) in a stainless steel protective tube with the surface of the epicarp in the center of the area to be heat-treated, as in Example 19. This measured the maximum temperature reached during the heat treatment.

[0222] (2) Second step (enzyme treatment step) After the first step was completed, each lemon fruit was subjected to the second step of enzyme treatment. Enzyme treatment was performed by immersing the whole lemon fruit in an enzyme solution containing 0.5% by mass / volume of "Acremocellulase KM" manufactured by Kyowa Kasei Co., Ltd., prepared in the same manner as in Example 1, at an average treatment temperature of 6°C for 27.5 hours.

[0223] (3) Third step (outer pericarp removal step) The lemon fruit that had been subjected to the enzyme treatment was taken out, and the outer peel was rubbed off by hand and washed with water, thereby detaching and removing the broken outer peel from the lemon fruit.

[0224] (4) Results Table 9 below shows the repetition number, the maximum temperature, the state of the outer skin after heat treatment, and the peeling results of the heat-treated areas after the second and third steps.

[0225] [Table 9]

[0226] According to Figure 35(B) and Table 9, in the first step, when heated with a gas burner flame, the surface temperature of the lemon fruit reached 712.4°C to 1035.0°C (average 858.2°C), and the entire exocarp was carbonized, forming a carbonized layer. Then, in the second step, the entire exocarp softened and crumbled, and in the third step, the exocarp could be easily removed, exposing the flesh. Therefore, even when heat-treated using a flame, by heating the surface temperature to 200°C or higher, preferably 700°C or higher, a suitable carbonized layer can be formed on the surface of the lemon fruit.As a result, it has been found that the method for producing peeled fruits and vegetables disclosed herein is suitable for producing peeled lemon fruit.

[0227] <Reference Experimental Example 1> Reference Experimental Example 1 will be described below with reference to Fig. 36. In Reference Experimental Example 1, the surface temperature of fruits and vegetables (lemon fruit) was measured at the start of carbonization with hot air. In Reference Experimental Example 1, only the first step was carried out, and the second and third steps were not carried out. Fruits and vegetables: lemon (Citrus limon) fruit 1 piece from Shizuoka Prefecture (1) First step (carbonized layer forming treatment step) (a) Treatment level Outermost layer carbonization (carbonized layer formation process using hot air) The heating equipment used was a heat gun, Makita Corporation's "HG6031VK," equipped with a "concentrated nozzle (round) part number A67262." The temperature adjustment dial was set to "5," and the switch was set to "2" (setting for a blowout temperature of 550°C). Control (non-carbonized) No heating (b) Processing Procedures For each lemon fruit, 10 locations on the surface of the outer peel within a circle of approximately 20 mm in diameter were heated with hot air under the above heating conditions. During this process, the hot air outlet of the heat gun was gradually brought closer to the treatment target (lemon) from a distance, and one heating treatment (one location) was terminated when carbonization occurred. This resulted in the formation of a carbonized layer in 10 locations on the outer peel of the lemon fruit (outermost layer carbonization). The outer peel of the lemon fruit that was not subjected to the heat treatment (the part other than the part that formed the carbonized layer) was used as a control (non-carbonized). (c) Temperature measurement The surface temperature of the area subjected to the carbonized layer formation treatment was measured by contacting a K-type thermocouple probe (diameter 1 mm × length 200 mm) in a stainless steel protective tube with the surface of the epicarp in the center of the area to be heat-treated, as in Example 19. This measured the maximum temperature reached during the heat treatment.

[0228] (2) Results FIG. 36 is a photographic image of the appearance of the lemon fruit of Reference Experimental Example 1 after the first step is completed. Table 10 below shows the maximum temperature of the epicarp surface during heat treatment and the state of the epicarp after heat treatment.

[0229] [Table 10]

[0230] According to FIG. 36 and Table 8, when heated with hot air in the first step, the surface temperature of the lotus root when the epicarp began to carbonize was 212.1°C to 229.8°C (average 219.4°C). Therefore, it was found that when heating with hot air, a carbonized layer can be formed on the surface of fruits and vegetables by heating them so that the surface temperature at the start of carbonization is 200°C or higher.

[0231] Example 24 Example 24 of the method for producing peeled fruits and vegetables of the present disclosure will be described below with reference to Figure 37. In Example 24, the heating method in the first step is changed to a laser heating method. Fruits and vegetables: Lotus (Nelumbo nucifera) rhizome (lotus root) Variety: "Lotus" (produced in Naruto City, Tokushima Prefecture) 1 section (1) First step (carbonized layer forming treatment step) (a) Treatment level Outermost layer carbonization (laser carbonization process) The heating equipment used was a laser processing machine, "Hajime" manufactured by O-Laser Co., Ltd. The light source of this laser processing machine is a CO2 laser with a wavelength of 10.6 μm. The processing conditions were laser output 15 W, speed 15 mm / sec, 1 pass, and air assist "off." Control (non-carbonized) No heating (b) Processing Procedures A carbonized layer was formed (outermost layer carbonization) by irradiating a laser onto an area of ​​the lotus root outer pericarp approximately 25 mm in diameter, as shown in Figure 37. However, there were protrusions on the lotus root surface, and due to limitations on the focal depth of the above-mentioned equipment, these protrusions were out of focus, resulting in insufficient light collection and resulting in some uncarbonized areas. The area other than the laser irradiated area was used as a control (non-carbonized).

[0232] (2) Second step (enzyme treatment step) After the first step was completed, each lotus root was subjected to the enzyme treatment in the second step. The whole lotus root was immersed in an enzyme solution containing 0.5% by mass / volume of "Acremocellulase KM" manufactured by Kyowa Kasei Co., Ltd., prepared in the same manner as in Example 1, for 17 hours at an average treatment temperature of 19°C, for enzyme treatment.

[0233] (3) Third step (outer pericarp removal step) The lotus roots that had been subjected to the enzyme treatment were taken out, and the outer skin was rubbed off by hand and washed with water, thereby removing the collapsed outer skin of the lotus roots.

[0234] (4) Results As shown in Figure 37(B), the area where the exocarp was carbonized in the first step had the exocarp softened and crumbled after the second step, and in the third step the exocarp could be easily removed, exposing the flesh. In contrast, in areas where the epicarp was not carbonized in the first step and areas that were irradiated with a laser but not carbonized, the epicarp did not soften or disintegrate even after the second step, and the epicarp could not be removed in the third step. Therefore, it was found that heating with a laser can also form a suitable carbonized layer in the peeled fruit and vegetable manufacturing method of the present disclosure. When obtaining fruit and vegetables in which only desired regions have been selectively peeled by the peeled fruit and vegetable manufacturing method of the present disclosure, a heating means that can precisely control the region to be carbonized, such as a laser, is suitable as a heating device for use in the first step. Note that the lack of focusing observed in Example 24 due to limitations on the focal depth can be avoided by, for example, adjusting the distance between the focusing lens and the fruit and vegetable while keeping the focal length constant, adjusting the focal length of the focusing lens, adjusting the focal depth of the focusing lens, or using collimated light (parallel light) so that the light is always focused on the surface of the fruit and vegetable.

[0235] Example 25 Example 25 of the method for producing peeled fruits and vegetables of the present disclosure will be described as follows with reference to Fig. 38. In Example 25, the heating method in the first step is changed to a heating method using superheated steam. Fruits and vegetables: Lotus (Nelumbo nucifera) rhizome (lotus root) Variety: "Lotus" (produced in Naruto City, Tokushima Prefecture) 1 section (1) First step (carbonized layer forming treatment step) (a) Treatment level Outermost layer carbonization (carbonized layer formation process using superheated steam) The heating equipment used was the "C15-7580" manufactured by Narika Co., Ltd., and the steam obtained by boiling tap water in a 300 mL Erlenmeyer flask heated with an electric wire heater was introduced into a copper tube (inner diameter 4 mm, wall thickness 1 mm).The coiled copper tube was heated from the outside using a gas burner, causing superheated steam (maximum temperature 324.2°C) to spray from the outlet of the copper tube. The copper tube was held so that the surface of the lotus root was approximately 5 mm from the outlet of the copper tube, and superheated steam was brought into contact with the surface of the lotus root to heat it and carbonize it. The gas burner used was a "Power Torch RZ-840" manufactured by Shinfuji Burner Co., Ltd., equipped with a commercial-grade "Power Gas Pro RZ-860." The flame and air adjustment knobs were fully open. The maximum flame temperature was 1400-1600°C. Control (non-carbonized) No heating (b) Processing Procedures As shown in Figure 38(A), a region of the lotus root outer pericarp approximately 20 mm in diameter was heated with superheated steam to form a carbonized layer (outermost layer carbonization). However, some areas remained uncarbonized. The area other than the heated area of ​​approximately 20 mm in diameter was used as a control (non-carbonized).

[0236] (2) Second step (enzyme treatment step) After the first step was completed, each lotus root was subjected to the enzyme treatment in the second step. The whole lotus root was immersed in an enzyme solution containing 0.5% by mass / volume of "Acremocellulase KM" manufactured by Kyowa Kasei Co., Ltd., prepared in the same manner as in Example 1, for 19 hours at an average treatment temperature of 8°C, for enzyme treatment.

[0237] (3) Third step (outer pericarp removal step) The lotus roots that had been subjected to the enzyme treatment were taken out, and the outer skin was rubbed off by hand and washed with water, thereby removing the collapsed outer skin of the lotus roots.

[0238] (4) Results As shown in Figure 38(B), the area where the epicarp was carbonized in the first step and its surrounding area underwent softening and disintegration in the second step, and in the third step the epicarp could be easily removed, exposing the flesh. In contrast, the area where the epicarp was carbonized in the first step and the area other than that (uncarbonized area) did not soften or disintegrate even after the second step, and the epicarp could not be removed in the third step. Therefore, it was found that heating with superheated steam can also form a carbonized layer suitable for the method of producing peeled fruits and vegetables of the present disclosure.

[0239] Example 26 Example 26 of the method for producing peeled fruits and vegetables of the present disclosure will be described as follows with reference to Fig. 39. In Example 26, the heating method in the first step is changed to a heating method using city gas 13A. Fruits and vegetables: Lotus (Nelumbo nucifera) rhizome (lotus root) Variety: "Lotus" (produced in Naruto City, Tokushima Prefecture) 1 section (1) First step (carbonized layer forming treatment step) (a) Treatment level Outermost layer carbonization (carbonized layer formation process using flame) The heating equipment used was a high-power burner (gas consumption 4.20kW) manufactured by Rinnai Corporation, model RTE65VAGP-GR. The heat control knob was turned all the way up, and the lotus root was heated in high-temperature stir-fry mode with an open flame in contact with the surface of the lotus root, causing it to carbonize. The fuel used was city gas of Gas Group 13A (main component: methane) supplied by Tokyo Gas Network Co., Ltd. Control (non-carbonized) No heating (b) Processing Procedures The lotus root was cut into approximately two equal parts in the longitudinal direction as shown in Figure 39(A), and the right half was heated with a gas burner under the above conditions to form a carbonized layer (outermost layer carbonized). The left half of the lotus root was left unheated (no carbonized layer formed) and used as a control (non-carbonized). Blackening was observed on the surface of the epicarp (right half) of the area that had been treated with the carbonized layer formation process.

[0240] (2) Second step (enzyme treatment step) After the first step was completed, each lotus root was subjected to the enzyme treatment in the second step. The whole lotus root was immersed in an enzyme solution containing 0.5% by mass / volume of "Acremocellulase KM" manufactured by Kyowa Kasei Co., Ltd., prepared in the same manner as in Example 1, for 21 hours at an average treatment temperature of 18°C, for enzyme treatment.

[0241] (3) Third step (outer pericarp removal step) The lotus roots that had been subjected to the enzyme treatment were taken out, and the outer skin was rubbed off by hand and washed with water, thereby removing the collapsed outer skin of the lotus roots.

[0242] (4) Results As shown in Figure 39(B), the area where the exocarp was carbonized in the first step had the exocarp softened and crumbled after the second step, and in the third step the exocarp could be easily removed, exposing the flesh. In contrast, in the areas other than the area where the epicarp was carbonized in the first step (the uncarbonized areas), the epicarp did not soften or disintegrate even after the second step, and the epicarp could not be removed in the third step. Therefore, it was found that heating with an open flame of city gas, which is mainly composed of methane, can also form a carbonized layer that is suitable for the manufacturing method of peeled fruits and vegetables disclosed herein.

[0243] Example 27 Examples 27a, 27b, and 27c of the method for producing peeled fruits and vegetables of the present disclosure are described below with reference to Figures 40 to 42. Examples 27a, 27b, and 27c are examples in which the enzyme solution used in the second step is changed. Fruits and vegetables: Lotus (Nelumbo nucifera) rhizome (lotus root) Variety: "Lotus" (produced in Naruto City, Tokushima Prefecture) 3 sections (1) First step (carbonized layer forming treatment step) (a) Treatment level Outermost layer carbonization (carbonized layer formation process using flame) The same heating equipment ("Power Torch RZ-840") and heating conditions as in Example 1 were used. Control (non-carbonized) No heating (b) Processing Procedures Each lotus root was cut into approximately two equal parts along the length, and the right half was heated with a gas burner under the above conditions to form a carbonized layer (outermost layer carbonized). The left half of the lotus root was left unheated (no carbonized layer formed) and used as a control (non-carbonized). Blackening was observed on the surface of the epicarp (right half) of the area that had been treated with the carbonized layer formation process. The target (non-carbonized) part was not heated, but the area near the boundary of the carbonized layer formation process was discolored due to the heat generated by the carbonized layer formation process.

[0244] (2) Second step (enzyme treatment step) After the first step was completed, each lotus root was subjected to the second step of enzyme treatment using the following three types of enzyme solutions. In Example 27a, the whole lotus root was immersed in an enzyme solution prepared by mixing Amano Enzyme Co., Ltd.'s "Hemicellulase "Amano" 90" (main activity: xylanase, origin: Aspergillus niger) with water to a concentration of 0.5% by volume for 33 hours at an average treatment temperature of 17°C, and enzyme treatment was performed. In Example 27b, Kyowa Kasei Co., Ltd.'s "Cellulase TP5-Kyowa" (main activity: cellulase / hemicellulase, source: Trichoderma sp. / main activity: esterase, source: Aspergillus sp.) was mixed with water to prepare an enzyme solution with a concentration of 0.5% by mass / volume. The whole lotus root was immersed in the enzyme solution for 43 hours at an average treatment temperature of 17°C for enzyme treatment. In Example 27c, the entire lotus root was immersed in an enzyme solution prepared by mixing Mitsubishi Chemical Corporation's "Sucrase N" (main activity: pectinase, origin: Aspergillus niger) with water to a concentration of 0.5% by mass / volume for 67 hours at an average treatment temperature of 17°C, and enzyme treatment was performed.

[0245] (3) Third step (outer pericarp removal step) Each lotus root that had been subjected to the enzyme treatment was taken out, the epicarp was rubbed off by hand, and washed with water, whereby the collapsed epicarp of the lotus root was detached and removed.

[0246] (4) Results As shown in Figures 40(B), 41(B), and 42(B), the areas where the epicarp was carbonized in the first step had the epicarp soften and crumble after the second step, and in the third step the epicarp could be easily removed, exposing the flesh. In contrast, in the areas where the epicarp was not carbonized in the first step, the epicarp did not soften or disintegrate even after the second step, and the epicarp could not be removed in the third step. Therefore, it has been found that the method for producing peeled fruits and vegetables disclosed herein is not limited to the type of enzyme, and regardless of the enzyme used, it is possible to peel fruits and vegetables more easily and efficiently, and to obtain peeled fruits and vegetables of excellent quality.

[0247] Example 28 Examples 28a and 28b of the method for producing peeled fruits and vegetables of the present disclosure will be described below with reference to Figures 43 and 44. Examples 28a and 28b are examples in which the treatment temperature in the second step is changed. Fruits and vegetables: Lotus (Nelumbo nucifera) rhizome (lotus root) Variety: "Lotus" (produced in Naruto City, Tokushima Prefecture) 2 sections (1) First step (carbonized layer forming treatment step) (a) Treatment level Outermost layer carbonization (carbonized layer formation process using flame) The same heating equipment ("Power Torch RZ-840") and heating conditions as in Example 1 were used. Control (non-carbonized) No heating (b) Processing Procedures Each lotus root was cut into approximately two equal parts along the length, and the right half was heated with a gas burner under the above conditions to form a carbonized layer (outermost layer carbonized). The left half of the lotus root was left unheated (no carbonized layer formed) and used as a control (non-carbonized). Blackening was observed on the surface of the epicarp (right half) of the area that had been treated with the carbonized layer formation process. The target (non-carbonized) part was not heated, but the area near the boundary of the carbonized layer formation process was discolored due to the heat generated by the carbonized layer formation process.

[0248] (2) Second step (enzyme treatment step) After the first step was completed, each lotus root was subjected to the second step of enzyme treatment using an enzyme solution at the following treatment temperature as follows. The enzyme used was an enzyme solution prepared by mixing Acremocellulase KM manufactured by Kyowa Kasei Co., Ltd. with water to adjust the concentration to 0.5% by mass / volume. In Example 28a, the lotus root was immersed in an enzyme solution for 6 hours at a treatment temperature of 40°C to carry out the enzyme treatment. In Example 28b, the lotus root was immersed in an enzyme solution for 8 hours at a treatment temperature of 55°C to carry out the enzyme treatment.

[0249] (3) Third step (outer pericarp removal step) Each lotus root that had been subjected to the enzyme treatment was taken out, the epicarp was rubbed off by hand, and washed with water, whereby the collapsed epicarp of the lotus root was detached and removed.

[0250] (4) Results As shown in Figure 43(B) and Figure 44(B), the area where the epicarp was carbonized in the first step had the epicarp soften and crumble after the second step, and in the third step the epicarp could be easily removed, exposing the flesh. In contrast, in the areas where the epicarp was not carbonized in the first step, the epicarp did not soften or disintegrate even after the second step, and the epicarp could not be removed in the third step. From the above, it has been found that by setting the processing temperature in the enzyme treatment in the second step to a high temperature, the processing time can be shortened as necessary, and therefore the method for producing peeled fruits and vegetables disclosed herein can peel lotus root more quickly.

[0251] Example 29 Examples 29a and 29b of the method for producing peeled fruits and vegetables of the present disclosure are described below with reference to Figures 45 to 48. In Examples 29a and 29b, the second step is changed to a chemical treatment step, and a basic substance alone or both an acidic substance and a basic substance are used as the epicarp disintegrating agent, and a color restoration step is further performed as a fourth step. Fruits and vegetables: Lotus (Nelumbo nucifera) rhizome (lotus root) Variety: "Lotus" (produced in Naruto City, Tokushima Prefecture) 2 sections (1) First step (carbonized layer forming treatment step) (a) Treatment level Outermost layer carbonization (carbonized layer formation process using flame) The same heating equipment ("Power Torch RZ-840") and heating conditions as in Example 1 were used. Control (non-carbonized) No heating (b) Processing Procedures The two sections of the lotus root were cut into approximately two equal halves along the length, and the right half was heated with a gas burner under the above conditions to form a carbonized layer (outermost layer carbonization). The left half of the lotus root was left unheated and uncarbonized, serving as a control (non-carbonized). Blackening was observed on the surface of the epicarp (right half) of the area that had been treated with the carbonized layer formation process.

[0252] (2) Second process (chemical treatment process) After the first step was completed, each lotus root was subjected to the second step of chemical treatment using the following exocarp disintegrating agent. Example 29a is an example using only a basic substance. After the first step, the lotus root was subjected to only a contact treatment with a basic substance. The lotus root was immersed in a 4% by volume aqueous solution of sodium hydroxide at a liquid temperature of 40°C for 30 minutes, and then washed with water. Example 29b is an example using both an acidic substance and a basic substance. After the first step was completed, the lotus root was subjected to a contact treatment in which it was contacted with an acidic substance and then a contact treatment in which it was contacted with a basic substance. The lotus root was immersed in 1% by volume of hydrochloric acid at a liquid temperature of 40°C for 30 minutes, and then washed with water. Next, the lotus root was immersed in 1% by volume of sodium hydroxide aqueous solution at a liquid temperature of 40°C for 30 minutes, and then washed with water.

[0253] (3) Third step (outer pericarp removal step) The outer skin of each lotus root that had been subjected to the above chemical treatment was scraped off by hand and washed with water, thereby removing the collapsed outer skin of the lotus root. (4) The fourth process (color restoration process) In the color restoration step, each lotus root that had been subjected to the above-mentioned outer pericarp removal treatment was immersed in 1% by volume hydrochloric acid at a liquid temperature of 40°C for 5 minutes, and then washed with water.

[0254] (5) Results As shown in Figures 45(B), 46, 47(B), and 48, in Examples 29a and 29b, the epicarp of the portion that was carbonized in the first step softened and disintegrated in the second step, and the epicarp was easily removed in the third step, exposing the flesh. By carrying out the color restoration step following the third step, the browning of the flesh that occurred in the second step when the lotus root was immersed in each epicarp disintegrating agent was reduced. In contrast, the exocarp of the part of the fruit that had not been carbonized in the first step did not soften or disintegrate even after the second step, and the exocarp could not be removed in the third step. The same result was obtained even when the third step was followed by a color restoration step. Therefore, it has been found that the method for producing peeled fruits and vegetables disclosed herein can peel fruits and vegetables more easily and efficiently, even when a chemical treatment step using an acidic or basic substance is performed as the second step, and peeled fruits and vegetables of excellent quality can be obtained.

[0255] Example 30 Examples 30a, 30b, and 30c of the method for producing peeled fruits and vegetables of the present disclosure are described below with reference to Figures 49 to 53. In Examples 30a, 30b, and 30c, the second step is changed to a chemical treatment step, and either only an acidic substance or both an acidic substance and a basic substance are used as the epicarp disintegrating agent. Fruits and vegetables: Grapefruit (Citrus x paradisi) Variety: 4 Star Ruby (South Africa) (1) First step (carbonized layer forming treatment step) (a) Treatment level Outermost layer carbonization (carbonized layer formation process using flame) The same heating equipment ("Power Torch RZ-840") and heating conditions as in Example 1 were used. Control (non-carbonized) No heating (b) Processing Procedures A roughly spherical grapefruit was virtually divided into two halves along a plane roughly including the center of the fruit. The right half was heated with a gas burner under the above conditions to form a carbonized layer (outermost layer carbonization). The left half was left unheated and used as a control (non-carbonized). Blackening was observed on the surface of the epicarp (right half) of the area that had been treated with the carbonized layer formation process.

[0256] (2) Second process (chemical treatment process) After the first step was completed, each grapefruit was subjected to the second chemical treatment step using the following outer peel disintegrating agent. Example 30a is an example in which chemical treatment was performed using only an acidic substance at a low temperature for a long period of time. After the first step was completed, the grapefruit was subjected to only a contact treatment in which it was brought into contact with an acidic substance. Two grapefruits were immersed in 1% by volume of hydrochloric acid for 9 hours at average liquid temperatures of 7°C and 12°C, respectively, and then washed with water. Example 30b is an example in which a chemical treatment was performed using both an acidic substance and a basic substance at high temperature for a short period of time. After the first step was completed, the grapefruit was subjected to a contact treatment in which it was contacted with an acidic substance and then with a basic substance. One grapefruit was immersed in 1% by volume hydrochloric acid at a solution temperature of 40°C for 30 minutes, and then washed with water. Next, the grapefruit was immersed in a 1% by volume aqueous solution of sodium hydroxide at a solution temperature of 40°C for 20 minutes, and then washed with water. Example 30c is an example in which chemical treatment was performed using both a weakly acidic substance and a weakly basic substance at low temperature for a long period of time. After the first step was completed, the grapefruit was sequentially subjected to a contact treatment in which it was contacted with a weakly acidic substance and then with a weakly basic substance. One grapefruit was immersed in a 30% by volume aqueous citric acid solution for 9 hours at an average liquid temperature of 7°C, and then washed with water. Next, the grapefruit was immersed in a 1% by volume aqueous sodium bicarbonate solution for 25 minutes at an average liquid temperature of 9°C, and then washed with water.

[0257] (3) Third step (outer pericarp removal step) The outer skin of each of the chemically treated grapefruits was manually scraped off and washed with water, thereby removing the broken outer skin of the grapefruit.

[0258] (4) Results As shown in Figures 49(B), 50(A), 50(B), 51(B), and 52, in Examples 30a and 30b, the half of the fruit whose epicarp was carbonized in the first step underwent the second step, during which the epicarp and mesocarp softened and collapsed, and in the third step the epicarp and mesocarp could be easily removed, exposing the flesh. As shown in Figure 53(B), in Example 30c, the half of the sample whose epicarp was carbonized in the first step underwent softening of the epicarp and mesocarp in the second step, but the degree of softening of the epicarp was less than when hydrochloric acid was used in the second step. In the third step, strong scraping was required to initially create holes in the epicarp, but after the holes were created, the epicarp and mesocarp could be easily removed, exposing the flesh. In contrast, in all of Examples 30a, 30b, and 30c, the half of the fruit in which the epicarp was not carbonized in the first step did not undergo softening or disintegration even after the second step, and the epicarp and mesocarp could not be easily removed in the third step. In Example 30a, the results were similar regardless of the treatment temperature of hydrochloric acid in the second step. Therefore, these examples also demonstrate that the method for producing peeled fruits and vegetables of the present disclosure can peel fruits and vegetables more easily and efficiently, even when a chemical treatment step is performed using an acidic or basic substance as the second step, and can produce peeled fruits and vegetables of excellent quality.

[0259] Although the embodiments and examples of the present disclosure have been described in detail above, the specific configurations are not limited to these embodiments and examples, and design changes that do not deviate from the gist of the present disclosure are included in the present disclosure. [Industrial Applicability]

[0260] The technology of the present disclosure can be used in a primary processing step of peeling fruits and vegetables. The peeled fruits and vegetables obtained by the primary processing step can be further used in a secondary processing step for producing cut fruits, cut vegetables, dried fruits, dried vegetables, frozen fruits, frozen vegetables, Japanese and Western sweets, salads, side dishes, pickles, and other foods, as well as brewed alcoholic beverages, distilled alcoholic beverages, mixed alcoholic beverages, sparkling alcoholic beverages, and other alcoholic beverages. Furthermore, it is expected that an apparatus that mechanizes or automates the manufacturing process according to the technology of the present disclosure can be provided at low cost.

Claims

1. A method for producing peeled fruits and vegetables in which the outer skin is removed from the fruits and vegetables, a first step of forming a carbonized layer on at least the surface of the epicarp; a second step of contacting the fruits and vegetables after the first step with an exocarp disintegrating agent; a third step of removing the outer skin of the fruit or vegetable after the second step; Including, A method for producing peeled fruits and vegetables, comprising:

2. 2. The method for producing peeled fruits and vegetables according to claim 1, wherein the first step includes a heat treatment of heating the surface of the fruits and vegetables to a surface temperature of 200°C or higher, and the heat treatment is carried out until the outer skin is charred.

3. 3. The method for producing peeled fruits and vegetables according to claim 2, wherein the heat treatment is carried out until the transpiration conductance of the surface of the fruits and vegetables after heating increases compared to before heating, until the weight of the fruits and vegetables after heating decreases compared to before heating, or until the color of the outer skin turns brown or black.

4. The method for producing peeled fruits or vegetables according to claim 3 , wherein the heat treatment is carried out until the transpiration conductance after heating increases to 1.5 to 26 times that before heating.

5. 2. The method for producing peeled fruits and vegetables according to claim 1, wherein the second step includes a step of introducing the exocarp disintegrating agent into the exocarp or into the exocarp and an area adjacent to the exocarp, using countless pores formed in the carbonized layer as introduction paths.

6. The method for producing peeled fruits or vegetables according to any one of claims 1 to 5, wherein the second step is carried out under atmospheric pressure.

7. The method for producing peeled fruits and vegetables according to any one of claims 1 to 5, wherein the fruits and vegetables have an outer skin having a cork layer, and the first step is a step of carbonizing the cork layer.

8. The method for producing peeled fruits and vegetables according to any one of claims 1 to 5, wherein the fruit and vegetables are fruit and vegetables whose outer skin has a cuticle layer, and the first step is a step of carbonizing the cuticle layer.

9. The method for producing peeled fruits and vegetables according to any one of claims 1 to 5, wherein the fruits and vegetables are any of root vegetables (excluding potatoes), potatoes, fruit vegetables, leafy vegetables, and fruits.

10. The method for producing peeled fruits and vegetables according to any one of claims 1 to 5, wherein the fruits and vegetables are lotus rhizomes or citrus fruits.

11. The method for producing peeled fruits or vegetables according to any one of claims 1 to 5, wherein the exocarp disintegrating agent used in the second step is an enzyme agent.

12. The method for producing peeled fruits and vegetables according to claim 11, wherein the enzyme preparation contains a carbohydrate-degrading enzyme.

13. The method for producing peeled fruits and vegetables according to claim 11, wherein the enzyme agent is an enzyme agent containing at least one carbohydrate-degrading enzyme selected from the group consisting of pectinase-based enzyme agents, hemicellulase-based enzyme agents, and cellulase-based enzyme agents.

14. The method for producing peeled fruits or vegetables according to any one of claims 1 to 5, wherein the exocarp disintegrating agent used in the second step is an acidic substance or a basic substance.

15. The method for producing peeled fruits and vegetables according to claim 14, wherein the acidic substance is at least one selected from the group consisting of hydrochloric acid, sulfuric acid, citric acid, ascorbic acid, and acetic acid, and the basic substance is at least one selected from the group consisting of sodium hydroxide, sodium carbonate, and sodium bicarbonate.

16. The method for producing peeled fruits or vegetables according to claim 14 , wherein the second step comprises sequentially carrying out a contact treatment of contacting the fruit or vegetables with the acidic substance and a contact treatment of contacting the fruit or vegetables with the basic substance.

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