Composition for heating edible meat

Abstract

Provided is a novel method for softening the texture of a heated meat that is produced by heating a raw meat with microwaves, the method being a method for softening an edible meat and comprising (1) a step for bringing the edible meat into contact with a composition containing at least one active ingredient selected from the group consisting of reduced glutathione, cysteine and salts thereof and (2) a step for exposing the edible meat to microwaves.

Description

Composition for heating meat

[0001] The present invention relates to a method for tenderizing meat by exposing it to microwaves and a method for producing tenderized microwave-heated meat.The present invention also relates to a meat tenderizing composition for microwave heating that can impart a soft texture to meat.

[0002] In recent years, with the diversification of lifestyles, there has been a demand for quick and easy cooking at home. In particular, cooking using microwave ovens has become widespread, and the uses of microwave ovens, which were previously used as a means of warming food, have expanded to include cooking raw ingredients. While there are a wide variety of dishes that can be cooked using microwave ovens, there has been an increase in the use of microwave ovens to cook raw meat due to the convenience of being able to cook main dishes in a short amount of time.

[0003] Microwave ovens heat food by exposing it to microwaves and inducing vibrations in the water molecules contained within it. For this reason, microwave heating is also called microwave heating. The greatest feature of microwave heating is that the temperature rises from within the food, as the food itself heats up due to the vibrations of the water molecules in the food. This mechanism is significantly different from that of cooking in a frying pan or pot, which heats food from the outside using conductive or convection heat. In other words, while cooking in a frying pan or pot heats food slowly from the outside, microwave cooking heats food rapidly from the inside, making it suitable for quick and convenient cooking.

[0004] However, microwave heating also has its drawbacks, particularly noticeable when cooking raw meat. The biggest drawback of cooking raw meat with microwave heating is that it develops a hard, rubbery texture upon heating. This phenomenon is also commonly observed when cooking eggs in a microwave oven (Non-Patent Document 1) and is also known as rubberization. Since it is not observed when cooking in a frying pan or pot, it is a phenomenon unique to microwave heating, and a major challenge is how to cook raw meat tenderly in a microwave oven without rubberizing it. The rubberization of raw meat caused by microwave heating has traditionally been thought to be hardening, caused by a significant reduction in water content within the meat due to the rapid evaporation of water molecules vibrated by microwaves. However, since the unnatural rubbery texture of cooked meat cannot be explained by the hardening of meat proteins due to the simple removal of water molecules, it is speculated that a mechanism other than the removal of water molecules is involved in this phenomenon.

[0005] The formation of disulfide bonds by exposing thiol groups to microwaves can be inferred from a report (Patent Document 1) showing that reduced cysteine ​​is converted to oxidized cysteine ​​by microwaves. In order to inhibit the formation of disulfide bonds in meat proteins during microwave cooking, it is necessary to inhibit the reaction between thiol groups in meat proteins by reducing the thiol groups. In other words, this may be possible by adding a reducing agent.

[0006] However, meat contains many proteins with different properties, such as actin and myosin, which make up myofibrils, and collagen, which makes up connective tissues such as perimysium. Because these proteins have complex higher-order structures, simply adding a reducing agent can only affect some of the thiol groups exposed on the surface of the meat protein. Therefore, adding a denaturant to unfold the meat protein and expose the thiol groups inside the three-dimensional structure, in combination with a reducing agent, can reduce many of the thiol groups in the meat protein. However, the increased exposure of thiol groups on the surface of the meat protein also promotes the formation of disulfide bonds by microwave irradiation. In particular, disulfide bonds are known to undergo rapid exchange reactions, i.e., cross-linking reactions, under alkaline conditions (Non-Patent Document 2), which promotes the polymerization and gelation of protein molecules. Therefore, the use of alkaline materials, which are typical examples of denaturants, may actually promote the rubberization of meat proteins.

[0007] Alkaline materials, which are denaturants commonly used in meat tenderization, have a strong denaturing effect on myofibrillar proteins, which have an isoelectric point of around pH 5.5, and tend to promote disulfide bond exchange reactions, which makes them more likely to induce polymerization of meat proteins, i.e., rubberization. However, for collagen, which has an isoelectric point of around pH 9.0, the approach using reducing agents is actually reduced.

[0008] There have been several reports on the induction of structural changes in proteins by microwave exposure. As mentioned above, Patent Document 1 shows that reduced cysteine ​​is converted to oxidized cysteine ​​by microwaves, and Patent Document 2 shows a method of binding meat substitutes by irradiating a textured protein consisting of soy protein and wheat flour with microwaves. Both findings support the formation of disulfide bonds in meat proteins by microwaves, but do not mention meat tenderization during microwave cooking.

[0009] As examples of findings involving adding a reducing agent to a target object and then exposing it to microwaves, there have been disclosed a method for improving the texture of microwave-safe buckwheat noodles by blending gluten with an edible oxidizing agent and / or an edible reducing agent (Patent Document 3), a method for obtaining a keratin fiber deformation effect by exposing it to microwaves in the presence of steam containing a composition containing a reducing agent (Patent Document 4), a method for obtaining a keratin fiber deformation effect by treating it with a composition containing a linear organic disulfide compound and then heating it with microwaves (Patent Document 5), and a method for obtaining a keratin fiber deformation effect by treating it with a reducing agent, drying it by microwave heating, etc., and then treating it with an oxidizing agent (Patent Document 6). All of these methods achieve the desired effect by cleaving disulfide bonds in proteins with a reducing agent, but no detailed consideration has been given to combining them with acids, let alone mentioning their application to meat tenderization in microwave cooking.

[0010] Examples of findings involving adding an acid or alkali to an object and then exposing it to microwaves include a method for tenderizing meat using a composition for microwave cooking of raw meat containing pyrophosphoric acid and one or more selected from malic acid, trehalose, phosphoric acid, and calcined calcium (Patent Document 7); a method for suppressing fishy odor by applying a seasoning containing an organic acid, starch, a thermosetting protein, and edible oils and fats to raw meat or raw seafood and then heating the meat in a microwave oven (Patent Document 8); a method for straightening hair by adding a composition containing a compound containing a guanidine moiety such as arginine and heating the hair with microwaves or the like (Patent Document 9); a method for uniformly cooking livestock or seafood meat by impregnating it with a high-concentration salt solution and a high-concentration alkali solution and then irradiating it with microwaves (Patent Document 10); and a method for producing peptides by irradiating animal or vegetable proteins in alkaline water with microwaves to partially hydrolyze them (Patent Document 11). In all cases, a certain desired effect is achieved by using a pH adjuster such as an acid or alkali, but most of these inventions use alkaline materials, and no consideration has been given to their use in combination with reducing agents, so they have not been optimized for meat tenderization during microwave cooking.

[0011] As examples of findings that change the structure of proteins by adding a reducing agent to a proteinaceous food material, there have been disclosed a method for producing fine-grained rice flour-based bread that rises well using rice flour, sorghum flour, and glutathione (Patent Document 12), a dough improver for rice flour bread that contains glutathione but does not contain wheat flour or gluten (Patent Document 13), a method for extracting gliadin and glutenin by cleaving disulfide bonds in gluten using a reducing agent such as sodium sulfite (Patent Document 14), and a method for producing baked products or pasta using a dough composed of a composition containing reduced thiol-based redox protein and cereal flour (Patent Document 15). In all of these methods, the cleavage of disulfide bonds in proteins by a reducing agent contributes to the desired effect, but microwave irradiation is not mentioned.

[0012] As a method of changing the protein structure by adding a combination of an acid or alkaline material and a reducing agent to a proteinaceous food material, a method of maintaining the softness and juiciness of meat by applying a composition containing roasted salt, glutathione, sugar alcohol or oligosaccharide, and processed starch to meat (Patent Document 16) has been disclosed, but there is no mention of exposure to microwaves.

[0013] Japanese Patent No. 5537820 Japanese Patent No. 4797893 Japanese Patent No. 3441450 Japanese Patent No. 6162041 Japanese Patent Publication No. 2014-516024 Japanese Patent No. 6317060 Japanese Patent Publication No. 2021-97624 Japanese Patent No. 3687072 Japanese Patent Publication No. 2016-539933 Japanese Patent Publication No. 2001-190247 Japanese Patent No. 5641466 Japanese Patent No. 6430117 Japanese Patent No. 5540347 Japanese Patent No. 3490093 Japanese Patent No. 3691053 Japanese Patent No. 4544160

[0014] Home Economics Journal, Vol. 36, No. 8, pp. 590-595 (1985) Organic Synthetic Chemistry, Vol. 35, No. 5, pp. 332-342 (1977)

[0015] The present invention has been made in consideration of the above-mentioned circumstances, and the problem to be solved by the present invention is to provide a novel method for softening, i.e., tenderizing, the texture of cooked meat obtained by microwave heating (particularly, cooking in a microwave oven) raw meat, and to provide a meat tenderizing composition for microwave heating.

[0016] The present inventors have focused on the relationship between the formation of disulfide bonds by microwaves and the cleavage of disulfide bonds and the reduction of thiol groups by reducing agents, and as a result of extensive research aimed at solving the above-mentioned problems, have found that tender meat can be obtained without rubber formation by adjusting the pH to an acidic range of 5.5 or less, bringing reduced glutathione or cysteine ​​into contact with meat, and then heating it with microwaves, and have thus completed the present invention.

[0017] [1] A method for tenderizing meat, comprising: (1) contacting meat with a composition containing at least one active ingredient selected from the group consisting of reduced glutathione, cysteine, and salts thereof, and (2) exposing the meat to microwaves. [2] The method according to [1], wherein meat is contacted with 10 μmol to 10,000 μmol of the active ingredient per 100 g of meat. [3] The method according to [1] or [2], wherein the composition contains an organic acid, an inorganic acid, or a salt thereof. [4] The method according to [3], wherein the organic acid, inorganic acid, or salt thereof is one or more selected from the group consisting of succinic acid, citric acid, tartaric acid, malic acid, acetic acid, gluconic acid, lactic acid, fumaric acid, phytic acid, disodium dihydrogen pyrophosphate, and calcium dihydrogen pyrophosphate. [5] The method according to any one of [1] to [4], wherein the pH of the composition when added to water is 5.5 or less. [6] The method according to [5], wherein the pH of the composition when added to water is 2 to 5.5. [7] The method according to [5] or [6], wherein the step of contacting meat with the composition is a step of immersing meat in the composition. [8] A method for producing heated meat, comprising: (1) a step of contacting meat with a composition containing at least one active ingredient selected from the group consisting of reduced glutathione, cysteine, and salts thereof, and (2) a step of exposing the meat to microwaves. [9] The method according to [8], wherein meat is contacted with 10 μmol to 10,000 μmol of the active ingredient per 100 g of meat.

[10] The method according to [8] or [9], wherein the composition contains an organic acid, an inorganic acid, or a salt thereof.

[11] The method according to

[10] , wherein the organic acid, inorganic acid, or salt thereof is one or more selected from the group consisting of succinic acid, citric acid, tartaric acid, malic acid, acetic acid, gluconic acid, lactic acid, fumaric acid, phytic acid, disodium dihydrogen pyrophosphate, and calcium dihydrogen pyrophosphate.

[12] The method according to any one of [8] to

[11] , wherein the pH of the composition when added to water is 5.5 or less.

[13] The method according to

[12] , wherein the pH of the composition when added to water is 2 to 5.5.

[14] The method according to

[12] or

[13] , wherein the step of contacting meat with the composition is a step of immersing meat in the composition.

[15] A meat tenderizing composition for microwave heating, comprising as an active ingredient at least one selected from the group consisting of reduced glutathione, cysteine, and salts thereof.

[16] The composition according to

[15] , wherein the composition comprises an organic acid, an inorganic acid, or a salt thereof.

[17] The composition according to

[16] , wherein the organic acid, inorganic acid, or salt thereof is one or more selected from the group consisting of succinic acid, citric acid, tartaric acid, malic acid, acetic acid, gluconic acid, lactic acid, fumaric acid, phytic acid, disodium dihydrogen pyrophosphate, and calcium dihydrogen pyrophosphate.

[18] The composition according to any one of

[15] to

[17] , wherein the pH of the composition when added to water is 5.5 or less.

[19] The composition according to

[18] , wherein the pH of the composition when added to water is 2 to 5.5.

[0018] According to the present invention, it is possible to provide a cooked meat product that is cooked in a microwave oven and is soft and has an excellent texture without becoming rubbery.

[0019] The present invention relates to a method for tenderizing meat (hereinafter sometimes abbreviated as "the tenderization method of the present invention"), which comprises: (1) the step of contacting meat with a composition containing at least one active ingredient selected from the group consisting of reduced glutathione, cysteine, and salts thereof; and (2) the step of exposing the meat to microwaves.

[0020] The reduced glutathione used in the present invention is a tripeptide in which glutamic acid, cysteine, and glycine are bonded in this order, with the glutamic acid and cysteine ​​bonded via a γ-glutamyl bond. Glutathione exists in reduced and oxidized forms, but the glutathione used in the present invention is the reduced form. Therefore, when simply referring to glutathione in this specification, it means reduced glutathione.

[0021] The salt of reduced glutathione is not particularly limited as long as it is orally ingestible. For example, salts of acidic groups such as carboxyl groups include ammonium salts, salts with alkali metals such as sodium and potassium, salts with alkaline earth metals such as calcium and magnesium, aluminum salts, zinc salts, salts with organic amines such as triethylamine, ethanolamine, morpholine, pyrrolidine, piperidine, piperazine, and dicyclohexylamine, and salts with basic amino acids such as arginine and lysine. Examples of salts of basic groups such as amino groups include salts with inorganic acids such as hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid, and hydrobromic acid, salts with organic carboxylic acids such as acetic acid, citric acid, benzoic acid, maleic acid, fumaric acid, tartaric acid, succinic acid, tannic acid, butyric acid, hybenzic acid, pamoic acid, enanthic acid, decanoic acid, teoclic acid, salicylic acid, lactic acid, oxalic acid, mandelic acid, malic acid, and methylmalonic acid, and salts with organic sulfonic acids such as methanesulfonic acid, benzenesulfonic acid, and p-toluenesulfonic acid. One type of salt may be used, or two or more types of salts may be used in combination.

[0022] The reduced glutathione used in the present invention may be a pure reduced glutathione, a yeast extract containing reduced glutathione, or a mixture containing oxidized glutathione and other substances.

[0023] The reduced glutathione, glutathione-containing yeast extract, and glutathione-containing mixture may be in any form, including solids such as powders and granules, and semisolids such as liquids and pastes. Glutathione can be obtained as a natural product, dried and crushed, extracted with a solvent, or synthesized by chemical synthesis, peptide synthesis, or Escherichia coli. Examples of glutathione or a salt thereof for use in the present invention include commercially available glutathione-containing yeast extracts.

[0024] The cysteine ​​used in the present invention may be a free cysteine, a cysteine ​​salt, or a combination thereof. Cysteine ​​may be in the L-form, the D-form, or a mixture thereof (e.g., racemic form), but the L-form is preferably used.

[0025] The salt of cysteine ​​is not particularly limited as long as it is orally ingestible. For example, salts of acidic groups such as carboxyl groups include ammonium salts, salts with alkali metals such as sodium and potassium, salts with alkaline earth metals such as calcium and magnesium, aluminum salts, zinc salts, salts with organic amines such as triethylamine, ethanolamine, morpholine, pyrrolidine, piperidine, piperazine and dicyclohexylamine, and salts with basic amino acids such as arginine and lysine. Examples of salts of basic groups such as amino groups include salts with inorganic acids such as hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid, and hydrobromic acid; salts with organic carboxylic acids such as acetic acid, citric acid, benzoic acid, maleic acid, fumaric acid, tartaric acid, succinic acid, tannic acid, butyric acid, hybenzic acid, pamoic acid, enanthic acid, decanoic acid, teoclic acid, salicylic acid, lactic acid, oxalic acid, mandelic acid, malic acid, and methylmalonic acid; and salts with organic sulfonic acids such as methanesulfonic acid, benzenesulfonic acid, and p-toluenesulfonic acid. One type of salt may be used, or two or more types of salts may be used in combination. Among these, preferred salts of cysteine ​​include cysteine ​​hydrochloride, cysteine ​​acetate, cysteine ​​citrate, and cysteine ​​succinate.

[0026] Furthermore, the cysteine ​​and salts thereof used in the present invention may be produced by any method, such as fermentation or extraction. The cysteine ​​and salts thereof used in the present invention may be yeast extracts containing them or mixtures with other substances. Cysteine ​​or salts thereof, cysteine-containing yeast extracts, and mixtures containing them may be in any form, including solids such as powders and granules, liquids, and semisolids such as pastes. Cysteine ​​and salts thereof may be obtained as natural products, dried and crushed products, extracts extracted with solvents, or products synthesized by chemical synthesis, peptide synthesis, or Escherichia coli. Examples of cysteine ​​or salts thereof used in the present invention include commercially available cysteine-containing yeast extracts.

[0027] In the present invention, meat refers to all forms of livestock meat, with raw meat being particularly preferred. In the present invention, "raw meat" refers to meat that has not been substantially heated after being harvested from an animal (e.g., poultry, livestock, etc.). Here, "substantially unheated" means either (i) meat that has not been heated at all, or (ii) meat that has been heated but has not denatured the proteins in the meat (e.g., frozen raw meat that has been heated simply to thaw it). Meat may be processed into any size or shape, such as block meat, cut meat (e.g., cube cut meat), sliced ​​meat (e.g., thick sliced ​​meat, thin sliced ​​meat), minced meat, ground meat, or surimi (surimi). However, since the present invention is characterized by its ability to be cooked tenderly without becoming rubbery in a microwave oven, it is desirable to use block meat, cut meat, sliced ​​meat, or minced meat to obtain the desired effect. The meat raw material may be derived from any animal, such as pig, cow, chicken, sheep, goat, horse, deer, camel, bear, rabbit, pigeon, duck, quail, or alpaca.

[0028] In the present invention, "tenderizing" meat means softening the meat, and means that the texture of the meat becomes softer.

[0029] In step (1), meat is contacted with a composition (sometimes abbreviated as the composition of the present invention) containing at least one active ingredient selected from the group consisting of reduced glutathione, cysteine, and salts thereof (hereinafter sometimes abbreviated as the active ingredient of the present invention). The amount of the active ingredient of the present invention contacted with the meat is not particularly limited as long as the meat tenderizing effect is not impaired. However, it is typically 10 μmol or more, preferably 20 μmol or more, and more preferably 30 μmol or more per 100 g of meat. From the viewpoint of taste quality, the upper limit is typically 10,000 μmol or less, preferably 5,000 μmol or less. The above contact amounts are all values ​​converted to free forms, and when two or more types are used in combination, the total value represents the total amount. Note that 1 mol of glutathione is 307.33 g, so 10 μmol is equivalent to 3.07 mg. Furthermore, when using a glutathione-containing yeast extract containing 10% glutathione, 10 μmol of glutathione corresponds to 30.73 mg of glutathione-containing yeast extract. Furthermore, since 1 mol of cysteine ​​weighs 121.16 g, 10 μmol corresponds to 1.21 mg. Furthermore, when using a cysteine-containing yeast extract containing 2% cysteine, 10 μmol of cysteine ​​corresponds to 60.58 mg of cysteine-containing yeast extract. For example, the converted values ​​are shown in Table 1.

[0030]

[0031] The proportion of the active ingredient to be brought into contact with raw meat can be adjusted appropriately depending on the type and amount of meat, heating conditions, etc., and is not particularly limited. However, when converted into the free form of the active ingredient, it is usually 1 x 10 －５ up to 3 parts by weight, preferably 1 x 10 －４ up to 0.5 parts by weight, more preferably 1 x 10 －３ More specifically, the proportion of glutathione is usually 3 x 10 to 0.3 parts by weight, calculated as a free form, per 100 parts by weight of meat. －５ up to 3 parts by weight, preferably 3 x 10 －４ up to 0.5 parts by weight, more preferably 3 x 10 －３More specifically, the proportion of cysteine ​​is usually 1 x 10 to 0.3 parts by weight, calculated as a free form, per 100 parts by weight of meat. －５ to 1 part by weight, preferably 1 x 10 －４ up to 0.5 parts by weight, more preferably 1 x 10 －３ 0.12 parts by weight.

[0032] The composition of the present invention may be in any form, such as a solid such as a powder or granules, a liquid such as a solution or suspension, or a semi-solid such as a paste, but from the viewpoint of storage stability and convenience, a solid such as a powder or granules is preferred. Also, from the viewpoint of efficiently obtaining a softening effect, a liquid or semi-solid may be used, but in the present invention, it is preferred to dissolve the composition in water or the like before use to make it into a liquid or semi-solid form.

[0033] The method for bringing the composition of the present invention into contact with meat is not particularly limited, as long as the composition of the present invention adheres to at least the surface of the meat. Examples include sprinkling the solid composition directly onto the meat, immersing the meat in a liquid or semi-solid composition, or applying a liquid or semi-solid composition to the surface of the meat. From the perspective of simplicity and efficient softening effect, the method of immersing the meat in a liquid composition is preferred.

[0034] Meat that has been contacted with the composition of the present invention, for example, meat that has been soaked in the composition of the present invention, may be appropriately massaged in a conventional manner to promote penetration of the composition of the present invention into the meat, and the meat may be left to stand in contact with the composition of the present invention for usually 5 seconds to 24 hours, preferably 10 seconds to 12 hours, more preferably 30 seconds to 8 hours, even more preferably 1 minute to 5 hours, and particularly preferably 2 minutes to 3 hours. When the meat is heated in a microwave oven while in contact with the active ingredient of the present invention, the time for microwave heating is also included in the above-mentioned time.

[0035] In the present invention, the step of contacting the composition with meat may involve contacting the composition while heating in a microwave oven, or may involve heating in a microwave oven after contacting the composition, or both. The temperature during contacting the composition while heating in a microwave oven is preferably 55°C to 130°C, more preferably 70°C to 110°C, from the viewpoint of sufficiently heating the meat. When heating in a microwave oven after contacting the composition, any temperature may be used, but if the contact is to be continued for a long period of time, a low temperature is desirable from the viewpoint of food hygiene.

[0036] The composition of the present invention may be a composition consisting of the active ingredient of the present invention alone or in combination, or may contain other ingredients. The amount of the active ingredient of the present invention contained in the composition of the present invention is typically greater than 0.01% and less than 100% by weight of the total composition of the present invention. However, to efficiently act on meat at a concentration of 10 μmol / 100g or more, a concentration of 0.02% or more and less than 100% is preferred, and 0.05% or more and less than 100% is even more preferred. More specifically, when reduced glutathione is added, the amount is typically greater than 0.02% and less than 100%, and preferably greater than 0.05% and less than 100%, by weight of the total composition of the present invention. When a glutathione-containing yeast extract containing 10% glutathione is added, the amount is typically greater than 0.2% and less than 100%, and preferably greater than 0.5% and less than 100%, by weight of the total composition of the present invention. The amount of cysteine ​​contained in the composition of the present invention is usually more than 0.001% but less than 100%, but in order to efficiently act on meat at 10 μmol or more per 100g of meat, it is preferably 0.008% or more but less than 100%, more preferably 0.02% or more but less than 100%. When a cysteine-containing yeast extract containing 2% cysteine ​​is blended, the amount is preferably 0.4% or more but less than 100%, more preferably 1.0% or more but less than 100%.

[0037] When the composition of the present invention is added (dissolved) in water, the pH of the composition is typically 5.5 or less, preferably 2 to 5.5, and more preferably 2.5 to 5.5, from the viewpoint of maximizing the meat tenderizing effect. The pH can be measured at room temperature by a conventional method. The pH varies depending on factors such as the type and amount of active ingredient, the amount of water in which it is dissolved, and other factors. For example, the pH can be measured at room temperature when a 1% yeast extract containing 10% reduced glutathione as an active ingredient is added.

[0038] When the composition of the present invention is added to water, the pH is preferably 5.5 or less, but if the pH is greater than 5.5 and less than 7.0, the meat can be tenderized even after exposure to microwaves by contacting a large amount of the active ingredient of the present invention with 100 g of meat. For example, by contacting 50 μmol to 10,000 μmol of the active ingredient of the present invention with 100 g of meat, the meat can be tenderized even after exposure to microwave heating, as described below.

[0039] The method for adjusting the pH of the composition of the present invention to 5.5 or less when dissolved in water is not particularly limited, but typically includes adding an organic acid, inorganic acid, or salt thereof to the composition of the present invention. The amount of organic acid, inorganic acid, or salt thereof added to the composition of the present invention varies depending on the type of organic acid, inorganic acid, or salt thereof and the types and amounts of other substances blended in the composition, but is usually more than 0.001% and less than 100%, preferably 0.01% to 90%, and more preferably 0.02% to 80%, of the total weight of the composition.

[0040] Examples of organic acids, inorganic acids, or salts thereof include succinic acid, citric acid, tartaric acid, malic acid, acetic acid, gluconic acid, lactic acid, fumaric acid, phytic acid, butyric acid, formic acid, disodium dihydrogen pyrophosphate, calcium dihydrogen pyrophosphate, sodium metaphosphate, etc. Among these, from the viewpoints of taste quality and buffering ability, succinic acid, citric acid, tartaric acid, malic acid, acetic acid, gluconic acid, lactic acid, fumaric acid, phytic acid, disodium dihydrogen pyrophosphate, and calcium dihydrogen pyrophosphate are preferred, and succinic acid, citric acid, tartaric acid, malic acid, and disodium dihydrogen pyrophosphate are more preferred.

[0041] For example, when a composition containing only yeast extract containing 10% reduced glutathione and citric acid is dissolved in water, the amount of citric acid to be added when the yeast extract is added at 1% is about 0.2% if the pH of the aqueous solution is adjusted to 4.0, and about 1.0% if the pH of the aqueous solution is adjusted to 3.0. These amounts are shown as an example and will vary depending on various factors such as the type of glutathione-containing yeast extract and the type of water in which it is dissolved.

[0042] In addition to the active ingredient of the present invention and the organic or inorganic acid, etc., the composition of the present invention may contain any other food ingredients or food additives, such as water, amino acids other than cysteine, nucleic acids, saccharides (e.g., sugar, etc.), salt, seasonings (e.g., soy sauce, vinegar, sake, vegetable paste, etc.), extracts (yeast extract, meat extract, vegetable extract), dextrin, lactose, etc., proteins such as vegetable proteins, gluten, egg white, egg yolk, gelatin, casein, etc., protein hydrolysates, partial protein hydrolysates, starches such as modified starch and pregelatinized starch, thickening polysaccharides such as xanthan gum, guar gum, etc., emulsifiers, acidulants, spices, colorants, flavorings, antioxidants, color formers, etc., as long as the purpose of the present invention is not impaired.

[0043] When the composition of the present invention is used by adding water in addition to the active ingredient of the present invention and the organic acid, inorganic acid or salt thereof, the proportion of water added to the composition is usually 0.001 to 999 parts by weight, preferably 0.003 to 199 parts by weight, and more preferably 0.005 to 99 parts by weight, per part by weight of the active ingredient in the composition of the present invention.

[0044] In step (2) of exposing meat to microwaves, exposing meat to microwaves means exposing the meat to microwaves, i.e., heating the meat with microwaves. Specifically, it means cooking the meat in a microwave oven. In the present invention, cooking in a microwave oven refers to a cooking method in which food is heated using a microwave oven. A microwave oven is a device that raises the temperature by irradiating microwaves to induce vibration of dipole water molecules, and can be any type, such as for home use, commercial use, or industrial use. Microwaves refer to radio waves with a frequency of 300 MHz to 30 GHz, and can be any frequency within this range, including 2450 MHz (2.45 GHz) or 915 MHz, which are used in general microwave ovens. When cooking raw food using a microwave oven, any energy amount can be used, including 100 watts to 3000 watts, which are used in general microwave ovens.

[0045] The heating time for cooking raw ingredients using a microwave oven can be any time, but is preferably 5 seconds to 120 minutes, preferably 10 seconds to 90 minutes, more preferably 30 seconds to 60 minutes, and even more preferably 1 to 20 minutes, depending on the type, size, and amount of meat to be cooked. For example, when 100 g of raw meat is immersed in a seasoning liquid and cooked in a typical microwave oven, the effects of the present invention can be fully achieved by cooking for 5 to 15 minutes at 600 watts or 3 to 10 minutes at 1000 watts. Specifically, tender braised pork belly can be obtained by placing 200 g of raw pork belly in a bowl containing 200 g of seasoning liquid in which the composition of the present invention has been dissolved, and heating for 10 minutes at 600 watts in a microwave oven.

[0046] The order of steps (1) and (2) in the method of the present invention is not particularly limited, but (2) may be performed after (1), or (1) may be performed after (2), or (1) and (2) may be performed simultaneously. For example, the composition of the present invention may be added to raw meat, allowed to stand for a certain period of time, and then microwave-heated; raw meat may be preheated, and then the composition of the present invention may be added and microwave-heated again; or the composition of the present invention may be added to raw meat and microwave-heated at the same time. Of these, from the viewpoint of simple cooking, adding the composition to raw meat and then microwave-heating is preferred.

[0047] Specifically, the composition of the present invention may be prepared in a liquid or semi-solid form, and meat may then be immersed in the composition, after which the meat may be removed from the composition and heated in a microwave oven; alternatively, the meat may be immersed in the prepared composition and heated in a microwave oven together with the composition. However, in order to allow the active ingredient to act sufficiently on the meat and maximize the meat tenderizing effect of the present invention, it is preferable to immerse the meat in the prepared composition and heat it in a microwave oven together with the composition.

[0048] Another aspect of the present invention is a meat tenderizing composition for microwave heating (sometimes abbreviated herein as "the meat tenderizing composition for microwave heating of the present invention") which contains at least one selected from the group consisting of reduced glutathione, cysteine, and salts thereof.

[0049] The meat tenderizing composition for microwave heating of the present invention is for microwave heating and is used to prevent meat, particularly raw meat, from hardening due to microwave heating and to tenderize the meat. The definitions, type, size, shape, and preferred range of microwaves and meat are as described above.

[0050] The definition and manufacturing method of the active ingredient of the present invention contained in the meat tenderizing composition for microwave heating of the present invention are as described above. The amount of the active ingredient of the present invention contained in the meat tenderizing composition for microwave heating of the present invention is typically greater than 0.01% but less than 100%, preferably 0.02% or more but less than 100%, and more preferably 0.05% or more but less than 100%, based on the total weight of the meat tenderizing composition for microwave heating of the present invention. Specifically, the amount of reduced glutathione or a salt thereof contained in the meat tenderizing composition for microwave heating of the present invention is typically greater than 0.01% but less than 100%, preferably 0.02% or more but less than 100%, and more preferably 0.05% or more but less than 100%, based on the total weight of the meat tenderizing composition for microwave heating of the present invention. When a glutathione-containing yeast extract containing 10% glutathione is added, the amount is preferably 0.2% or more but less than 100%, and more preferably 0.5% or more but less than 100%, based on the total weight of the composition of the present invention. The amount of cysteine ​​contained in the composition of the present invention is usually more than 0.001% but less than 100%, preferably 0.008% or more but less than 100%, and more preferably 0.02% or more but less than 100%. When a cysteine-containing yeast extract containing 2% cysteine ​​is blended, the amount is preferably 0.4% or more but less than 100%, and more preferably 1.0% or more but less than 100%.

[0051] The meat tenderizing composition for microwave heating of the present invention may contain an organic acid, an inorganic acid, or a salt thereof in addition to the active ingredient of the present invention. The amount of the organic acid, inorganic acid, or salt thereof added to the composition varies depending on the type of the acid and the types and amounts of other substances blended in the composition, but is usually more than 0.001% and less than 100%, preferably 0.01% to 90%, more preferably 0.02% to 80%, of the total weight of the composition.

[0052] When the meat tenderizing composition for microwave heating of the present invention contains the active ingredient of the present invention and an organic acid, an inorganic acid, or a salt thereof, the weight ratio of (active ingredient of the present invention):(organic acid, inorganic acid, or a salt thereof) contained in the composition of the present invention is not particularly limited, but is preferably 1:0.001 to 1000.

[0053] The form of the meat tenderizing composition for microwave heating of the present invention is not particularly limited, and examples thereof include solids such as powders and granules, liquids such as solutions and suspensions, and semisolids such as pastes. From the viewpoint of storage stability, solids such as powders and granules are preferred, and a form in which the composition is dissolved in a solvent such as water before use is preferred. Furthermore, from the viewpoint of simplicity and efficient softening effect, a solvent such as water may be added to form the composition in a liquid or semisolid form.

[0054] When the meat tenderizing composition for microwave heating of the present invention is used by dissolving it in a solvent such as water, the amount of water per part by weight of the active ingredient in the composition of the present invention is 0.001 to 999 parts by weight, preferably 0.003 to 199 parts by weight, and more preferably 0.005 to 99 parts by weight.

[0055] When the meat tenderizing composition for microwave heating of the present invention is dissolved in water, the pH of the composition is usually 5.5 or less, preferably 2 to 5.5, and more preferably 2.5 to 5.5, from the viewpoint of maximizing the meat tenderizing effect.

[0056] The meat tenderizing composition for microwave heating of the present invention may further contain, in addition to the active ingredients of the present invention and organic acids, inorganic acids or salts thereof, water, oils and fats, sugars (e.g., sugar, etc.), salt, organic salts, inorganic salts, seasonings (e.g., soy sauce, vinegar, sake, etc.), extracts, acidulants, spices, colorants, thickeners, antioxidants, emulsifiers, color formers, etc., as long as the object of the present invention is not impaired.

[0057] The meat tenderizing composition for microwave heating of the present invention may further contain ingredients of a heated meat-containing food (described below) other than raw meat, in addition to the active ingredient of the present invention and an organic acid, an inorganic acid or a salt thereof, as long as the object of the present invention is not impaired.

[0058] In one embodiment, the meat tenderizing composition for microwave heating of the present invention can be provided as a seasoning (e.g., a sauce, etc.), and the meat tenderizing composition for microwave heating of the present invention may be a seasoning composition.

[0059] The method for producing the meat tenderizing composition for microwave heating of the present invention is not particularly limited, and can be, for example, a conventional production method or a method equivalent thereto in the field of seasonings, etc. The meat tenderizing composition for microwave heating of the present invention may be subjected to treatments conventionally used in the production of seasonings, etc. (e.g., thermal sterilization treatments such as retort treatment, hot packing, and hot water sterilization; non-thermal sterilization treatments such as ultraviolet irradiation and high-pressure treatment; alcohol bacteriostatic treatment, sterilization treatment by filtration, etc.) as needed.

[0060] There are no particular limitations on the method for contacting the microwave-heated meat tenderizing composition of the present invention with meat, but a method in which the composition of the present invention adheres to at least the surface of the meat is preferred. For example, the microwave-heated meat tenderizing composition of the present invention can be contacted with meat by immersing raw meat in the microwave-heated meat tenderizing composition of the present invention or by applying the microwave-heated meat tenderizing composition of the present invention to raw meat.

[0061] When using the meat tenderizing composition for microwave heating of the present invention, the amount of the composition to be contacted with meat is not particularly limited and can be adjusted appropriately depending on the content of the active ingredient in the present invention, heating conditions, etc. Specifically, the amount of the active ingredient in the meat tenderizing composition for microwave heating of the present invention is typically 10 μmol or more, preferably 20 μmol or more, and more preferably 30 μmol or more per 100 g of meat, and the upper limit is typically 10,000 μmol or less, preferably 5,000 μmol or less, from the viewpoint of taste quality. The above contact amounts are all values ​​converted into free forms, and when two or more types are used in combination, they represent the total value of both. Furthermore, conversion to weight is as described above.

[0062] Meat that has been contacted with the meat tenderizing composition for microwave heating of the present invention (e.g., raw meat immersed in the composition of the present invention) may be kneaded appropriately in a conventional manner before use to promote penetration of the composition of the present invention into the meat. Furthermore, the meat tenderizing composition for microwave heating of the present invention may be left in contact with the meat (e.g., in a state where the meat has been immersed in the meat tenderizing composition for microwave heating of the present invention) for usually 5 seconds to 24 hours, preferably 10 seconds to 12 hours, and more preferably 30 seconds to 8 hours before use.

[0063] In the present invention, when meat is subjected to microwave heating, a microwave-compatible container may be used, i.e., the meat tenderizing composition for microwave heating of the present invention and the meat may be placed in a microwave-compatible container and brought into contact with each other, and the meat may be heated by irradiating the container with microwaves.

[0064] The meat tenderizing composition for microwave heating of the present invention may be provided in a state where it is pre-packaged in a microwave-compatible container or as a product. Such a product is highly convenient because it does not require a separate microwave-compatible container when meat is heated by contacting it with the meat tenderizing composition for microwave heating of the present invention. Furthermore, when the meat tenderizing composition for microwave heating of the present invention is provided in a state where it is pre-packaged in a microwave-compatible container, ingredients of a heated meat-containing food (described below) other than meat may be packed in the container together with the composition of the present invention.

[0065] According to the present invention, heated meat with a soft texture can be provided, and the meat tenderizing composition for microwave heating of the present invention can be suitably used as a composition for modifying the texture of heated meat. "Texture modification" of heated meat according to the present invention means that the texture of the meat becomes soft. The presence or absence and degree of the texture modification effect of heated meat according to the present invention can be evaluated, for example, by sensory evaluation by a specialist panel, as shown in the examples described below.

[0066] Another aspect of the present invention includes a method for producing heated meat (sometimes referred to herein simply as the "production method of the present invention"), which comprises: (1) the step of contacting meat with a composition containing at least one selected from the group consisting of reduced glutathione, cysteine, and salts thereof; and (2) the step of exposing the meat to microwaves.

[0067] The definitions and preferred ranges of steps (1) and (2) used in the production method of the present invention are as described above.

[0068] In the present invention, "heated meat" means meat that has been cooked, and may be provided as a food product as is, or the heated meat may be used as an ingredient and, if necessary, may be combined with other ingredients and further treated by cooking, processing, etc. In the present invention, a food product containing heated meat is referred to as a "heated meat-containing food product," and the heated meat obtained by the production method of the present invention may be provided as a heated meat-containing food product as is, or, if necessary, may be combined with other ingredients and further treated by cooking, processing, etc. before being provided as a heated meat-containing food product.

[0069] In the present invention, the heated meat or heated meat-containing food is not particularly limited as long as it contains heated meat obtained by the manufacturing method of the present invention, and examples include teriyaki, shogayaki, steak, sauteed, grilled meat, roasted pork, yakitori, tandoori chicken, spare ribs, braised pork, meat and potato stew, chikuzenni, ham, etc.

[0070] According to the production method of the present invention, heated meat or a heated meat-containing food product having a softer and improved texture can be provided. That is, according to the production method of the present invention, heated meat or a heated meat-containing oil-containing food product having a softer and improved texture than that obtained by cooking using a pot, frying pan, or the like can be obtained by simple cooking in a short time using a microwave oven.

[0071] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples in any way.

[0072] Example 1: Domestic pork belly meat was cut into 6 cm wide, 6 cm high, and 2 cm thick pieces. Four pieces of pork belly meat were placed in a heat-resistant bag, and 200 g of each test solution was added and sealed. Each cut piece of pork belly weighed approximately 50 g, for a total of four pieces, totaling approximately 200 g. For each test solution, glutathione-containing yeast extract was dissolved in water to provide a glutathione concentration of 0 to 1000 μmol per 100 g of meat, as shown in Table 2. The pH of the solution was further adjusted to 3.0 to 8.0. Eight glutathione concentrations were selected: 0, 1, 10, 30, 50, 75, 100, and 1000 μmol, and seven pH values ​​were selected: 3.0, 4.0, 5.0, 5.5, 6.0, 7.0, and 8.0. A total of 56 test solutions were used. A commercially available yeast extract containing 10% reduced glutathione was used as the glutathione-containing yeast extract. 1 mol of reduced glutathione is 307.33 g. The pH of the aqueous solution was adjusted using citric acid or sodium carbonate. Citric acid was "Citric Acid (Crystal)" (Kyushu Kako Co., Ltd.), and sodium carbonate was "Purified Sodium Carbonate (Anhydrous)" (Daito Chemical Co., Ltd.). Since the pH of a 100 μmol / 100g aqueous solution of glutathione-containing yeast extract was approximately 6.0, citric acid was used to prepare an aqueous solution more acidic than this, and sodium carbonate was used to prepare an aqueous solution more alkaline than this.

[0073] The heat-resistant bag containing the prepared aqueous solution and pork belly was left to stand at room temperature for 15 minutes, and then heated at 95°C for 30 minutes using a steam convection oven "FSCC WE 61G" (Fujimack Co., Ltd.). The steam convection oven was set to steam mode with 100% steam, so that the sample in the heat-resistant bag was heated by conductive heat from the water vapor, creating heating conditions similar to those for stewing in a pot. After heating, the sample was removed from the steam convection oven, and the cooked pork belly was removed from the heat-resistant bag and subjected to sensory evaluation.

[0074] The sensory evaluation was conducted by three panelists familiar with meat texture. The tenderness of the pork belly was evaluated using a scoring system ranging from 0.0 to 10.0, with 5.0 being the tenderness of the test group with 0 μmol of glutathione / 100 g of meat (no added glutathione) and pH 7.0. The softness of the pork belly was evaluated using a scoring system ranging from 0.0 to 10.0. The softer the pork belly, the higher the score. 5.0 indicates a tenderness that can be eaten without problems as a pork belly stew. The sensory evaluation was evaluated by scoring the force required to bite through the entire pork belly, and the scoring scale, i.e., the difference in the score, was as follows: 0.5 points indicates a slight difference, 1.0 points indicates a difference, 2.0 points indicates a significant difference, 3.0 points indicates a very significant difference, 4.0 points indicates an extremely significant difference, and 5.0 points indicates an even more extremely significant difference. For example, a score of 6.0 means that the sample is "different" from the reference sample with a score of 5.0, i.e., "softer." The sensory scores for each test group were determined by consensus among three panelists. The results are shown in Table 2.

[0075] The sensory evaluation results shown in Table 2 were used to analyze the pork belly tenderization effect of glutathione addition in the test groups at each pH. Specifically, the increase in sensory score was calculated for each pH range when glutathione was added at 1 to 1,000 μmol / 100 g of meat compared to the glutathione-free group. For example, at pH 7.0, the pork belly tenderization effect of adding 100 μmol / 100 g of glutathione was 5.2 points when 100 μmol / 100 g of glutathione was added, compared to the glutathione-free group, which was 5.0 points. Therefore, the calculation was "5.2 points - 5.0 points = 0.2 points," resulting in a tenderization effect of 0.2 points. The results are shown in Table 5.

[0076] Next, eight pork belly pieces cut to the same size were placed in a snow-peaked saucepan and 400 g of each test solution was added. The weight of the eight cut pork belly pieces was approximately 400 g. For each test solution, glutathione-containing yeast extract was dissolved in water to achieve 0 or 100 μmol of glutathione per 100 g of meat, as shown in Table 3. The pH of the solution was then adjusted to 4.0-8.0. The glutathione concentration was set to two levels: 0 or 100 μmol, and the pH was set to four levels: 4.0, 5.5, 6.0, and 8.0. A total of eight test solutions were prepared. The pH of the solution was adjusted using citric acid or sodium carbonate. Because the pH of a 100 μmol / 100 g solution of glutathione-containing yeast extract was approximately 6.0, citric acid was used to prepare solutions that were more acidic, and sodium carbonate was used to prepare solutions that were more alkaline.

[0077] The pot containing the prepared aqueous solution and pork belly was left at room temperature for 15 minutes, then heated over low heat for 30 minutes. A drop lid was placed on the pot during heating. After heating, the cooked pork belly was removed from the pot and subjected to sensory evaluation. The sensory evaluation was conducted by three panelists familiar with meat texture. The tenderness of the pork belly was evaluated using a scoring system ranging from 0.0 to 10.0 points, with 5.0 being the tenderness of the test group heated in a steam convection oven with 0 μmol of glutathione per 100 g of meat (no added glutathione) and pH 7.0. The evaluation method and score definitions are as described above. The results are shown in Table 3.

[0078] Four pork belly pieces cut to the same size were placed in a ceramic bowl, and 200 g of each test solution was added. The weight of the four cut pork belly pieces was approximately 200 g. For each test solution, glutathione-containing yeast extract was dissolved in water to achieve a glutathione concentration of 0 to 1000 μmol per 100 g of meat, as shown in Table 4. The pH of the solution was then adjusted to 3.0 to 8.0. Eight glutathione concentrations were set: 0, 1, 10, 30, 50, 75, 100, and 1000 μmol / 100 g of meat, and seven pH values ​​were set: 3.0, 4.0, 5.0, 5.5, 6.0, 7.0, and 8.0. A total of 56 test solutions were used. The pH of the solution was adjusted using citric acid or sodium carbonate. Since the pH of a 100 μmol / 100g aqueous solution of glutathione-containing yeast extract is approximately 6.0, citric acid was used to prepare an aqueous solution on the more acidic side, and sodium carbonate was used to prepare an aqueous solution on the more alkaline side.

[0079] The bowl containing the prepared aqueous solution and pork belly was left to stand at room temperature for 15 minutes, then wrapped in plastic wrap and heated for 10 minutes at 600W in a microwave oven "RE-V90B-S" (Sharp Corporation). After heating, the cooked pork belly was removed from the bowl and subjected to sensory evaluation. The sensory evaluation was conducted by three panelists familiar with meat texture. The tenderness of the pork belly was evaluated using a scoring system ranging from 0.0 to 10.0 points, with 5.0 being the tenderness of the test group heated in a steam convection oven with 0 μmol of glutathione / 100 g of meat (no added glutathione) and pH 7.0. The evaluation method and score definitions are as described above. The results are shown in Table 4.

[0080] The sensory evaluation results shown in Table 4 were analyzed for the softening effect of the addition of glutathione on pork belly meat at each pH level. That is, the increase in sensory score at each pH level was calculated by adding 1 to 1,000 μmol of glutathione per 100 g of meat compared to the control group without glutathione. The calculation method was as described above. The results are shown in Table 6.

[0081] Next, the pork belly tenderization effect of glutathione addition, i.e., the increase in sensory score compared to the control without glutathione, was compared between steam convection oven cooking (Table 5) and microwave cooking (Table 6). As mentioned above, the heat conduction conditions for steam convection oven cooking are similar to those for stewing in a pot, and the sensory evaluation results are consistent. The increase in sensory score was calculated by subtracting the value for "meat tenderization effect of glutathione addition in steam convection oven cooking (equivalent to stewing)" shown in Table 5 from the value for "meat tenderization effect of glutathione addition in microwave cooking" shown in Table 6. This shows the extent to which the meat tenderization effect of glutathione addition is greater in microwave cooking than in stewing, i.e., the contribution of microwave cooking. The calculation results are shown in Table 7.

[0082]

[0083]

[0084]

[0085]

[0086]

[0087]

[0088] As shown in Table 2, in steam convection oven cooking, the meat texture was toughest in the pH range of 5.0 to 5.5, and tended to become softer as the pH moved toward the acidic or alkaline side. Furthermore, at all pH levels, the meat tenderizing effect was confirmed to depend on the amount of glutathione added (Table 5). Furthermore, as shown in Table 3, the meat tenderizing effect of glutathione addition was also confirmed in pot stewing, with the tendency for dependency on pH and amount of glutathione added being similar to that in steam convection oven cooking, and the sensory evaluation results were identical. From the above, it can be seen that steam convection oven cooking and pot stewing cooking are the same, meaning that the results of steam convection oven cooking can explain the phenomena that occur during pot stewing cooking.

[0089] Next, as shown in Table 4, in microwave cooking, the meat texture tended to become harder as the pH became more alkaline, and the meat texture tended to become softer as the pH became more acidic, which was a different trend from that observed in steam convection oven cooking. Furthermore, at all pH levels, the meat tenderizing effect was confirmed to be dependent on the amount of glutathione added, but this effect tended to be greater than that observed in steam convection oven cooking, and was particularly significant at lower pH levels (Table 6).

[0090] Therefore, the contribution of microwave cooking to the meat tenderizing effect of glutathione addition was calculated by subtracting the meat tenderizing effect of glutathione addition under each pH condition during steam convection oven cooking (Table 5) from the meat tenderizing effect of glutathione addition under each pH condition during microwave cooking (Table 6). As shown in Table 7, the contribution of microwave cooking was greater the higher the amount of glutathione added, and greater the contribution of microwave cooking was, and greater the lower the pH. In particular, at pH 5.5 or below, the addition of 10 μmol / 100 g or more of glutathione resulted in a difference of more than 1.0 in the contribution of microwave cooking to the meat tenderizing effect of glutathione. In other words, the meat tenderizing effect of glutathione was significantly greater during microwave cooking than during steam convection oven cooking and pot stewing, and this effect was evident under low pH conditions, particularly at pH 5.5 or below. Thus, it is not easy to imagine that the meat tenderizing effect of glutathione is particularly pronounced during microwave cooking, i.e., microwave heating, and that it is strongly dependent on pH. This phenomenon occurs because microwaves harden the meat by forming disulfide bonds in the proteins that make up the meat, and this reaction is more likely to occur on the alkaline side, while on the acidic side, glutathione makes it easier for disulfide bonds to be reduced, resulting in tenderization.

[0091] Example 2: Four pork belly pieces cut to the same size as in Example 1 were placed in a ceramic bowl, and 200 g of each test solution was added. The weight of the four cut pork belly pieces was approximately 200 g. For each test solution, glutathione-containing yeast extract was dissolved in water to provide 0 or 100 μmol of glutathione per 100 g of meat, as shown in Table 8. The pH of the solution was then adjusted to 4.0 or 8.0. The glutathione concentration was set to 0 or 100 μmol, and the pH was set to 4.0 or 8.0. The pH of the solution was adjusted in three ways: with citric acid, succinic acid, and disodium dihydrogen pyrophosphate for pH 4.0, and with sodium carbonate and arginine for pH 8.0. A total of 10 test solutions were used. The two test plots in which the pH was adjusted to 4.0 when citric acid was added and the two test plots in which the pH was adjusted to 8.0 when sodium carbonate was added were replicate tests of Example 1. Citric acid was "Citric Acid (Crystal)" (Kyushu Kako Co., Ltd.), succinic acid was "Succinic Acid" (Kawasaki Kasei Kasei Co., Ltd.), disodium dihydrogen pyrophosphate was "Disodium dihydrogen pyrophosphate" (Taihei Chemical Industry Co., Ltd.), sodium carbonate was "Purified Sodium Carbonate (Anhydrous)" (Daito Chemical Co., Ltd.), and arginine was "L-Arginine" (Ajinomoto Co., Inc.).

[0092] The bowl containing the prepared aqueous solution and pork belly was left to stand at room temperature for 15 minutes, then wrapped in plastic wrap and heated in a microwave oven at 600W for 10 minutes. After heating, the cooked pork belly was removed from the bowl and subjected to sensory evaluation. The sensory evaluation was conducted by three panelists familiar with meat texture. The tenderness of the pork belly was evaluated using a scoring system ranging from 0.0 to 10.0 points, with 5.0 being the tenderness of the test group heated in a steam convection oven as described in Example 1, with 0 μmol of glutathione per 100 g of meat (no added glutathione) and pH 7.0. The evaluation method and score definitions are as described in Example 1. The results are shown in Table 8.

[0093]

[0094] As shown in Table 8, the meat tenderizing effect of adding 100 μmol of glutathione per 100 g of meat during microwave cooking was confirmed under conditions where the pH was adjusted to 4.0 with citric acid and conditions where the pH was adjusted to 8.0 with sodium carbonate, and the effect was significantly greater under conditions where the pH was adjusted to 4.0 with citric acid. This result perfectly reproduces the test results of Example 1. Therefore, similar tests were conducted using succinic acid, an organic acid similar to citric acid, and disodium dihydrogen pyrophosphate, an acid salt of an inorganic acid, to adjust the pH to 4.0. In both cases, the addition of glutathione improved the tenderness rating, and the difference in rating, i.e., the improvement in tenderness, was 3.1 points, consistent with the case where citric acid was used. The slightly higher tenderness score for disodium dihydrogen pyrophosphate compared with citric acid and succinic acid is presumably due to its function as a polyphosphate, which promotes the dissociation of the meat proteins actin and myosin. Furthermore, when a similar test was conducted using arginine, an alkaline amino acid, to adjust the pH to 8.0, the meat hardened due to the alkalinity, as with sodium carbonate. The increase in tenderness score with the addition of glutathione was only negligible (0.4 points), consistent with the increase with sodium carbonate. The increase in tenderness significantly differed between the acidic and alkaline pH adjustments, and the meat tenderizing effect of glutathione addition was more pronounced when the pH was adjusted to the acidic side, regardless of which pH adjuster was used. From the above results, it was confirmed that when cooking meat using microwave heating, the meat tenderizing effect of adding glutathione, particularly the meat tenderizing effect of adding 10 μmol or more of glutathione per 100 g of meat under conditions of pH 5.5 or less, can be obtained significantly regardless of the pH adjusted using any organic acid, inorganic acid, or salt thereof.

[0095] Example 3: Four pork belly pieces cut to the same size as in Example 1 were placed in a ceramic bowl, and 200 g of each test solution was added. The weight of the four cut pork belly pieces was approximately 200 g. As shown in Table 9, the aqueous solutions for each test were prepared by dissolving glutathione-containing yeast extract or cysteine-containing yeast extract in water to achieve a glutathione or cysteine ​​concentration of 0 to 1,000 μmol per 100 g of meat, and then adjusting the pH of the aqueous solution to 3.0 to 7.0 using citric acid or sodium carbonate. Eight concentrations were used: no additives, 100 μmol of glutathione / 100 g of meat, and 1, 10, 30, 50, 100, and 1,000 μmol of cysteine / 100 g of meat. A total of 16 test groups were used. For glutathione, a commercially available yeast extract containing 10% reduced glutathione was used, and for cysteine, a commercially available yeast extract containing approximately 2% cysteine ​​was used. Note that the test group without addition and the test group with glutathione added at 100 μmol / 100 g of meat were replicate tests of Example 1. Furthermore, for the addition concentrations tested for cysteine ​​but not for glutathione, the data obtained in Example 1 can be referenced.

[0096] The bowl containing the prepared aqueous solution and pork belly was left to stand at room temperature for 15 minutes, then wrapped in plastic wrap and heated in a microwave oven at 600W for 10 minutes. After heating, the cooked pork belly was removed from the bowl and subjected to sensory evaluation. The sensory evaluation was conducted by three panelists familiar with meat texture. The tenderness of the pork belly was evaluated using a scoring system ranging from 0.0 to 10.0 points, with 5.0 being the tenderness of the test group heated in a steam convection oven as described in Example 1, with 0 μmol of glutathione per 100 g of meat (no added glutathione) and pH 7.0. The evaluation method and score definitions are as described in Example 1. The results are shown in Table 9.

[0097]

[0098] As shown in Table 9, the meat tenderizing effect of adding 100 μmol of glutathione per 100 g of meat during microwave cooking was confirmed under conditions adjusted to pH 4.0, completely reproducing the test results of Example 1. Therefore, when 100 μmol of cysteine, which has a thiol group like glutathione, was added per 100 g of meat, the meat tenderizing effect was similar to that of glutathione addition, and the difference in tenderness score, i.e., the improvement in tenderizing effect, was 3.1 points, consistent with that of glutathione addition. Furthermore, when 1 to 1000 μmol of cysteine ​​was added per 100 g of meat under conditions adjusted to pH 3.0 to 7.0, the meat tenderizing effect was similar to that of glutathione addition shown in Table 4 of Example 1, and the difference in tenderness score was also consistent with that of glutathione addition shown in Table 6 of Example 1. From the above results, it was confirmed that when cooking meat by microwave heating, the meat tenderizing effect achieved by adding 10 μmol / 100g of meat or more, particularly under conditions of pH 5.5 or less, is not limited to glutathione, but can also be achieved remarkably with cysteine.

[0099] [Example 4] Pork belly meat was cut into 6 cm wide, 6 cm high, and 2 cm thick pieces, as in Example 1. Pork loin meat was sliced ​​1 cm thick and then cut into 2 cm wide strips. Beef thigh meat was cut into cubes with sides measuring 3 cm. Chicken thigh meat was cut into bite-sized pieces weighing 25 g each. 200 g of each cut meat was placed in a ceramic bowl, and 200 g of an aqueous solution containing 0 or 100 μmol of glutathione per 100 g of meat and adjusted to pH 4.0 with citric acid was added. The test using pork belly meat was a follow-up test of Example 1.

[0100] The bowls containing the prepared aqueous solutions and various meats were left to stand at room temperature for 15 minutes, then covered with plastic wrap and heated in a microwave oven at 600W for 10 minutes. After heating, the cooked meat was removed from the bowls and subjected to sensory evaluation. The sensory evaluation was performed by three panelists familiar with meat texture, who used symbols to evaluate the degree of tenderness achieved by adding 100 μmol of glutathione per 100 g of meat compared to 0 μmol of glutathione per 100 g of meat, i.e., no glutathione addition. This evaluation evaluated the effect of adding glutathione to each type of meat, and no comparison was made between different types of meat.

[0101] The symbols used in the sensory evaluation were "+" (slightly soft), "++" (soft), "+++" (significantly soft), "++++" (very significantly soft), and "++++++" (extremely significantly soft). The sensory scores for each test group were determined by consensus among the three panelists. The results are shown in Table 10.

[0102]

[0103] As shown in Table 10, adding 100 μmol of glutathione per 100 g of meat during microwave cooking of pork belly meat at a pH of 4.0 was confirmed to have a significant meat tenderizing effect, completely reproducing the test results of Example 1. Furthermore, the significant meat tenderizing effect of adding glutathione was confirmed for pork loin, beef thigh, and chicken thigh meat, just as when using pork belly. These results confirm that when cooking meat using microwave heating, the meat tenderizing effect, particularly the meat tenderizing effect achieved by adding 10 μmol of glutathione or more per 100 g of meat at a pH of 5.5 or less, is not limited to pork belly meat, and can be achieved remarkably with any type or cut of meat.

[0104] INDUSTRIAL APPLICABILITY The present invention is extremely useful in the food industry because it enables meat to be cooked softly and easily in a short time using a microwave oven, for example, in cooking by microwave heating.

[0105] This application is based on patent application No. 2022-039570 filed in Japan, the contents of which are incorporated in their entirety herein.

Claims

1. (1) Immersing raw meat in a composition containing at least one active ingredient selected from the group consisting of reduced glutathione, cysteine, and salts thereof; and (2) Exposing the soaked raw meat to microwaves A method for tenderizing meat, comprising:

2. 2. The method according to claim 1, wherein the meat is immersed in a composition containing 10 μmol to 10,000 μmol of the active ingredient per 100 g of meat.

3. The method of claim 1 or 2, wherein the composition comprises an organic acid, an inorganic acid, or a salt thereof.

4. 4. The method according to claim 3, wherein the organic acid, inorganic acid or salt thereof is one or more selected from the group consisting of succinic acid, citric acid, tartaric acid, malic acid, acetic acid, gluconic acid, lactic acid, fumaric acid, phytic acid, disodium dihydrogen pyrophosphate and calcium dihydrogen pyrophosphate.

5. 3. The method of claim 1, wherein the pH of the composition when added to water is 5.5 or less.

6. 6. The method of claim 5, wherein the pH of the composition when added to water is 2 to 5.

5.

7. (1) Immersing raw meat in a composition containing at least one active ingredient selected from the group consisting of reduced glutathione, cysteine, and salts thereof; and (2) Exposing the soaked raw meat to microwaves A method for producing heated meat, comprising:

8. 8. The method according to claim 7, wherein the meat is immersed in a composition containing 10 μmol to 10,000 μmol of the active ingredient per 100 g of meat.

9. 9. The method of claim 7 or 8, wherein the composition comprises an organic acid, an inorganic acid, or a salt thereof.

10. 10. The method of claim 9, wherein the organic acid, inorganic acid, or salt thereof is one or more selected from the group consisting of succinic acid, citric acid, tartaric acid, malic acid, acetic acid, gluconic acid, lactic acid, fumaric acid, phytic acid, disodium dihydrogen pyrophosphate, and calcium dihydrogen pyrophosphate.

11. 9. The method according to claim 7 or 8, wherein the pH of the composition when added to water is 5.5 or less.

12. 12. The method of claim 11, wherein the pH of the composition when added to water is from 2 to 5.

5.

13. A meat tenderizing composition for microwave heating, comprising as an active ingredient at least one selected from the group consisting of reduced glutathione, cysteine ​​and salts thereof, and one or more selected from the group consisting of succinic acid, citric acid, tartaric acid, malic acid, acetic acid, gluconic acid, lactic acid, fumaric acid, phytic acid, disodium dihydrogen pyrophosphate and calcium dihydrogen pyrophosphate.

14. 14. The composition of claim 13, wherein the pH of the composition when added to water is 5.5 or less.

15. The composition according to claim 14, wherein the pH of the composition when added to water is from 2 to 5.5.