Method for producing γ-aminobutyric acid

Abstract

To provide a technique that can efficiently enrich GABA from plant materials.SOLUTION: A method for producing γ-aminobutyric acid includes the step in which, in processed plant materials selected from the group consisting of crushed plant matter, squeezed juices, water-based extracts, and their concentrated forms, lactic acid bacteria that produce glutamate decarboxylase and yeast are cultured. This method makes it possible to efficiently enrich GABA from plant materials.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a method for producing γ-aminobutyric acid. Specifically, the present invention relates to a method for producing γ-aminobutyric acid using a processed product obtained from a plant as a material. [Background technology]

[0002] γ-aminobutyric acid (hereinafter referred to as "GABA") is a non-protein amino acid produced by the decarboxylation of L-glutamic acid by glutamate decarboxylase, and is widely present in the living world, albeit in small amounts. Specifically, GABA is contained in food materials such as vegetables and fruits, and is one of the components ingested in the diet.

[0003] It is known that GABA acts as an inhibitory neurotransmitter in higher animals. In addition, it has been reported that GABA has physiological effects such as lowering blood pressure (suppressing increase) by vasodilation (see Non-Patent Document 1), preventing arteriosclerosis, improving liver function, improving kidney function, and stabilizing the mind (see Non-Patent Document 2). Furthermore, GABA is known to have various physiological functions such as suppressing the increase in neutral fat (preventing obesity), alleviating menopausal symptoms, improving brain function such as improving memory and enhancing learning ability, and promoting alcohol metabolism (see Non-Patent Documents 3-5).

[0004] Because of these beneficial physiological effects, GABA has attracted attention as a functional food ingredient; however, food ingredients contain very small amounts of GABA, and it has traditionally been difficult to ingest an effective amount from food to achieve the above-mentioned physiological activities.

[0005] Therefore, methods for increasing the GABA content in food materials have been studied. It has been reported that lactic acid bacteria such as Lactobacillus brevis (Levilactobacillus brevis) and Lactobacillus plantarum (Lactiplantibacillus plantarum) have glutamic acid decarboxylase and are capable of producing GABA from glutamic acid in food materials (Non-Patent Documents 6-8). In methods for increasing the GABA content in food materials, lactic acid bacteria are usually used, and glutamic acid or yeast extract may also be added to the medium (Patent Documents 1-5 and Non-Patent Documents 9-11).

[0006] In order to increase the GABA content in food materials, it seems reasonable to use food materials with a high glutamic acid content as the fermentation material. Among them, tomatoes contain a lot of glutamic acid, so they are sometimes selected as the above-mentioned fermentation material. However, in such a study using tomatoes, it has been shown that when processed tomatoes with a filtrate coloring degree of more than 0.2 at Brix 3% are used as the fermentation material in lactic acid fermentation, the conversion rate to GABA is significantly reduced (Patent Document 6). Therefore, when tomatoes are used as the fermentation material, it is necessary to use ones with a sufficiently low coloring degree, so tomato puree and concentrated tomato paste that are generally used in food processing cannot be used, and the characteristic of tomatoes, which has a high glutamic acid content, cannot be effectively utilized. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2000-210075 A [Patent Document 2] JP 2004-215529 A [Patent Document 3] JP 2003-333990 A [Patent Document 4] JP 2006-314207 A [Patent Document 5] JP 2007-289008 A [Patent Document 6] JP 2007-060990 A [Non-patent literature]

[0008] [Non-Patent Document 1] Journal of the Japanese Society for Food Science and Technology, 49, 409-415, 2002 [Non-Patent Document 2] Osaka Bioenvironmental Science Institute Report "GABA High Concentration Fermented Extract" (2002); Yoshie Ueno et al., Kyoto M&T General Center Information, June 2001, Research Report) [Non-Patent Document 3] Psychopharmacology, 56, 127-132 (1978) [Non-Patent Document 4] Journal of the Japanese Society for Food Science and Technology, vol.47, 596-603 (2000) [Non-Patent Document 5] Food and Development, 63, 4-6 (2001) [Non-Patent Document 6] Journal of Bioengineering, vol.75, 239-244 (1997) [Non-Patent Document 7] Food Microbiology, vol.22 497-504 (2003) [Non-Patent Document 8] Journal of Bioengineering, vol.85, 109-114 (2007) [Non-Patent Document 9] J. Brew. Soc. Japan, Vol.98, No.3, p.221-224 (2003) [Non-Patent Document 10] Food Style, 21, 2003.3 (Vol.7, No.3), p.64-68 [Non-Patent Document 11] Food Style, 21, 2004.3 (Vol.8, No.3), p.64-68 Summary of the Invention [Problem to be solved by the invention]

[0009] Plant materials are natural materials, and those used as fermentation materials have complex compositions containing a wide variety of ingredients, so even if they simply contain glutamic acid, it is difficult for enzymes to react with them efficiently. In the case of tomatoes, it is not possible to perform an enzyme reaction using materials with a high degree of coloring, so it can be said that this is a plant material in which the efficiency of the enzyme reaction is significantly low. Thus, it has been difficult to efficiently enrich GABA from plant materials such as tomatoes.

[0010] Therefore, an object of the present invention is to provide a technique for efficiently enriching GABA from plant materials. [Means for solving the problem]

[0011] As a result of intensive research, the present inventors have found that GABA can be efficiently enriched by co-culturing yeast in the lactic acid fermentation of plant materials. Based on this finding, the present invention was completed through further research.

[0012] That is, the present invention provides the following aspects. Item 1. A method for producing γ-aminobutyric acid, comprising a step of culturing lactic acid bacteria and yeast that produce glutamic acid decarboxylase in a processed plant product selected from the group consisting of crushed plant material, squeezed juice, water extract, and concentrates thereof. Item 2. The method according to Item 1, wherein the plant is a tomato. Item 3. The method according to Item 2, wherein the coloring degree of the plant processed product is more than 0.2 when the Brix is ​​3%. Item 4. The method according to any one of Items 1 to 3, wherein the lactic acid bacteria is selected from the group consisting of lactic acid bacteria of the genus Levilactobacillus, lactic acid bacteria of the genus Lactiplantibacillus, and lactic acid bacteria of the genus Lactococcus. Item 5. The method according to any one of Items 1 to 4, wherein the lactic acid bacterium is selected from the group consisting of Levilactobacillus brevis, Lactiplantibacillus plantarum, and Lactococcus lactis. Item 6. The method according to any one of Items 1 to 5, wherein the yeast is selected from the group consisting of yeasts of the genus Saccharomyces and yeasts of the genus Wickerhamomyces. Item 7. The method according to any one of Items 1 to 6, wherein the yeast is selected from the group consisting of Saccharomyces cerevisiae, Saccharomyces bayanus, and Wickerhamomyces anomalus. Item 8. A process for obtaining a plant processed product enriched in γ-aminobutyric acid by the production method according to any one of items 1 to 7; and cooking the food or drink using the processed plant product enriched in γ-aminobutyric acid. Effect of the Invention

[0013] According to the present invention, a technique is provided that can efficiently enrich GABA from plant materials. [Brief description of the drawings]

[0014] [Figure 1] The graph shows the time course of GABA production using concentrated tomato paste when L. brevis SP48 strain was cultured alone and when it was co-cultured with baker's yeast. [Diagram 2] The amount of GABA produced using concentrated tomato paste is shown when L. brevis SP48 strain is cultured alone and when co-cultured with yeast. [Diagram 3]1 shows the effect of yeast co-cultivation with L. brevis strains other than SP48 on GABA production using concentrated tomato paste. [Figure 4] The effect of yeast co-cultivation with lactic acid bacteria species other than L. brevis on GABA production using concentrated tomato paste is shown. [Diagram 5] Shows the effect of the presence or absence of glutamic acid or yeast extract on GABA production using concentrated tomato paste. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] 1. Method for producing γ-aminobutyric acid The method for producing γ-aminobutyric acid of the present invention is characterized by comprising a step of culturing lactic acid bacteria and yeast that produce glutamic acid decarboxylase in a processed plant product selected from the group consisting of crushed plants, squeezed juice, water extracts, and concentrates thereof. The method for producing γ-aminobutyric acid of the present invention will be described in detail below.

[0016] In the culturing step, typically, a mixture of processed plant products containing a processed plant product, lactic acid bacteria, and yeast in water is subjected to culture conditions for the lactic acid bacteria and yeast.

[0017] 1-1. Plant processed products The processed plant product used in the present invention is selected from the group consisting of crushed plant material, squeezed juice, water extract, and concentrates thereof.

[0018] The plant is not particularly limited as long as it contains glutamic acid, and examples thereof include soybeans, edamame beans, broad beans, mung beans, red beans, dried gourd, garlic, green peas, broccoli, mustard, corn, spinach, cauliflower, cabbage, okra, green asparagus, soybean sprouts, spinach, daikon radish, lettuce, bamboo shoots, chrysanthemums, onions, pumpkins, chives, cucumbers, tomatoes, celery, and Examples of the plant include matsuna, snow peas, kidney beans, Chinese cabbage, lotus root, eggplant, green peppers, turnips, carrots, lettuce, green onions, bean sprouts, burdock, Chinese yam, potato, taro, sweet potato, avocado, melon, kiwi fruit, strawberry, banana, watermelon, mandarin orange, pineapple, fig, navel orange, grapefruit, grape, persimmon, plum, Japanese plum, peach, apple, pear, shiitake mushroom, mushroom, enoki mushroom, nameko mushroom, etc. One of these plants may be used alone, or multiple types may be used in combination. Among these plants, tomato is particularly preferable.

[0019] Specific forms of the plant processed products, such as crushed products, squeezed juice, water extracts, and concentrates thereof, may be those obtained by normal processing in the food processing field. Specific examples of crushed products or concentrates thereof include slurry, puree, and paste. Specific examples of squeezed juice or concentrates thereof include straight juice, concentrated juice, and concentrated reconstituted juice of fruit juice and vegetable juice. Water extracts include those extracted with non-heated water and those extracted with heated water (hot water, etc.). Furthermore, concentrates may be those from which water has been at least partially removed, and in addition to the above, dried products (freeze-dried products, spray-dried products) may also be mentioned.

[0020] The method for producing γ-aminobutyric acid of the present invention can effectively enrich GABA even in plant processed products with a high degree of coloration, which is inherently difficult to enrich GABA in. Therefore, a suitable example of a plant processed product of the present invention is a plant processed product with a high degree of coloration. A specific example of the coloration of such a plant processed product is one with a coloration degree of more than 0.2 in the case of Brix 3%. The coloration degree in the case of Brix 3% specifically refers to the value obtained as the absorbance at 450 nm of the aqueous liquid when the plant processed product is prepared as an aqueous liquid that can pass through a membrane filter with Brix 3% and a pore size of 0.45 μm. In addition, the Brix value refers to the reading of a sugar refractometer at a sample temperature (liquid temperature) of 20° C. based on the JAS standard. The lower limit of the coloration degree in the case of Brix 3% may be 0.201 or more, 0.3 or more, or 0.35 or more. On the other hand, the upper limit of the coloration degree in the case of Brix 3% is not particularly limited, but is preferably 3.0 or less, preferably 2.0 or less, and more preferably 1.5 or less.

[0021] A particularly suitable example of the processed plant product in the present invention is a processed tomato product (preferably a puree or paste, more preferably a paste) having a coloring degree of more than 0.2 when Brix is ​​3%.

[0022] The content of the processed plant products in the mixture of processed plant products is not particularly limited, but may be, for example, 5% or more, preferably 7% or more, more preferably 8% or more, more preferably 9% or more, and even more preferably 9.2% or more in Brix value. The upper limit of the content of the processed plant products in the mixture of processed plant products is not particularly limited, but may be, for example, 20% or less, preferably 17% or less, and more preferably 16% or less in Brix value.

[0023] It is preferable that the processed plant product is heat-sterilized before being subjected to culture conditions.

[0024] 1-2.Lactic acid bacteria The lactic acid bacteria used in the present invention are not particularly limited, but are limited to those that produce glutamic acid decarboxylase. Specific examples of the lactic acid bacteria used in the present invention include, for example, lactic acid bacteria of the genus Levilactobacillus, lactic acid bacteria of the genus Lactiplantibacillus, and lactic acid bacteria of the genus Lactococcus. Examples of the lactic acid bacteria of the genus Levilactobacillus include, for example, Levilactobacillus brevis and Levilactobacillus parabrevis. Examples of the lactic acid bacteria of the genus Lactiplantibacillus include, for example, Lactiplantibacillus plantarum and Lactiplantibacillus pentousus. Examples of lactococcus bacteria include Lactococcus lactis, Lactococcus cremoris, and the like.

[0025] These lactic acid bacteria may be used alone or in combination of two or more species. Among these lactic acid bacteria, preferred are Lactobacillus brevis, Lactiplantibacillus plantarum, and Lactococcus lactis.

[0026] The form of the lactic acid bacteria is not particularly limited, and it is possible to use those in the form of liquid, slurry, dry, etc. Furthermore, the lactic acid bacteria may be used in the form of a dry dispersion in water, or may be used after pre-culture.

[0027] The amount of lactic acid bacteria used is not particularly limited, but can be, for example, 0.005 to 10% by weight, preferably 0.008 to 3% by weight in the plant processed product mixture.

[0028] 1-3. Yeast The yeast used in the present invention is not particularly limited, and examples thereof include yeasts of the genus Saccharomyces, yeasts of the genus Wickerhamomyces, etc. Examples of yeasts of the genus Saccharomyces include Saccharomyces cerevisiae, Saccharomyces bayanus, Saccharomyces pastorianus, etc. Examples of yeasts of the genus Wickerhamomyces include Wickerhamomyces anomalus, etc.

[0029] These yeasts may be used alone or in combination of two or more kinds. Among these yeasts, preferred are Saccharomyces chervishes, Saccharomyces bayanus, and Wickerhamomyces anomala.

[0030] The form of the yeast is not particularly limited, and yeast in a liquid form, a slurry form, a dry form, etc. may be used. Furthermore, the yeast may be used in a dry form by dispersing it in water, or may be used after pre-culture.

[0031] The amount of yeast used is not particularly limited, but may be, for example, 0.005 to 10% by weight, preferably 0.008 to 3% by weight, in the plant processed product mixture.

[0032] 1-4.Culture conditions By subjecting the mixture of processed plant products to the culture conditions of lactic acid bacteria and yeast, the yeast in the culture promotes the conversion reaction of glutamic acid in the processed plant products to GABA by glutamic acid decarboxylase produced by the lactic acid bacteria. As a result, GABA is produced in the mixture of processed plant products. In other words, a processed plant product enriched in GABA is obtained.

[0033] The culture conditions for providing the plant processed product mixture can be appropriately set based on the conditions under which the lactic acid bacteria and yeast used can produce the product. For example, the temperature for culture is, for example, 20 to 40° C., preferably 25 to 35° C. The time required for culture is, for example, 20 to 100 hours, preferably 24 to 72 hours.

[0034] 1-5. Other processes The production method of the present invention can include any other steps in addition to the above-mentioned culturing step.

[0035] A specific example of the other step is a step of heat sterilizing the plant processed product or a water dilution of the plant processed product, which is performed before the above-mentioned culturing step. The conditions of heat sterilization are not particularly limited and can be appropriately determined based on the conditions usually used in heat sterilization of food. Specific conditions of heat sterilization include, for example, 88 to 100°C and 10 seconds to 35 minutes.

[0036] Specific examples of other steps include steps carried out after the above-mentioned culturing step, such as concentrating the GABA-enriched plant processed product, diluting it with the plant processed product before the culture treatment, freezing it, and / or packaging and heat sterilizing it.

[0037] 2. Manufacturing methods for food and beverages As described above, the method for producing γ-aminobutyric acid can provide a plant processed product enriched in GABA. The plant processed product enriched in GABA obtained in this manner can be used as a functional material for producing various foods and beverages. Therefore, the present invention also provides a method for producing a food or beverage, which includes a step of obtaining a plant processed product enriched in γ-aminobutyric acid by the above-mentioned production method, and a step of cooking the food or beverage using the plant processed product enriched in γ-aminobutyric acid.

[0038] The food and drink may be general food and drink and health functional food. The health functional food may be specific health food, nutritional functional food, functional food, etc. The manufacturing method of the present invention makes it possible to obtain food and drink rich in GABA, so that the obtained food and drink may be labeled with food functionality based on the functionality of GABA. Such functional labeling may include functional labeling such as the effect of relieving temporary mental stress associated with clerical work, the effect suitable for people with high blood pressure, the effect of helping to improve sleep quality, and the effect of helping to improve memory, which is part of the cognitive function that declines with age. EXAMPLES

[0039] The present invention will be specifically described below by way of examples, but the present invention should not be construed as being limited to the following examples.

[0040] [Materials used] The following tomato paste was used as the processed vegetable product. The "coloration at Brix 3%" of the tomato paste was measured by diluting the tomato paste with water to a Brix of 3%, centrifuging (3000 rpm x 10 minutes), filtering the supernatant through a high-flow parcel filter, and filtering through a membrane filter with a pore size of 0.45 μm, and measuring the absorbance of the filtrate at 450 nm.

[0041] [Table 1]

[0042] [Table 2]

[0043] [Table 3]

[0044] [Methods for measuring glutamate and GABA] Measurement of glutamic acid and GABA in the samples was performed using LC-MS / MS as follows. Sample treatment: The sample was diluted with 0.1% formic acid (v / v), dispersed by ultrasonication, and filtered through a 0.45 μm filter to prepare a specimen. Standards: GABA manufactured by Tokyo Chemical Industry Co., Ltd. and glutamic acid manufactured by Nacalai Tesque, Inc. were used. LC-MS / MS: A Waters AQUITY UPLC H-Class PLUS system and Xevo TQ-S micro system were used. Measurement conditions: An Intrade Amino Acid 150 x 2 mm column (Intact) was used, and elution was performed with a gradient of acetonitrile / formic acid (100 / 0.3 (v / v)) and acetonitrile / ammonium formate (20 / 80 (v / v)). The ionization mode was ESI positive.

[0045] [Conversion rate of glutamic acid to GABA] The conversion rate from glutamic acid to GABA (hereinafter also referred to as GABA conversion rate) was calculated by the following formula.

[0046]

number

[0047] In the formula, [GABA] 0 is the GABA concentration at the start of culture (mM), [GABA] t represents the GABA concentration at time t after the start of culture. [Glu] 0 indicates the glutamate concentration (mM) at the start of culture.

[0048] [GABA enrichment ratio] The GABA enrichment factor was calculated as the relative value of the GABA conversion rate obtained in the Example or Comparative Example to be evaluated for GABA enrichment, assuming that the GABA conversion rate obtained when tomato liquid was treated using only lactic acid bacteria without using yeast was 1. When the GABA enrichment factor exceeds 1, it can be evaluated that a GABA enrichment effect has been obtained, and the larger the GABA enrichment factor, the more excellent the GABA enrichment effect can be evaluated.

[0049] [Test Example 1] Tomato liquid was prepared by diluting Portuguese cold-break tomato paste with water to Brix 10%, and 800 g was placed in each of two 1000 ml medium bottles and sterilized at 90°C for 30 minutes. One of the two sterilized tomato liquid bottles was inoculated with 4 ml of a suspension of 200 mg of lactic acid bacteria Leviractobacillus brevis SP48 in 10 ml of sterilized water and 4 ml of a suspension of 100 mg of baker's yeast in 10 ml of sterilized water, and cultured at 30°C for 72 hours (Example 1). The other of the two sterilized tomato liquid bottles was subjected to the same operation except that baker's yeast was not inoculated (Comparative Example 1).

[0050] [Table 4]

[0051] The tomato juice obtained was sampled 0, 16, 24, 39, 48, 63, and 72 hours after the start of the culture, and the amount of glutamic acid and GABA were measured. The results are shown in Figure 1. As shown in Figure 1, when the SP48 strain was used alone (Comparative Example 1), a large amount of glutamic acid remained even after 72 hours, and the amount of GABA produced was about 40 mg / 100 g, whereas when the SP48 strain was used in combination with yeast (Example 1), the amount of glutamic acid significantly decreased from about 270 mg / 100 g to a level of 5 mg / 100 g or less after 48 hours, and the amount of GABA produced significantly increased to 140 mg / 100 g, confirming a high GABA enrichment effect.

[0052] [Test Example 2] Portuguese cold-break tomato paste was diluted 3-fold with water to prepare tomato juice (Brix 9.27%), which was then sterilized at 90°C for 30 minutes. 7 CFU / ml. In addition, Saccharomyces cherbiscie NBRC0210, NBRC1046, and NBRC2347, Saccharomyces bayanus NBRC11022, and Wickerhamomyces anomala NBRC0146 strains were precultured in glucose peptone liquid medium (Nissui Pharmaceutical Co., Ltd.) at 2% by weight each, or baker's yeast was inoculated at 0.01 g / 100 g, and cultured at 30°C for 72 hours. The GABA production amount and GABA conversion rate of the tomato juice obtained after 72 hours, as well as the GABA enrichment factor, are shown in Table 5 and Figure 2. As shown in Table 5 and Figure 2, when Lactobacillus brevis SP48 strain was used alone (Comparative Example 2), the GABA production amount was 21.7%, whereas when yeast was used in combination (Examples 2 to 7), the GABA conversion rate exceeded 70% in all cases, resulting in a significant increase in the GABA production amount and a high GABA enrichment effect.

[0053] [Table 5]

[0054] [Test Example 3] As in Test Example 2, Portuguese cold-break tomato paste was diluted with water to prepare a tomato liquid with Brix 9.26%, which was then sterilized at 90°C for 30 minutes. Leviractobacillus brevis mh4219, JCM1059, and NBRC12520 were pre-cultured in MRS broth (manufactured by BIOKAR Diagnostics (France)) and inoculated into the sterilized tomato liquid at 2% by weight. Furthermore, baker's yeast was inoculated at 0.01g / 100g and cultured at 30°C for 72 hours (Examples 8 to 10). The same procedure was performed except that baker's yeast was not inoculated (Comparative Examples 3 to 5). The GABA production amount, GABA conversion rate, and GABA enrichment ratio of the obtained tomato liquid are shown in Table 6 and Figure 3. As shown in Table 6 and Figure 3, even when a Leviractobacillus brevis strain other than the SP48 strain was used, the GABA conversion rate and GABA production amount were significantly increased when yeast was used (Examples 8 to 10) compared to when no yeast was used (Comparative Examples 3 to 5), confirming a high GABA enrichment effect.

[0055] [Table 6]

[0056] [Test Example 4] The ability to produce GABA from glutamic acid exists in strains other than those belonging to Lactobacillus brevis. In the same manner as in Test Example 3, Lactiplantibacillus plantarum OFC413 (NITE P-03660), Lactiplantibacillus plantarum NBRC12006, Lactococcus lactis NBRC12007, and Lactococcus lactis MOS-11 (NITE P-03661), which had been precultured in MRS broth, were inoculated into the sterilized tomato liquid at 2% by weight. In addition, baker's yeast (0.01 g / 100 g) was inoculated and cultured at 30° C. for 72 hours (Examples 11 to 14). Also, the same operation was performed except that baker's yeast was not inoculated (Comparative Examples 6 to 9). The amount of GABA produced and the GABA conversion rate of the obtained tomato liquid, as well as the GABA enrichment ratio, are shown in Table 8 and FIG. 4. As shown in Table 8 and Figure 4, even when lactic acid bacteria species other than Lactobacillus brevis were used, the GABA conversion rate and GABA production amount were significantly increased when yeast was used (Examples 11 to 14) compared to when no yeast was used (Comparative Examples 6 to 9), confirming a high GABA enrichment effect.

[0057] [Table 7]

[0058] [Test Example 5] The effects of the method using yeast extract or the method using glutamic acid, which are known methods for enriching GABA in food materials, were confirmed using tomato paste with the coloring levels shown in Table 1. Specifically, Portuguese cold-break tomato paste was diluted with water to prepare a tomato liquid with Brix of 9.27%, to which 0.5% by weight of yeast extract or 5% by weight of glutamic acid was added, and then sterilized at 90°C for 30 minutes. To this, 2% by weight of Leviractobacillus brevis mh4219 strain or 2 × 106 Leviractobacillus brevis SP48 strain, which had been precultured in MRS medium, were added. 7The tomato juice was inoculated to a concentration of CFU / ml and cultured at 30° C. for 72 hours. The amount of GABA produced, the GABA conversion rate, and the GABA enrichment ratio of the obtained tomato juice are shown in FIG. 5 and Table 8. Table 8 also shows the results of Comparative Example 3 and Example 8 obtained in Test Example 3. As shown in FIG. 5 and Table 8, even when lactic acid bacteria and glutamic acid or yeast extract were used in combination with tomato paste having the coloring degree shown in Table 1, little or no GABA enrichment effect was observed.

[0059] [Table 8]

[0060] Example 15 Greek tomato paste was diluted with water to a Brix of 9.5%, sterilized at 99°C for 18 seconds using a double-tube sterilizer, and 2 t of the paste was placed in a 3 t aseptic tank. Next, 200 g of Leviractobacillus brevis SP48 strain and 200 g of baker's yeast were dispersed in 5 L of sterilized water, then placed in the tank and fermented at 30°C for 48 hours. After that, the mixture was sterilized at 99°C for 18 seconds, and packed into bag-in-boxes in 15 kg portions. The fermented tomato liquid had a GABA content of 257 mg / 100 g (112 mg / 100 g before fermentation), a glutamic acid content of 3.1 mg / 100 g, and a pH of 4.2 (25°C). The fermented tomato liquid had a good flavor and could be used as a raw material for minestrone, curry, meat sauce, etc. Minestrone was prepared using this fermented tomato liquid according to the recipe shown in Table 9, filled into aluminum pouches, and sterilized in retort. This minestrone soup (150g / meal) contained 41mg of GABA per meal, an amount that allowed it to be labeled with functional claims that it has the effect of relieving temporary mental stress associated with clerical work and that it is suitable for people with high blood pressure.

[0061] [Table 9]

[0062] (Example 16) Turkish acid cold break tomato paste was diluted with water to Brix 15% and sterilized at 99℃ for 18 seconds. Saccharomyces chervische NBRC2347 pre-cultured in glucose peptone liquid medium and Levilactobacillus brevis mh4219 pre-cultured in carrot juice with Brix 7% were inoculated at 2% each and fermented at 30℃ for 72 hours. After fermentation, the mixture was mixed at a ratio of 1 part untreated tomato paste to 1 part fermented tomato liquid, and water was added to adjust the Brix to 5%. The mixture was filled into 160ml cans and sterilized in a hot water bath at 85℃ for 30 minutes. As a result, a tomato drink containing 117mg of GABA per can was obtained. In addition to the functional claims of Example 15, this product contained an amount of GABA that could be functionally claimed to be useful for improving sleep quality and memory, which is part of the cognitive function that declines with age. [Accession number]

[0063] Lactiplantibacillus plantarum OFC413, Accession number: NITE P-03660, Date of deposit: June 3, 2022, Depository institution: National Institute of Technology and Evaluation, Patent Microorganisms Deposit Center Lactococcus lactis MOS-11, Accession number: NITE P-03661, Date of deposit: June 3, 2022, Depository institution: National Institute of Technology and Evaluation Patent Microorganisms Deposit Center

Claims

1. A method for producing glutamic acid decarboxylase comprising the step of culturing lactic acid bacteria and yeast in a processed plant product selected from the group consisting of crushed plant material, squeezed juice, water extract, and concentrates thereof, The coloring degree of the plant processed product at Brix 3% is more than 0.2, A method for producing γ-aminobutyric acid, wherein the plant is a tomato.

2. The method according to claim 1, wherein the lactic acid bacteria is selected from the group consisting of lactic acid bacteria of the genus Levilactobacillus, lactic acid bacteria of the genus Lactiplantibacillus, and lactic acid bacteria of the genus Lactococcus.

3. 2. The method of claim 1, wherein the lactic acid bacteria is selected from the group consisting of Levilactobacillus brevis, Lactiplantibacillus plantarum, and Lactococcus lactis.

4. The method according to claim 1 , wherein the yeast is selected from the group consisting of yeasts of the genus Saccharomyces and Wickerhamomyces.

5. 2. The method of claim 1, wherein the yeast is selected from the group consisting of Saccharomyces cerevisiae, Saccharomyces bayanus, and Wickerhamomyces anomalus.

6. A step of obtaining a plant processed product enriched in γ-aminobutyric acid by the production method according to claim 1; and cooking a food or drink using the processed plant product enriched with γ-aminobutyric acid.

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