Method for manufacturing vegetable products and method for softening vegetables

Abstract

To provide a method for producing vegetable dishes, etc., in which raw vegetables can be effectively softened. [Solution] A method for producing cooked vegetables, comprising immersing raw vegetables in a pectinase-containing solution with a pH of 6.0 or higher, and heating them for 3 minutes or more under conditions of a gauge pressure of -50 kPa or lower and a liquid temperature of 40°C or higher and less than 80°C.

Description

Technical Field

[0001] The present invention relates to a method for producing a vegetable cooked product, and more particularly to a method for producing a vegetable cooked product containing vegetables cooked in a soft manner. The present invention also relates to a method for softening vegetables, a kit for cooking vegetables, a liquid for immersing vegetables, and the like.

Background Art

[0002] In recent years, due to the increasing health consciousness, even ordinary consumers tend to actively consume vegetables, and in particular, the cases of cooking large-cut vegetables or whole vegetables by boiling them for a long time are increasing. On the other hand, with the diversification of lifestyles, the cooking time for weekday dinners tends to be shortened, and consumers have a great need to cook large-cut vegetables or whole vegetables soft in a short time. Generally, it is necessary to boil large vegetables for a long time to cook them soft. Therefore, a pressure cooker may be used to make vegetables softer even in short-time boiling cooking, but there is a limit to the level of softness that can be achieved in short-time cooking.

[0003] Conventionally, many methods for softening vegetables have been reported. For example, a method using one or more selected from the group consisting of arginine and its salts and a carbonate (Patent Document 1), a method of immersing root vegetables in a baking soda solution and then boiling them in an acidic solution (Patent Document 2), a method using lipase and cellulase (Patent Document 3), etc. have been reported. Although these methods can all obtain a certain softening effect, when attempting to soften large vegetables, it may take time until the active ingredients penetrate into the vegetables, and the level of the softening effect obtained may not be sufficient in some cases.

[0004] Many methods have been reported to efficiently penetrate vegetables with active ingredients for softening them, including methods that involve treating vegetables under reduced pressure in the presence of these active ingredients. For example, one method has been reported (Patent Document 4) in which green and yellow vegetables are brought into contact with an enzyme having at least one activity selected from pectinase activity, cellulase activity, and hemicellulase activity in a weakly acidic to alkaline environment, subjected to pressure treatment, and then the enzyme activity is stopped by steam at 85-120°C to increase the flexibility of the green and yellow vegetables while maintaining their color and shape. However, this method does not include steps such as heating the vegetables under reduced pressure, resulting in insufficient penetration of the enzyme into the vegetables. In particular, large vegetables suffer from insufficient enzyme penetration and do not achieve a sufficient softening effect. Generally, it is believed that vegetables harden at temperatures in the range of approximately 40-70°C due to the action of endogenous pectin methylesterase contained within them. Therefore, it is usually best to avoid treating vegetables at this temperature range for efficient softening.

[0005] Patent Document 5 discloses a method for producing softened mushrooms, characterized by immersing mushrooms in a solution containing an enzyme having either cellulase activity or hemicellulase activity, an enzyme having any activity selected from the group consisting of pectinase activity, glucanase activity, and chitinase activity, and adipic acid; maintaining the solution under reduced pressure for a certain period of time; then restoring the pressure to atmospheric pressure; and finally maintaining the solution at 35-55°C. This technique softens mushrooms, and it has been difficult to apply this technique to large vegetables and other items where enzyme penetration is difficult.

[0006] Patent Document 6 discloses a method for producing softened plant materials, characterized by contacting plant materials such as vegetables with a degrading enzyme having at least one activity selected from cellulase activity, hemicellulase activity, and pectinase activity, performing multiple vacuum treatments, and then heating the plant materials at 90-120°C and 10-70% humidity for 5-120 minutes to deactivate the degrading enzyme. However, this technology does not include steps such as heating under reduced pressure in the presence of the enzyme, and therefore the penetration of the enzyme into the plant material is insufficient. In particular, it has been difficult to apply this technology to large vegetables and other items where enzyme penetration is difficult.

[0007] Patent Document 7 discloses a method for producing enzyme-containing food, characterized by having an enzyme introduction step in which various food ingredients, not limited to vegetables, are subjected to reduced pressure, and while maintaining the reduced pressure state, are brought into contact with a liquid component containing one or more enzymes selected from the group consisting of cellulase, hemicellulase, xylanase, pectinase, amylase, protease, papain, and lipase, and then the pressure is increased to above atmospheric pressure to introduce the enzyme into the food ingredients; and after the enzyme introduction step, an enzyme reaction step performed under pressure is followed by a freezing step, and the enzyme reaction step is performed simultaneously with or after thawing. However, this technology has the problem that it is time-consuming because it requires a freezing and thawing step, and that it takes even more time if the enzyme-containing food is further cooked by a heating step.

[0008] Patent Document 8 discloses a method for rapidly introducing enzymes into plant tissue to change its hardness while maintaining its original shape, characterized by freezing and thawing raw or heated plant food material, then immersing it in an enzyme solution having at least pectinase activity and holding it under reduced pressure of 10-60 mmHg for 5-60 minutes. However, this technique has the drawback of being time-consuming because it requires a freezing and thawing process, and requiring even more time if the plant food material is further cooked by heating. There are various units for expressing pressure, but mmHg represents the absolute pressure in millimeters of mercury. Converting 10-60 mmHg to gauge pressure (unit: kPa) gives approximately -100 to -93 kPa (the atmospheric pressure used as the gauge pressure reference for conversion is 101325 Pa, i.e., 101.325 kPa).

[0009] Thus, although many methods for softening vegetables have been reported, most of them are designed by separating a vacuum process aimed at introducing enzymes into the food, a freezing and thawing process to facilitate enzyme introduction, from a heating process at a high temperature of 90°C or higher to deactivate the enzymes, or a heating process at a high temperature for cooking purposes. There are few reports of methods that can soften large vegetables in a short time, and in particular, there have been no reports of methods that include a process of heating the food at a medium temperature of 40°C to less than 80°C under vacuum conditions while the food is in contact with enzymes. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] Japanese Patent Publication No. 2019-170251 [Patent Document 2] Patent No. 6506941 [Patent Document 3] Japanese Patent Publication No. 2010-213723 [Patent Document 4] Japanese Patent Publication No. 2008-237196 [Patent Document 5] Japanese Patent Publication No. 2016-036291 [Patent Document 6] Patent No. 5801544 [Patent Document 7] Patent No. 5881418 [Patent Document 8] Patent No. 3686912 [Overview of the project] [Problems that the invention aims to solve]

[0011] This invention has been made in view of the above circumstances, and the problem it aims to solve is to provide a method for producing vegetable products in which raw vegetables (especially large raw vegetables) can be effectively cooked until soft, that is, in which raw vegetables can be effectively softened. Furthermore, in one embodiment, the present invention aims to provide a novel method for softening vegetables (especially large vegetables) that can effectively soften them. Furthermore, in one embodiment, the present invention aims to provide a new vegetable cooking kit that can effectively soften and cook vegetables (especially large vegetables). Furthermore, in one embodiment, the present invention aims to provide a novel vegetable immersion solution that can effectively soften vegetables (especially large vegetables). [Means for solving the problem]

[0012] The inventors of this invention diligently studied to solve the above-mentioned problems and discovered that vegetables can be effectively softened by immersing them in a pectinase-containing solution adjusted to a neutral to alkaline range and then heating them under reduced pressure. Through further research, they completed the present invention. In other words, the present invention is as follows:

[0013] [1] A method for producing cooked vegetables, comprising immersing raw vegetables in a pectinase-containing solution with a pH of 6.0 or higher, and heating them for 3 minutes or more under conditions of a gauge pressure of -50 kPa or lower and a liquid temperature of 40°C or higher but less than 80°C. [2] The manufacturing method according to [1], further comprising subjecting the raw vegetables to cooking after the heat treatment. [3] The manufacturing method according to [1] or [2], wherein the pectinase-containing solution is filled in a container that is resistant to reduced pressure and heat. [4] The manufacturing method according to any one of [1] to [3], wherein the pectinase content in the pectinase-containing solution is 0.03 U or more per 1 g of raw vegetables before heat treatment. [5] The manufacturing method according to any one of [1] to [4], wherein the raw vegetable material includes one or more vegetables having at least one side measuring 2 cm or more. [6] A method for softening vegetables, comprising immersing the vegetables in a pectinase-containing solution with a pH of 6.0 or higher, and heating them for 3 minutes or more under conditions of a gauge pressure of -50 kPa or lower and a liquid temperature of 40°C or higher but less than 80°C. [7] The softening method according to [6], further comprising subjecting the vegetables to cooking after the heat treatment. [8] The softening method according to [6] or [7], wherein the pectinase-containing solution is filled in a container that is resistant to reduced pressure and heat. [9] The softening method according to any one of [6] to [8], wherein the pectinase content in the pectinase-containing solution is 0.03 U or more per 1 g of vegetables before heat treatment.

[10] The softening method according to any one of [6] to [9], wherein the vegetables include one or more vegetables having at least one side of 2 cm or more.

[11] A vegetable cooking kit comprising pectinase for preparing a pectinase-containing solution and a material for adjusting the pH of the pectinase-containing solution to 6.0 or higher, A kit is provided in which a pectinase-containing solution, prepared using at least the aforementioned pectinase, the aforementioned material, and water, has a pH of 6.0 or higher, and is used for immersing vegetables in a heat treatment process at a gauge pressure of -50 kPa or lower and a liquid temperature of 40°C or higher and less than 80°C for 3 minutes or more.

[12] The kit according to

[11] , wherein the vegetables are subjected to cooking after the heat treatment.

[13] The kit according to

[11] or

[12] , wherein the pectinase-containing solution is filled into a container that is resistant to reduced pressure and heat.

[14] The kit according to any one of

[11] to

[13] , wherein the content of pectinase in the pectinase-containing liquid is 0.03 U or more per 1 g of the vegetable before heat treatment.

[15] The kit according to any one of

[11] to

[14] , wherein the vegetable includes one or more vegetables having at least one side of 2 cm or more.

[16] A liquid for vegetable immersion, which contains pectinase and has a pH of 6.0 or more, and is used for heat-treating the immersed vegetable for 3 minutes or more under the conditions of a gauge pressure of -50 kPa or less and a liquid temperature of 40°C or more and less than 80°C.

[17] The liquid according to

[16] , wherein the vegetable is subjected to heat cooking after the heat treatment.

[18] The liquid according to

[16] or

[17] , wherein the liquid is filled in a container having decompression resistance and heat resistance.

[19] The liquid according to any one of

[16] to

[18] , wherein the content of pectinase in the liquid is 0.03 U or more per 1 g of the vegetable before heat treatment.

[20] The liquid according to any one of

[16] to

[19] , wherein the vegetable includes one or more vegetables having at least one side of 2 cm or more.

Advantages of the Invention

[0014] According to the present invention, there is provided a method for producing a processed vegetable product in which raw vegetables can be effectively softened. Since the raw vegetables can be effectively softened while maintaining their shape even if they are large-sized vegetables, the present invention also provides a method for producing a processed vegetable product in which large-sized raw vegetables can be effectively softened. According to the present invention, there is also provided a method for softening vegetables that can effectively soften vegetables. Since this softening method can effectively soften vegetables while maintaining their shape regardless of the size of the vegetables, the present invention also provides a method for softening large-sized vegetables. According to the present invention, a vegetable cooking kit is provided that can effectively soften and cook vegetables. Since the kit can effectively soften and cook even large vegetables while maintaining their shape, the present invention also provides a vegetable cooking kit that can effectively soften and cook large vegetables. The present invention also provides a vegetable immersion solution that can effectively soften vegetables. Since this solution can effectively soften vegetables while maintaining their shape, even large vegetables, regardless of their size, the present invention also provides a vegetable immersion solution for large vegetables. [Brief explanation of the drawing]

[0015] [Figure 1] This diagram shows an example of a vegetable shape (cubic) and its three-dimensional orientation (X, Y, Z). [Figure 2] This figure shows an example of a vegetable shape (perfectly spherical) and its three-dimensional orientation (X, Y, Z). [Figure 3] This diagram shows an example of a vegetable shape (cylindrical) and its three-dimensional orientation (X, Y, Z). [Modes for carrying out the invention]

[0016] The method for producing vegetable products of the present invention (which may be referred to as "the method of production of the present invention" in this specification) includes immersing raw vegetables in a pectinase-containing solution having a specific pH and heating them under specific conditions.

[0017] In the manufacturing method of the present invention, the types of vegetables used as raw materials for vegetable dishes are not particularly limited, but examples include root vegetables, leafy and stem vegetables, fruit vegetables, fruit-like vegetables, and spice vegetables. In this specification, vegetables used as raw materials for vegetable dishes may be referred to as "raw vegetable." In this invention, "vegetable" refers to herbaceous plants that can be eaten. Specific examples of root vegetables include carrots, burdock, radishes, lotus roots, potatoes, sweet potatoes, turnips, and beets; specific examples of leafy and stem vegetables include Chinese cabbage, cabbage, broccoli, cauliflower, lettuce, spinach, leeks, onions, asparagus, bean sprouts, and bok choy; specific examples of fruit vegetables include tomatoes, bell peppers, eggplants, cucumbers, snow peas, and okra; specific examples of fruit-like vegetables include strawberries, melons, and watermelons; and specific examples of spice vegetables include ginger. These may be used individually or in combination of two or more. Root vegetables are preferred as raw materials in the manufacturing method of the present invention, as they are difficult to soften quickly through methods such as boiling, making the present invention particularly useful.

[0018] The raw vegetables used in the manufacturing method of the present invention are usually raw vegetables. In the present invention, "raw vegetables" refers to vegetables that are partially or entirely raw, and is a concept that includes vegetables immediately after harvest, vegetables stored only at room temperature or in the refrigerator after harvest, vegetables that have been frozen after harvest (frozen vegetables), vegetables that have been thawed after freezing, vegetables that have been blanched, and vegetables that have been partially heated (for example, vegetables that have only the surface grilled or seared with a burner, etc.). The present invention can effectively soften the raw parts of vegetables. From the viewpoint of easy cooking, it is preferable that the raw vegetables used in the manufacturing method of the present invention are entirely raw (for example, vegetables immediately after harvest, vegetables stored only at room temperature or in the refrigerator after harvest, etc.).

[0019] The shape of the raw vegetables used in the manufacturing method of the present invention is not particularly limited. For example, they may be in their original shape (the shape they have when harvested), or they may be cut into any shape (e.g., cubic, spherical, cylindrical, etc.).

[0020] The size of the raw vegetables used in the manufacturing method of the present invention is not particularly limited, but it is preferable to include at least one vegetable with at least one side of a specific length. Specifically, it is preferable to include a vegetable with at least one side of 2 cm or more, more preferable to include a vegetable with at least one side of 2.5 cm or more, and even more preferable to include a vegetable with at least one side of 3 cm or more. The larger the size of the raw vegetables, the easier it is to obtain the effects of the present invention. In this invention, "at least one side of a vegetable is N cm or longer" (where N is any positive number) means that when three mutually orthogonal directions (X, Y, Z) are set for any orientation of the vegetable, the length of at least one of these three directions (one side) is N cm or longer. To illustrate with a specific example (however, this example does not limit the present invention in any way), if the shape of the vegetable is a cube with 3 cm on each side as shown in Figure 1, or a perfect sphere with a diameter of 3 cm as shown in Figure 2, then all three sides of the vegetable (i.e., all three directions of X, Y, and Z) are 2 cm or longer, and it may fall under the category of "a vegetable with at least one side of 2 cm or longer". In this specification, "a vegetable with at least one side of 2 cm or longer" may be referred to as a "large vegetable". Furthermore, if the shape of the vegetable is cylindrical with a base diameter of 1 cm and a height of 3 cm, as shown in Figure 3 as one embodiment, the lengths of the three sides of the vegetable (in the X, Y, and Z directions) will be 1 cm, 1 cm, and 3 cm, respectively. Since the length of the longest side (length in the Z direction) is 3 cm, this vegetable may also fall under the category of "vegetables with at least one side of 2 cm or more" (large vegetables), etc. Furthermore, if the raw vegetable used in the manufacturing method of the present invention includes vegetables with at least one side measuring N cm or more, the raw vegetable may further include vegetables with at least one side measuring N cm or more, as well as vegetables with all three sides measuring less than N cm.

[0021] The raw vegetables used in the manufacturing method of the present invention may have inedible parts (e.g., stems, peels, cores, etc.) removed, or they may not have inedible parts removed. The present invention can soften not only vegetables from which inedible parts have been removed, but also vegetables from which inedible parts have not been removed, in a short time. The raw vegetables used in the manufacturing method of the present invention do not need to undergo any prior pretreatment before being immersed in the pectinase-containing solution, but for example, holes may be made in the surface of the vegetables in advance to increase the penetration of the pectinase-containing solution into the inside of the vegetables.

[0022] In the manufacturing method of the present invention, raw vegetables can be immersed in a pectinase-containing solution alone, but depending on the type of vegetable dish, other ingredients may be immersed in the pectinase-containing solution together with the raw vegetables. In other words, raw vegetables may coexist with other ingredients in the pectinase-containing solution. Examples of ingredients other than raw vegetables that can be immersed in the pectinase-containing solution include meats, beans, grains, fruits, mushrooms, seafood, seaweed, noodles, water-based pastes, etc., but any ingredients and processed products may be used as long as they do not impair the purpose of the present invention. Furthermore, as mentioned above, the raw vegetables used in the manufacturing method of the present invention are usually raw vegetables, but cooked vegetables (i.e., vegetables that are not entirely raw) may be used as ingredients other than raw vegetables. To give a specific example (however, the present invention is not limited in any way by such a specific example), if the vegetable dish obtained by the manufacturing method of the present invention is, in one embodiment, nikujaga (meat and potato stew), the raw vegetables (potatoes, carrots, onions, etc.) and pork may be immersed together in a pectinase-containing solution, and these may be allowed to coexist in the pectinase-containing solution. Even if the pork is immersed together with the raw vegetables in a pectinase-containing solution in this way, according to the present invention, a vegetable dish (nikujaga) in which all the vegetables have softened can be obtained in a short time.

[0023] In the manufacturing method of the present invention, the pectinase-containing solution into which the raw vegetables are immersed is an aqueous solution containing pectinase. In the present invention, "pectinase" refers to an enzyme that has the activity to catalyze the reaction of hydrolyzing pectin (enzyme number: EC3.2.1.15, etc.). In the present invention, the activity possessed by pectinase is also referred to as "pectinase activity". Pectinase activity includes the above-mentioned activity (activity to catalyze the reaction of hydrolyzing pectin, more specifically, activity to catalyze the reaction of hydrolyzing the α-1,4 glycosidic bond of the polygalacturonic acid chain that constitutes pectin), as well as pectin lyase activity that decomposes polygalacturonic acid chain by β-elimination, pectin methylesterase activity that demethylates the methyl ester group of pectin, and protopectinase activity that acts on water-insoluble protopectin to release water-soluble pectin.

[0024] The enzymatic activity of pectinase can be measured by the following procedure. In other words, the enzymatic activity of pectinase can be measured by incubating the enzyme with a substrate and measuring the enzyme-dependent degradation of the substrate. Substrate degradation can be measured, for example, by the generation of reducing ends (i.e., an increase in reducing power). The increase in reducing power can be measured, for example, by the dinitrosalicylic acid (DNS) method, the Somogyi-Nelson method, etc. In this invention, 1 U (unit) is defined as the amount of enzyme that, when an enzymatic reaction is carried out with polygalacturonic acid as a substrate, produces an increase in reducing power equivalent to 1 μmol of galacturonic acid per minute at 45°C and pH 4.5. Here, an increase in reducing power equivalent to a certain amount of galacturonic acid may be interpreted as the production of that amount of galacturonic acid. The amount of galacturonic acid produced can be measured, for example, by known methods used for the quantitative determination of compounds, such as HPLC, LC / MS, GC / MS, and NMR.

[0025] The pectinase used in the present invention is preferably active in the neutral and alkaline ranges of pH 6.0 or higher.

[0026] The method for preparing the pectinase used in the present invention is not particularly limited and may be prepared by a method known to the present or by a method equivalent thereto. The present invention may also use commercially available pectinase, and a specific example of a commercially available pectinase is the product named "Pectinase XP-534NEO" from Nagase ChemteX Corporation.

[0027] The pectinase content in the pectinase-containing solution used in the manufacturing method of the present invention is usually 0.02 U or more per 1 g of raw vegetables before heat treatment, preferably 0.03 U or more, and more preferably 0.05 U or more, from the viewpoint of being able to sufficiently soften the vegetables in a short time. Furthermore, the pectinase content in the pectinase-containing solution is preferably 1500 U or less, and more preferably 1000 U or less, per 1 g of raw vegetables before heat treatment, from the viewpoint of being able to maintain the shape of the vegetables even when the raw vegetables include large vegetables.

[0028] The pH of the pectinase-containing solution used in the production method of the present invention is preferably 6 or higher, and more preferably 6.5 or higher. The upper limit of the pH of the pectinase-containing solution is not particularly limited, and the pH may be 14 or lower, but is preferably 10 or lower. The pH values ​​in the present invention are measured at a liquid temperature of 25°C.

[0029] In the present invention, the pH of the pectinase-containing solution can be adjusted using a substance that can buffer the solution to an alkaline state. Examples of such substances include, but are not limited to, sodium bicarbonate, sodium carbonate, potassium carbonate, calcium carbonate, calcium oxide, trisodium citrate, trisodium phosphate, disodium dihydrogen pyrophosphate, sodium polyphosphate, and arginine. In one embodiment, the substance used to adjust the pH of the pectinase-containing solution may be a commercially available food additive, and a specific example is sodium carbonate sold by Air Water Performance Chemicals Inc. under the product name "Purified Sodium Carbonate (Anhydrous)".

[0030] The pectinase-containing solution used in the manufacturing method of the present invention may contain, in addition to the pectinase, a material for adjusting the pH of the solution (a substance that can buffer the pectinase-containing solution to an alkaline state). However, as long as the objective of the present invention is not impaired, other food materials and food additives may be optionally included. Specific examples of such optional food materials and food additives include, but are not limited to, seasonings (e.g., salt, sugar, amino acids, nucleic acids, yeast extract, meat extract, vegetable extract, vegetable paste, etc.), excipients (e.g., dextrin, lactose, etc.), proteins (e.g., vegetable protein, gluten, egg white, egg yolk, gelatin, casein, etc.), protein hydrolysates, partially hydrolyzed proteins, starches (e.g., modified starch, pregelatinized starch, etc.), thickening polysaccharides (e.g., xanthan gum, guar gum, etc.), emulsifiers, colorants, enzymes, flavorings, etc. These food ingredients and food additives may be used individually or in combination of two or more.

[0031] The method for preparing the pectinase-containing solution used in the manufacturing method of the present invention is not particularly limited and may be prepared by a known method or a similar method. The method for preparing the pectinase-containing solution usually includes the step of adding pectinase to an aqueous solution (e.g., water). The timing (timing) of adding the pectinase to the aqueous solution is not particularly limited as long as it is before the raw vegetables immersed in the pectinase-containing solution are heat-treated under specific conditions. For example, the pectinase may be added to an aqueous solution in which the raw vegetables have not been immersed, and then the raw vegetables may be immersed, or the pectinase may be added to an aqueous solution in which the raw vegetables have been immersed beforehand. Alternatively, the pectinase and raw vegetables may be added to the aqueous solution simultaneously. The method for preparing the pectinase-containing solution also includes the step of adjusting the pectinase-containing solution to a specific pH (e.g., 6 or higher). The timing of adjusting the pH of the pectinase-containing solution is not particularly limited as long as it is done before the raw vegetables soaked in the pectinase-containing solution are heat-treated under specific conditions. For example, the pH of the pectinase-containing solution may be adjusted before soaking the raw vegetables in the pectinase-containing solution, or after soaking the raw vegetables in the pectinase-containing solution.

[0032] In the manufacturing method of the present invention, it is important that the raw vegetables, which have been immersed in a pectinase-containing solution having a specific pH, are heat-treated under specific conditions, and moreover, that the heat treatment is carried out under specific reduced pressure conditions. In this specification, the heat treatment applied to the raw vegetables under specific reduced pressure conditions may be referred to as "reduced pressure heat treatment" for convenience of explanation.

[0033] In the manufacturing method of the present invention, the reduced-pressure heat treatment is preferably performed at a gauge pressure of -50 kPa or less, more preferably -55 kPa or less, and even more preferably -60 kPa or less, from the viewpoint that even large vegetables can be sufficiently penetrated into the interior of the vegetables by the pectinase-containing solution and softened sufficiently in a short time. The lower the gauge pressure of the reduced-pressure heat treatment performed in the manufacturing method of the present invention, the better, and there is no particular limit to the lower value of the gauge pressure.

[0034] In the manufacturing method of the present invention, the reduced-pressure heat treatment is performed such that, from the viewpoint of efficiently penetrating the inside of even large vegetables with pectinase-containing liquid and softening them sufficiently in a short time, the liquid temperature (the temperature of the pectinase-containing liquid having a specific pH in which the raw vegetables are immersed) is preferably 40°C or higher, more preferably 42°C or higher, and even more preferably 45°C or higher. Furthermore, from the viewpoint of ensuring that the vegetables are sufficiently softened, the liquid temperature is preferably less than 80°C, more preferably 78°C or lower, and even more preferably 75°C or lower.

[0035] In the manufacturing method of the present invention, the vacuum heating treatment is preferably performed for 3 minutes or more, more preferably for 4 minutes or more, and even more preferably for 5 minutes or more, from the viewpoint that even large vegetables can be sufficiently penetrated into the interior of the vegetables by the pectinase-containing solution and softened sufficiently in a short time. There is no particular upper limit to the time of the vacuum heating treatment in the manufacturing method of the present invention, but it is usually 30 minutes or less.

[0036] The vacuum heating treatment in the manufacturing method of the present invention may be carried out by any method as long as the above-mentioned specific conditions (gauge pressure, liquid temperature, time) are satisfied. For example, one method is to fill a container that has vacuum resistance and heat resistance (for example, a hard chamber such as a pot) with a pectinase-containing liquid having a specific pH and raw vegetables, and then perform vacuum treatment and heat treatment using equipment that has vacuum and heating functions. Such equipment is not particularly limited as long as it has vacuum and heating functions, but a specific example is the vacuum low-temperature cooking appliance sold by ESPEC Clear Lab Co., Ltd. under the product name "VidePro". Even when the raw vegetables include large vegetables, it is more preferable that the vacuum heating treatment in the manufacturing method of the present invention be carried out using a container that has vacuum resistance and heat resistance, from the viewpoint that the shape of the vegetables is easily maintained regardless of the type of vegetable, and therefore, in the manufacturing method of the present invention, it is preferable that the pectinase-containing liquid be filled into a container that has vacuum resistance and heat resistance.

[0037] The manufacturing method of the present invention may include subjecting the treated vegetables to cooking after vacuum heat treatment. When the manufacturing method of the present invention includes subjecting the treated vegetables to cooking after vacuum heat treatment, the cooking method is not particularly limited and may be carried out by a known method or a similar method depending on the type of vegetable dish, etc. Specific cooking methods include, but are not limited to, baking (roasting, stir-frying), boiling, simmering, steaming, deep-frying, microwave heating, hot air heating, infrared heating, oven heating, superheated steam heating, and combinations thereof. In one embodiment, when the cooking method includes boiling and simmering, the pectinase-containing liquid used in the vacuum heat treatment may be used for boiling and simmering. In other words, in the manufacturing method of the present invention, the reduced-pressure heat treatment can be performed by heat-treating raw vegetables immersed in a pectinase-containing solution having a specific pH under specific reduced-pressure conditions, as described above. However, after such reduced-pressure heat treatment, the treated vegetables may be boiled or simmered using the pectinase-containing solution used in the reduced-pressure heat treatment as a heat transfer medium. Various conditions for heating (e.g., temperature, time, etc.) are not particularly limited as long as they do not impair the purpose of the present invention, and may be set appropriately depending on the type of vegetable product, raw vegetables, and heating method. The pressure conditions during heating are also not particularly limited, and heating may be performed at atmospheric pressure, or under pressurized or reduced pressure as necessary.

[0038] The manufacturing method of the present invention may further include, in addition to the vacuum heating treatment and heating, cooking steps, etc., other than the vacuum heating treatment and heating, depending on the type of raw vegetables and vegetable products, etc., as long as the objective of the present invention is not impaired.

[0039] According to the manufacturing method of the present invention, raw vegetables can be effectively softened in a short time, and the resulting vegetable dish may contain softened vegetables. Therefore, the manufacturing method of the present invention may be a method for producing a vegetable dish containing softened vegetables. The manufacturing method of the present invention can effectively soften large raw vegetables (vegetables with at least one side measuring 2 cm or more) in a short time while maintaining their shape, and therefore, in one embodiment, it may be a method for producing a vegetable dish containing large vegetables, preferably a method for producing a vegetable dish containing softened large vegetables. Furthermore, the manufacturing method of the present invention can effectively soften raw vegetables in a short time regardless of the type of raw vegetable, and therefore, in one embodiment, it may be a method for producing a vegetable dish containing various vegetables (e.g., root vegetables, leafy and stem vegetables, fruit vegetables, fruity vegetables, spice vegetables, etc.), and preferably a method for producing a vegetable dish containing various softened vegetables. In the present invention, the degree of softening of the vegetables (i.e., the softness of the vegetables) can be evaluated by methods known in the present invention or by methods equivalent thereto. For example, the softness of the vegetables can be evaluated by sensory evaluation by a trained expert panel.

[0040] The present invention also provides a method for softening vegetables. The method for softening vegetables provided by the present invention may be referred to herein as "the softening method of the present invention." The softening method of the present invention includes immersing vegetables in a pectinase-containing solution having a specific pH and heating them under specific conditions.

[0041] The types of vegetables to which the softening method of the present invention can be used are not particularly limited and may be the same as the raw vegetables used in the manufacturing method of the present invention described above, and the preferred embodiments are also the same.

[0042] The vegetables to which the softening method of the present invention can be used are usually raw vegetables, similar to the raw vegetables used in the manufacturing method of the present invention described above. Furthermore, the shape of the vegetables to which the softening method of the present invention can be used is not particularly limited, similar to the raw vegetables used in the manufacturing method of the present invention described above. The size of the vegetables to which the softening method of the present invention can be used is not particularly limited, but it may be the same size as the raw vegetables used in the manufacturing method of the present invention described above, and the same is true for preferred sizes. The vegetables to which the softening method of the present invention can be used may have the inedible parts removed, or they may not have the inedible parts removed, similar to the raw vegetables used in the manufacturing method of the present invention described above.

[0043] The pectinase-containing solution used to immerse the vegetables in the softening method of the present invention may be the same as the pectinase-containing solution used to immerse the raw vegetables in the production method of the present invention described above, and the preferred embodiments and preparation methods are also the same.

[0044] In the softening method of the present invention, the heat treatment of vegetables immersed in a pectinase-containing solution having a specific pH can be carried out in the same manner as the reduced-pressure heat treatment (heat treatment under specific reduced-pressure conditions applied to raw vegetables) performed in the manufacturing method of the present invention described above, and the preferred embodiment is also the same.

[0045] The softening method of the present invention may include, similar to the manufacturing method of the present invention described above, subjecting the treated vegetables to cooking after a vacuum heating treatment.

[0046] The softening method of the present invention can effectively soften vegetables in a short time. Since the softening method of the present invention can effectively soften even large vegetables (vegetables with at least one side measuring 2 cm or more) in a short time while maintaining their shape, one embodiment may be a method for softening large vegetables. Furthermore, since the softening method of the present invention can effectively soften vegetables regardless of their type, one embodiment may be a method for softening various types of vegetables (e.g., root vegetables, leafy and stem vegetables, fruit vegetables, fruit-like vegetables, spice vegetables, etc.).

[0047] The present invention also provides a vegetable cooking kit comprising pectinase for preparing a pectinase-containing solution and a material for adjusting the pH of the pectinase-containing solution to 6.0 or higher. The vegetable cooking kit provided by the present invention may be referred to as "the kit of the present invention" in this specification, and the pectinase for preparing the pectinase-containing solution and the material for adjusting the pectinase-containing solution to a specific pH, which are included in the kit of the present invention, may be collectively referred to as "essential components of the kit of the present invention."

[0048] Among the essential components of the kit of the present invention, the pectinase used to prepare the pectinase-containing solution may be the same as that contained in the pectinase-containing solution in the production method of the present invention described above, and the preferred embodiments and preparation methods are also the same.

[0049] Among the essential components of the kit of the present invention, the material for adjusting the pectinase-containing solution to a specific pH may be the same as the substance used to adjust the pH of the pectinase-containing solution in the production method of the present invention described above, and the preferred embodiments are also the same.

[0050] The kit of the present invention may further comprise other food materials and food additives in addition to the essential components described above (pectinase for preparing a pectinase-containing solution and materials for adjusting the pectinase-containing solution to a specific pH). Specific examples of such food materials and food additives are the same as the specific examples of food materials and food additives optionally used in the pectinase-containing solution in the production method of the present invention described above.

[0051] In addition to the essential components of the kit of the present invention, a pectinase-containing solution having a specific pH can be prepared by further using at least water. This pectinase-containing solution may be the same as the pectinase-containing solution into which the raw vegetables are immersed in the production method of the present invention described above, and the preferred embodiments and preparation methods are also the same.

[0052] A pectinase-containing solution having a specific pH, prepared using at least the essential components of the kit of the present invention and water, is used to immerse vegetables and heat-treat them under specific conditions. The type of vegetables immersed in the pectinase-containing solution is not particularly limited and may be the same as the raw vegetables used in the manufacturing method of the present invention described above, and the preferred embodiment is the same. The vegetables immersed in the pectinase-containing solution are usually raw vegetables, similar to the raw vegetables used in the manufacturing method of the present invention described above. The shape of the vegetables immersed in the pectinase-containing solution is not particularly limited, similar to the raw vegetables used in the manufacturing method of the present invention described above. The size of the vegetables immersed in the pectinase-containing solution is not particularly limited, but may be the same as the raw vegetables used in the manufacturing method of the present invention described above, and the preferred size is the same. The vegetables immersed in the pectinase-containing solution may have the inedible parts removed, or they may not have the inedible parts removed, similar to the raw vegetables used in the manufacturing method of the present invention described above. The heat treatment of the vegetables can be carried out in the same manner as the reduced-pressure heat treatment (heat treatment applied to raw vegetables under specific reduced-pressure conditions) performed in the manufacturing method of the present invention described above, and the preferred embodiment is also the same.

[0053] Vegetables immersed in a pectinase-containing solution having a specific pH, prepared using at least the essential components of the kit of the present invention and water, may be subjected to cooking after heat treatment. The method of cooking is not particularly limited and may be the same as the cooking methods that can be performed in the manufacturing method of the present invention described above (cooking methods in which vegetables that have undergone vacuum heat treatment may be served), and the preferred embodiments are also the same.

[0054] The kit of the present invention allows vegetables to be softened and cooked effectively in a short time, thus enabling the production of vegetable dishes containing softened vegetables. Because the kit of the present invention allows for the effective softening and cooking of large vegetables (vegetables with at least one side measuring 2 cm or more) while maintaining their shape, the kit of the present invention may, in one embodiment, be a cooking kit for large vegetables. Furthermore, because the kit of the present invention can effectively soften and cook vegetables regardless of their type, the kit of the present invention may, in one embodiment, be a cooking kit for various vegetables (e.g., root vegetables, leafy and stem vegetables, fruit vegetables, fruit-like vegetables, spice vegetables, etc.).

[0055] The present invention also provides a vegetable immersion solution containing pectinase and having a specific pH. The vegetable immersion solution provided by the present invention may be referred to as "the solution of the present invention" in this specification.

[0056] The pectinase contained in the liquid of the present invention may be the same as that contained in the pectinase-containing liquid in the production method of the present invention described above, and the preferred embodiments and preparation methods are also the same.

[0057] The liquid of the present invention may be the same as the pectinase-containing liquid used to immerse the raw vegetables in the above-described method of production of the present invention, and the preferred embodiments and preparation methods are also the same.

[0058] The liquid of the present invention is for soaking vegetables, and the types of vegetables that can be soaked in the liquid of the present invention are not particularly limited and may be the same as the raw vegetables used in the manufacturing method of the present invention described above, and the preferred embodiments are also the same.

[0059] The vegetables immersed in the liquid of the present invention are usually raw vegetables, similar to the raw vegetables used in the manufacturing method of the present invention described above. Furthermore, the shape of the vegetables immersed in the liquid of the present invention is not particularly limited, similar to the raw vegetables used in the manufacturing method of the present invention described above. The size of the vegetables immersed in the liquid of the present invention is not particularly limited, but may be the same size as the raw vegetables used in the manufacturing method of the present invention described above, and preferred sizes are also the same. The vegetables immersed in the liquid of the present invention may have the inedible parts removed, or they may not have the inedible parts removed, similar to the raw vegetables used in the manufacturing method of the present invention described above.

[0060] The liquid of the present invention is used to heat-treat immersed vegetables under specific conditions. The heat treatment of the vegetables can be carried out in the same manner as the vacuum heat treatment (heat treatment under specific vacuum conditions applied to raw vegetables) performed in the manufacturing method of the present invention described above, and the preferred embodiment is also the same.

[0061] Vegetables immersed in the liquid of the present invention may be subjected to cooking after heat treatment. The method of cooking is not particularly limited and may be the same as the cooking methods that can be performed in the manufacturing method of the present invention described above (cooking methods in which vegetables that have undergone vacuum heat treatment may be served), and the preferred embodiments are also the same.

[0062] The liquid of the present invention can effectively soften vegetables in a short time. Therefore, the liquid of the present invention may be used for softening vegetables. In particular, since the liquid of the present invention can effectively soften even large vegetables (vegetables with at least one side measuring 2 cm or more) in a short time while maintaining their shape, it may, in one embodiment, be a immersion solution for large vegetables, or it may be used for softening large vegetables. Furthermore, since the liquid of the present invention can effectively soften vegetables regardless of their type, it may, in one embodiment, be a immersion solution for various vegetables (e.g., root vegetables, leafy and stem vegetables, fruit vegetables, fruity vegetables, spice vegetables, etc.), or it may be used for softening various vegetables.

[0063] The present invention will be described in more detail in the following examples, but the present invention is not limited in any way by these examples. Furthermore, unless otherwise specified, the raw materials used in the following examples are all commercially available for food use. The pH values ​​in the following examples were all measured using a commercially available pH meter at a liquid temperature of 25°C. Furthermore, in this specification, "%" refers to "weight%" unless otherwise specified. [Examples]

[0064] <Test 1> (Preparation of vegetable dishes) • Vegetable dishes from test area 1-1 Carrot dishes were prepared using the following procedure (1A) to (4A) (hereinafter also referred to as "vegetable dishes from test plot 1-1"). (1A) Preparation of raw vegetables For the vegetable dishes, the raw carrots used as ingredients were cut into 3cm cubes while still raw. (2A) Preparation of the vegetable soaking solution A vegetable soaking solution was prepared by mixing 150g of water and 50g of commercially available noodle soup base (manufactured by Yamaki Co., Ltd., product name "Mentsuyu") in a stainless steel mug. The pH of the solution was 5.2. (3A) Immersion of raw vegetables in vegetable pickling solution and setting of the solution into the cooking device Three pieces of raw vegetables (carrots cut into cubes) prepared in procedure (1A) were placed in the mug prepared in procedure (2A) and immersed in the vegetable soaking solution prepared in procedure (2A). Next, the mug was placed in the pot of a cooking appliance (manufactured by ESPEC Clear Lab Co., Ltd., product name "Veedo Pro") which has a vacuum and heating function, and the pot was covered with a lid. In order to improve heat conductivity, a small amount of water was placed in the pot of the cooking appliance beforehand, just enough so that the mugs placed in the pot would not float. (4A) Heat treatment and cooking The mug set in the cooking device in the above procedure (3A) was heated at 70°C for 10 minutes at atmospheric pressure (i.e., gauge pressure 0 kPa). Then, it was heated at 90°C for 15 minutes at atmospheric pressure. After heating, the vegetables (carrots) were removed from the mug to obtain the cooked carrot product.

[0065] • Vegetable dishes from test area 1-2 In the procedure described above (4A), the carrot dish was prepared using the same procedure as in Test Section 1-1, except that instead of heating the mug set in the cooker at atmospheric pressure (i.e., gauge pressure 0 kPa) at 70°C for 10 minutes at 70°C, it was heated under reduced pressure of -70 kPa gauge pressure for 10 minutes. (This will also be referred to below as "Test Section 1-2 vegetable dish").

[0066] • Vegetable dishes from test area 1-3 In the procedure described above (2A), 150g of water and 50g of commercially available noodle soup base (manufactured by Yamaki Co., Ltd., product name "Noodle Soup Base") were added to a stainless steel mug and mixed. After mixing, the pH of the solution was adjusted to 4.0 using tartaric acid (manufactured by Showa Chemical Co., Ltd., product name "L-Tartaric Acid"). In the procedure described above (4A), instead of heating the mug set in the cooker at 70°C for 10 minutes at atmospheric pressure (i.e., gauge pressure 0kPa) at 70°C, the carrot dish was prepared using the same procedure as in Test Section 1-1 (hereinafter also referred to as "Test Section 1-3 vegetable dish").

[0067] • Vegetable dishes from test area 1-4 In the procedure described above (2A), 150g of water and 50g of commercially available noodle soup base (manufactured by Yamaki Co., Ltd., product name "Noodle Soup Base") were added to a stainless steel mug and mixed. The pH of the solution was then adjusted to 7.0 using sodium carbonate (manufactured by Air Water Performance Chemical Co., Ltd., product name "Purified Sodium Carbonate (Anhydrous)"), and in the procedure described above (4A), instead of heating the mug set in the cooker at 70°C for 10 minutes at atmospheric pressure (i.e., gauge pressure 0kPa) at 70°C, the carrot dish was prepared using the same procedure as in Test Section 1-1 (hereinafter also referred to as "Test Section 1-4 vegetable dish").

[0068] • Vegetable dishes from test plots 1 and 5 In the procedure described above (2A), 150g of water and 50g of commercially available noodle soup base (manufactured by Yamaki Co., Ltd., product name "Noodle Soup Base") were added to a stainless steel mug and mixed. The pH of the solution was then adjusted to 8.0 using sodium carbonate (manufactured by Air Water Performance Chemical Co., Ltd., product name "Purified Sodium Carbonate (Anhydrous)"), and in the procedure described above (4A), instead of heating the mug set in the cooker at 70°C for 10 minutes at atmospheric pressure (i.e., gauge pressure 0kPa) at 70°C, the carrot dish was prepared using the same procedure as in Test Section 1-1 (hereinafter also referred to as "Test Section 1-5 vegetable dish").

[0069] • Vegetable dishes from test plots 1 and 6 In the procedure described above (2A), 150g of water and 50g of commercially available noodle soup base (manufactured by Yamaki Co., Ltd., product name "Mentsuyu") were added to a stainless steel mug and mixed. Then, cellulase (manufactured by Amano Enzyme Co., Ltd., product name "Cellulase T "Amano" 4") was added to the liquid in an amount equivalent to 0.1% by weight relative to the raw vegetables and dissolved. Furthermore, in the procedure described above (4A), instead of heating the mug set in the cooker at 70°C for 10 minutes at atmospheric pressure (i.e., gauge pressure 0kPa) for 10 minutes, the carrot dish was prepared using the same procedure as in Test Section 1-1 (hereinafter also referred to as "Test Section 1-6 vegetable dish").

[0070] • Vegetable dishes from test plots 1 and 7 In the procedure described above (2A), 150g of water and 50g of commercially available noodle soup base (manufactured by Yamaki Co., Ltd., product name "Mentsuyu") were added to a stainless steel mug and mixed. Then, hemicellulase (manufactured by Amano Enzyme Co., Ltd., product name "Hemicellulase "Amano" 90") was added to the liquid in an amount equivalent to 0.1% by weight relative to the raw vegetables and dissolved. Furthermore, in the procedure described above (4A), instead of heating the mug set in the cooker at 70°C for 10 minutes at atmospheric pressure (i.e., gauge pressure 0kPa) for 10 minutes, the carrot dish was prepared using the same procedure as in Test Section 1-1 (hereinafter also referred to as "Test Section 1-7 vegetable dish").

[0071] • Vegetable dishes from test plots 1 and 8 In the procedure described above (2A), 150g of water and 50g of commercially available noodle soup base (manufactured by Yamaki Co., Ltd., product name "Mentsuyu") were added to a stainless steel mug and mixed. Then, pectinase (manufactured by Nagase ChemteX Corporation, product name "Pectinase XP-534NEO", activity of 5700U per gram of enzyme) was added to the liquid in an amount equivalent to 0.1% by weight relative to the raw vegetables (equivalent to 5.7U per gram of raw vegetables) and dissolved. Furthermore, in the procedure described above (4A), instead of heating the mug set in the cooker at 70°C for 10 minutes at atmospheric pressure (i.e., gauge pressure of 0kPa) for 10 minutes, the carrot dish was prepared using the same procedure as in Test Section 1-1 (hereinafter also referred to as "Test Section 1-8 vegetable dish").

[0072] (Sensory evaluation) A panel of experts conducted a sensory evaluation of the softness of the vegetable dishes (carrot softness) in test sections 1-1 to 1-8 using a scoring system. The expert panel consisted of three panelists well-versed in food texture, and the scoring was determined in 0.1-point increments based on the following scale, with the agreement of all panelists. The expert panel was also trained in advance to ensure that all panelists shared a common understanding of the evaluation scale described below. [Scale for evaluating softness] 1 point: Hard 2 points: Slightly soft 3 points: Soft 4 points: Very soft 5 points: Extremely soft

[0073] The evaluation results are shown in Table 1 below.

[0074] [Table 1]

[0075] As shown in Table 1, compared to the vegetable preparation in Test Section 1-1, where the vegetables were heat-treated at atmospheric pressure (gauge pressure 0 kPa), the vegetable preparation in Test Section 1-2, where the vegetables were heat-treated at reduced pressure (gauge pressure -70 kPa), scored higher in softness, indicating accelerated softening of the vegetables. Furthermore, the vegetable preparations in Test Sections 1-4 and 1-5, where the pH of the vegetable immersion solution was adjusted to 7.0 or 8.0 and the vegetables were heat-treated at reduced pressure (gauge pressure -70 kPa), scored even higher in softness than the vegetable preparation in Test Section 1-2. In the vegetable preparations from test groups 1-6 to 1-8, where enzymes capable of breaking down plant tissue structure (cellulase, hemicellulase, or pectinase) were added to the vegetable immersion solution and the vegetables were heat-treated under reduced pressure of -70 kPa, the vegetable preparations scored higher in terms of vegetable softness compared to the vegetable preparation from test group 1-2. In particular, the vegetable preparations from test group 1-8, where pectinase was added to the vegetable immersion solution, scored higher. These results suggest that when vegetables are heat-treated by immersion in a liquid, the softening of the vegetables is promoted by performing the heat treatment under reduced pressure, adjusting the immersion solution to be neutral to alkaline, and adding pectinase to the immersion solution.

[0076] <Exam 2> (Preparation of vegetable dishes) • Vegetable dishes from test area 2-1 Carrot dishes were prepared using the following procedure (1B) to (4B) (hereinafter also referred to as "vegetable dishes from test plot 2-1"). (1B) Preparation of raw vegetables For the vegetable dishes, the raw carrots used as ingredients were cut into 3cm cubes while still raw. (2B) Preparation of the vegetable soaking solution A vegetable soaking solution was prepared by mixing 150g of water and 50g of commercially available noodle soup base (manufactured by Yamaki Co., Ltd., product name "Mentsuyu") in a stainless steel mug. The pH of the solution was 5.2. (3B) Immersion of raw vegetables in vegetable pickling solution and setting of the solution into the cooking device Three pieces of raw vegetables (carrots cut into cubes) prepared in procedure (1B) were placed in the mug prepared in procedure (2B) and immersed in the vegetable soaking solution prepared in procedure (2B). Next, the mug was placed in the pot of a cooking appliance (manufactured by ESPEC Clear Lab Co., Ltd., product name "Veedo Pro") which has a vacuum and heating function, and the pot was covered with a lid. In order to improve heat conductivity, a small amount of water was placed in the pot of the cooking appliance beforehand, just enough so that the mugs placed in the pot would not float. (4B) Heat treatment and cooking The mug set in the cooking device in the above procedure (3B) was heated at 70°C for 10 minutes under reduced pressure of -70kPa gauge pressure. Then, it was heated at 90°C for 15 minutes under normal pressure. After heating, the vegetables (carrots) were removed from the mug to obtain the cooked carrot product.

[0077] • Vegetable dishes from test area 2-2 In the procedure described above (2B), 150g of water and 50g of commercially available noodle soup base (manufactured by Yamaki Co., Ltd., product name "Mentsuyu") were added to a stainless steel jug and mixed. Then, the pH of the solution was adjusted to 7.5 using sodium carbonate (manufactured by Air Water Performance Chemical Co., Ltd., product name "Purified Sodium Carbonate (Anhydrous)"), except that the carrot dish was prepared using the same procedure as in Test Section 2-1 (hereinafter also referred to as "Test Section 2-2 vegetable dish").

[0078] • Vegetable dishes from test area 2-3 In the procedure described above (2B), 150g of water and 50g of commercially available noodle soup base (manufactured by Yamaki Co., Ltd., product name "Mentsuyu") were added to a stainless steel jug and mixed. Then, pectinase (manufactured by Nagase ChemteX Corporation, product name "Pectinase XP-534NEO", activity of 5700U per gram of enzyme) was added to the solution in an amount equivalent to 0.1% by weight relative to the raw vegetables (equivalent to 5.7U per gram of raw vegetables) and dissolved. Otherwise, a carrot dish was prepared using the same procedure as in Test Section 2-1 (hereinafter also referred to as "Test Section 2-3 vegetable dish").

[0079] • Vegetable dishes from test area 2-4 In the procedure described above (2B), 150g of water and 50g of commercially available noodle soup base (manufactured by Yamaki Co., Ltd., product name "Mentsuyu") were added to a stainless steel jug and mixed. Then, pectinase (manufactured by Nagase ChemteX Corporation, product name "Pectinase XP-534NEO", activity of 5700U per gram of enzyme) was added to the solution in an amount equivalent to 0.1% by weight relative to the raw vegetables (equivalent to 5.7U per gram of raw vegetables) and dissolved. The pH of the solution was also adjusted to 7.5 using sodium carbonate (manufactured by Air Water Performance Chemical Co., Ltd., product name "Purified Sodium Carbonate (Anhydrous)"), but the carrot dish was prepared using the same procedure as in Test Section 2-1 (hereinafter also referred to as "Test Section 2-4 vegetable dish").

[0080] • Vegetable dishes from test area 2-5 In the above procedure (2B), 150g of water and 50g of commercially available noodle soup base (manufactured by Yamaki Co., Ltd., product name "Mentsuyu") are added to a stainless steel jug and mixed. Then, pectinase (manufactured by Nagase ChemteX Corporation, product name "Pectinase XP-534NEO", activity of 5700U per gram of enzyme) is added to the solution in an amount equivalent to 0.1% by weight of the raw vegetables (equivalent to 5.7U per gram of raw vegetables) and dissolved. The pH of the solution is then adjusted using sodium carbonate (air-water). Carrot dishes were prepared using the same procedure as in Test Section 2-1, except that the pH was adjusted to 7.5 using "Purified Sodium Carbonate (Anhydrous)" manufactured by Water Performance Chemicals Co., Ltd., and in the procedure (4B) described above, the jug set in the cooker was heated at 70°C for 10 minutes at atmospheric pressure (i.e., gauge pressure 0 kPa) instead of being heated at 70°C for 10 minutes under reduced pressure of gauge pressure -70 kPa. (Hereafter referred to as "Test Section 2-5 vegetable dishes").

[0081] • Vegetable dishes from test area 2-6 In the procedure described above (2B), 150g of water and 50g of commercially available noodle soup base (manufactured by Yamaki Co., Ltd., product name "Mentsuyu") were added to a stainless steel jug and mixed. Then, cellulase (manufactured by Amano Enzyme Co., Ltd., product name "Cellulase T "Amano" 4") was added to the liquid in an amount equivalent to 0.1% by weight relative to the raw vegetables and dissolved. Except for this, the carrot dish was prepared in the same manner as in Test Section 2-1 (hereinafter also referred to as "Test Section 2-6 vegetable dish").

[0082] • Vegetable dishes from test area 2-7 In the procedure described above (2B), 150g of water and 50g of commercially available noodle soup base (manufactured by Yamaki Co., Ltd., product name "Mentsuyu") were added to a stainless steel jug and mixed. Then, cellulase (manufactured by Amano Enzyme Co., Ltd., product name "Cellulase T "Amano" 4") was added to the solution in an amount equivalent to 0.1% by weight relative to the raw vegetables and dissolved. The pH of the solution was also adjusted to 7.5 using sodium carbonate (manufactured by Air Water Performance Chemical Co., Ltd., product name "Purified Sodium Carbonate (Anhydrous)"), but otherwise, a carrot dish was prepared using the same procedure as in Test Section 2-1 (hereinafter also referred to as "Test Section 2-7 vegetable dish").

[0083] • Vegetable dishes from test area 2-8 In the procedure described above (2B), 150g of water and 50g of commercially available noodle soup base (manufactured by Yamaki Co., Ltd., product name "Mentsuyu") were added to a stainless steel jug and mixed. Then, hemicellulase (manufactured by Amano Enzyme Co., Ltd., product name "Hemicellulase "Amano" 90") was added to the liquid in an amount equivalent to 0.1% by weight relative to the raw vegetables and dissolved. Except for this, the carrot dish was prepared in the same manner as in Test Section 2-1 (hereinafter also referred to as "Test Section 2-8 vegetable dish").

[0084] • Vegetable dishes from test area 2-9 In the procedure described above (2B), 150g of water and 50g of commercially available noodle soup base (manufactured by Yamaki Co., Ltd., product name "Noodle Soup Base") were added to a stainless steel jug and mixed. Then, hemicellulase (manufactured by Amano Enzyme Co., Ltd., product name "Hemicellulase "Amano" 90") was added to the solution in an amount equivalent to 0.1% by weight relative to the raw vegetables and dissolved. The pH of the solution was also adjusted to 7.5 using sodium carbonate (manufactured by Air Water Performance Chemical Co., Ltd., product name "Purified Sodium Carbonate (Anhydrous)"), except that the carrot dish was prepared using the same procedure as in Test Section 2-1 (hereinafter also referred to as "Test Section 2-9 vegetable dish").

[0085] (Sensory evaluation) The softness of the vegetable dishes in test sections 2-1 to 2-9 (specifically the softness of the carrots) was evaluated by a panel of experts using a scoring system, similar to the method used in Test 1. The evaluation results are shown in Table 2 below.

[0086] [Table 2]

[0087] As shown in Table 2, the vegetable preparation in Test Group 2-2, where the pH of the vegetable immersion solution was adjusted to 7.5 and the vegetables were heat-treated under reduced pressure of -70kPa, scored higher in vegetable tenderness compared to the vegetable preparation in Test Group 2-1, where the pH of the vegetable immersion solution was not adjusted and the vegetables were heat-treated under reduced pressure of -70kPa. Similarly, the vegetable preparation in Test Group 2-3, where pectinase was added to the vegetable immersion solution and the vegetables were heat-treated under reduced pressure of -70kPa, also scored higher in vegetable tenderness. Furthermore, the vegetable preparation in Test Group 2-4, where pectinase was added to the vegetable immersion solution, the pH was adjusted to 7.5, and the vegetables were heat-treated under reduced pressure of -70kPa, showed a significantly higher score in vegetable tenderness. In the vegetable dish in test section 2-2, the softness score was "2.0," a difference of "0.5" points (2.0 - 1.5 = 0.5 points) from the score in test section 2-1. Similarly, in the vegetable dish in test section 2-3, the softness score was "1.9," a difference of "0.4" points (1.9 - 1.5 = 0.4 points). However, in contrast to these, the softness score of the vegetable dish in test section 2-4 was "4.5," a difference of "3.0" points (4.5 - 1.5 = 3.0 points) from the score in test section 2-1. This significantly exceeded the sum of the differences between the scores in test sections 2-2 and 2-3 and test section 2-1, which was "0.9" points (0.5 + 0.4 = 0.9 points). Therefore, it was suggested that the vegetable softening-promoting effect obtained in test section 2-4 (i.e., the test section in which pectinase was added to the vegetable immersion solution, the pH was adjusted to 7.5, and the vegetables were heat-treated under reduced pressure) was not an additive effect, but rather a synergistic effect, of the vegetable softening-promoting effect obtained in test section 2-2 (i.e., the test section in which the pH of the vegetable immersion solution was adjusted to 7.5 and the vegetables were heat-treated under reduced pressure) and the vegetable softening-promoting effect obtained in test section 2-3 (the test section in which pectinase was added to the vegetable immersion solution and the vegetables were heat-treated under reduced pressure).Furthermore, in test group 2-5, where pectinase was added to the vegetable immersion solution and the pH was adjusted to 7.5, and the vegetables were heat-treated at atmospheric pressure, the softness score of the vegetables was a low "1.8". This suggests that the synergistic effect of promoting vegetable softening obtained in test group 2-4 is obtained when the vegetables are heat-treated under reduced pressure. In summary, immersing vegetables in a pectinase-containing solution adjusted to a neutral to alkaline range and then heat-treating them under reduced pressure significantly promotes vegetable softening, and this vegetable softening effect is suggested to be synergistic. It is also suggested that this effect is not obtained when the vegetables are heat-treated at atmospheric pressure, but is obtained when the vegetables are heat-treated under reduced pressure.

[0088] <Exam 3> (Preparation of vegetable dishes) • Vegetable dishes from test area 3-1 Carrot dishes were prepared using the following procedure (1C) to (4C) (hereinafter also referred to as "vegetable dishes from test plot 3-1"). (1C) Preparation of raw vegetables For the vegetable dishes, the raw carrots used as ingredients were cut into 3cm cubes while still raw. (2C) Preparation of vegetable soaking solution In a stainless steel jug, 150g of water and 50g of commercially available noodle soup base (manufactured by Yamaki Co., Ltd., product name "Mentsuyu") were added and mixed. Then, pectinase (manufactured by Nagase ChemteX Corporation, product name "Pectinase XP-534NEO", activity of 5700U per gram of enzyme) was added to the solution in an amount equivalent to 0.1% by weight relative to the raw vegetables (equivalent to 5.7U per gram of raw vegetables) and dissolved. The pH of the solution was then adjusted to 7.5 using sodium carbonate (manufactured by Air Water Performance Chemical Co., Ltd., product name "Purified Sodium Carbonate (Anhydrous)") to prepare the vegetable soaking solution. (3C) Immersion of raw vegetables in vegetable pickling solution and setting of the solution into the cooking device Three pieces of raw vegetables (carrots cut into cubes) prepared in procedure (1C) were placed in the mug prepared in procedure (2C) and immersed in the vegetable soaking solution prepared in procedure (2C). Next, the mug was placed in the pot of a cooking appliance (manufactured by ESPEC Clear Lab Co., Ltd., product name "Veedo Pro") which has a vacuum and heating function, and the pot was covered with a lid. In order to improve heat conductivity, a small amount of water was placed in the pot of the cooking appliance beforehand, just enough so that the mugs placed in the pot would not float. (4C) Heat treatment and cooking The mug set in the cooking device in the above procedure (3C) was heated at 70°C for 10 minutes at atmospheric pressure (i.e., gauge pressure 0 kPa). Then, it was heated at 90°C for 15 minutes at atmospheric pressure. After heating, the vegetables (carrots) were removed from the mug to obtain the cooked carrot product.

[0089] • Vegetable dishes from test area 3-2 In the procedure described above (4C), instead of heating the mug set in the cooker at atmospheric pressure (i.e., gauge pressure 0 kPa) at 70°C for 10 minutes, the carrot dish was prepared using the same procedure as in Test Section 3-1, except that a reduced pressure of -70 kPa was maintained at 25°C for 10 minutes, followed by heating at atmospheric pressure (i.e., gauge pressure 0 kPa) at 70°C for 10 minutes. (Hereafter referred to as "Test Section 3-2 vegetable dish").

[0090] • Vegetable dishes from test area 3-3 In the procedure described above (4C), the carrot dish was prepared using the same procedure as in Test Section 3-1, except that instead of heating the jug set in the cooker at atmospheric pressure (i.e., gauge pressure 0 kPa) at 70°C for 10 minutes at 70°C, it was heated under reduced pressure of -70 kPa gauge pressure for 10 minutes. (This will also be referred to below as "Test Section 3-3 vegetable dish").

[0091] (Sensory evaluation) The softness of the vegetable dishes in test sections 3-1 to 3-3 (specifically the softness of the carrots) was evaluated by a panel of experts using a scoring system, similar to the method used in Test 1. The evaluation results are shown in Table 3 below.

[0092] [Table 3]

[0093] As shown in Table 3, in Test Group 3-1, the vegetable preparation, in which pectinase was added to the vegetable immersion solution, the pH was adjusted to 7.5, and the vegetables were heat-treated at atmospheric pressure, received a low score for vegetable tenderness. Similarly, in Test Group 3-2, the vegetable preparation, in which pectinase was added to the vegetable immersion solution, the pH was adjusted to 7.5, a reduced pressure of -70kPa was maintained at 25°C, and then the vegetables were heated at atmospheric pressure, also received a low score for vegetable tenderness, similar to Test Group 3-1. On the other hand, in Test Group 3-3, the vegetable preparation, in which pectinase was added to the vegetable immersion solution, the pH was adjusted to 7.5, and the vegetables were heat-treated under reduced pressure of -70kPa, received a significantly higher score for vegetable tenderness. These results suggest that the excellent vegetable softening effect obtained by immersing vegetables in a pectinase-containing solution adjusted to a neutral to alkaline range and then heating them under reduced pressure is not sufficiently achieved when the vegetables are not heated. Therefore, it is considered important to perform the heat treatment of vegetables under reduced pressure at a moderate temperature of around 70°C in order to obtain this excellent effect.

[0094] <Exam 4> (Preparation of vegetable dishes) • Vegetable dishes from test plots 4-1 and 4-2 Each carrot dish was prepared using the following procedure (1D) to (4D) (hereinafter referred to as "vegetable dish from test plot 4-1" and "vegetable dish from test plot 4-2," respectively). (1D) Preparation of raw vegetables For the vegetable dishes, the raw carrots used as ingredients were cut into 3cm cubes while still raw. (2D) Preparation of vegetable soaking solution In a stainless steel jug, 150g of water and 50g of commercially available noodle soup base (manufactured by Yamaki Co., Ltd., product name "Mentsuyu") were added and mixed. Then, pectinase (manufactured by Nagase ChemteX Corporation, product name "Pectinase XP-534NEO", activity of 5700U per gram of enzyme) was added to the solution in an amount equivalent to 0.1% by weight relative to the raw vegetables (equivalent to 5.7U per gram of raw vegetables) and dissolved. The pH of the solution was then adjusted using tartaric acid (manufactured by Showa Chemical Co., Ltd., product name "L-Tartaric Acid") to the pH shown in Table 4 below, thereby preparing the vegetable soaking solution. (3D) Immersion of raw vegetables in vegetable pickling solution and setting of the solution into the cooking device. Three pieces of raw vegetables (carrots cut into cubes) prepared in procedure (1D) were placed in the mug prepared in procedure (2D) and immersed in the vegetable soaking solution prepared in procedure (2D). Next, the mug was placed in the pot of a cooking appliance (manufactured by ESPEC Clear Lab Co., Ltd., product name "Veedo Pro") which has a vacuum and heating function, and the pot was covered with a lid. In order to improve heat conductivity, a small amount of water was placed in the pot of the cooking appliance beforehand, just enough so that the mugs placed in the pot would not float. (4D) Heat treatment and cooking The mug set in the cooking device according to the above procedure (3D) was heated at 70°C for 10 minutes under reduced pressure of -70kPa gauge pressure. Then, it was heated at 90°C for 15 minutes under normal pressure. After heating, the vegetables (carrots) were removed from the mug to obtain the cooked carrot product.

[0095] • Vegetable dishes from test plots 4-3 to 4-7 In the procedure described above (2D), instead of using tartaric acid (manufactured by Showa Chemical Co., Ltd., product name "L-tartaric acid"), sodium carbonate (manufactured by Air Water Performance Chemical Co., Ltd., product name "purified sodium carbonate (anhydrous)") was used to adjust the pH of the vegetable soaking solution to the pH shown in Table 4 below. Otherwise, each carrot dish was prepared using the same procedure as in Test Sections 4-1 and 4-2 (hereinafter also referred to as "Test Section 4-3 dish" to "Test Section 4-7 dish," respectively).

[0096] (Sensory evaluation) The softness of the vegetable dishes in test sections 4-1 to 4-7 (specifically the softness of the carrots) was evaluated by a panel of experts using a scoring system, similar to the method used in Test 1. The evaluation results are shown in Table 4 below.

[0097] [Table 4]

[0098] As shown in Table 4, the vegetable preparations in test groups 4-1 and 4-2, where the pH of the vegetable immersion solution was adjusted to 4.0 or 5.0 and the vegetables were heat-treated under reduced pressure, received low scores for vegetable tenderness. In contrast, the vegetable preparations in test groups 4-3 to 4-7, where the pH of the vegetable immersion solution was adjusted to 6.0 to 8.0 and the vegetables were heat-treated under reduced pressure, all received high scores for vegetable tenderness. From these results, it was concluded that the excellent vegetable tenderization effect obtained by immersing vegetables in a pectinase-containing solution adjusted to a neutral to alkaline range and then heat-treating them under reduced pressure is not sufficiently obtained if the immersion solution is not adjusted to a neutral to alkaline range. Therefore, it is considered important to adjust the immersion solution to a neutral to alkaline range (preferably pH 6.0 or higher, more preferably 6.5 or higher) in order to obtain this excellent effect.

[0099] <Test 5> (Preparation of vegetable dishes) • Vegetable dishes from test plots 5-1 to 5-13 Each carrot dish was prepared according to the following procedures (1E) to (4E) (hereinafter referred to as "vegetable dish from test plot 5-1" to "vegetable dish from test plot 5-13," respectively). (1E) Preparation of raw vegetables For the vegetable dishes, the raw carrots used as ingredients were cut into 3cm cubes while still raw. (2E) Preparation of the vegetable soaking solution In a stainless steel mug, 150g of water and 50g of commercially available noodle soup base (manufactured by Yamaki Co., Ltd., product name "Mentsuyu") were added and mixed. Then, pectinase (manufactured by Nagase ChemteX Corporation, product name "Pectinase XP-534NEO", enzyme activity of 5700U per gram) was added to the solution in the amount shown in Table 5 below relative to the raw vegetables and dissolved. The pH of the solution was then adjusted to 7.5 using sodium carbonate (manufactured by Air Water Performance Chemical Co., Ltd., product name "Purified Sodium Carbonate (Anhydrous)") to prepare the vegetable soaking solution. (3E) Immersion of raw vegetables in vegetable pickling solution and setting of the solution into the cooking device Three pieces of raw vegetables (carrots cut into cubes) prepared in the procedure (1E) were placed in the mug prepared in the procedure (2E) and immersed in the vegetable soaking solution prepared in the procedure (2E). Next, the mug was placed in the pot of a cooking appliance (manufactured by ESPEC Clear Lab Co., Ltd., product name "Veedo Pro") which has a vacuum and heating function, and the pot was covered with a lid. In order to improve heat conductivity, a small amount of water was placed in the pot of the cooking appliance beforehand, just enough so that the mugs placed in the pot would not float. (4E) Heat treatment and cooking The mug set in the cooker in the above procedure (3E) was heated at 70°C for 10 minutes under reduced pressure of -70kPa gauge pressure. Then, it was heated at 90°C for 15 minutes under normal pressure. After heating, the vegetables (carrots) were removed from the mug to obtain the cooked carrot product.

[0100] (Sensory evaluation) The softness of the vegetable dishes in test sections 5-1 to 5-13 (specifically the softness of the carrots) was evaluated by a panel of experts using a scoring system, similar to the method used in Test 1. The evaluation results are shown in Table 5 below.

[0101] [Table 5]

[0102] As shown in Table 5, the vegetable preparations in test groups 5-2 to 5-13, in which pectinase was added to the vegetable soaking solution in an amount of 0.0285 to 1710.0 U per gram of raw vegetables and then the vegetables were heat-treated under reduced pressure, all scored highly for vegetable tenderness. In test groups 5-12 and 5-13, in which pectinase was added to the vegetable soaking solution in an amount of 1140.0 U or 1710.0 U per gram of raw vegetables and then the vegetables were heat-treated under reduced pressure, the vegetable preparations showed a tendency for the vegetables to break down slightly, but the scores for vegetable tenderness were remarkably high. These results suggest that the excellent vegetable softening effect obtained by immersing vegetables in a pectinase-containing solution adjusted to a neutral to alkaline range and then heating them under reduced pressure is preferably achieved when the amount of pectinase added to the solution in which the vegetables are immersed is 0.03 U or more per gram of vegetables before heating, more preferably 0.03 to 1500 U, and even more preferably 0.05 to 1000 U.

[0103] <Exam 6> (Preparation of vegetable dishes) • Vegetable dishes from test plots 6-1 to 6-5 Each carrot dish was prepared according to the following procedure (1F) to (4F) (hereinafter referred to as "vegetable dish from test plot 6-1" or "vegetable dish from test plot 6-5," respectively). (1F) Preparation of raw vegetables For the vegetable dishes, the raw carrots used as ingredients were cut into 3cm cubes while still raw. (2F) Preparation of vegetable soaking solution In a stainless steel jug, 150g of water and 50g of commercially available noodle soup base (manufactured by Yamaki Co., Ltd., product name "Mentsuyu") were added and mixed. Then, pectinase (manufactured by Nagase ChemteX Corporation, product name "Pectinase XP-534NEO", activity of 5700U per gram of enzyme) was added to the solution in an amount equivalent to 0.1% by weight relative to the raw vegetables (equivalent to 5.7U per gram of raw vegetables) and dissolved. The pH of the solution was then adjusted to 7.5 using sodium carbonate (manufactured by Air Water Performance Chemical Co., Ltd., product name "Purified Sodium Carbonate (Anhydrous)") to prepare the vegetable soaking solution. (3F) Immersion of raw vegetables in vegetable pickling solution and setting of the solution into the cooking device Three pieces of raw vegetables (carrots cut into cubes) prepared in the above procedure (1F) were placed in the jug from the above procedure (2F) and immersed in the vegetable soaking solution prepared in the above procedure (2F). Next, the jug was placed in the pot of a cooking appliance (manufactured by ESPEC Clear Lab Co., Ltd., product name "Veedo Pro") which has a vacuum and heating function, and the pot was covered with a lid. In order to improve heat conductivity, a small amount of water was placed in the pot of the cooking appliance beforehand, just enough so that the jug would not float. (4F) Heat treatment and cooking The mug set in the cooking device in the procedure described above (3F) was heated at 70°C for 10 minutes under reduced pressure as shown in Table 6 below. Then, it was heated at 90°C for 15 minutes under normal pressure. After heating, the vegetables (carrots) were removed from the mug to obtain the cooked carrot product.

[0104] (Sensory evaluation) The softness of the vegetable dishes in test sections 6-1 to 6-5 (specifically the softness of the carrots) was evaluated by a panel of experts using a scoring system, similar to the method used in Test 1. The evaluation results are shown in Table 6 below.

[0105] [Table 6]

[0106] As shown in Table 6, the vegetable dishes in Test Group 6-1, which were heat-treated under reduced pressure of a gauge pressure of -45 kPa, scored slightly lower in terms of vegetable tenderness, while the vegetable dishes in Test Groups 6-2 to 6-5, which were heat-treated under reduced pressure of a gauge pressure of -50 to -70 kPa, all scored highly in terms of vegetable tenderness. From these results, it was considered that the excellent vegetable tenderization effect obtained by immersing vegetables in a pectinase-containing solution adjusted to a neutral to alkaline range and heat-treating them under reduced pressure is preferably achieved when the pressure (gauge pressure) during the heat treatment is -50 kPa or less, more preferably -55 kPa or less, and even more preferably -60 kPa or less.

[0107] <Exam 7> (Preparation of vegetable dishes) • Vegetable dishes from test plots 7-1 to 7-7 Each carrot dish was prepared using the following procedure (1G) to (4G) (hereinafter referred to as "vegetable dish from test plot 7-1" or "vegetable dish from test plot 7-7," respectively). (1G) Preparation of raw vegetables For the vegetable dishes, the raw carrots used as ingredients were cut into 3cm cubes while still raw. (2G) Preparation of vegetable soaking solution In a stainless steel jug, 150g of water and 50g of commercially available noodle soup base (manufactured by Yamaki Co., Ltd., product name "Mentsuyu") were added and mixed. Then, pectinase (manufactured by Nagase ChemteX Corporation, product name "Pectinase XP-534NEO", activity of 5700U per gram of enzyme) was added to the solution in an amount equivalent to 0.1% by weight relative to the raw vegetables (equivalent to 5.7U per gram of raw vegetables) and dissolved. The pH of the solution was then adjusted to 7.5 using sodium carbonate (manufactured by Air Water Performance Chemical Co., Ltd., product name "Purified Sodium Carbonate (Anhydrous)") to prepare the vegetable soaking solution. (3G) Immersion of raw vegetables in vegetable pickling solution and setting of the solution into the cooking device. Three pieces of raw vegetables (carrots cut into cubes) prepared in the procedure (1G) were placed in the jug prepared in the procedure (2G) and immersed in the vegetable soaking solution prepared in the procedure (2G). Next, the jug was placed in the pot of a cooking appliance (manufactured by ESPEC Clear Lab Co., Ltd., product name "Veedo Pro") which has a vacuum and heating function, and the pot was covered with a lid. In order to improve heat conductivity, a small amount of water was placed in the pot of the cooking appliance beforehand, just enough so that the jug would not float. (4G) Heat treatment and cooking The mug set in the cooker in the above procedure (3G) was heated under reduced pressure of -70kPa gauge pressure for 10 minutes at the temperatures shown in Table 7 below. Then, it was heated at atmospheric pressure at 90°C for 15 minutes. After heating, the vegetables (carrots) were removed from the mug to obtain the cooked carrot product.

[0108] (Sensory evaluation) The softness of the vegetable dishes in test sections 7-1 to 7-7 (specifically the softness of the carrots) was evaluated by a panel of experts using a scoring system, similar to the method used in Test 1. The evaluation results are shown in Table 7 below.

[0109] [Table 7]

[0110] As shown in Table 7, the vegetable preparation in Test Group 7-1, where vegetables were heat-treated under reduced pressure at a liquid temperature (temperature of the liquid in which pectinase was added and vegetables were immersed) of 35°C, had a slightly lower score for vegetable tenderness. In contrast, the vegetable preparations in Test Groups 7-2 to 7-7, where vegetables were heat-treated under reduced pressure at a liquid temperature of 40-70°C, all had high scores for vegetable tenderness. From these results, it was concluded that the excellent vegetable tenderization effect obtained by immersing vegetables in a pectinase-containing liquid adjusted to a neutral to alkaline range and heat-treating them under reduced pressure is obtained when the liquid temperature during the heat treatment is 40°C or higher. The liquid temperature during the heat treatment is preferably 40°C or higher and less than 80°C, more preferably 42°C or higher and less than 80°C, and even more preferably 45°C or higher and less than 80°C. Furthermore, when the liquid temperature during the heat treatment of vegetables under reduced pressure is 80°C or higher, it becomes physically difficult to reduce the pressure to below -50kPa (since the saturated water vapor pressure at 80°C is -53.792kPa and the saturated water vapor pressure at 82°C is -49.787kPa, theoretically it is impossible to reduce the pressure to below -50kPa while heating at 82°C). Additionally, depending on the characteristics of the pectinase used, there is a high possibility that it will be deactivated and a sufficient softening-promoting effect cannot be obtained. For these reasons, it was considered that setting the liquid temperature to 80°C or higher when heat treating vegetables under reduced pressure is unsuitable for the present invention.

[0111] <Test 8> (Preparation of vegetable dishes) • Vegetable dishes from test area 8-1 Carrot dishes were prepared using the following procedure (1H) to (4H) (hereinafter also referred to as "vegetable dishes from test plot 8-1"). (1H) Preparation of raw vegetables For the vegetable dishes, the raw carrots used as ingredients were cut into 3cm cubes while still raw. (2H) Preparation of vegetable soaking solution In a stainless steel jug, 150g of water and 50g of commercially available noodle soup base (manufactured by Yamaki Co., Ltd., product name "Mentsuyu") were added and mixed. Then, pectinase (manufactured by Nagase ChemteX Corporation, product name "Pectinase XP-534NEO", activity of 5700U per gram of enzyme) was added to the solution in an amount equivalent to 0.1% by weight relative to the raw vegetables (equivalent to 5.7U per gram of raw vegetables) and dissolved. The pH of the solution was then adjusted to 7.5 using sodium carbonate (manufactured by Air Water Performance Chemical Co., Ltd., product name "Purified Sodium Carbonate (Anhydrous)") to prepare the vegetable soaking solution. (3H) Immerse the raw vegetables in the vegetable pickling solution and set the solution into the cooking device. Three pieces of raw vegetables (carrots cut into cubes) prepared in the above procedure (1H) were placed in the mug prepared in the above procedure (2H) and immersed in the vegetable soaking solution prepared in the above procedure (2H). Next, the mug was placed in the pot of a cooking appliance (manufactured by ESPEC Clear Lab Co., Ltd., product name "Veedo Pro") which has a vacuum and heating function, and the pot was covered with a lid. In order to improve heat conductivity, a small amount of water was placed in the pot of the cooking appliance beforehand, just enough so that the mugs placed in it would not float. (4H) Heat treatment and cooking The mug set in the cooker in the above procedure (3H) was heated at 70°C for 9 minutes under normal pressure (i.e., gauge pressure 0 kPa), and then heated at 70°C for 1 minute under reduced pressure of -70 kPa gauge pressure. After that, it was heated at 90°C for 15 minutes under normal pressure. The vegetables (carrots) were removed from the heated mug to obtain the cooked carrot product.

[0112] • Vegetable dishes from test area 8-2 In the procedure described above (4H), instead of heating the jug set in the cooker at atmospheric pressure (i.e., gauge pressure 0 kPa) at 70°C for 9 minutes, and then heating it under reduced pressure of -70 kPa at 70°C for 1 minute, the carrot dish was prepared using the same procedure as in Test Section 8-1, except that it was heated at atmospheric pressure (i.e., gauge pressure 0 kPa) at 70°C for 7 minutes, and then under reduced pressure of -70 kPa at 70°C for 3 minutes. (Hereafter referred to as "Test Section 8-2 vegetable dish").

[0113] • Vegetable dishes from test plot 8-3 In the procedure described above (4H), instead of heating the jug set in the cooker at atmospheric pressure (i.e., gauge pressure 0 kPa) at 70°C for 9 minutes, and then heating it under reduced pressure of -70 kPa at 70°C for 1 minute, the carrot dish was prepared using the same procedure as in Test Section 8-1, except that it was heated at atmospheric pressure (i.e., gauge pressure 0 kPa) at 70°C for 5 minutes, and then heating it under reduced pressure of -70 kPa at 70°C for 5 minutes. (Hereafter referred to as "Test Section 8-3 vegetable dish").

[0114] • Vegetable dishes from test area 8-4 In the procedure described above (4H), the jug set in the cooker was heated at 70°C for 9 minutes at atmospheric pressure (i.e., gauge pressure 0 kPa), and then, instead of heating it at 70°C for 1 minute under reduced pressure of -70 kPa, the carrot dish was prepared using the same procedure as in Test Section 8-1 (hereinafter also referred to as "Test Section 8-4 vegetable dish").

[0115] (Sensory evaluation) The softness of the vegetable dishes in test sections 8-1 to 8-4 (specifically the softness of the carrots) was evaluated by a panel of experts using a scoring system, similar to the method used in Test 1. The evaluation results are shown in Table 8 below.

[0116] [Table 8]

[0117] As shown in Table 8, the vegetable dish in test group 8-1, where the vegetables were heat-treated under reduced pressure for 1 minute, received a slightly lower score for vegetable tenderness. In contrast, the vegetable dishes in test groups 8-2 and 8-3, where the vegetables were heat-treated under reduced pressure for 3 minutes or 5 minutes, both received high scores for vegetable tenderness. From these results, it was concluded that the excellent vegetable tenderization effect obtained by immersing vegetables in a pectinase-containing solution adjusted to a neutral to alkaline range and heat-treating them under reduced pressure is achieved when the heat-treating time is 3 minutes or more, and the duration of the heat-treating is preferably 3 minutes or more, and more preferably 5 minutes or more.

[0118] <Exam 9> (Preparation of vegetable dishes) • Vegetable dishes from test plots 9-1 to 9-7 Each carrot dish was prepared according to the following procedures (1I) to (4I) (hereinafter referred to as "vegetable dish from test plot 9-1" to "vegetable dish from test plot 9-7," respectively). (1) Preparation of raw vegetables For the vegetable dishes, the raw vegetables used were carrots, which were cut into cubes of the size shown in Table 9 below. (2I) Preparation of the vegetable soaking solution In a stainless steel jug, 150g of water and 50g of commercially available noodle soup base (manufactured by Yamaki Co., Ltd., product name "Mentsuyu") were added and mixed. Then, pectinase (manufactured by Nagase ChemteX Corporation, product name "Pectinase XP-534NEO", activity of 5700U per gram of enzyme) was added to the solution in an amount equivalent to 0.1% by weight relative to the raw vegetables (equivalent to 5.7U per gram of raw vegetables) and dissolved. The pH of the solution was then adjusted to 7.5 using sodium carbonate (manufactured by Air Water Performance Chemical Co., Ltd., product name "Purified Sodium Carbonate (Anhydrous)") to prepare the vegetable soaking solution. (3I) Immersion of raw vegetables in vegetable pickling solution and setting of the solution into the cooking device Three pieces of raw vegetables (carrots cut into cubes) prepared in procedure (1I) were placed in the jug prepared in procedure (2I) and immersed in the vegetable soaking solution prepared in procedure (2I). Next, the jug was placed in the pot of a cooking appliance (manufactured by ESPEC Clear Lab Co., Ltd., product name "Veedo Pro") which has a vacuum and heating function, and the pot was covered with a lid. In order to improve heat conductivity, a small amount of water was placed in the pot of the cooking appliance beforehand, just enough so that the jug would not float. (4I) Heat treatment and cooking The mug set in the cooking device in the above procedure (3I) was heated at 70°C for 10 minutes at atmospheric pressure (i.e., gauge pressure 0 kPa). Then, it was heated at 90°C for 15 minutes at atmospheric pressure. After heating, the vegetables (carrots) were removed from the mug to obtain the cooked carrot product.

[0119] • Vegetable dishes from test plots 9-8 to 9-14 In the procedure described above (4I), instead of heating the jug set in the cooker at 70°C for 10 minutes at atmospheric pressure (i.e., gauge pressure 0 kPa) at 70°C, the carrot dishes were prepared using the same procedure as in test sections 9-1 to 9-7 (hereinafter also referred to as "test section 9-8 vegetable dish" to "test section 9-14 vegetable dish").

[0120] (Sensory evaluation) The softness of the vegetable dishes (carrot softness) in test sections 9-1 to 9-14 was evaluated by a panel of experts using a scoring method, similar to Test 1. The evaluation results are shown in Table 9 below.

[0121] [Table 9]

[0122] As shown in Table 9, vegetable dishes from test groups 9-8 to 9-14, where vegetables were heat-treated under reduced pressure of -70 kPa, all received high scores for vegetable tenderness, regardless of the cut size of the raw vegetables. On the other hand, in test groups 9-1 to 9-7, where vegetables were heat-treated at atmospheric pressure, the cut size of the vegetables significantly affected the tenderness; smaller cut sizes resulted in higher tenderness scores, while larger cut sizes resulted in lower scores. In particular, vegetable dishes from test groups 9-1 and 9-2, which used vegetables with at least one side measuring 1.0 cm or less, received high scores, while vegetable dishes from test groups 9-3 to 9-7, which used vegetables with at least one side measuring 2.0 cm or more, received low scores. These results suggest that heat-treatment under reduced pressure is necessary to sufficiently soften large vegetables in a short time. Regarding the excellent vegetable softening effect obtained by immersing vegetables in a pectinase-containing solution adjusted to a neutral to alkaline range and then heat-treating them under reduced pressure, it was considered that the size of the vegetables that clearly demonstrates the advantage of performing the heat treatment under reduced pressure is preferably one side of 2 cm or more, more preferably one side of 2.5 cm or more, and even more preferably one side of 3 cm or more.

[0123] <Test 10> (Preparation of vegetable dishes) • Vegetable dishes from test area 10-1 Carrot dishes were prepared using the following procedure (1J) to (4J) (hereinafter also referred to as "vegetable dishes from test plot 10-1"). (1J) Preparation of raw vegetables For the vegetable dishes, the raw carrots used as ingredients were cut into 3cm cubes while still raw. (2J) Preparation of vegetable soaking solution In a stainless steel jug, 150g of water and 50g of commercially available noodle soup base (manufactured by Yamaki Co., Ltd., product name "Mentsuyu") were added and mixed. Then, pectinase (manufactured by Nagase ChemteX Corporation, product name "Pectinase XP-534NEO", activity of 5700U per gram of enzyme) was added to the solution in an amount equivalent to 0.1% by weight relative to the raw vegetables (equivalent to 5.7U per gram of raw vegetables) and dissolved. The pH of the solution was then adjusted to 7.5 using sodium carbonate (manufactured by Air Water Performance Chemical Co., Ltd., product name "Purified Sodium Carbonate (Anhydrous)") to prepare the vegetable soaking solution. (3J) Immersion of raw vegetables in vegetable pickling solution and setting of said solution into cooking equipment Three pieces of raw vegetables (carrots cut into cubes) prepared in the procedure (1J) were placed in the mug prepared in the procedure (2J) and immersed in the vegetable soaking solution prepared in the procedure (2J). Next, the mug was placed in the pot of a cooking appliance (manufactured by ESPEC Clear Lab Co., Ltd., product name "Veedo Pro") which has a vacuum and heating function, and the pot was covered with a lid. In order to improve heat conductivity, a small amount of water was placed in the pot of the cooking appliance beforehand, just enough so that the mugs placed in the pot would not float. (4J) Heat treatment and cooking The mug set in the cooking device in the above procedure (3J) was heated at 70°C for 10 minutes under reduced pressure of -70kPa gauge pressure. Then, it was heated at 90°C for 15 minutes under normal pressure. After heating, the vegetables (carrots) were removed from the mug to obtain the cooked carrot product.

[0124] • Vegetable dishes from test plot 10-2 Carrot dishes were prepared using the following procedure (1K) to (4K) (hereinafter also referred to as "vegetable dishes from test plot 10-2"). (1K) Preparation of raw vegetables For the vegetable dishes, the raw carrots used as ingredients were cut into 3cm cubes while still raw. Preparation of (2K) Vegetable soaking solution In a vacuum packaging bag, 150g of water and 50g of commercially available noodle soup base (manufactured by Yamaki Co., Ltd., product name "Mentsuyu") were added and mixed. Then, pectinase (manufactured by Nagase ChemteX Corporation, product name "Pectinase XP-534NEO", activity of 5700U per gram of enzyme) was added to the solution in an amount equivalent to 0.1% by weight relative to the raw vegetables (equivalent to 5.7U per gram of raw vegetables) and dissolved. The pH of the solution was then adjusted to 7.5 using sodium carbonate (manufactured by Air Water Performance Chemical Co., Ltd., product name "Purified Sodium Carbonate (Anhydrous)") to prepare the vegetable soaking solution. (3K) Immersion of raw vegetables in vegetable pickling solution and setting of the solution into the cooking device. Three pieces of raw vegetables (carrots cut into cubes) prepared in the above procedure (1K) were placed into the vacuum packaging bag prepared in the above procedure (2K) and immersed in the vegetable immersion solution prepared in the above procedure (2K). Next, the bag was vacuum-packed using a chamber-type vacuum packaging machine (MULTIVAC C200, manufactured by Multivac Japan Co., Ltd.) at an absolute pressure of 25 mbar. Note that an absolute pressure of 25 mbar is equivalent to a gauge pressure of -99 kPa. The vacuum-packed bags were placed in the pot of a cooking appliance with a vacuum and heating function (VeedoPro, manufactured by ESPEC Clear Lab Co., Ltd.) and the pot was covered. (4K) Heat treatment and cooking The vacuum packaging bag set in the cooker according to the above procedure (3K) was heated at 70°C for 10 minutes at atmospheric pressure (i.e., gauge pressure 0 kPa). Then, it was heated at 90°C for 15 minutes at atmospheric pressure. The vegetables (carrots) were removed from the heated vacuum packaging bag to obtain cooked carrots.

[0125] • Vegetable dishes from test plot 10-3 In the procedure described above (3K), the carrot dish was prepared using the same procedure as in Test Section 10-2, except that vacuum packaging was performed at an absolute pressure of 300 mbar instead of 25 mbar (hereinafter also referred to as "Test Section 10-3 vegetable dish"). Note that an absolute pressure of 300 mbar is equivalent to a gauge pressure of -71 kPa.

[0126] • Vegetable dishes from test plot 10-4 In the procedure described above (3K), the carrot dish was prepared using the same procedure as in Test Section 10-2, except that vacuum packaging was performed at an absolute pressure of 500 mbar instead of 25 mbar (hereinafter also referred to as "Test Section 10-4 vegetable dish"). Note that an absolute pressure of 500 mbar is equivalent to a gauge pressure of -51 kPa.

[0127] (Sensory evaluation) The softness of the vegetable dishes (softness of carrots) in test sections 10-1 to 10-4 was evaluated by a panel of experts using a scoring system, similar to Test 1. The evaluation results are shown in Table 10 below.

[0128] [Table 10]

[0129] As shown in Table 10, in test group 10-1, the vegetable preparation was prepared by adding pectinase to the vegetable immersion solution, adjusting the pH to 7.5, and then heat-treating the vegetables under reduced pressure of -70 kPa, resulting in a high score for vegetable tenderness. In test groups 10-2 to 10-4, the vegetable preparation was prepared by vacuum-packing the vegetables and then heat-treating them at atmospheric pressure. While there was a tendency for the vegetable tenderness score to be relatively higher with lower vacuum packaging pressure, the scores were generally lower, showing a significant difference from the effect obtained in test group 10-1. Regarding the reasons why sufficient vegetable softening was not obtained in test plots 10-2 to 10-4, while not adhering to any particular theory, it is thought that the excellent vegetable softening effect obtained by immersing vegetables in a pectinase-containing solution adjusted to the neutral to alkaline range and then heat-treating them under reduced pressure requires the heat treatment to be continued under reduced pressure for a certain period of time. However, vacuum packaging is a packaging method that reduces the pressure inside the packaging material and seals it without heating, and vacuum packaging performed using a vacuum packaging machine has a limited operating time. Within such a limited time, it is difficult to completely remove the air from inside large vegetables and allow the pectinase-containing solution to penetrate. Furthermore, when vegetables in a vacuum-packaged state are heated afterward, the air remaining inside the vegetables expands during heating, causing the pressure inside the packaging material to return, making it difficult to maintain a reduced pressure during the heat treatment. For example, in order to promote vegetable softening by heat-treating vegetables at atmospheric pressure after vacuum packaging, it is thought that it is necessary to actively remove air during the heat treatment. The results shown in Table 10 indicate that the excellent vegetable softening effect obtained by immersing vegetables in a pectinase-containing solution adjusted to a neutral to alkaline range and then heating them under reduced pressure cannot be sufficiently obtained by vacuum-packing vegetables in soft packaging materials and heating them under normal pressure. Therefore, it is considered important to heat-treat vegetables under reduced pressure.

[0130] <Test 11> (Preparation of vegetable dishes) • Vegetable dishes from test plots 11-1 to 11-9 Each vegetable dish was prepared using the following procedure (1L) to (3L) (hereinafter referred to as "vegetable dish from test plot 11-1" to "vegetable dish from test plot 11-9," respectively). (1L) Preparation of vegetable soaking solution In a dedicated pot of a cooking appliance with vacuum and heating functions (manufactured by ESPEC Clear Lab Co., Ltd., product name "Veed Pro"), 1500g of water and 500g of commercially available noodle soup base (manufactured by Yamaki Co., Ltd., product name "Mentsuyu") were added and mixed. Then, pectinase (manufactured by Nagase ChemteX Corporation, product name "Pectinase XP-534NEO", activity of 5700U per gram of enzyme) was added to the solution in an amount equivalent to 0.1% by weight relative to the raw vegetables (equivalent to 5.7U per gram of raw vegetables) and dissolved. The pH of the solution was then adjusted to 7.5 using sodium carbonate (manufactured by Air Water Performance Chemical Co., Ltd., product name "Purified Sodium Carbonate (Anhydrous)") to prepare the vegetable soaking solution. (2L) Immerse raw vegetables in vegetable soaking solution. The various vegetables shown in Table 11 were placed whole into the pot prepared in the procedure (1L) described above, in the same condition as when sold at a mass retailer (entirely raw), and immersed in the vegetable soaking solution prepared in the procedure (1L). The pot was then covered. The vegetables were used without removing the peel or stems. (3L) Heat treatment and cooking The pot (2L) described above was heated at 70°C for 10 minutes under reduced pressure of -70kPa gauge pressure. Then, it was heated at atmospheric pressure at 90°C for 15 minutes. The vegetables were removed from the pot after heating to obtain the cooked vegetables.

[0131] (Sensory evaluation) A panel of experts conducted a sensory evaluation of the tenderness of vegetable dishes in test sections 11-1 through 11-9 (the tenderness of various vegetables). The expert panel consisted of three panelists well-versed in food texture, and the evaluation of tenderness was conducted based on the following criteria with the agreement of all panelists. They also left comments on their impressions of each vegetable dish they evaluated. The expert panel was trained in advance to ensure that all panelists shared a common understanding of the evaluation criteria described below. [Criteria for evaluating softness] ○: Very soft △: Slightly soft ×: Hard

[0132] The evaluation results are shown in Table 11 below.

[0133] [Table 11]

[0134] As shown in Table 11, in test groups 11-1 to 11-9, where pectinase was added to the vegetable immersion solution, the pH was adjusted to 7.5, and various whole, uncut vegetables were heat-treated under reduced pressure of -70 kPa, all of the vegetable preparations received high marks for vegetable tenderness, confirming that the vegetables were sufficiently softened in a short time. It was confirmed that the excellent vegetable softening effect obtained by immersing vegetables in a pectinase-containing solution adjusted to the neutral to alkaline range and heat-treating them under reduced pressure is obtainable not only when cut vegetables are used, but also when whole vegetables are used. Furthermore, it was shown that when whole vegetables are used, sufficient softening can be obtained even if vegetables with peels and stems are used without removing them. Moreover, it was suggested that this excellent effect can be obtained regardless of the type of vegetable used.

[0135] As described above, the results of experiments 1 to 11 suggest that immersing vegetables in a pectinase-containing solution adjusted to a neutral to alkaline range and then heating them under reduced pressure effectively softens the vegetables. [Industrial applicability]

[0136] The present invention provides a method for producing vegetable products in which raw vegetables can be effectively softened. Since this method can effectively soften even large raw vegetables while maintaining their shape, the present invention also provides a method for producing vegetable products in which large raw vegetables can be effectively softened. The present invention also provides a method for softening vegetables that can effectively soften them. This softening method can effectively soften vegetables regardless of their size, even large vegetables, while maintaining their shape; therefore, a method for softening large vegetables is also provided by the present invention. According to the present invention, a vegetable cooking kit is provided that can effectively soften and cook vegetables. Since the kit can effectively soften and cook even large vegetables while maintaining their shape, the present invention also provides a vegetable cooking kit that can effectively soften and cook large vegetables. The present invention also provides a vegetable immersion solution that can effectively soften vegetables. Since this solution can effectively soften vegetables while maintaining their shape, even large vegetables, regardless of their size, the present invention also provides a vegetable immersion solution for large vegetables.

Claims

1. A method for producing cooked vegetable products, comprising immersing raw vegetables in a pectinase-containing solution with a pH of 6.0 or higher, and heating them for 3 minutes or more under conditions of a gauge pressure of -50 kPa or lower and a liquid temperature of 40°C or higher but less than 80°C.

2. The manufacturing method according to claim 1, further comprising subjecting the raw vegetables to cooking after the heat treatment.

3. The manufacturing method according to claim 1, wherein the pectinase-containing solution is filled in a container that is resistant to reduced pressure and heat.

4. The manufacturing method according to claim 1, wherein the pectinase content in the pectinase-containing solution is 0.03 U or more per 1 g of raw vegetables before heat treatment.

5. The manufacturing method according to claim 1, wherein the raw vegetable material includes one or more vegetables having at least one side measuring 2 cm or more.

6. A method for softening vegetables, comprising immersing the vegetables in a pectinase-containing solution with a pH of 6.0 or higher, and heating them for 3 minutes or more under conditions of a gauge pressure of -50 kPa or lower and a liquid temperature of 40°C or higher but less than 80°C.

7. A vegetable preparation kit comprising pectinase for preparing a pectinase-containing solution and a material for adjusting the pH of the pectinase-containing solution to 6.0 or higher, A kit is provided in which a pectinase-containing solution, prepared using at least the pectinase, the material, and water, has a pH of 6.0 or higher, and is used to immerse vegetables and heat-treat them for 3 minutes or more under conditions of a gauge pressure of -50 kPa or less and a liquid temperature of 40°C or higher and less than 80°C.

8. A vegetable soaking solution containing pectinase and having a pH of 6.0 or higher, A liquid used to heat-treat immersed vegetables for 3 minutes or more under conditions of a gauge pressure of -50 kPa or less and a liquid temperature of 40°C or higher but less than 80°C.

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