Meat chunk-like food and production method therefor

Abstract

[Problem] To provide a meat chunk-like food and a production method therefor, the meat chunk-like food comprising: a grain protein composition not containing an additive such as a binder and having excellent taste and food texture; and an Aspergillus oryzae body. [Solution] A solid culture obtained by solid-culturing Aspergillus oryzae with a grain protein composition extracted from grains and sufficiently extending hyphae is subjected to two operations, including a step for performing coagulation by heat treatment and a step for performing compression by vacuum, to obtain a meat chunk-like food having an appearance like char siu.

Description

Chunk meat-like food and method for producing the same

[0001] The present invention relates to a chunk meat-like food made from plant-based materials and a method for producing the same.

[0002] In recent years, from the perspectives of the increasing health consciousness, the depletion and soaring prices of protein resources, and the sustainable development goal of reducing the environmental impact of meat production, research and development of meat substitute foods mainly composed of plant-based protein raw materials have been promoted. Plant-based protein raw materials are mainly organized under high temperature and high pressure by an extruder process, but current products are mostly minced meat-like, and are limited to small pieces such as thinly sliced meat-like at most.

[0003] Therefore, as a method for producing a chunk meat-like food mainly composed of plant-based protein raw materials, for example, a method of producing of producing chunk meat by binding minced meat-like or thinly sliced meat-like plant-based proteins with a binder (a binding agent), or a cross-linking method combining an enzyme such as transglutaminase, sodium alginate, and calcium (Patent Documents 1 and 2) have been proposed. However, consumers tend to strongly desire foods without additives, and in addition, the risks of "ultra-processed foods" containing various additives such as sweeteners, preservatives, and pigments to enhance taste and texture have been pointed out, and there are a certain number of consumers who view unknown additives with unease.

[0004] On the other hand, as one of the meat substitute proteins, mycoprotein made from filamentous fungi is known. The present inventors reported that a meat-like koji mold body composed of koji mold can be separated and recovered from the remaining rice culture substrate by adding water and mixing it with a solid culture of koji mold obtained by solid-culturing koji mold on steamed rice (Patent Document 3). As a further improvement, in order to eliminate the step of removing the remaining rice culture substrate, after gelatinizing the starch by gelatinizing the grains and allowing amylase to act thereon, the solid culture obtained by solid-culturing koji using the grain protein composition obtained by separating the saccharified liquid by solid-liquid separation as a culture substrate becomes a minced meat-like meat-like koji mold body composition with good taste has been reported (Patent Document 4).

[0005] Even meat substitutes made from grain protein compositions and mycoproteins have a minced meat-like shape, and it is difficult to obtain a meat-like food product using only plant-based protein materials without the use of a binder. Furthermore, since a texture close to meat is required for use as a meat substitute, currently, no meat-like food product that can reproduce the texture of meat using only plant-based materials has been obtained.

[0006] Japanese Patent Publication No. 7040689, Japanese Unexamined Patent Publication No. 2023-58145, Japanese Patent Publication No. 7264556, Japanese Patent Publication No. 7441567

[0007] The present invention aims to provide a block meat-like food product containing a grain protein composition and Aspergillus oryzae, which has excellent taste and texture without containing additives such as binders, and a method for producing the same.

[0008] As a result of diligent ingenuity, the inventors have discovered that a block-meat-like food product with the appearance of char siu can be obtained by solid-state culturing Aspergillus oryzae in a grain protein composition extracted from grains, allowing the mycelium to extend sufficiently, and then performing two operations: a process of coagulation by heat treatment and a process of compression under vacuum. This manufacturing method makes it possible to produce a block-meat-like food product that utilizes the original functions and flavors of grain protein and Aspergillus oryzae without adding a binder to the solid-state culture consisting of grain protein and Aspergillus oryzae.

[0009] The present invention relates to a meat-like food product described in [1] or [9] below, and to a method for producing a meat-like food product described in [2] to [8] below. [1] A meat-like food product comprising grain protein and Aspergillus oryzae mycelium, but without a binder. [2] A method for producing a meat-like food product, characterized by comprising the following steps (1) to (3): (1) a step of obtaining a solid culture product comprising a grain protein composition and Aspergillus oryzae mycelium by solid-state culturing Aspergillus oryzae in a grain protein composition; (2) a step of heat-treating the solid culture product at 70°C or higher for 10 minutes or more; (3) a step of compressing the solid culture product at a vacuum of 95% or higher. [3] The method for producing the food product described in [2] above, wherein the grain in the grain protein composition is at least one selected from the group consisting of brown rice, wheat, barley, corn, and pulverized products of these grains. [4] The manufacturing method according to [2] or [3] above, wherein the grain protein composition is obtained by saccharifying the pregelatinized starch in the grain with amylase, and then removing the saccharified liquid by solid-liquid separation. [5] The manufacturing method according to any one of [2] to [4] above, wherein the solid culture is made by extending the mycelium until it becomes koji board. [6] The manufacturing method according to any one of [2] to [5] above, wherein the product is impregnated with a seasoning liquid in any of steps (1) to (3). [7] The manufacturing method according to any one of [2] to [6] above, wherein cooking in a steam convection oven is performed after step (2). [8] The manufacturing method according to any one of [2] to [7] above, wherein vacuum freeze-drying is performed after step (3). [9] A block meat-like food produced by the manufacturing method according to any one of [2] to [8] above.

[0010] According to the present invention, a meat-like food product that resembles meat in taste and texture, without the need for additives such as binders, can be mass-produced using a simple method. The solid culture used in the present invention contains a grain protein composition as a substrate and koji mold cells with extended koji mycelium. Due to the enzymatic action of the koji mold, the proteins in the substrate and the koji itself are broken down into amino acids, resulting in a more flavorful and delicious meat-like koji mold composition. The meat-like food product obtained by heating and compressing this is a meat substitute food with excellent taste, texture, and nutritional value. Furthermore, a delicious and nutritious preserved food can be obtained by vacuum freeze-drying.

[0011] The fracture curves for each heating treatment condition of 70°C, 100°C, and 120°C are shown. The fracture curves for each compression treatment condition of vacuum degrees of 95.0%, 98.0%, and 99.5% are shown. The fracture curves for differences in the order of heating and compression treatments are shown. The fracture curves for differences in whether or not steam convection oven cooking was performed are shown. A photograph of the block meat-like food produced in Example 5 that was cooked in a steam convection oven is shown. A photograph of the block meat-like food produced in Example 7 that was freeze-dried under vacuum is shown.

[0012] The solid culture used in the present invention is a solid culture obtained by solid-culture of Aspergillus oryzae using a grain protein composition as a solid substrate, and contains the grain protein composition as the substrate and Aspergillus oryzae cells in which the Aspergillus oryzae mycelium has been extended.

[0013] Aspergillus is a general term for filamentous fungi used to make koji, and the aspergillus used in this invention is preferably the aspergillus used in the production of fermented foods, 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. Additionally, Rhizopus (a type of fungus) and Mucor (a type of mold) are used in the production of mochi koji and tempeh, which are fermented foods made from filamentous fungi consumed in Southeast Asia.

[0014] The grains used as raw materials for the solid culture medium in this invention are seeds of grasses, such as rice, wheat, and corn. These may be coarsely crushed or contain rice bran (such as brown rice or partially milled rice) or wheat or corn bran. First, the grains are washed and soaked in water to absorb water, and then thoroughly steamed using a steamer, steam sterilizer, etc., to gelatinize the starch. For example, when using rice as the grain, steamed rice is usually obtained at a steaming temperature of 100 to 120°C for a steaming time of 10 to 60 minutes, but the conditions are not limited to these, and the steaming conditions are appropriately changed depending on the type and shape of the grain.

[0015] After steaming the grains, a small amount of water is added and allowed to cool. Then, amylase is added and the mixture is heated at approximately 10-50°C for several hours to hydrolyze the gelatinized starch in the grains and convert it into liquefied sugar. The amount of water added is not particularly limited, as long as it is an amount suitable for enzymatic hydrolysis of the starch in the grains. Amylase is a general term for enzymes that can hydrolyze starch, and the amylase used in this invention is mainly α-amylase, which is a liquefaction enzyme. It cleaves the bonds between glucose molecules in the gelatinized starch through hydrolysis, converting it into liquefied sugar.

[0016] In this way, after the hydrolysis reaction in which steamed grains are treated with amylase to saccharify them, the starch in the grains is saccharified into a highly viscous saccharified liquid. To remove this liquid, the saccharified liquid and the grain protein composition are separated by solid-liquid separation. Any known separation method such as filtration, centrifugation, or compression can be used for solid-liquid separation. For example, using a filter press or screw press yields a grain protein composition with a moisture content of about 40-70%. The moisture in the composition contains oligosaccharides, which can be used directly as nutrients for the solid culture medium of Aspergillus oryzae.

[0017] The grain protein composition recovered by solid-liquid separation has only the starch in the center that is saccharified and removed by solid-liquid separation. As a result, the inside is porous with air pockets, resulting in a low bulk density and easy oxygen supply, making it a grain protein composition structurally suitable for koji cultivation. Furthermore, since approximately 75% of the dry weight is protein and it also contains oligosaccharides, it serves as a major nutrient source for koji mold.

[0018] The resulting grain protein composition can be directly inoculated with koji starter. In this invention, the form of koji starter may be spores or mycelium, and the amount of koji starter added is 0.1 to 1.5% by weight of the solid content of the solid culture medium, preferably about 1% by weight. The culture temperature after inoculation is preferably 20 to 40°C, and the culture time is arbitrary, but is about 1 to 10 days. For the koji mold to grow densely, in the case of a rice protein composition, it takes about 2 to 3 to 5 days of static culture at room temperature. Solid culture is preferably carried out until the mycelium has grown sufficiently and the koji is in the form of a plate rather than granules.

[0019] When Aspergillus oryzae proliferates on a grain protein composition, hyphae grow, and around the grain protein composition, a condition called "hassei" occurs, where the Aspergillus oryzae hyphae penetrate the substrate. In solid cultures where hassei has become dense, the hyphae surround the grain protein composition, and the enzymatic action of Aspergillus oryzae breaks down not only the koji itself but also the substrate proteins into amino acids, resulting in a stronger umami flavor.

[0020] The resulting solid culture is then subjected to (2) heat treatment and (3) compression treatment. The heat treatment and compression treatment can be performed in either order, or both treatments can be performed simultaneously. Performing the heat treatment after compression results in a greater breaking load (hardness) than a block meat-like food obtained by performing the heat treatment followed by compression, but the waveform disturbance of the breaking curve occurs similarly, and the heterogeneous and complex texture breaking curve shows a similar trend.

[0021] (2) The heat treatment involves heating at 70°C or higher for 10 minutes or more, preferably at 80°C to 130°C for 5 to 60 minutes. The heating apparatus is not particularly limited, but depending on the heating temperature, it can be heated in a water bath or autoclave, for example. This heating simultaneously deactivates the enzymes in the solid culture and causes thermal coagulation of the proteins, but if the temperature or time is insufficient, the binding may be weak and it may not form a solid mass. Furthermore, by cooking in a steam convection oven after the heat treatment, the breaking load (hardness) is greatly increased, and a meat-like food with a chewy texture can be obtained.

[0022] The compression process in (3) is carried out at a vacuum of 95% or higher. The compression device is not particularly limited as long as it can degas the inside of the solid culture, and a vacuum compressor or press molding machine, which are common as food processing machines, can be used. A press molding machine can efficiently process the solid culture to a certain shape and thickness, but a vacuum compressor is preferable to obtain the heterogeneous and complex texture of the solid culture. Furthermore, by performing vacuum freeze-drying after the process in (3), the long-term storage life can be greatly improved.

[0023] Furthermore, in step (2) or (3), or in the step of obtaining the solid culture in (1), the meat-like food product may be flavored by impregnating it with a seasoning liquid. The seasoning liquid is not limited, and all liquids commonly used for seasoning can be used. Examples of seasoning liquids include salt, sugar, soy sauce, sake, mirin, dashi, oils and fats, and mixtures thereof.

[0024] The meat-like food of the present invention is a food having the appearance and texture of meat of a certain size or larger. Preferably, each piece is 1 cm or larger and can be used as thick-cut meat, steak meat, meat for cutlets, diced meat, or meat for char siu. It is a meat-like food that has a taste and texture similar to meat, even without containing additives such as binders other than grain protein and koji mold, and can be used as a nutritious and delicious meat substitute.

[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 "weight percent".

[0026] [Example 1] [Production of Solid Culture] 10 kg of rice was washed and soaked in water for 1 hour, then steamed at 100°C for 40 minutes, and water was added so that the solid content of the rice was 30%. The pH was adjusted to about 5 at a liquid temperature of 55°C or lower, 10 g of 100 g of gluten (Amano Enzyme Co., Ltd.) was added, and the mixture was stirred. After standing at room temperature for 12 hours, the rice protein composition was recovered from the saccharification reaction product by screw press. As the koji mold, koji mold powder of A. oryzae was used. 2 w / w% of rice koji was inoculated onto the wet weight of the above rice protein composition, and the koji was cultured statically at room temperature of 25°C for 3 days using a conventional method. Breaking of the koji mold (a state in which the mycelium of the koji mold penetrates the substrate) occurred around the rice protein composition, and a koji plate with elongated mycelium was obtained.

[0027] [Example 2] [Investigation of Heat Treatment Conditions] The solid culture obtained in Example 1 was placed in a heat-resistant polypropylene bag and heat-treated at 70°C, 100°C, and 120°C for 10 minutes each to obtain a block meat-like food product. A water bath was used for the 70°C and 100°C conditions, and an autoclave (manufactured by Hirayama Seisakusho) was used for the 120°C condition. The fracture curve and fracture load (hardness) of the untreated and heat-treated samples were measured using a fracture meter under the following conditions. - Creep meter (model number RE2-33005C: Yamaden Co., Ltd.) - The sample was cut to 2 cm long, 3 cm wide, and 2 cm high, placed in a frame, and measured - The plunger was 5 mm brass - The fracture load was measured from the top at a speed of 1.0 mm per second until the plunger penetrated the sample to a strain rate of 90%. - Five measurements were taken per sample, and the average value of the fracture load was calculated.

[0028] This test measures the force (load) required to deform or break a material when compressed at a constant rate. The breaking loads for the untreated, 70°C, 100°C, and 120°C samples were 2.25 N, 3.27 N, 3.28 N, and 5.64 N, respectively. The breaking load (hardness) increased with increasing heat treatment temperature. Figure 1 shows the breaking curves for different heat treatment conditions. Applying heat treatment above 70°C resulted in more waveform distortion compared to the untreated breaking curve, indicating a heterogeneous and complex texture.

[0029] [Example 3] [Investigation of Compression Processing Conditions] The solid culture obtained in Example 1 was placed in a heat-resistant polypropylene bag and compressed using a vacuum packing machine (manufactured by Tosei) at vacuum levels of 95.0%, 98.0%, and 99.5% to obtain a meat-like food product. The fracture curves and fracture loads (hardness) of the untreated and compressed samples were measured in the same manner as in Example 2. The fracture loads of the untreated, and the samples treated at vacuum levels of 95.0%, 98.0%, and 99.5% were 2.25 N, 5.49 N, 6.55 N, and 6.28 N, respectively, and the fracture load (hardness) improved with increasing vacuum level. Figure 2 shows the fracture curves for different compression processing conditions. By applying compression processing at a vacuum level of 95.0% or higher, waveform disturbance occurred compared to the fracture curve of the untreated sample, and a heterogeneous and complex texture was confirmed.

[0030] [Example 4] [Investigation of the order of heat treatment and compression treatment] The solid culture obtained in Example 1 was placed in a heat-resistant polypropylene bag and heat-treated in an autoclave (Hirayama Seisakusho) at 120°C for 10 minutes, and then vacuum-compressed at 99.5% vacuum using a vacuum packing machine (TOSEI) (Sample: AC → VC). Alternatively, it could be vacuum-compressed at 99.5% vacuum using a vacuum packing machine, and then heat-treated in an autoclave at 120°C for 10 minutes (Sample: VC → AC). The fracture curves and fracture loads (hardness) were measured for the untreated sample, sample AC → VC, and sample VC → AC using the same method as in Example 2.

[0031] The breaking loads for untreated sample, sample AC → VC, and sample VC → AC were 2.25 N, 5.76 N, and 7.59 N, respectively. The breaking load increased after heat treatment following compression. Figure 3 shows the breaking curves for different orders of heat and compression treatments. Although the breaking load differed depending on the order of heat and compression treatments, the waveform distortion showed a similar trend, and heterogeneous and complex textured breaking curves were observed.

[0032] [Example 5] [Investigation of steam convection cooking] The solid culture obtained in Example 1 was placed in a heat-resistant polypropylene bag and heat-treated in an autoclave at 120°C for 10 minutes (Sample: AC). Then, the sample removed from the heat-resistant polypropylene bag was heated in a steam convection oven (manufactured by Rational Japan) at 110°C for 40 minutes (Sample: AC → SC). The fracture curve and fracture load (hardness) were measured for the untreated sample, sample AC, and sample AC → SC in the same manner as in Example 2.

[0033] Figure 4 shows the fracture curves with and without steam convection oven cooking. The fracture loads for untreated sample, sample AC, and sample AC→SC are 2.25 N, 5.64 N, and 20.6 N, respectively. It was confirmed that steam convection oven cooking after heat treatment significantly increased the fracture load (hardness). Figure 5 shows the appearance of the meat-like food product cooked in a steam convection oven.

[0034] [Example 6] [Impregnation with seasoning liquid] 10 g of seasoning liquid (all-purpose dashi, Otafuku sauce) was sprayed onto 100 g of the solid culture obtained in Example 1, and the mixture was heated in an autoclave at 120°C for 10 minutes. After that, it was vacuum compressed in a vacuum packing machine at a vacuum level of 99.5%. Adding the seasoning liquid resulted in a meat-like food product with good palatability.

[0035] [Example 7] [Vacuum Freeze-Drying] 100 g of the meat-like food obtained in Example 4 was dried using a vacuum freeze-dryer (manufactured by Tokyo Rikakikai) by a conventional method to obtain a dried product (moisture content 0.5% by weight). Figure 6 shows the appearance of the meat-like food after vacuum freeze-drying.

Claims

1. A block-meat-like food containing grain protein and Aspergillus oryzae mycelium, without any binder.

2. A method for producing a block meat-like food product, comprising the following steps (1) to (3): (1) A step of obtaining a solid culture containing a grain protein composition and Aspergillus oryzae cells with extended Aspergillus oryzae mycelium by solid culture of Aspergillus oryzae in a grain protein composition; (2) A step of heat-treating the solid culture at 70°C or higher for 10 minutes or more; (3) A step of compressing the solid culture at a vacuum of 95% or higher.

3. The manufacturing method according to claim 2, wherein the grain in the grain protein composition is at least one selected from the group consisting of brown rice, wheat, barley, corn, and pulverized products of these grains.

4. The manufacturing method according to claim 2, wherein the cereal protein composition is obtained by saccharifying pregelatinized starch in cereals with amylase, and then removing the saccharified liquid by solid-liquid separation.

5. The manufacturing method according to claim 2, wherein the solid culture is allowed to elongate until it becomes a koji sheet.

6. The manufacturing method according to claim 2, wherein the product is impregnated with a seasoning liquid in any of the steps (1) to (3) above.

7. The manufacturing method according to claim 2, wherein steam convection oven cooking is performed after step (2) above.

8. The manufacturing method according to claim 2, wherein vacuum freeze-drying is performed after step (3) above.

9. A block meat-like food product manufactured by the manufacturing method described in any one of claims 2 to 8.

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