Meat-like food containing legume protein and cereal koji and method for producing same

Abstract

To provide a meat-like food manufactured by extruder treatment of a legume protein raw material, the food exhibiting improved taste and mouthfeel.SOLUTION: By mixing a legume protein material such as soybean with a cereal koji such as rice koji and water, and subjecting the mixture to extruder treatment, it is possible to produce a meat-like food having excellent taste and mouthfeel, the meat-like food containing free amino acids obtained by enzymatic hydrolysis of the protein by enzymes contained in the cereal koji, and chitin and glucan which are cell wall components of koji mold.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a meat-like food obtained by texturing pulse proteins and a method for producing the same. [Background technology]

[0002] The production of textured protein foods using pulse protein ingredients such as defatted soybeans and isolated soybean protein as the main ingredient through extrusion processing is widely practiced. As the importance of vegetable proteins as alternative protein ingredients increases, there is a demand for further improvements in the taste and texture of protein foods, and various attempts have been made to achieve this, such as using other ingredients and additives and changing the production conditions. As a method for improving the taste and texture of extruder-processed textured soy protein, it is widely known that the poor flavor of soy protein is improved by adding a calcium compound. For example, a method for obtaining textured soy protein with reduced harsh soybean taste and sweetness has been reported (Patent Document 1), which includes a step of adding an aqueous calcium chloride solution to a raw material containing a soy protein material so that the amount of calcium chloride added is 0.03 to 0.08 parts by mass per 100 parts by mass of the soy protein material.

[0003] Additionally, technologies for improving taste and texture have been reported, such as a method for obtaining textured soy protein with high water absorption by adding soybean lees to defatted soybeans and subjecting them to high-temperature, high-pressure processing in an extruder without cooling the processed product in a die (Patent Document 2), and a method for adding cyclodextrin that has already been encapsulated with seasoning ingredients as a secondary ingredient (Patent Document 3). Furthermore, a method for improving the taste of soy protein that does not use an extruder has been reported (Patent Document 4), in which powder of red rice koji cultivated with Monascus filamentous fungi is added to soy protein to give a composition ratio of 0.5 to 5% by weight, followed by addition of water and storage at a temperature of 5 to 30°C for 4 hours or more, thereby improving the beany smell, taste, and texture of soy protein. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-162432 [Patent Document 2] Japanese Patent Application Laid-Open No. 2015-144593 [Patent Document 3] Japanese Patent Application Publication No. 6-98686 [Patent Document 4] Japanese Patent Application Publication No. 6-141782 [Non-patent literature]

[0005] [Non-Patent Document 1] Journal of the Brewing Society of Japan (1971) Vol.66, No.7, pp.653-657 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to produce and provide a meat-like food product produced by extruding a pulse protein raw material, which has improved taste and texture. [Means for solving the problem]

[0007] As a result of extensive ingenuity, the inventors discovered that by mixing a pulse protein raw material such as soybeans with cereal koji such as rice koji and water and processing the mixture in an extruder, the enzymes contained in the cereal koji hydrolyze the protein to produce free amino acids, making it possible to produce a meat-like food with excellent taste and texture, and thus completed the present invention.

[0008] The present invention relates to the following (1) and (2) methods for producing meat-like foods, and (3) a meat-like food. (1) A method for producing a meat-like food, comprising mixing raw materials containing a bean protein material, grain koji, and water, and then kneading and extruding the mixture under pressure and heat using an extruder. (2) The manufacturing method described in (1) above, wherein the raw material containing the bean protein material contains an excipient. (3) A meat-like food product with excellent taste and texture, produced by the method described in (1) or (2) above, which contains free amino acids produced by the enzymes contained in grain koji hydrolyzing proteins, and chitin and glucan, which are components of the cell wall of koji mold. [Effects of the Invention]

[0009] The meat-like food of the present invention not only improves flavor and nutritional value through the combination of pulse protein and grain protein contained in the grain koji, but also improves eating quality by allowing the enzymes contained in the grain koji to react with both proteins in the extruder to produce free amino acids, and also improves texture by texturing the mixture of pulse protein and grain protein during the extruder process.

[0010] Koji is known to break down carbohydrates, proteins, and lipids using enzymes such as amylase, protease, and lipase. Extruder processing involves kneading raw materials while heating them at high temperatures and then extruding them under pressure with a screw inside the device to form and process them. However, it was unclear how much the enzyme reaction progressed during extruder processing. The present invention has demonstrated that koji can be used as an enzyme reaction system because the enzymes and substrate proteins are more frequently contacted by heating the kneaded materials inside the extruder.

[0011] It was confirmed that by adjusting the product temperature in the extruder to around 50°C, the optimum temperature for enzyme reactions, the enzyme reacts with the protein, hydrolyzing part of the protein and increasing the amount of free amino acids.Meat-like foods that are rich in free amino acids and contain chitin and glucan, components of the cell wall of koji mold, have better taste and texture. DETAILED DESCRIPTION OF THE INVENTION

[0012] The meat-like food of the present invention is a textured vegetable protein food produced by extruding a mixture of raw materials containing a legume protein material, cereal koji, and water. The beans of the present invention are not particularly limited as long as they are beans, but beans with a high protein content that can provide a sufficient meat-like texture are preferably used, such as soybeans, peas, chickpeas, fava beans, and lentils.

[0013] The pulse protein of the present invention refers to a protein derived from these pulses, such as soybean protein, pea protein, chickpea protein, fava bean protein, etc. The pulse protein material of the present invention encompasses any form of pulse protein-containing material processed from pulses. For example, if the pulse is soybean, examples include full-fat soybeans such as whole soybeans and half-split soybeans, reduced-fat soybeans and defatted soybeans from which fats and oils have been removed, concentrated soy protein obtained by concentrating the protein by washing with aqueous ethanol, isolated soybean protein, soy milk, okara, whey, etc. There are no limitations on the form, such as powder, granules, or paste. One or more of these can be appropriately selected.

[0014] In addition to beans, the raw material containing this pulse protein material may optionally contain excipients such as starch, modified starch, dextrin, polysaccharides, etc. It may also contain additives such as emulsifiers, antioxidants, organic acids, pH adjusters, coloring agents, vitamins, etc. that are typically added to raw materials in methods for producing textured vegetable proteins.

[0015] The grains of the grain koji of the present invention are seeds of grass crops, such as rice, wheat, corn, etc. Grains include crushed or pulverized grains, rice bran from brown rice or polished rice, wheat or corn with remaining bran, and rice bran and bran. The grain koji of the present invention includes rice koji and barley koji, which are generally called grain koji and are made by gelatinizing these grains, and commercially available products thereof. Grain koji production is a commonly used method in which koji mold spores are spread on grain raw materials that have been gelatinized (saccharified) and then allowed to grow on the surface to produce koji.

[0016] First, the grains are washed and soaked in water to absorb the water, and then thoroughly steamed in a steamer, steam sterilizer, or the like to gelatinize the starch. For example, when using rice as the grain, steamed rice is typically obtained at a steaming temperature of 100-120°C for a steaming time of 10-60 minutes, but these conditions are not limited to these and the steaming conditions can be changed as appropriate depending on the type and shape of the grain. The gelatinized grain raw material is cooled, and then inoculated with koji starter, which is grown at a specified temperature to produce koji. The prepared grain koji can be used as it is as raw grain koji, or dried grain koji that can be stored by drying the grain koji can be used. In the present invention, it is preferable to crush the grain koji into granules or powder and use it in this form in order to promote the enzymatic reaction of the grain koji in the extruder.

[0017] Koji mold is a general term for the filamentous fungi that produce koji, and the species used in the production of fermented foods include those from the genera Aspergillus and Monascus, such as Aspergillus oryzae, Aspergillus sojae, Aspergillus kawachii, Aspergillus luchuensis, Aspergillus awamori, Aspergillus niger, Aspergillus glaucus, Aspergillus tamari, Monascus pilosus, Monascus purpureus, and Monascus anka. In addition, the rhizopus genus of rice mold and the mucor genus of rice mold, which are used to produce mochi koji and tempeh, which are fermented foods eaten in Southeast Asia using filamentous fungi, can also be used. The main components of the cell wall of koji mold are chitin and glucan, as shown in Table 3 of Non-Patent Document 1.

[0018] Furthermore, in order to further enhance the meat-like texture and taste of the meat-like food product to be produced, it is preferable to use grain koji with a high protein content, and for this purpose, the protein content of the grain that will be used as the koji culture medium can be increased in advance. For example, a small amount of water is added to steamed grains, and the grains are allowed to cool. After this, amylase is added and the grains are saccharified at around 10-50°C for several hours to hydrolyze the gelatinized starch in the grains and liquefy them into sugars. The starch in the grains is saccharified to produce a viscous grain saccharified liquid, which can be removed by solid-liquid separation to obtain grains with a high protein content. This is then inoculated with seed koji, grown at a specified temperature, and used to produce koji, resulting in grain koji with a high protein content. Furthermore, grain koji with a high protein content can be obtained by using rice, corn, and other grains as a solid medium for koji mold to produce koji, even from the rice residue after separation of the saccharified liquid, which is the first step in the production of ethanol and sweeteners from such grains.

[0019] In the method for producing a meat-like food of the present invention, the raw material containing the pulse protein material and the cereal koji can be mixed in any ratio, and either mixed and then fed to the extruder, or fed to the extruder separately before mixing. If the amount of enzyme derived from cereal koji is too small, the amount of free amino acids produced by protein hydrolysis will be small, so it is preferable to mix the grain koji so that it contains 1 part by weight or more of the pulse protein material per 10 parts by weight of the pulse protein material, on a dry weight basis.Furthermore, from the perspective of ease of texturization, it is preferable to mix the grain koji so that it contains 1 part by weight or more of the pulse protein material per 10 parts by weight of the grain koji, on a dry weight basis.

[0020] Water may be added when mixing the raw material containing the pulse protein material with the grain koji, or may be added to the mixed raw material in the extruder via a supply line to the extruder. The amount of water added varies depending on the type of meat-like food, but generally, 20 to 90 parts by mass of water is added per 100 parts by weight of the total weight of the raw material containing the pulse protein material and the grain koji.

[0021] The extruder used in the present invention may be a single-screw extruder, but a twin-screw extruder is usually used. The extruder is equipped with, for example, a twin screw and its drive unit, a cylinder, a temperature control unit that controls the temperature of the raw materials being mixed and kneaded in the cylinder to a desired temperature, and a die at the outlet. The die is used to extrude the mixture mixed and kneaded in the cylinder out of the cylinder in a desired shape, and may be equipped with a cutting head at the outlet.

[0022] The pressure applied in the extruder is not particularly limited as long as the raw materials can be sufficiently mixed and extruded. The heating temperature in the extruder is also not particularly limited, but the heating temperature at least near the inlet of the extruder is adjusted to a temperature that allows the kneaded product to be kneaded at a temperature of approximately 50°C, the optimum temperature for the enzyme reaction. The temperature at the outlet of the extruder cylinder is usually adjusted to 100 to 180°C.

[0023] The method for producing a meat-like food of the present invention may include a step of drying the textured vegetable protein produced by extruder treatment, or may include a step of shaping or cutting the textured vegetable protein into a desired shape. The shape of the meat-like food product of the present invention is not limited, but granular or flaked form is preferred. The size and shape of the meat-like food can be adjusted by, for example, changing the shape of the die at the outlet of the extruder or the conditions of the cutting head, so the size is adjusted depending on the application.

[0024] The meat-like food of the present invention can be used as a meat substitute food as is, or can be dried and used. The meat-like food of the present invention may also be mixed with one or more other meat substitute ingredients, or mixed with meat. It is particularly natural when mixed with minced meat. Examples of such foods include hamburger steaks, meatballs, gyoza dumplings, shumai, and meat bun fillings, as well as various processed meat foods.

[0025] The present invention will be described in detail below based on examples, but the present invention is not limited to these examples. In the examples, "%" means "% by weight." [Example]

[0026] [Example 1] [Production of rice protein composition and koji production using the medium] Water was added to 35 kg of washed rice in a heating vessel to bring the total volume to 100 L. 2.5 mL of lactic acid was added to adjust the pH to approximately 5.0. The temperature was raised, and 50 mL of thermostable amylase BIOTHERMOSIZE X-55D (Biogreen Enzyme (Thailand) Co. Ltd.) was added at 70°C, just before the start of starch gelatinization. The mixture was held for 1 hour after reaching the boiling point, and then the rice saccharified solution was separated from the saccharification reaction product using a screw press to recover the rice protein composition. This rice protein composition was used as a solid medium, and 1% by weight of rice koji was inoculated and cultured in a solid state. The rice koji was then cultured at room temperature for 48 hours to produce koji. The rice koji was dried overnight at 40°C and then crushed to obtain a rice koji powder that passed an 18-mesh mesh.

[0027] [Comparative Example] [Extruder processing] The rice koji and water obtained in Example 1 were mixed at a 2:1 ratio and subjected to an extruder treatment (treatment conditions: feed barrel 80°C, intermediate barrel 100°C, end barrel 150°C, die plate temperature 150°C), but no structure was formed. The amount of free amino acids in this extruder-treated product (Comparative Example 1) was measured using the following device. The measurement results are shown in Table 1 below. Soy protein (Solpy 6000H, manufactured by Nisshin Oillio Co., Ltd.) and water were mixed at a ratio of 2:1 and texturized by extrusion under the same conditions as in Comparative Example 1. The amount of free amino acids in this extruded product (Comparative Example 2) was measured, and the results are shown in Table 1. The amount of free amino acids was measured using an L-8900 high-speed amino acid analyzer (Hitachi High-Technologies Corporation). The extruder used was a twin-screw extruder EA-20 (Suehiro EPM Co., Ltd.).

[0028] [Example 2] [Production of meat-like food by extruding a mixture of soy protein and rice koji] The rice koji produced in Example 1, soy protein (Solpy 6000H, manufactured by Nisshin Oillio Co., Ltd.), and water were mixed at a ratio of the total of rice koji and soy protein to water of 2:1, and then extruded. The weight ratios of rice koji to soy protein for the extruder treatment were 5:5, 7:3, and 8:2. The amount of free amino acids under each condition is shown in Table 1. The measured values ​​in Table 1 are the measured values ​​of the extruder-treated product at a predetermined weight ratio, and the calculated values ​​are the amounts of free amino acids calculated from the measured values ​​of Comparative Examples 1 and 2 when mixed at a predetermined weight ratio. All measured values ​​exceeded the calculated values, confirming the synergistic effect of the mixed treatment of rice koji and soy protein.

[0029] [Table 1]

[0030] From the results in Table 1 showing the amount of free amino acids in the extruder-treated products of the Comparative Example and the Example, the amount of free amino acids contained in the extruder-treated product of the Example was higher than the calculated value for all 18 types of amino acids. In particular, the actual measured values ​​were significantly higher than the calculated values ​​for threonine, glutamic acid, alanine, valine, methionine, isoleucine, leucine, tyrosine, phenylalanine, lysine, histidine, arginine, etc., accounting for more than two-thirds of the 18 amino acids. Of these, glutamic acid and alanine in particular are amino acids that contribute to umami and sweetness, and are therefore considered to be factors in improving the taste. Furthermore, lysine, histidine, and arginine are amino acids that are low in rice protein and abundant in soy protein, suggesting a good compatibility between grain protein and legume protein, as exemplified by the combination of rice and soybeans.

Claims

1. A method for producing a meat-like food, comprising mixing a raw material containing a legume protein material, grain koji, and water, and then kneading and extruding the mixture under pressure and heat using an extruder.

2. The method of claim 1 , wherein the raw material containing the pulse protein material contains an excipient.

3. A meat-like food product with excellent taste and texture, produced by the method of claim 1 or 2, which contains free amino acids produced by the enzymes contained in grain koji hydrolyzing proteins, and chitin and glucan, which are components of the cell wall of koji mold.

Images