Food with improved texture after microwave heating and method for improving texture after microwave heating

Abstract

To provide food products that have an improved texture after microwave heating and have a suitable texture after microwave heating. [Solution] Microwaveable food with porous particles attached to at least part of its surface.

Description

[Technical Field]

[0001] This invention relates to food products, and more specifically, to food products whose texture has been improved after microwave heating. Furthermore, this invention also relates to methods for improving the texture of food products after microwave heating. [Background technology]

[0002] Microwave ovens are one of the most widely used cooking appliances in Japan, and many foods are marketed with the intention of being heated in a microwave oven before consumption. However, it is known that foods heated in a microwave oven can become soft on the surface and have a reduced texture, which has become a significant problem, especially for foods such as dumplings and grilled chicken, where a certain degree of firmness on the surface is preferred.

[0003] To address these problems, conventional solutions have been proposed, such as using special food containers and packaging in which a microwave-absorbing heating element layer is provided on the contact surface with the food, and then performing microwave heating (Patent Documents 1-3).

[0004] In recent years, global interest in achieving a sustainable society has been growing, and the food industry is also making efforts to reduce the generation of packaging waste. Against this backdrop, there has been a need to develop a new method that can impart firmness to food after microwave heating without using special food packaging.

[0005] On the other hand, for microwave-safe, pre-fried frozen foods consisting of a base and a coating layer, it has been proposed to provide a layer of a coating agent consisting of acetylated monoglycerides, proteins, and / or oils between the base and the coating layer to prevent a decrease in the crispness of the coating layer after microwave cooking (Patent Document 4). Furthermore, in order to create fried-like foods with a crispy texture simply by heating them in a microwave without deep-frying, it has been proposed to use a batter mix in which the rate of temperature rise due to microwave heating on the batter surface is greater than that inside the batter (Patent Document 5). [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2004-182 [Patent Document 2] Japanese Patent Publication No. 2006-55026 [Patent Document 3] Japanese Patent Publication No. 2013-43658 [Patent Document 4] International Publication No. 99 / 27800 [Patent Document 5] Japanese Patent Publication No. 2002-218931 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] This invention has been made in view of the above circumstances, and one of the problems it aims to solve is to provide food that has an improved texture after microwave heating and has a suitable texture after microwave heating. Furthermore, one aspect of the present invention is to provide a method for improving the texture of food after microwave heating. Furthermore, one aspect of the present invention is to provide a method for producing microwave-heated food with improved texture and a desirable texture. Furthermore, one aspect of the present invention is to provide an agent that can improve the texture of food after microwave heating. [Means for solving the problem]

[0008] The inventors diligently studied to solve the above-mentioned problems and found that by attaching porous particles to the part of the food surface where hardness is to be added, hardness is imparted to that part after microwave heating. Based on this finding, the inventors conducted further research and completed the present invention. In other words, the present invention is as follows:

[0009] [Item 1] Microwave-heated food having porous particles attached to at least part of its surface. [Clause 2] The food according to Claim 1, wherein the porous particles are at least one selected from the group consisting of silica gel particles, zeolite particles, calcium silicate particles, and activated carbon particles. [Item 3] The food according to item 1 or item 2, wherein the pore volume of the porous particles is 0.05 mL / g or more. [Item 4] The food according to any one of items 1 to 3, wherein the amount of porous particles attached to the food is 0.000001% by weight or more. [Item 5] The food described in any one of items 1 to 4, wherein the food is a cooked food. [Item 6] The food according to any one of items 1 to 5, wherein the food is a frozen food. [Item 7] The food according to any one of items 1 to 6, wherein the food is a processed grain food or an animal food. [Item 8] The food according to item 7, wherein the grain processed food is a noodle-filled food or a rice food. [Item 9] A method for improving the texture of microwave-heated food after microwave heating, comprising attaching porous particles to at least a portion of the surface of the microwave-heated food. [Clause 10] The improvement method according to Clause 9, wherein the porous particles are at least one selected from the group consisting of silica gel particles, zeolite particles, calcium silicate particles, and activated carbon particles. [Item 11] The improvement method according to item 9 or 10, wherein the pore volume of the porous particles is 0.05 mL / g or more. [Item 12] The improvement method according to any one of items 9 to 11, wherein the amount of porous particles attached to at least a portion of the surface of the food is 0.000001% by weight or more relative to the food. [Item 13] The improvement method according to any one of items 9 to 12, wherein the food is a heated product. [Item 14] The improvement method according to any one of items 9 to 13, wherein the food is a frozen food. [Item 15] The improvement method according to any one of items 9 to 14, wherein the food is a grain processed food or an animal product. [Item 16] The improvement method according to Item 15, wherein the processed grain food is a wrapped filled noodle strip food or a cooked rice food. [Item 17] A method for producing a microwave-heated food, comprising attaching porous particles to at least a part of the surface of a food and subjecting the food to microwave heating. [Item 18] The production method according to Item 17, wherein the porous particles are at least one selected from the group consisting of silica gel particles, zeolite particles, calcium silicate particles and activated carbon particles. [Item 19] The production method according to Item 17 or 18, wherein the pore volume of the porous particles is 0.05 mL / g or more. [Item 20] The production method according to any one of Items 17 to 19, wherein the amount of the porous particles attached to at least a part of the surface of the food is 0.000001 wt% or more relative to the food. [Item 21] The production method according to any one of Items 17 to 20, wherein the food is a heat-cooked product. [Item 22] The production method according to any one of Items 17 to 21, wherein the food is a frozen food. [Item 23] The production method according to any one of Items 17 to 22, wherein the food is a processed grain food or an animal-derived food. [Item 24] The production method according to Item 23, wherein the processed grain food is a wrapped filled noodle strip food or a cooked rice food. [Item 25] A texture improving agent for a food after microwave heating, which contains porous particles and is intended to be attached to at least a part of the surface of a food for microwave heating. [Item 26] The agent according to Item 25, wherein the porous particles are at least one selected from the group consisting of silica gel particles, zeolite particles, calcium silicate particles and activated carbon particles. [Item 27] The agent according to Item 25 or 26, wherein the pore volume of the porous particles is 0.05 mL / g or more. [Item 28] The agent according to any one of Items 25 to 27, wherein the amount of the porous particles attached to at least a part of the surface of the food is 0.000001 wt% or more relative to the food. [Item 29] The agent according to any one of Items 25 to 28, wherein the food is a heat-cooked product. [Item 30] The agent according to any one of Items 25 to 29, wherein the food is a frozen food. [Item 31] The agent according to any one of Items 25 to 30, wherein the food is a processed grain food or an animal-derived food. [Item 32] The agent according to Item 31, wherein the processed grain food is a wrapped filling noodle strip food or a cooked rice food. Effects of the Invention

[0010] According to the present invention, the texture after microwave heating is improved, and a food having a favorable texture after microwave heating is provided. The food can be imparted with hardness on at least a part of the surface of the food after microwave heating. Furthermore, according to the present invention, a method capable of improving the texture of a food after microwave heating is also provided. The method can impart hardness to at least a part of the surface of the food after microwave heating. The present invention also provides a method for producing a microwave-heated food with improved texture and favorable texture. According to the method, a microwave-heated food in which hardness is imparted to at least a part of the surface of the food can be obtained. Furthermore, according to the present invention, an agent capable of improving the texture of a food after microwave heating is also provided. The agent can impart hardness to at least a part of the surface of the food after microwave heating. Modes for Carrying Out the Invention

[0011] One of the features of the food of the present invention is that porous particles are adhered to at least a part of the surface thereof.

[0012] In the present invention, the term "porous particles" means particles having a plurality of small voids (pores) communicating with the outside on the inside or surface of the particles, or an aggregate thereof. The porous particles may be primary particles having a plurality of pores, or may be secondary particles in which pores (inter-particle voids) are formed by aggregation of a plurality of primary particles or the like.

[0013] The types of porous particles that can be used in the present invention are not particularly limited as long as they are edible, but examples include silica gel particles, calcium silicate particles, zeolite particles, activated carbon particles, cellulose particles, etc. Among these, silica gel particles and activated carbon particles are preferred, and silica gel particles are particularly preferred from the viewpoint of heat generation efficiency. Here, "silica gel particles" refers to silica gel in powder form (powder, fine granules, granules, or a combination thereof). The silica gel particles used in the present invention are preferably those mainly composed of silicon dioxide (SiO2), and specifically, it is preferable that they contain 90% by weight or more of silicon dioxide, and more preferably 95% by weight or more. Also, "calcium silicate particles" refers to powdered calcium silicate (e.g., calcium metasilicate, calcium orthosilicate, tricalcium silicate, etc.). "Zeolite particles" refers to powdered zeolite (natural zeolite, synthetic zeolite). "Activated carbon particles" refers to powdered activated carbon (porous carbon). The porous particles described above may be used individually or in combination of two or more types.

[0014] Examples of porous particle shapes that can be used in the present invention include, but are not limited to, spherical (e.g., perfectly spherical, nearly perfectly spherical, oblong, etc.), polyhedral (e.g., rectangular parallelepiped, cubic, etc.), cylindrical, conical, rod-shaped, needle-shaped, and plate-shaped.

[0015] In the present invention, the average particle diameter of porous particles that can be used is not particularly limited, but from the viewpoint of suppressing roughness in the texture of the food product of the present invention, it is preferably 5 to 40 μm, more preferably 8 to 30 μm, and particularly preferably 10 to 20 μm. In the present invention, the average particle diameter (median diameter) refers to the particle diameter (D50) at the point in the volume-based cumulative particle size distribution curve measured by laser diffraction-scattering that, when the total volume of the particle collection is taken as 100%, the cumulative volume from the fine particle side reaches 50%.

[0016] In the present invention, it is preferable that the porous particles used have a specific pore volume. By having a specific pore volume in the porous particles, hardness can be more effectively imparted to the surface of food after microwave heating.

[0017] Specifically, the pore volume of the porous particles is preferably 0.05 mL / g or more, more preferably 0.07 mL / g or more, even more preferably 0.3 mL / g or more, even more preferably 0.6 mL / g or more, and particularly preferably 1.2 mL / g or more. The upper limit of the pore volume of the porous particles is not particularly limited, but is usually 3 mL / g or less, preferably 2.5 mL / g or less, and more preferably 2 mL / g or less. In the present invention, the pore volume of the porous particles is determined by the BET method.

[0018] The method for producing the porous particles used in the present invention is not particularly limited, and any known method or a similar method may be used. For example, silica gel particles can be produced by neutralizing an aqueous solution of sodium silicate with an acid (e.g., hydrochloric acid, sulfuric acid, etc.) to precipitate a precipitate, washing and drying it, and then crushing and granulating it as appropriate. In addition, commercially available products (commercially available products) may be used as porous particles.

[0019] The type of food product of the present invention is not particularly limited as long as it is desired that hardness be imparted to at least a part of the surface of the food product, but cooked food products are preferred. In the present invention, "cooked food product" means a food product whose manufacturing process includes subjecting raw materials or processed products thereof to cooking. That is, the manufacturing process of a cooked food product includes subjecting the raw materials or processed products thereof to cooking. The type of cooking included in the manufacturing process of a cooked food product is not particularly limited, but examples include baking, stir-frying, steaming, deep-frying, simmering, boiling, microwave heating, far-infrared heating, hot air heating, superheated steam heating, etc. The manufacturing process of a cooked food product may include only one of these cooking methods, or it may include two or more. If the manufacturing process of a cooked food product includes two or more cooking methods, the two or more cooking methods may be performed sequentially in an appropriate order, or they may be performed simultaneously. Furthermore, as mentioned above, the term "cooked food" refers to a type of food and does not necessarily mean that the food is already cooked. Cooked food can be classified according to the stage of its manufacturing process into cooked food, food in the process of cooking, food before cooking (i.e., food that will be cooked in the future), etc. In this specification, unless otherwise specified, "cooked food" is used as a concept that encompasses all of these states.

[0020] The food of the present invention preferably contains a food material or a processed product thereof as a raw material, which can increase in hardness upon heating. Examples of materials that can increase in hardness upon heating include food materials containing protein. Examples of food materials containing protein include food materials containing animal protein such as meat (e.g., livestock meat, poultry meat, seafood meat, wild game meat, etc.), eggs (e.g., bird eggs, fish eggs, etc.), and milk (e.g., cow's milk, goat's milk, etc.); and food materials containing plant protein such as beans (e.g., soybeans, peas, broad beans, etc.) and grains (e.g., wheat, rice, corn, etc.). Specific examples of processed products of food materials that can increase in hardness upon heating include dough (e.g., noodle sheets, etc.) made by processing grains (e.g., wheat, etc.), which are a type of plant protein; cooked rice made by processing (cooking) rice, which is a type of plant protein; and meat substitutes (e.g., soy meat, etc.) made by processing beans (e.g., soybeans, etc.), which are a type of plant protein, but are not particularly limited as long as they can increase in hardness upon heating. Furthermore, food materials whose plasticity can change depending on the moisture content (e.g., coatings, burnt rice, etc.) are also suitable as raw materials for the food of the present invention, as their hardness can increase when the moisture content is reduced, for example by heating causing water to evaporate. Food materials or processed products thereof that can increase in hardness upon heating are preferably used to constitute at least a part of the surface of the food of the present invention.

[0021] In one embodiment, the food of the present invention may be a processed grain food. In the present invention, "processed grain food" means a food made using grains (e.g., wheat, rice, etc.) and / or processed products thereof (e.g., noodle sheets, cooked rice, etc.). Specific examples of processed grain foods include filled noodle foods, noodle foods (e.g., fried noodles, fried rice noodles, fried udon noodles, etc.), cooked rice foods, etc.

[0022] In this invention, "filled noodle wrapper food" refers to a food comprising at least a filling (commonly also called "filling") and a noodle wrapper (commonly also called "noodle wrapper" or "wrapper") that encloses part or all of the filling. Specific examples of filled noodle wrapper foods include dumplings, shumai, spring rolls, ravioli, xiaolongbao, wontons, and baozi.

[0023] In this invention, "rice-based food" refers to food that contains rice as an ingredient (in other words, food made using rice). Specific examples of rice-based food include fried rice, pilaf, paella, gratin, rice balls, mixed rice dishes, bibimbap, nasi goreng, and the like.

[0024] In one embodiment, the food of the present invention may be an animal-based food. In the present invention, "animal-based food" means a food whose raw materials include materials of animal origin. Examples of animal-derived materials include, but are not limited to, meat (e.g., livestock meat, poultry meat, seafood meat, wild game meat, etc.), eggs (bird eggs, fish eggs, etc.), milk, and processed products thereof. In one embodiment, the raw materials of an animal-based food may consist only of materials of animal origin, but in another embodiment, non-animal-derived materials (e.g., plant-derived materials, etc.) may be further included in addition to the animal-derived materials. Specific examples of animal-based foods include, but are not limited to, meat products (i.e., foods containing meat as a raw material, e.g., cooked meat products, etc.), egg products (i.e., foods containing eggs as a raw material), and dairy products (i.e., foods containing milk as a raw material). Examples of processed meat products include, but are not limited to, processed meat products of livestock such as beef and pork (e.g., cooked beef, cooked pork, etc.); processed poultry products such as chicken and duck (e.g., cooked chicken, cooked duck, etc.); and processed seafood products such as fish, octopus, squid, and shellfish (e.g., cooked fish, octopus, squid, and shellfish). Specific examples of cooked beef products, which are a type of processed beef product (i.e., foods that contain beef as a raw material and whose manufacturing process includes heating the raw material or its processed product), include, but are not limited to, hamburgers (e.g., beef hamburgers, hamburgers made from ground beef containing beef, etc.), patties (e.g., beef patties, patties made from ground beef containing beef, etc.), beef steaks, roast beef, grilled beef, beef croquettes, beef cutlets, beef gratin, etc. Specific examples of cooked pork products, which are a type of processed pork product (i.e., foods that contain pork as a raw material and whose manufacturing process includes heating the raw material or its processed product), include, but are not limited to, grilled pork, pork croquettes, bacon, pork cutlets, hamburgers (e.g., pork hamburgers, hamburgers made from ground meat containing pork, etc.), patties (e.g., pork patties, patties made from ground meat containing pork, etc.), and pork gratin. Specific examples of cooked chicken products, which are a type of processed chicken product (i.e., foods that contain chicken as a raw material and whose manufacturing process includes heating or cooking the raw material or its processed product), include, but are not limited to, grilled chicken, yakitori, roast chicken, fried chicken, karaage chicken, and chicken gratin. Examples of cooked fish products (i.e., foods that contain fish as a raw material and whose manufacturing process includes heating or cooking the raw material or its processed product) include, but are not limited to, grilled fish, steamed fish, fried fish, tempura fish, and fish gratin.

[0025] The food of the present invention is preferably for microwave heating, that is, the food of the present invention is suitably used as microwave heating food. In the present invention, "microwave heating" food refers to food that is heated using a microwave oven at least before consumption (preferably immediately before consumption). In other words, it refers to food that can be consumed after being heated using a microwave oven.

[0026] In the present invention, "microwave heating" refers to a heating process performed using a microwave oven, and more specifically, a heating process in which microwaves are irradiated onto an object to be heated (food) to heat it. Microwave heating can be performed to cook food, but is not limited to this, and may also be performed for purposes such as thawing frozen food or reheating cold food. The various conditions for microwave heating in which the food of the present invention can be served (e.g., microwave output, heating time, etc.) can be set appropriately according to the purpose of heating, the type and amount of the object to be heated (the food of the present invention), etc., and are not particularly limited, but the microwave output (rated high-frequency output according to the measurement method specified in Japanese Industrial Standard C9250 (Microwave Oven)) is usually 100 to 3000 W, preferably 300 to 1500 W, and more preferably 400 to 700 W. The heating time (microwave irradiation time) can be adjusted appropriately according to the microwave output, the purpose of heating, the type and amount of the object to be heated, etc., but is usually 0.5 to 30 minutes (preferably 1 to 15 minutes).

[0027] The amount of porous particles adhering to the surface of the food of the present invention is not particularly limited and can be appropriately adjusted depending on the type of food and the area of ​​the part to which the porous particles are adhering. However, from the viewpoint of more effectively imparting hardness to the surface of the food after microwave heating, the amount of porous particles adhering is preferably 0.000001% by weight or more, more preferably 0.000005% by weight or more, and particularly preferably 0.00001% by weight or more, relative to the food of the present invention. The upper limit of the amount of porous particles adhering to the surface of the food of the present invention is also not limited, but from the viewpoint of generating more heat from the porous particles by microwave heating, it is preferably 0.15% by weight or less, more preferably 0.1% by weight or less, even more preferably 0.08% by weight or less, and particularly preferably 0.06% by weight or less, relative to the food of the present invention.

[0028] In this invention, the amount of porous particles adhering to the surface of food can be calculated by determining the ratio of the amount (weight) of porous particles used in the production of the food to the weight of the food, if the amount of porous particles used in the production of the food is known. However, if the amount of porous particles used in the production of the food is unknown, the amount of porous particles adhering to the surface of the food may be determined by Fourier transform infrared spectroscopy (FT-IR) analysis. More specifically, a calibration curve can be created from the FT-IR analysis results of multiple standard samples (foods with a predetermined amount of porous particles attached to their surface), and the amount of porous particles attached to the surface of the sample to be quantified can be determined using this calibration curve. Here, the calibration curve can be created by plotting the amount of porous particles attached to the surface of the standard sample against the ratio of the peak intensity (peak area, peak height) of the porous particles obtained by FT-IR analysis to the peak intensity of the internal standard substance. The internal standard substance can be a substance that is present in large quantities in food; for example, if the food is dumplings, wheat flour can be used as the internal standard substance. The analytical wavelengths for porous particles and internal standard substances are not particularly limited and can be set appropriately depending on the type, etc., but for example, the analytical wavelength for activated carbon particles is 399 cm⁻¹. -1 The analytical wavelength for silica gel particles is 426 cm⁻¹. -1 The analytical wavelength for wheat flour is 999 cm². -1 The settings can be adjusted as follows. The analytical instrument used for FT-IR analysis is not particularly limited, but for example, an FT-IR analyzer manufactured by Thermo Fisher Scientific can be used.

[0029] The ratio of the total surface area of ​​the food product to the total surface area to which porous particles are attached is not particularly limited, but from the viewpoint of obtaining sufficient heat generation from the porous particles by microwave heating, it is preferably 10% or more, more preferably 20% or more, and particularly preferably 30% or more. The ratio may also be 100% or less, but from the viewpoint of generating stronger heat from the porous particles by microwave heating, it is preferably 90% or less, more preferably 80% or less, and particularly preferably 70% or less. In the present invention, the total surface area of the food product and the total area of the portion of the food product surface to which the porous particles are adhered may be measured by a method known per se or a method equivalent thereto.

[0030] In the food product of the present invention, the adhesion amount of the porous particles per unit area is preferably 0.000001 g / cm from the viewpoint of sufficiently obtaining heat generation of the porous particles by microwave heating 2 or more, more preferably 0.00001 g / cm 2 or more, and particularly preferably 0.00002 g / cm 2 or more. Further, the adhesion amount of the porous particles per unit area is preferably 0.01 g / cm from the viewpoint of causing the porous particles to generate more intense heat by microwave heating 2 or less, more preferably 0.009 g / cm 2 or less, and particularly preferably 0.0085 g / cm 2 or less. In the present invention, the adhesion amount of the porous particles per unit area is calculated by dividing the total weight (g) of the porous particles adhered to the food product by the total area (cm of the portion of the food product surface to which the porous particles are adhered 2 )

[0031] The present invention relates to a method for producing food products, which includes attaching porous particles to at least a portion of the surface of the food product. The method for attaching porous particles to at least a portion of the surface of the food product is not particularly limited and can be carried out by methods known to the present invention or by methods similar thereto. For example, porous particles can be attached to the surface of the food product by sprinkling them on at least a portion of the surface of the food product while they are still in powder form. In this case, the porous particles may be sprinkled on the surface of the food product alone, or they may be mixed with other powdered food materials and sprinkled on the surface of the food product. Alternatively, porous particles can be attached to the surface of the food product by adding them to a liquid and applying the liquid to the surface of the food product. In this case, the liquid to which the porous particles are added is not particularly limited as long as it can be used as a raw material for food or in the food product manufacturing process, but examples include water (e.g., purified water, tap water, etc.), oil (e.g., edible vegetable oil, edible animal oil, etc.), organic solvents (e.g., ethanol, acetic acid, lactic acid, etc.) and mixtures thereof. It is preferable that the liquid to which the porous particles are added contains oil. In one embodiment, when a mixture of water and oil is used as the liquid to which porous particles are added, the mixture may be an emulsion. The liquid to which porous particles are added (i.e., a liquid containing porous particles) may contain, in addition to the porous particles, food materials and food additives other than porous particles (e.g., emulsifiers, emulsifying aids, etc.), as long as the objective of the present invention is not impaired.

[0032] The method for producing the food of the present invention is not particularly limited except that it includes attaching porous particles to at least a portion of the surface of the food, and may include conventional manufacturing steps depending on the type of food. For example, if the food of the present invention is a cooked product, the manufacturing step may include subjecting the raw materials or processed products thereto to cooking. Furthermore, the method for producing the food of the present invention may include subjecting the food to refrigeration or freezing. That is, the food of the present invention may, in one embodiment, be a chilled food or a frozen food.

[0033] In the method for producing the food of the present invention, the timing of attaching the porous particles to the food is not particularly limited as long as it is before the food of the present invention is subjected to microwave heating. For example, if the food of the present invention is a cooked product, the porous particles may be attached to the food before it is subjected to cooking, and then the food may be subjected to cooking, or the porous particles may be attached to the food after it has been subjected to cooking (cooked food). If the food of the present invention is a frozen food, the porous particles may be attached to the food before it is frozen, and then the food may be subjected to freezing, or the porous particles may be attached to the food after it has been frozen (food in a frozen state).

[0034] In one embodiment, the food of the present invention may be both a cooked food and a frozen food (i.e., a cooked frozen food), and in such cases, the timing of attaching the porous particles to the food is not limited. For example, porous particles may be attached to the food before it is cooked, then the food may be cooked, and the resulting cooked food may be frozen; porous particles may be attached to the cooked food, then the food may be frozen; or the cooked food may be frozen, and the resulting frozen food may be attached. Alternatively, porous particles may be attached to the food before it is cooked, then the food may be frozen, and the food may be frozen before it is cooked, and the resulting frozen food may be attached. The frozen food obtained in this way may be cooked as needed before consumption and then microwaved.

[0035] The food product of the present invention may have an improved texture after microwave heating and may possess a desirable texture after microwave heating. More specifically, the food product of the present invention may be given hardness to at least a portion of its surface (the portion to which porous particles are attached and its vicinity) after microwave heating. While not bound by any particular theory, it is presumed that the porous particles attached to the food product generate heat when microwaved, thereby giving hardness to the portion to which the porous particles are attached and its vicinity. In the present invention, the texture of the food product (hardness after microwave heating, etc.) can be evaluated, for example, by sensory evaluation by a panel of experts.

[0036] The present invention also provides a method for improving the texture of food after microwave heating (hereinafter also referred to as "the improvement method of the present invention"). One of the features of the improvement method of the present invention is that it includes attaching porous particles to at least a portion of the surface of the food.

[0037] The porous particles used in the improved method of the present invention are the same as those used in the food of the present invention as described above, and the preferred embodiments are also the same.

[0038] In the improved method of the present invention, the food to which porous particles are attached is the same as the food of the present invention described above, and the preferred type and form of the food are also the same.

[0039] The method for attaching porous particles to at least a portion of the surface of food in the improved method of the present invention is the same as the method for attaching porous particles to at least a portion of the surface of food in the food manufacturing method of the present invention described above, and the preferred embodiments and attachment amounts are also the same.

[0040] The improved method of the present invention can improve the texture of food after microwave heating. More specifically, the improved method of the present invention can impart hardness to at least a portion of the surface of the food after microwave heating (the portion to which porous particles are attached and its vicinity). Therefore, in one embodiment, the improved method of the present invention may be a method for imparting hardness to food after microwave heating. The various microwave heating conditions under which the food to which the improved method of the present invention is used can be served are the same as those for the microwave heating under which the food to which the present invention can be served, and the preferred conditions are also the same.

[0041] The present invention also provides a method for producing microwave-heated food (hereinafter also referred to as "the production method of the present invention"). The production method of the present invention is characterized by comprising attaching porous particles to at least a portion of the surface of food and subjecting the food to microwave heating. In the present invention, "microwave-heated food" means food that has been subjected to microwave heating once or more times.

[0042] The porous particles used in the manufacturing method of the present invention are the same as those used in the food of the present invention as described above, and the preferred embodiments are also the same.

[0043] The food to which porous particles are attached in the manufacturing method of the present invention is the same as the food of the present invention described above, and the preferred type and form of the food are also the same.

[0044] The method for attaching porous particles to at least a portion of the surface of food in the manufacturing method of the present invention is the same as the method for attaching porous particles to at least a portion of the surface of food in the food manufacturing method of the present invention described above, and the preferred embodiments and attachment amounts are also the same.

[0045] In the manufacturing method of the present invention, the various microwave heating conditions that allow the food to be served with porous particles attached are the same as those for microwave heating that allows the food of the present invention to be served, and the preferred conditions are also the same.

[0046] According to the manufacturing method of the present invention, microwave-heated food with improved texture and a desirable texture can be obtained. More specifically, according to the manufacturing method of the present invention, microwave-heated food in which hardness is imparted to at least a portion of the surface of the food (the portion to which porous particles are attached and its vicinity) can be obtained.

[0047] The present invention also provides an agent for improving the texture of food after microwave heating (hereinafter also referred to as "the agent of the present invention"). One of the features of the agent of the present invention is that it contains porous particles.

[0048] The porous particles contained in the agent of the present invention are the same as those used in the food of the present invention as described above, and the preferred embodiments are also the same.

[0049] The form of the agent of the present invention is not particularly limited and can be solid (including powder, granules, etc.), liquid (including slurry, etc.), gel, paste, etc.

[0050] In one embodiment, the agent of the present invention may consist solely of porous particles. In another embodiment, the agent of the present invention may contain other components in addition to porous particles. For example, in addition to porous particles, the agent of the present invention may further contain a conventional base (e.g., water, oil, organic solvent, etc.) depending on the form of the agent of the present invention.

[0051] The content of porous particles in the agent of the present invention is 0.1% by weight or more, 1% by weight or more, 10% by weight or more, 20% by weight or more, or 30% by weight or more, relative to the agent of the present invention. Alternatively, the content of porous particles in the agent of the present invention may be 100% by weight or less, 99.9% by weight or less, 90% by weight or less, 80% by weight or less, or 70% by weight or less, relative to the agent of the present invention.

[0052] The preparation of the agent of the present invention can be manufactured by conventional methods used in the field of food additives and the like.

[0053] The agent of the present invention is preferably intended to be attached to at least a portion of the surface of food. The food to which the agent of the present invention can be attached is the same as the food of the present invention described above, and the preferred type and form of food are also the same. Furthermore, the method for attaching the agent of the present invention to at least a portion of the surface of food is the same as the method for attaching porous particles to at least a portion of the surface of food in the food manufacturing method of the present invention described above, and the preferred form and amount of attachment are also the same.

[0054] The agent of the present invention can improve the texture of food after microwave heating. More specifically, the agent of the present invention can impart hardness to at least a portion of the surface of food after microwave heating (the portion to which porous particles are attached and its vicinity). Therefore, in one embodiment, the agent of the present invention may be an agent for imparting hardness to food after microwave heating. The various microwave heating conditions under which food using the agent of the present invention can be served are the same as those under which food using the present invention can be served, and the preferred conditions are also the same.

[0055] 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. Furthermore, in the following examples, the pore volume of the porous particles (silica gel particles, activated carbon particles, zeolite particles, and calcium silicate particles) was determined by the BET method. The average particle size of the porous particles was measured as the volume-based median diameter (D50) by laser diffraction-scattering. [Examples]

[0056] [Test 1] <Preparation of frozen dumplings in Example 1-1> Frozen dumplings (dumplings in a frozen state) were prepared using the following procedure (1) to (7) (hereinafter also referred to as "Frozen dumplings of Example 1-1").

[0057] (1) Making dumpling wrappers The dough, made by mixing wheat flour, water, and salt, was rolled to a thickness of approximately 0.7 mm using a roller-type noodle-making machine to produce a noodle sheet. Next, the noodle sheet was cut into an oval shape (major axis: 90 mm, minor axis: 80 mm) to produce dumpling wrappers (weight per sheet: 5 g).

[0058] (2) Preparation of the filling for the dumplings Ground meat, finely chopped vegetables, and seasonings were mixed together to create the filling for the dumplings.

[0059] (3) Making raw dumplings 12g of the filling was wrapped in the wrapper prepared in (1) above to make a semi-circular raw dumpling (uncooked dumpling).

[0060] (4) Preparation of batter A batter was prepared by dissolving starch and an emulsifying agent in water according to the proportions shown in Table 1 below, and then mixing in oil in which the emulsifier was dispersed.

[0061] [Table 1]

[0062] (5) Application of batter 1 g of the batter prepared in (4) above was mixed with 0.001 g of silica gel particles (SYLOPAGE® 760, manufactured by Fuji Silysia Chemical Co., Ltd., pore volume: 0.4 mL / g, average particle size: 10 μm) and uniformly dispersed. Then, the entire amount of the batter was applied to the bottom surface (the surface that will be grilled) of the raw dumplings prepared in (3) above. The area of ​​the raw dumplings to which the batter was applied (coated surface) was approximately 12 cm². 2 That was the case.

[0063] (6) Cooking raw dumplings In (5) above, raw dumplings coated with batter were subjected to cooking (steaming and baking) to produce cooked dumplings. Steaming was performed for 6 minutes using a gas stove and steamer. After steaming, baking was performed on a hot plate at 230°C for 4 minutes. Furthermore, the baking was performed with the bottom of the dumplings in contact with the hot plate.

[0064] (7) Freezing of dumplings (Preparation of frozen dumplings) The dumplings prepared in (6) above were subjected to rapid freezing at -35°C to obtain frozen dumplings.

[0065] <Preparation of frozen dumplings in Examples 1-2 to 1-7> Frozen dumplings were prepared using the same procedure as in Example 1-1, except that the amount of silica gel particles added to the batter in step (5) of Example 1-1 was changed from 0.001 g to the amounts shown in Table 2 below (0.003 to 0.1 g). (Hereafter, these will also be referred to as "Frozen Dumplings of Example 1-2" to "Frozen Dumplings of Example 1-7," respectively).

[0066] <Preparation of Frozen Dumplings in Comparative Example 1-1> Frozen dumplings were prepared using the same procedure as in Example 1-1, except that no batter was applied to the raw dumplings (i.e., the raw dumplings prepared in step (3) of the frozen dumpling preparation procedure in Example 1-1 were used directly for the heating process in step (6)). (Hereafter referred to as "frozen dumplings of Comparative Example 1-1").

[0067] <Preparation of Frozen Dumplings in Comparative Example 1-2> Frozen dumplings were prepared using the same procedure as in Example 1-1, except that no silica gel particles were added to the batter in step (5) of the frozen dumpling preparation procedure in Example 1-1 (i.e., the batter prepared in step (4) was applied directly to the raw dumplings). (This will also be referred to as "comparative example 1-2 frozen dumplings" below.)

[0068] <Sensory evaluation> Five frozen dumplings each from Examples 1-1 to 1-7 and Comparative Examples 1-1 and 1-2 were heated in a microwave oven (500W) for 2 minutes. Then, a sensory evaluation was performed on the hardness of the browned surface of each dumpling after microwave heating. The sensory evaluation of the hardness of the fried surface of the dumplings after microwave heating was conducted by a trained expert panel using a scoring method. Specifically, the expert panel tasted each of the dumplings from Examples 1-1 to 1-7 and Comparative Examples 1-1 and 1-2 after microwave heating and collectively scored them in 1-point increments according to the evaluation criteria below. The expert panel consisted of 10 panelists with more than 3 years of experience in food research and development. The panelists shared an understanding of the evaluation criteria below (evaluation criteria for the hardness of the fried surface of the dumplings) and were trained in advance to ensure that there was common understanding among the panelists regarding how much the hardness of the fried surface needed to change for a 1-point change in the score.

[0069] (Evaluation criteria for the firmness of the cooked surface of dumplings) 5 points: The cooked surface is hard overall. 4 points: Most of the cooked surface is hard. 3 points: Part of the cooked surface is hard. 2 points: Most of the cooked surface is soft. 1 point: The entire surface is soft.

[0070] The evaluation results are shown in Table 2 below.

[0071] [Table 2]

[0072] As shown in Table 2, in all of the frozen dumplings of Examples 1-1 to 1-7, in which silica gel particles were attached to the cooked surface, the cooked surface became firm after microwave heating. On the other hand, the frozen dumplings of Comparative Examples 1-1 and 1-2, which did not have silica gel particles attached, did not develop hardness on the cooked surface after microwave heating.

[0073] <Preparation of frozen dumplings in Examples 1-8 to 1-14> In the frozen dumpling preparation procedure (5) of Example 1-1, activated carbon particles ("Bamboo Charcoal Powder 5P" manufactured by Glico Nutritional Foods Co., Ltd., pore volume: 0.086 mL / g) were used instead of silica gel particles, and mixed into 1 g of batter in the amount shown in Table 3 below (0.001 to 0.1 g) and uniformly dispersed. Frozen dumplings were prepared using the same procedure as in Example 1-1 (hereinafter referred to as "frozen dumplings of Example 1-8" to "frozen dumplings of Example 1-14," respectively).

[0074] <Sensory evaluation> Five frozen dumplings each from Examples 1-8 to 1-14 were heated in a microwave oven (500W) for 2 minutes. Then, the hardness of the browned surface of each dumpling after microwave heating was evaluated in the same manner as described above. The evaluation results are shown in Table 3 below.

[0075] [Table 3]

[0076] As shown in Table 3, in all of the frozen dumplings of Examples 1-8 to 1-14, which had activated carbon particles attached to the grilled surface, the grilled surface became firm after microwave heating.

[0077] <Preparation of frozen dumplings in Examples 1-15> Frozen dumplings were prepared using the same procedure as in Example 1-1, except that silica gel particles with a pore volume of 1.6 mL / g ("SYLOPAGE® 720" manufactured by Fuji Silysia Chemical Co., Ltd.) were used instead of silica gel particles with a pore volume of 0.4 mL / g in the procedure (5) for preparing the frozen dumplings of Example 1-1 (hereinafter also referred to as "frozen dumplings of Example 1-15").

[0078] <Sensory evaluation> Five frozen dumplings from Examples 1-15 were heated in a microwave oven (500W) for 2 minutes. Then, the hardness of the browned surface of each dumpling after microwave heating was evaluated in the same manner as described above. The evaluation results are shown in Table 4 below.

[0079] [Table 4]

[0080] As shown in Table 4, the frozen dumplings of Examples 1-15, in which silica gel particles were attached to the browned surface, had hardened browned surfaces after microwave heating.

[0081] <Preparation of frozen dumplings in Examples 1-16 to 1-20> Frozen dumplings were prepared using the same procedure as in Example 1-1, except that in step (5) of the frozen dumpling preparation procedure in Example 1-1, activated carbon particles having pore volumes (0.438 to 1.380 mL / g) as shown in Table 5 below (all manufactured by Ajinomoto Fine Techno Co., Ltd.) were used instead of silica gel particles (hereinafter referred to as "frozen dumplings of Example 1-16" to "frozen dumplings of Example 1-20," respectively).

[0082] <Sensory evaluation> Five frozen dumplings each from Examples 1-16 to 1-20 were heated in a microwave oven (500W) for 2 minutes. Then, the hardness of the browned surface of each dumpling after microwave heating was evaluated in the same manner as described above. The evaluation results are shown in Table 5 below.

[0083] [Table 5]

[0084] As shown in Table 5, in all of the frozen dumplings of Examples 1-16 to 1-20, which had activated carbon particles attached to the grilled surface, the grilled surface became firm after microwave heating.

[0085] <Preparation of frozen dumplings in Examples 1-21 and 1-22> Frozen dumplings were prepared using the same procedure as in Example 1-1, except that in step (5) of the frozen dumpling preparation procedure in Example 1-1, zeolite particles (Heiltropfen's "Zeolite Powder," pore volume: 0.16 mL / g, average particle size: 10 μm) or calcium silicate particles (Tomita Pharmaceutical Co., Ltd.'s "Fluorite PS-10," pore volume: 1.8 mL / g, average particle size: 10 μm) were used instead of silica gel particles (hereinafter referred to as "Frozen Dumplings of Example 1-21" and "Frozen Dumplings of Example 1-22," respectively).

[0086] <Sensory evaluation> Five frozen dumplings each from Examples 1-21 and 1-22 were heated in a microwave oven (500W) for 2 minutes. Then, the hardness of the browned surface of each dumpling after microwave heating was evaluated in the same manner as described above. The evaluation results are shown in Table 6 below.

[0087] [Table 6]

[0088] As shown in Table 6, both the frozen dumplings of Example 1-21, which had zeolite particles attached to the grilled surface, and the frozen dumplings of Example 1-22, which had calcium silicate attached to the grilled surface, had a hardened grilled surface after microwave heating.

[0089] [Exam 2] <Preparation of frozen grilled chicken in Example 2-1> Raw chicken (120g), cut into roughly rectangular pieces measuring 10cm x 8cm x 2.5cm, was steamed in a steam convection oven at 98°C for 6 minutes, and then grilled in a grill oven at 250°C for 5 minutes to brown the skin side. The skin side of the resulting grilled chicken was then coated with 3g of canola oil containing 0.001g of silica gel particles (SYLOPAGE® 760, manufactured by Fuji Silicia Chemical Co., Ltd., pore volume: 0.4mL / g). The area of ​​the grilled chicken coated with canola oil (coated surface) was approximately 40cm². 2Subsequently, the grilled chicken was subjected to rapid freezing at -35°C to obtain frozen grilled chicken (hereinafter also referred to as "frozen grilled chicken of Example 2-1").

[0090] <Preparation of frozen grilled chicken in Examples 2-2 to 2-7> Frozen grilled chicken was prepared using the same procedure as in Example 2-1, except that the amount of silica gel particles dispersed in canola oil was changed from 0.001 g to the amounts shown in Table 3 below (0.003 to 0.1 g). (Hereafter, these will also be referred to as "Frozen Grilled Chicken of Example 2-2" to "Frozen Grilled Chicken of Example 2-7," respectively.)

[0091] <Preparation of Frozen Grilled Chicken in Comparative Example 2-1> Frozen grilled chicken was prepared using the same procedure as in Example 2-1, except that no canola oil was applied to the grilled chicken (hereinafter also referred to as "Frozen Grilled Chicken of Comparative Example 2-1").

[0092] <Preparation of Frozen Grilled Chicken in Comparative Example 2-2> Frozen grilled chicken was prepared using the same procedure as in Example 2-1, except that the canola oil coated on the grilled chicken was changed from one with dispersed silica gel particles to one without any dispersed silica gel particles (hereinafter also referred to as "comparative example 2-2 frozen grilled chicken").

[0093] <Sensory evaluation> The frozen grilled chickens of Examples 2-1 to 2-7 and Comparative Examples 2-1 and 2-2 were heated in a microwave oven (500W) for 4 minutes, and then a sensory evaluation was conducted on the hardness of the skin surface of each grilled chicken after microwave heating. The sensory evaluation of the skin hardness of the grilled chicken after microwave heating was conducted using a scoring method by a trained expert panel. Specifically, the expert panel tasted each of the grilled chicken samples from Examples 2-1 to 2-7 and Comparative Examples 2-1 and 2-2 after microwave heating, and collectively scored them in 1-point increments according to the evaluation criteria below. The expert panel consisted of 10 panelists with more than 3 years of experience in food research and development. The panelists shared an understanding of the evaluation criteria below (evaluation criteria for the skin hardness of grilled chicken) and were pre-trained to ensure that there was common understanding among them regarding how much the skin hardness needed to change for a 1-point change in the score.

[0094] (Evaluation criteria for the firmness of grilled chicken skin) 5 points: The skin is hard overall. 4 points: Most of the skin surface is hard. 3 points: Part of the skin is hard. 2 points: Most of the skin is soft. 1 point: The entire surface of the skin is soft.

[0095] The evaluation results are shown in Table 7 below.

[0096] [Table 7]

[0097] As shown in Table 7, in all of the frozen grilled chickens of Examples 2-1 to 2-7, which had silica gel particles attached to the skin surface, the skin surface became firm after microwave heating. On the other hand, the frozen grilled chicken of Comparative Examples 2-1 and 2-2, which did not have silica gel particles attached, did not develop firmness on the skin surface after microwave heating.

[0098] [Exam 3] <Preparation of frozen grilled fish in Example 3-1> A 50g fish fillet with skin was cooked in a frying pan over medium heat for 5 minutes. The skin side of the cooked fish was then coated with 3g of canola oil containing 0.1g of silica gel particles (SYLOPAGE® 760, manufactured by Fuji Silicia Chemical Co., Ltd., pore volume: 0.4mL / g). The area of ​​the cooked fish coated with canola oil (coated surface) was approximately 30cm². 2 Subsequently, the grilled fish was subjected to rapid freezing at -35°C to obtain frozen grilled fish (hereinafter also referred to as "frozen grilled fish of Example 3-1").

[0099] <Preparation of frozen grilled fish in Comparative Example 3-1> Frozen grilled fish was prepared using the same procedure as in Example 3-1, except that no canola oil was applied to the grilled fish (hereinafter also referred to as "Frozen Grilled Fish of Comparative Example 3-1").

[0100] <Preparation of Frozen Grilled Fish in Comparative Example 3-2> Frozen grilled fish was prepared using the same procedure as in Example 3-1, except that the canola oil coated on the grilled fish was changed from one with dispersed silica gel particles to one without any dispersed silica gel particles (hereinafter also referred to as "comparative example 3-2 frozen grilled fish").

[0101] <Sensory evaluation> The frozen grilled fish of Example 3-1 and Comparative Examples 3-1 and 3-2 were heated in a microwave oven (500W) for 4 minutes, and then a sensory evaluation was conducted on the hardness of the skin portion of each grilled fish after microwave heating. The sensory evaluation of the firmness of the skin portion of grilled fish after microwave heating was conducted by a trained expert panel using a scoring method. Specifically, the expert panel tasted each of the grilled fish from Example 3-1 and Comparative Examples 3-1 and 3-2 after microwave heating and collectively scored them in 1-point increments according to the evaluation criteria below. The expert panel consisted of 10 panelists with more than 3 years of experience in food research and development. The panelists shared an understanding of the evaluation criteria below (evaluation criteria for the firmness of the skin portion of grilled fish) and were trained in advance to ensure that there was common understanding among the panelists regarding how much the firmness of the skin portion should change for a 1-point change in the score.

[0102] (Evaluation criteria for the firmness of the skin of grilled fish) 5 points: The skin is tough overall. 4 points: Most of the skin is hard. 3 points: Part of the skin is tough. 2 points: Most of the skin is soft. 1 point: The entire skin area is soft.

[0103] The evaluation results are shown in Table 8 below.

[0104] [Table 8]

[0105] As shown in Table 8, the frozen grilled fish of Example 3-1, in which silica gel particles were attached to the skin area, had a firm texture in the skin area after microwave heating. On the other hand, the frozen grilled fish of Comparative Examples 3-1 and 3-2, which did not have silica gel particles attached, did not develop firmness in the skin area after microwave heating.

[0106] The results of tests 1-3 suggest that by attaching porous particles to the part of the food surface where hardness is desired, that part becomes hard after microwave heating. [Industrial applicability]

[0107] According to the present invention, the texture after microwave heating is improved, and a food product having a suitable texture after microwave heating is provided. After microwave heating, at least a portion of the surface of the food product may be given a firmer texture. Furthermore, the present invention also provides a method for improving the texture of food after microwave heating. This method can impart hardness to at least a portion of the surface of the food after microwave heating. Furthermore, the present invention also provides a method for producing microwave-heated food with improved texture and a desirable texture. According to this method, microwave-heated food can be obtained in which at least a portion of the surface of the food is given hardness. Furthermore, the present invention also provides an agent that can improve the texture of food after microwave heating. This agent can impart hardness to at least a portion of the surface of food after microwave heating.

Claims

1. Microwave-safe food products in which porous particles are attached to at least part of the surface.

2. The food according to claim 1, wherein the porous particles are at least one selected from the group consisting of silica gel particles, zeolite particles, calcium silicate particles, and activated carbon particles.

3. The food according to claim 1, wherein the pore volume of the porous particles is 0.05 mL / g or more.

4. The food according to claim 1, wherein the amount of porous particles attached is 0.000001% by weight or more relative to the food.

5. The food according to claim 1, wherein the food is a cooked food.

6. The food according to claim 1, wherein the food is a frozen food.

7. The food according to claim 1, wherein the food is a processed grain food or an animal food.

8. The food according to claim 7, wherein the grain processed food is a noodle-filled food or a rice food.

9. A method for improving the texture of microwave-heated food after microwave heating, comprising attaching porous particles to at least a portion of the surface of the microwave-heated food.

10. A method for producing microwave-heated food, comprising attaching porous particles to at least a portion of the surface of the food and subjecting the food to microwave heating.

11. A texture-improving agent for microwave-heated foods, containing porous particles and intended to adhere to at least a portion of the surface of such foods.

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