Method for manufacturing food material enriched with γ-aminobutyric acid

Abstract

To provide a method for manufacturing a food material by which it is possible to efficiently enrich γ-aminobutyric acid even under low temperature conditions required for food sanitation and quality management.SOLUTION: It is designed to generate γ-aminobutyric acid by mixing mushroom containing glutamic acid decarboxylase, and cheese into a paste, followed by retaining this. Representative examples of the mushroom containing glutamic acid decarboxylase include Flammulina velutipes. It is possible to generate more γ-aminobutyric acid by adding glutamic acid or its salt.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a method for producing a food material that can efficiently enrich γ-aminobutyric acid even under low-temperature conditions required for food hygiene and quality control by combining mushrooms with other foods.

Background Art

[0002] γ-aminobutyric acid is a type of amino acid and plays an important role in the central nervous system as a neurotransmitter. It has been reported that γ-aminobutyric acid, i.e., GABA, has functions such as "lowering blood pressure in those with high blood pressure", "relieving temporary mental stress and fatigue", and "improving the quality of sleep". Many functional foods labeled with GABA as a functional ingredient have been notified, and more than 1,000 products have been commercialized (as of May 2024, from the search of the information on the notification of functional foods by the Consumer Affairs Agency).

[0003] We have already notified and commercialized fresh enokitake products such as "Enotan" and "Enotan large strains", and the frozen paste product "Enoki Ice (registered trademark)" as functional foods related to GABA. There is also an expectation for the development of processed food products that utilize their functional components.

[0004] γ-aminobutyric acid is produced from glutamic acid by the action of glutamic acid decarboxylase. It is known to increase by stressing stored agricultural products, and methods such as applying treatments such as anaerobic conditions, far-infrared irradiation, and freezing, or immersing in a solution containing sodium glutamate, which is a raw material for γ-aminobutyric acid, have been developed.

[0005] Regarding the technology for enriching γ-aminobutyric acid in mushrooms, methods such as immersing dried fruiting bodies in warm water containing sodium glutamate (Patent Document 1), dispersing and mixing fruiting bodies in water together with glutamic acid or its salt (Patent Document 2), holding fruiting bodies under anaerobic conditions (Patent Document 3), and applying environmental changes such as humidification and drying to dried shiitake mushrooms (Patent Document 4) have been developed.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Summary of the Invention

Problems to be Solved by the Invention

[0007] Technologies for enriching γ - aminobutyric acid using glutamic acid or its salts (Patent Documents 1 and 2) have achieved efficient production. However, at the production temperature, it is described as a feature that the method of Patent Document 1 maintains 30 - 50°C and the method of Patent Document 2 maintains 10 - 20°C respectively, and both are within the temperature range of 10 - 60°C where there is a concern about the risk of reproduction of microorganisms such as bacteria. Furthermore, it also overlaps with the production temperature range (10 - 46°C) of the toxin enterotoxin in Staphylococcus aureus, which is one of the pyogenic bacteria that causes food poisoning. Therefore, when dealing with fresh mushrooms, from the perspective of food hygiene and quality control, production at a low temperature not exceeding 10°C has been desired.

[0008] Also, in the methods of Patent Documents 1 and 2, an additive of glutamic acid or its salt is used as a material for enriching γ - aminobutyric acid, but there are not a few consumers who have a psychological resistance to additives, and as one of the options, a technology that does not use additives has also been demanded.

[0009] Therefore, aiming at the development of a technology that can enrich γ-aminobutyric acid even under temperature conditions below 10°C, instead of adding glutamic acid or its salts using mushrooms as a raw material, other foods containing natural free glutamic acid are utilized.

[0010] Cheese is a food rich in glutamic acid, but it contains almost no γ-aminobutyric acid. According to Patent Document 5, many of the lactic acid bacteria used to make cheese may have extremely weak enzyme activity for producing γ-aminobutyric acid, and the development of a new cheese starter with enhanced enzyme activity is underway.

[0011] Therefore, one of the objects of the present invention is to provide a technology that can efficiently produce a food material enriched with γ-aminobutyric acid even at a low temperature of 1 to 10°C by combining with cheese instead of adding glutamic acid or its salts using mushrooms as a raw material. Of course, the temperature conditions related to this technology are not limited to 1 to 10°C. For example, when the risk in food hygiene management is avoided and the safety of raw materials can be ensured, such as using mycelia aseptically mass-proliferated by liquid culture or fruit bodies cultivated in a clean environment, it is also possible to increase the temperature to the optimum temperature (55°C) of glutamic acid decarboxylase for production.

[0012] Furthermore, another object is to provide a technology that enables the use of cheese with a low glutamic acid content as an enrichment material in the same technology.

Means for Solving the Problem

[0013] The present invention has the following configuration to achieve the above object. Focusing on the fact that cheese contains a large amount of free amino acids, it was decided to convert glutamic acid contained in cheese into γ-aminobutyric acid by glutamic acid decarboxylase possessed by mushrooms. As a result, according to the method for producing a food material enriched with γ-aminobutyric acid according to the present invention, γ-aminobutyric acid is produced by mixing a mushroom containing glutamic acid decarboxylase and cheese, preparing it into a paste form, and holding it. Further, according to an example of the method for producing a food material enriched with γ-aminobutyric acid according to the present invention, the mushroom containing the glutamic acid decarboxylase is characterized in being enoki mushroom.

[0014] On the other hand, the free amino acid content also varies depending on the type of cheese, and tends to increase as the aging period becomes longer. Therefore, it aimed at the development of a technology that can be used as a material for enriching γ-aminobutyric acid even for cheeses with a low glutamic acid content such as non-aged types. As a result, according to an example of the method for producing a food material enriched with γ-aminobutyric acid according to the present invention, it is characterized in that glutamic acid or its salt is added.

Effects of the Invention

[0015] In the present invention, by mixing mushrooms and cheese and preparing them into a paste form, the content of γ-aminobutyric acid can be efficiently increased even under low-temperature conditions required for food hygiene and quality control. By using this as a food material, it becomes possible to easily develop and register a functional display food having γ-aminobutyric acid, that is, GABA as a functional ingredient. As consumers' health awareness increases, by obtaining a "functional display food", the functionality of the food can be appealed, and an increase in the added value and consumption expansion of processed products using mushrooms and cheese as raw materials are expected.

[0016] γ-aminobutyric acid is contained in large amounts in fermented foods such as yogurt and pickles, but is hardly contained in common cheese even though it is the same fermented food. By using the present invention, it is possible to produce new food materials and products that add functionality to the nutrition and deliciousness using cheese as a raw material.

[0017] In the cultivation of mushrooms, especially the cultivation of Enoki mushrooms, as a result of promoting the efficiency of productivity through scale expansion, year-round professional management based on employment has become the mainstream. However, the image of the mushroom season is strongly associated with autumn to winter, and the demand from spring to summer is sluggish, presenting a major challenge in boosting production. Therefore, if food materials with functionality as a starting point using Enoki mushrooms as raw materials can be reused in various processed foods such as confectioneries and side dishes, stable demand can be expected throughout the year, leading to the stabilization of management.

Brief Description of the Drawings

[0018]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0019] Hereinafter, examples of a method for producing a food material enriched with γ-aminobutyric acid according to the present invention will be described in detail based on FIGS. 1 to 4.

[0020] The mushroom to be used can be either mycelium or fruit body. In the case of the fruit body, after harvesting, it is preferably stored at refrigeration temperature (4 to 8°C) for within 7 days. The main mushrooms having glutamate decarboxylase include Enoki mushroom, Shiitake mushroom, Beech mushroom, King oyster mushroom, Nameko mushroom, Maitake mushroom, Hiratake mushroom, Shimeji mushroom, Button mushroom, Wood ear mushroom, Matsutake mushroom, etc. Note that the amount of γ-aminobutyric acid contained in the raw material does not significantly affect the production amount after treatment.

[0021] The type of cheese to be used can be any of natural cheese, processed cheese, or processed products made from these cheeses as raw materials, and can be selected bearing in mind the purpose of the final product. Note that if it is not desired to add glutamate or its salt, semi-hard or hard types of cheese with a high glutamate content, or ripened cheeses such as white mold or blue mold types are suitable. If the presence or absence of additives is not an issue, a wide range of types of cheese regardless of the length of the ripening period can be selected.

[0022] The food material enriched with γ-aminobutyric acid obtained by the above method can be handled in various forms such as paste, frozen, or dry powder according to the water content, storage period, addition amount, etc. in the usage scenario. When seeking the functions of γ-aminobutyric acid, that is, GABA, such as "lowering the blood pressure of those with high blood pressure", "relieving temporary mental stress and fatigue", and "improving the quality of sleep", the recommended daily intake amounts are 20 mg, 28 mg, and 100 mg respectively. By appropriately mixing the paste or dry powder as a food material, the development and commercialization of secondary processed products (final products) as functional foods are expected.

[0023] The content of the present invention will be described in detail by way of examples. These examples are merely part of the production examples, and this example (production method) does not limit the content and scope of the present invention.

[0024] The roots of fresh enoki mushrooms stored at refrigeration temperature (6°C) were removed, and the mushrooms were cut into strips about 2 - 3 cm wide. The cut enoki mushrooms, an equal amount (by weight) of cheese, and half the amount of water were put into a food processor and prepared into a paste. The obtained paste was transferred to a container made of PP and left standing (held and aged) in a refrigerator at 7 ± 2°C for 3 - 24 hours to produce γ-aminobutyric acid through an enzymatic reaction. The obtained paste with a high γ-aminobutyric acid content was packed into a bag (a heat-resistant, high-oxygen-barrier film bag) and sealed. After a boiling treatment (98°C for 30 minutes) to suppress enzyme inactivation and the initial bacterial count, it was cooled with running water.

[0025] Note that the mixing ratio of enoki mushrooms, cheese, and water (even without adding water) is arbitrarily set considering factors such as the type of cheese, the production time, the amount of γ-aminobutyric acid produced per 100 g of the paste, and the intended use.

[0026] When adding glutamic acid or its salt to the paste, the concentration is set within a range that does not impair the taste of the final product (such as being too strong in umami and having a bad aftertaste, or feeling bitter). For example, when the glutamic acid concentration in the final product containing 20% of the paste prepared by mixing enoki mushrooms and cheese is 0.5%, the glutamic acid concentration of the paste is allowed to be up to 2.5%.

[0027] The obtained prepared paste was stored frozen (-20°C) according to the intended use in the final product, and a part of it was dried into a dry powder by vacuum freeze-drying.

[0028] This will be specifically described in the following test examples. [[ID=]]

[0029] As Test 1, to confirm the effect of adding glutamic acid at low temperatures, 0.3% sodium glutamate was added to the enoki mushroom paste, and the time-course changes in the production amount of γ-aminobutyric acid at 25°C and 9°C were investigated. As a result (Figure 1), regardless of the presence or absence of added sodium glutamate, the production amount increased with time in all groups. The non-added group at 25°C after 6 hours was 39.6 mg per 100 g of paste (corrected value of 35.3 mg after subtracting the pre-production content of 4.3 mg), the added group was 92.2 mg (87.9 mg), while the non-added group at 9°C was 29.6 mg (25.3 mg), and the added group was 44.3 mg (40.0 mg). Therefore, the added group at 9°C showed a 58% increase compared to the non-added group at the same temperature, and the addition effect was recognized. However, compared to the same comparison at 25°C, it was a 149% increase, so it was relatively modest compared to that. Also, in terms of the production amount, the added group at 9°C only decreased by 54% compared to the added group at 25°C. Therefore, it was speculated that under temperature conditions below 10°C, even if sodium glutamate is added to the enoki mushroom paste, the production efficiency of γ-aminobutyric acid is low, and it is not easy to enrich it to a level that can be put into practical use as a technology for producing food materials for the development of functional foods.

[0030] As Test 2, instead of adding sodium glutamate, edam cheese rich in glutamic acid (containing 544 mg per 100 g) was used, and the amount of γ-aminobutyric acid produced at low temperature (9 °C) in a paste prepared by mixing it in equal amounts with enoki mushrooms (equivalent to adding 0.2% in terms of glutamic acid) was investigated. As a result (Fig. 2), the amount produced per 100 g of the paste after 24 hours was extremely high at 110.8 mg in the group where enoki mushrooms and edam cheese were mixed (corrected value of 99.3 mg after subtracting the initial content of 11.5 mg), 6.4 times that of the group with only enoki mushrooms (no addition) at 26.9 mg (15.4 mg in the same way), and 3.3 times that of the group with 0.3% sodium glutamate added to enoki mushrooms at 41.2 mg (29.7 mg in the same way). From this, it was judged that the paste prepared by mixing enoki mushrooms and edam cheese has the potential to efficiently increase the amount of γ-aminobutyric acid produced even at low temperatures below 10 °C. Note that the amount of γ-aminobutyric acid produced after 24 hours in the group with only edam cheese was 0.9 mg per 100 g of the paste, and it was confirmed that almost no production occurred in cheese alone without enoki mushrooms.

[0031] In addition, as Test 3, in order to confirm the γ-aminobutyric acid production efficiency at room temperature of the paste prepared by mixing enoki mushrooms and edam cheese, the amount of γ-aminobutyric acid produced at 20 °C was investigated. As a result (Table 1), the amount produced per 100 g of the paste after 24 hours was 130.7 mg (corrected value of 119.2 mg after subtracting the initial content of 11.5 mg), a 20% increase compared to 110.8 mg (99.3 mg in the same way) in the mixed group at 9 °C, and a 57% increase compared to 87.3 mg (75.8 mg in the same way) in the group with 0.3% sodium glutamate added at 20 °C. From this, it was confirmed that the paste prepared by mixing enoki mushrooms and edam cheese has the potential to efficiently increase the amount of γ-aminobutyric acid produced not only at low temperatures but also at room temperature above 10 °C. Note that the production amount in the mixed group with edam cheese at 9 °C exceeded that in the group with 0.3% sodium glutamate added at 20 °C by 31%, highlighting the high γ-aminobutyric acid production efficiency of edam cheese at low temperatures.

[0032]

Table 1

[0033] Edam cheese is a natural cheese, and lactic acid bacteria and enzymes that produce γ-aminobutyric acid may remain alive. Therefore, as Test 4, the amount of γ-aminobutyric acid produced at a low temperature (9°C) of a paste prepared using Edam cheese that had been boiled (98°C · 30 minutes) to inactivate the enzymes was investigated. As a result (Figure 3), the amount produced per 100 g of the paste after 24 hours was 26.9 mg (corrected value of 15.4 mg obtained by subtracting the pre-production content of 11.5 mg) in the enoki mushroom only (no addition) group, whereas the group prepared using enzyme-inactivated Edam cheese maintained a high value of 106.4 mg (same as 94.9 mg), remaining at 4% less than 110.8 mg (same as 99.3 mg) in the non-enzyme-inactivated group. From this, it was highly likely that Edam cheese contained almost no lactic acid bacteria or enzymes that produce γ-aminobutyric acid, and that almost all of the enzymes present in the paste were derived from enoki mushrooms, and it was judged that a large amount of γ-aminobutyric acid was produced from the abundant glutamic acid contained in Edam cheese by those enzymes.

[0034] When mixing enoki mushrooms, cheese, and water to prepare a paste, the production efficiency of γ-aminobutyric acid may vary depending on the amount of water added. Therefore, as Test 5, the mixing ratio of enoki mushrooms and Edam cheese was fixed at 1:1, only the amount of water added was changed, and the amount of γ-aminobutyric acid produced at a low temperature (9°C) was investigated. As a result (Table 2), the production amount per 100 g of the paste after 24 hours was 84.1 mg (corrected value of 70.4 mg after subtracting the pre-production content of 13.7 mg) in the 1:1:2 section of enoki mushrooms: Edam cheese: water, 109.9 mg (same as 96.2 mg) in the 1:1:1 section, 133.0 mg (same as 119.3 mg) in the 1:1:0.5 section, and 157.8 mg (same as 144.1 mg) in the 1:1:0 (no water added) section, increasing as the water addition ratio decreased. However, when converted per 100 g [raw weight] of enoki mushrooms, the 1:1:1 section with all equal amounts mixed was 288.6 mg. Indexing this as 100, the 1:1:2 section with the water addition doubled was 281.6 mg and 98, conversely, the 1:1:0.5 section reduced to 1 / 2 was 298.3 mg and 103, and the 1:1:0 section without water added was 288.2 mg and 100. It was found that there was almost no difference in production efficiency due to the difference in the amount of water added.

[0035]

Table 2

[0036] As Test 6, in order to evaluate the practicality of γ-aminobutyric acid production due to differences in cheese types, three types of cheese were used: Gouda cheese with different glutamic acid contents (aging type: 834 mg of glutamic acid per 100 g), T-process cheese (aged and non-aged mixed type: 186 mg per 100 g), and mozzarella cheese (non-aged type: 32 mg per 100 g). Pastes prepared by mixing each with an equal amount of enoki mushrooms, and the γ-aminobutyric acid production amounts of the same mixed pastes added with 0.3% sodium glutamate were investigated at low temperature (7°C). As a result (Figure 4 and Table 3), the production amount per 100 g of the paste after 24 hours was as follows: for the enoki mushroom only (no addition) group, it was 32.3 mg (corrected value of 28.9 mg after subtracting the pre-production content of 3.4 mg), and for the sodium glutamate addition group of enoki mushrooms, it was 49.4 mg (46.0 mg for the same); for the Gouda cheese mixed group, it was 184.7 mg (181.3 mg for the same), and for the sodium glutamate addition group of Gouda cheese, it was 249.1 mg (245.7 mg for the same); for the T-process cheese mixed group, it was 99.7 mg (96.3 mg for the same), and for the sodium glutamate addition group of T-process cheese, it was 213.6 mg (210.2 mg for the same); for the mozzarella cheese mixed group, it was 79.1 mg (75.7 mg for the same), and for the sodium glutamate addition group of mozzarella cheese, it was 204.3 mg (200.9 mg for the same). It was found that the higher the glutamic acid content of the cheese, the more γ-aminobutyric acid was produced. Also, by adding 0.3% sodium glutamate to the mixed paste of enoki mushrooms and cheese, the production amount was further increased, but the difference due to the type of cheese became smaller. From these facts, when comparing the increase amount of γ-aminobutyric acid when adding sodium glutamate to the paste of enoki mushrooms with the increase amount when adding sodium glutamate to the mixed paste of enoki mushrooms and various cheeses, it was found that for Gouda cheese, it was 3.8 times, for T-process cheese, it was 6.7 times, and for mozzarella cheese, it was 7.3 times, all showing a significant increase. It was confirmed that the lower the glutamic acid content of the cheese, the higher the production efficiency of γ-aminobutyric acid tended to be. Such a particularly remarkable phenomenon caused by the addition of sodium glutamate was produced by the synergistic effect with cheese, and it was found that even cheeses with low glutamic acid content can be used as a material for enriching γ-aminobutyric acid.

[0037]

Table 3

[0038] Based on these facts, as a target value for enrichment of the γ-aminobutyric acid content in the paste prepared by mixing enoki mushrooms and cheese, taking 150 mg or more per 100 g of the paste as one criterion, the practicality was evaluated based on the data 3 hours, 6 hours, and 24 hours after production. As a result, if the condition is not adding sodium glutamate, choose Gouda cheese (production for 6 hours or more), and if the condition is adding 0.3% sodium glutamate, it was judged that any of Gouda cheese (production for 3 hours or more), T-process cheese (production for 3 hours or more), and mozzarella cheese (production for 6 hours or more) can be selected.

[0039] As Test 7, in order to compare the characteristics related to γ-aminobutyric acid enrichment due to differences in mushroom types, shiitake mushrooms, which have glutamate decarboxylase like enoki mushrooms, button mushrooms, and oyster mushrooms were used. A paste prepared by mixing an equal amount with Gouda cheese, and the amount of γ-aminobutyric acid produced at low temperature (7°C) of the same mixed paste added with 0.3% sodium glutamate was investigated. As a result (Table 4), the production amount per 100 g of the paste after 24 hours was 27.7 mg (corrected value of 23.4 mg after subtracting the pre-production content of 4.3 mg) in the non-added group of shiitake mushrooms, 49.1 mg (same as 44.8 mg) in the sodium glutamate added group, while it was 128.8 mg (same as 124.5 mg) in the Gouda cheese mixed group, and 203.5 mg (same as 199.2 mg) in the sodium glutamate added group. Similarly, in the non-added group of button mushrooms, it was 26.1 mg (corrected value of 22.7 mg after subtracting the pre-production content of 3.4 mg), 44.0 mg (same as 40.6 mg) in the sodium glutamate added group, while it was 95.6 mg (same as 92.2 mg) in the Gouda cheese mixed group, 153.7 mg (same as 150.3 mg) in the sodium glutamate added group, in the non-added group of oyster mushrooms it was 11.4 mg (corrected value of 10.2 mg after subtracting the pre-production content of 1.2 mg), and 20.5 mg (same as 19.3 mg) in the sodium glutamate added group, while it was 86.2 mg (same as 85.0 mg) in the Gouda cheese mixed group, and 113.4 mg (same as 112.2 mg) in the sodium glutamate added group. Thus, although differences were seen in the amount of γ-aminobutyric acid produced depending on the mushroom type, in the mixed paste with Gouda cheese for any mushroom, the potential to increase the production amount more efficiently than the paste with only sodium glutamate added to the mushroom was confirmed. At that time, when comparing the increase amount of γ-aminobutyric acid when sodium glutamate was added to the mushroom paste with the increase amount when sodium glutamate was added to the mixed paste of mushroom and Gouda cheese, shiitake mushrooms were 3.5 times, button mushrooms were 3.2 times, and oyster mushrooms were 3.0 times. A synergistic effect with cheese was confirmed as in the case of enoki mushrooms, and the increase was significant for any mushroom.From these facts, it was confirmed that, regardless of the type of mushroom, any mushroom having glutamate decarboxylase can be used as a material for enriching γ-aminobutyric acid by mixing the mushroom with cheese, preparing it into a paste form, and holding it, and, if necessary, adding glutamate or its salt to the paste.

[0040]

Table 4

[0041] As described above, various preferred embodiments of the present invention have been described with examples. However, the present invention is not limited to these embodiments, and it goes without saying that many modifications can be made without departing from the spirit of the invention.

Claims

**Claim 1** A method for producing a food material enriched with γ-aminobutyric acid, characterized by mixing a mushroom containing glutamate decarboxylase and cheese, preparing the mixture into a paste form, and holding the paste to produce γ-aminobutyric acid. **Claim 2** The method for producing a food material enriched with γ-aminobutyric acid according to claim 1, wherein the mushroom containing glutamate decarboxylase is Flammulina velutipes. **Claim 3** The method for producing a food material enriched with γ-aminobutyric acid according to claim 1 or 2, characterized in that glutamate or a salt thereof is added.

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