Buckwheat seed rich in Γ-aminobutyric acid, method for enriching buckwheat seed with Γ-aminobutyric acid, and method for producing buckwheat seed rich in Γ-aminobutyric acid, buckwheat flour, and processed buckwheat product

Abstract

To provide a method for enriching buckwheat seeds with GABA (γ-aminobutyric acid) by which a sufficient GABA-enriching effect is obtained in a relatively short time and the number of general viable bacteria which is an index of easiness of putrefaction and putrefaction is suppressed and to provide a method for producing buckwheat seeds highly containing GABA, buckwheat flour and a buckwheat processed product. And to provide buckwheat seeds highly containing GABA in which the GABA is contained in a fixed amount or more and the number of general viable bacteria is suppressed to a fixed amount or less.SOLUTION: The method for producing buckwheat seeds having a high GABA content comprises (S101) adding water to shell-removed buckwheat seeds, (S102) subjecting the seeds to a pressure treatment (S104) and then drying the seeds (S105). The buckwheat seeds having a high GABA content are buckwheat seeds subjected to a pressurizing treatment together with water, wherein the free GABA of the buckwheat seeds dried after the pressurizing treatment is equal to or more than 30mg / 100g dry matter, and the general viable cell count of the undried buckwheat seeds at 0 hour after the pressurizing treatment is 1. 0E + 04 or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to buckwheat seeds having a high content of γ-aminobutyric acid, a method for enriching buckwheat seeds with γ-aminobutyric acid, and methods for producing buckwheat seeds, buckwheat flour, and buckwheat processed products having a high content of γ-aminobutyric acid. [Background technology]

[0002] γ-Aminobutyric acid (GABA) is a non-protein amino acid that is widely distributed throughout the living world and has been reported to have various physiological functions in higher animals, such as improving blood pressure, reducing stress, alleviating fatigue, and improving sleep quality. In recent years, a variety of functional foods and foods for specified health uses that display and advertise these physiological functions of γ-aminobutyric acid have been launched on the market, and γ-aminobutyric acid is one of the substances with extremely high industrial applicability (for example, notifications regarding the various functions of γ-aminobutyric acid can be confirmed on the Consumer Affairs Agency's website, "Foods with Function Claims Notification Information Search" (https: / / www.caa.go.jp / policies / policy / food_labeling / foods_with_function_claims / search)).

[0003] γ-aminobutyric acid is biosynthesized by the decarboxylation of glutamic acid by glutamic acid decarboxylase (GAD), which uses glutamic acid as a substrate and consumes protons to produce γ-aminobutyric acid and carbon dioxide. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-166804 [Patent Document 2] Japanese Patent Application Laid-Open No. 2009-207446 Summary of the Invention [Problem to be solved by the invention]

[0005] Methods for enriching foods with γ-aminobutyric acid have been studied to date. Among these, the inventor has investigated methods for enriching γ-aminobutyric acid in buckwheat seeds, seeds, or flour milled from buckwheat, a grain or pseudo-cereal that is the raw material for buckwheat, a staple food in Japan.

[0006] Patent Document 1 (JP Patent Publication No. 2006-166804) describes the invention of "a food material characterized by being prepared by soaking raw buckwheat in water at a temperature of 60°C or less, and enriched with at least one of gamma-aminobutyric acid, inositol, phytic acid, niacin, and rutin" (Claim 1).

[0007] As in the invention described in Patent Document 1, when buckwheat seeds or the like are added with water and left at room temperature, the GAD inside acts to increase the γ-aminobutyric acid content over time. However, buckwheat seeds are said to have a higher bacterial count than, for example, other cereal seeds, and there is a risk of spoilage and deterioration over time. Therefore, in the actual examples in Patent Document 1, the seeds are treated at a relatively low temperature of 15°C to delay spoilage and deterioration. However, the treatment time is still limited, and the glutamic acid decarboxylation reaction also proceeds slowly. As a result, even with treatment for the maximum period of 24 hours, the γ-aminobutyric acid content is only 32 mg / 100 g, limiting the enrichment effect.

[0008] Furthermore, Patent Document 2 (JP Patent Publication No. 2009-207446) describes the following invention: "A method for producing buckwheat seeds with a high GABA content, which comprises adding water to the seeds so that they can fully absorb the water, keeping them out of contact with running water, and aging and storing them in an anaerobic atmosphere while maintaining a temperature above freezing and at a temperature at which they will not germinate, thereby increasing the content of gamma-aminobutyric acid in the buckwheat seeds, and then drying the buckwheat seeds so as not to decrease the content of gamma-aminobutyric acid." (Claim 1).

[0009] The invention described in Patent Document 2 involves aging and preserving buckwheat seeds for a longer period of time while preventing spoilage and deterioration at an even lower temperature of about 4°C than the invention described in Patent Document 1. While this invention achieves a sufficient enrichment effect of γ-aminobutyric acid over a sufficient period of time, it has the drawback that it takes a long time, for example at least about 5 days, for the γ-aminobutyric acid content to exceed 30 mg / 100 g, and therefore the seeds tend to lose their freshness. [Means for solving the problem]

[0010] The present invention has been made in consideration of the above circumstances, and aims to provide a method for enriching buckwheat seeds with γ-aminobutyric acid, which can achieve a sufficient γ-aminobutyric acid enrichment effect in a relatively short time and can also suppress the general viable bacterial count, which is an indicator of susceptibility to spoilage and deterioration, as well as a method for producing buckwheat seeds, buckwheat flour, and buckwheat processed products with a high γ-aminobutyric acid content, and to provide buckwheat seeds with a high γ-aminobutyric acid content, which contain a certain level or more of γ-aminobutyric acid and have a general viable bacterial count suppressed to a certain level or less.

[0011] The present invention solves the above problems by the solution means described below as one embodiment.

[0012] The method for producing buckwheat seeds with a high content of γ-aminobutyric acid according to the present invention is characterized in that water is added to buckwheat seeds from which husks have been removed, followed by pressure treatment and drying.

[0013] In the above manufacturing method, the pressure treatment is preferably carried out in the range of 20 to 80 MPa. Furthermore, in the above manufacturing method, the pressure treatment is preferably carried out in the range of 5 minutes to 4 hours. Furthermore, in the above manufacturing method, the pressure treatment is preferably carried out in the range of 20 to 60°C.

[0014] In the manufacturing method, the buckwheat seeds from which the husks have been removed may be vacuum-packaged with water added thereto, and the pressure treatment may be carried out on the vacuum-packaged buckwheat seeds. Alternatively, the buckwheat seeds from which the husks have been removed may be placed in a pressure vessel of a pressure device, and the pressure vessel may be filled almost completely with water before the pressure treatment.

[0015] In the above-described manufacturing method, for example, buckwheat seeds with a high content of γ-aminobutyric acid can be obtained, in which the amount of free γ-aminobutyric acid in the buckwheat seeds dried after the pressure treatment is 30 mg / 100 g dry matter or more, and the general viable bacterial count in the undried buckwheat seeds 0 hours after the pressure treatment is 1.0E+04 cfu / g or less.

[0016] Furthermore, the method for producing buckwheat flour with a high content of γ-aminobutyric acid according to the present invention is characterized in that water is added to buckwheat seeds from which husks have been removed, the seeds are pressurized, dried, and then milled.

[0017] Furthermore, the method for producing a buckwheat processed product with a high content of γ-aminobutyric acid according to the present invention is characterized in that water is added to buckwheat seeds from which husks have been removed, followed by pressure treatment and processing.

[0018] Furthermore, the method for enriching buckwheat seeds with γ-aminobutyric acid according to the present invention is characterized in that water is added to buckwheat seeds from which husks have been removed and a pressure treatment is carried out.

[0019] In the method for enriching γ-aminobutyric acid, it is preferable to add water to the buckwheat seeds from which the husks have been removed, and then subject the pressure treatment to a pressure range of 20 to 80 MPa and a temperature range of 20 to 60°C for 5 minutes to 4 hours.

[0020] Furthermore, the buckwheat seeds with a high content of gamma-aminobutyric acid according to the present invention are buckwheat seeds that have been subjected to pressure treatment together with water, and are characterized in that the amount of free gamma-aminobutyric acid in the buckwheat seeds that have been dried after the pressure treatment is 30 mg / 100 g dry matter or more, and the general viable bacterial count in the undried buckwheat seeds 0 hours after the pressure treatment is 1.0E+04 cfu / g or less. [Effects of the Invention]

[0021] According to the present invention, a sufficient effect of enriching buckwheat seeds with γ-aminobutyric acid can be obtained in a relatively short time, and the general viable bacterial count, which is an indicator of susceptibility to spoilage and deterioration, can also be reduced. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 1 is a flowchart showing an example of a method for producing buckwheat seeds with a high content of γ-aminobutyric acid according to an embodiment of the present invention, and a subsequent method for producing buckwheat flour and processed buckwheat products with a high content of γ-aminobutyric acid. [Figure 2] FIG. 2 is a graph showing the results of Example 1. [Figure 3] FIG. 3 is a graph showing the results of Example 2. [Figure 4] FIG. 4 is a graph showing the results of Example 3. [Figure 5] FIG. 5 is a graph showing the results of Example 4. [Figure 6] 6A and 6B are graphs showing the results of Example 5. Fig. 6A shows the analysis results of the amount of free γ-aminobutyric acid, and Fig. 6B shows the test results of the general viable cell count. [Figure 7] FIG. 7 is a graph showing the results of Example 5, and shows the analysis results of the amount of free amino acids, including free γ-aminobutyric acid. DETAILED DESCRIPTION OF THE INVENTION

[0023] In the present invention, "buckwheat seeds" refer to harvested buckwheat seeds from which the husk (pericarp) has been removed. Although this organ corresponds to a "seed" in biological and agricultural terms, it may be referred to and described as "buckwheat seeds," "hollowed seeds," "hulled seeds," "brown buckwheat," etc. in the distribution market. These "buckwheat seeds," "hollowed seeds," "hulled seeds," "brown buckwheat," etc. in the distribution market also correspond to "buckwheat seeds" in the present invention. In the method of the present invention, buckwheat seeds are added with water to absorb moisture, and buckwheat seeds that are not dried after that become swollen, while those with a relatively high amount of water added take on a porridge-like appearance. However, whether the seeds are dried or dried, they are still "buckwheat seeds."

[0024] "Buckwheat" is an annual plant of the genus Fagopyrum in the Polygonaceae family, which is the source of buckwheat noodles, a staple food in Japan. Any buckwheat species, including Fagopyrum esculentum, which is the mainstream in Japan, and Fagopyrum tataricum, commonly known as tartary buckwheat, can be applied to the present invention. Any variety can also be applied to the present invention.

[0025] The method for enriching buckwheat seeds with γ-aminobutyric acid according to the present invention is characterized in that water is added to hulled buckwheat seeds and pressure treatment is performed. The method for producing γ-aminobutyric acid-rich buckwheat seeds according to the present invention is characterized in that water is added to hulled buckwheat seeds and pressure treatment is performed, followed by drying. The γ-aminobutyric acid-rich buckwheat seeds according to the present invention are buckwheat seeds that have been pressure-treated together with water, and are characterized in that the amount of free γ-aminobutyric acid in the buckwheat seeds dried after the pressure treatment is 30 mg / 100 g dry matter or more, and the viable cell count of the undried buckwheat seeds 0 hours after the pressure treatment is 1.0E+04 cfu / g or less.

[0026] As described above, the method for producing buckwheat seeds with a high content of γ-aminobutyric acid according to the present invention involves the implementation of the γ-aminobutyric acid enrichment method according to the present invention, and results in a product having the characteristics of the buckwheat seeds with a high content of γ-aminobutyric acid according to the present invention. Therefore, the following description of the method for producing buckwheat seeds with a high content of γ-aminobutyric acid will also serve to explain the γ-aminobutyric acid enrichment method according to the present invention and the buckwheat seeds with a high content of γ-aminobutyric acid according to the present invention. Furthermore, since the methods for producing buckwheat flour and buckwheat processed products with a high content of γ-aminobutyric acid according to the present invention follow the methods for producing buckwheat seeds with a high content of γ-aminobutyric acid according to the present invention, these methods will also be described.

[0027] [Method for producing buckwheat seeds with a high content of γ-aminobutyric acid, and method for enriching buckwheat seeds with γ-aminobutyric acid] As shown in Figure 1, the method for producing buckwheat seeds with a high content of γ-aminobutyric acid begins with removing the husk (pericarp) from harvested buckwheat seeds to obtain buckwheat seeds (S101). Buckwheat husks, which are typically black, are organs equivalent to the chaff, lemma, or lemma of cereals, and removing this husk is a process equivalent to the hulling or hulling of cereals. This process can be performed by a method using a known dedicated husking machine, other known methods, or methods equivalent thereto. Alternatively, commercially available buckwheat products from which the husk has already been removed may be prepared.

[0028] It is important to use hulled buckwheat seeds as the target for glutamic acid decarboxylation by GAD. In hulled buckwheat, water absorption within each kernel tends to be uneven, and the water absorption state is difficult to determine visually, making them difficult to handle. On the other hand, in buckwheat flour milled from buckwheat seeds, the progress of glutamic acid decarboxylation is promoted, but adding water causes clumps. Further pressure leads to a state similar to that of buckwheat flour dissolved in water and kneaded. When dried, the resulting product becomes a solid mass, deviating from the buckwheat flour form. In contrast, in hulled buckwheat seeds, sufficient water absorption promotes the progress of glutamic acid decarboxylation, and drying after enriching γ-aminobutyric acid allows the seeds to return to their original buckwheat form.

[0029] Next, water necessary for glutamic acid decarboxylation is added to the hulled buckwheat seeds (S102). Any water suitable for food processing can be used without particular limitations, including purified water such as distilled water and ion-exchanged water, as well as tap water. It is also acceptable to add specific ingredients to the water as long as the object of the present invention can be achieved. For example, Patent Document 1 (JP 2006-166804 A) shows an example in which the addition of sodium chloride and / or magnesium chloride improves the enrichment effect of γ-aminobutyric acid, and Patent Document 2 (JP 2009-207446 A) shows an example in which the addition of vinegar and / or glutamic acid (sodium glutamate) improves the enrichment effect of γ-aminobutyric acid. Considered as additional ingredients are these ingredients, as well as other ingredients such as pH adjusters, preservatives, coloring ingredients, and seasoning ingredients. While the present invention does not prohibit the addition of ingredients involved in promoting glutamic acid decarboxylation, it is not necessarily required as a means to solve the problem. That is, according to the present invention, it is possible to obtain a sufficient effect of enriching γ-aminobutyric acid and a bactericidal and bacteriostatic effect in a short time using only water.

[0030] The amount of water to be added to buckwheat seeds is not limited, but an amount equal to or slightly greater than the amount that the buckwheat seeds can absorb is optimal. If the amount of water added is extremely small, for example, 20% to 30% of the weight of the buckwheat seeds, the glutamic acid decarboxylation reaction will not proceed sufficiently, making it difficult to obtain a sufficient γ-aminobutyric acid enrichment effect in a short period of time. On the other hand, adding a large amount of water will not cause any problems with the glutamic acid decarboxylation reaction, but will require energy and time for subsequent drying. Therefore, it is recommended to add water in an amount (e.g., ml) of approximately 60±20%, more preferably 60±10%, and even more preferably 60±5% of the weight of the buckwheat seeds (e.g., g). After adding the water, the buckwheat seeds may be stirred appropriately to thoroughly distribute the water throughout the seeds.

[0031] Furthermore, when the buckwheat seeds to which water has been added are subjected to pressure treatment in the next step S104, it is preferable to vacuum-package the buckwheat seeds and water combination following the "water addition" in step S102 (S103). This allows each buckwheat seed to be evenly pressurized in the next step S104, making it easier to obtain relatively homogeneous buckwheat seeds. Specifically, in the next step S104, for example, when the buckwheat seeds and water combination is packaged and sealed in some form and placed in a pressure device (pressurized container), the gas (atmosphere) can be evacuated from the package containing the buckwheat seeds and water (for example, a bag made of synthetic resin with a relatively high barrier property, such as a nylon plastic bag) and the vacuum-packaged.

[0032] Next, water is added to the hulled buckwheat seeds, which are vacuum-packed and then pressurized (S104). This allows water to penetrate the buckwheat seeds quickly within a short period of time, and promotes glutamic acid decarboxylation by GAD, enriching γ-aminobutyric acid. At the same time, the buckwheat seeds can be sterilized and bacteriostatic. However, if the pressure treatment is continued for too long, resistant bacteria may begin to grow in the pressurized environment, depending on the pressure treatment conditions. In contrast, with this pressure treatment, sufficient enrichment of γ-aminobutyric acid is completed before or shortly after the growth of the resistant bacteria begins, and drying in the next step S105 can be started immediately after the pressure treatment is completed, preventing spoilage and deterioration while reducing the general viable bacterial count.

[0033] The pressure treatment can be performed using a known pressure device. Specifically, any device capable of pressurizing food that can be used for food processing, such as a food pressure device, a thermal pressure processing device, or a high-pressure processing device, may be used, although the product name varies depending on the manufacturer or seller. In a commonly used pressure device, a pressure vessel containing the object to be pressurized is filled almost completely with water, and the pressure vessel is then applied. Therefore, instead of the packaged or vacuum-packaged buckwheat seeds and water (S103), the buckwheat seeds can be filled almost completely with water by placing unpackaged buckwheat seeds in the pressure vessel and performing the hydration of the buckwheat seeds (S102) and the subsequent pressure treatment (S104). This method also allows each buckwheat seed to be pressurized relatively evenly.

[0034] The conditions for the pressure treatment should be set taking into consideration the balance between the amount of γ-aminobutyric acid to be enriched and the general viable bacterial count. The pressure treatment is preferably carried out within a range of 20 to 80 MPa. The pressure treatment is preferably carried out within a range of 5 minutes to 4 hours. The pressure treatment is preferably carried out within a range of 20 to 60°C.

[0035] When buckwheat seeds are pressurized, γ-aminobutyric acid continues to increase sharply in the early stages, about 30 minutes after the start of the treatment, and then shows a favorable increase, albeit at a relatively slower rate. However, at pressures of 100 MPa or higher, after the steep increase in γ-aminobutyric acid, the amount of γ-aminobutyric acid remains almost unchanged or shows a relatively slower decrease. This is thought to be because GAD is damaged and inactivated when relatively high pressures of 100 MPa or higher are continuously applied. According to the examples, the pressure of the pressurization treatment is preferably in the range of 20 to 80 MPa, and a sufficient γ-aminobutyric acid enrichment effect can be obtained in a short period of time at a pressure weaker than the upper limit of 80 MPa; therefore, for example, a range of 20 to 70 MPa is also preferred, a range of 20 to 60 MPa is also preferred, a range of 20 to 50 MPa is also preferred, a range of 20 to 40 MPa is also preferred, a range of 20 to 30 MPa is also preferred, a range of 30 to 80 MPa is also preferred, a range of 30 to 70 MPa is also preferred, a range of 30 to 60 MPa is also preferred, a range of 30 to 50 MPa is also preferred, a range of 30 to 40 MPa is also preferred, a range of 40 to 80 MPa is also preferred, a range of 40 to 70 MPa is also preferred, a range of 40 to 60 MPa is also preferred, a range of 40 to 50 MPa is also preferred, and a range of 50±5 MPa is also preferred.

[0036] Furthermore, the general viable bacterial count after pressure treatment generally tends to decrease with increasing pressure and increasing treatment time. However, according to the examples, the general viable bacterial count at 4 hours after the start of pressure application is slightly higher than the peak decrease at 3 hours. This is thought to be because resistant bacteria begin to grow in the pressurized environment. However, 4 hours after the start of pressure application is thought to be the time when resistant bacteria have just begun to grow, and the general viable bacterial count is suppressed to a certain acceptable level or less. Considering the balance between the amount of γ-aminobutyric acid enriched and the general viable bacterial count suppressed, the pressure treatment time is preferably in the range of 5 minutes to 4 hours, more preferably 15 minutes to 4 hours, more preferably 30 minutes to 4 hours, more preferably 1 hour to 4 hours, and more preferably 2 hours to 4 hours. Alternatively, the range of 5 minutes to 3.5 hours is also preferred, more preferably 15 minutes to 3.5 hours, more preferably 30 minutes to 3.5 hours, more preferably 1 hour to 3.5 hours, and more preferably 2 hours to 3.5 hours. Alternatively, a range of 5 minutes to 3 hours is also preferred, a range of 15 minutes to 3 hours is more preferred, a range of 30 minutes to 3 hours is more preferred, a range of 1 hour to 3 hours is more preferred, a range of 2 hours to 3 hours is even more preferred, or a range of 3 hours ± 30 minutes is also preferred.

[0037] Furthermore, according to the examples, although the effect of enriching γ-aminobutyric acid can be achieved by applying pressure at temperatures of 25°C, 40°C, 50°C, and 60°C, the amount of γ-aminobutyric acid enriched is slightly lower at 50°C to 60°C compared to the amount of γ-aminobutyric acid at 25°C to 40°C. This is thought to be because, since glutamic acid decarboxylation is an enzymatic reaction, there is an optimum temperature, and at temperatures above 50°C, GAD is thermally denatured and inactivated, or the reaction rate falls outside the optimum temperature range for GAD, slowing down. On the other hand, the general viable bacterial count generally tends to decrease as the temperature increases, and particularly excellent bactericidal and bacteriostatic effects are achieved at temperatures above 50°C.

[0038] Furthermore, according to the examples, an excellent enrichment effect of nearly 40 mg / 100 g dry matter was obtained at 25°C. Furthermore, considering that Patent Document 1 (JP 2006-166804 A) and Patent Document 2 (JP 2009-207446 A) show that the effect of GAD itself is observed even at significantly low temperatures, for example, below 15°C, the temperature of the pressure treatment is preferably in the range of 20 to 60°C, more preferably 20 to 50°C, more preferably 20 to 45°C, and even more preferably 20 to 40°C. Alternatively, the range of 25 to 60°C is also preferred, more preferably 25 to 50°C, more preferably 25 to 45°C, and even more preferably 25 to 40°C. Alternatively, the range of 30 to 60°C is also preferred, more preferably 30 to 50°C, more preferably 30 to 45°C, and even more preferably 30 to 40°C. Alternatively, the range of 40±5°C is also preferred.

[0039] Subsequently, the buckwheat seeds are subjected to pressure treatment and then dried (S105). At the end of the pressure treatment, buckwheat seeds with a high content of γ-aminobutyric acid are obtained. However, the buckwheat seeds after pressure treatment have absorbed water and become swollen, and seeds with a relatively high amount of water have a porridge-like appearance. In contrast, drying the buckwheat seeds allows them to return to the form of dried grains before hydration, which is the form typically distributed. The drying can be carried out by opening the vacuum-packed or otherwise sealed buckwheat seeds and using a known food dryer or other known method, or a method equivalent thereto. However, depending on the temperature range, germination, spoilage, and deterioration may occur easily. Therefore, drying at temperatures above 60°C is preferable, as it also provides sterilization and bacteriostasis. While γ-aminobutyric acid has a relatively high heat resistance, considering the possibility of thermal decomposition or thermal denaturation of other nutritional components, constant temperature drying at, for example, approximately 70±10°C is preferred. Furthermore, more rapid drying can be achieved by, for example, ventilation drying. The optimal drying time varies depending on the amount of water added, drying conditions, etc., and also on the desired degree of dryness, so it can be set appropriately. Alternatively, the drying state can be checked from the appearance and the operation can be terminated when the buckwheat seeds have reached the desired degree of dryness. Through the above steps, buckwheat seeds that appear to be dried grains from harvested buckwheat seeds with the husks (pericarp) removed can be obtained in an extremely short time, but are enriched in γ-aminobutyric acid.

[0040] [Buckwheat seeds with high gamma-aminobutyric acid content] Specifically, buckwheat seeds with a high γ-aminobutyric acid content of at least 30 mg / 100 g dry matter can be obtained. Furthermore, buckwheat seeds with a γ-aminobutyric acid content of 35 mg / 100 g dry matter or more, 40 mg / 100 g dry matter or more, or even 45 mg / 100 g dry matter or more can be obtained. The "γ-aminobutyric acid content" here refers to the buckwheat seeds ground in a mill or equivalent grinder after drying. 1 g of the sample is added to 10 ml of a 2% (w / v) sulfosalicylic acid aqueous solution and stirred, followed by extraction by ultrasonic cleaning at 25°C, 38 kHz, 240 W, for 15 minutes. The sample is then centrifuged at 3000 rpm for 5 minutes, and 1 ml of the supernatant is filtered through a filter (pore size: 0.45 μm) to obtain an analytical sample. This analytical sample is subjected to analysis based on the post-column derivatization method using ninhydrin reagent, and the amount of free γ-aminobutyric acid (mg / 100 g dry matter) is calculated from the analytical results. For the calculation, the moisture content of the ground buckwheat seed sample is measured. The moisture content can be measured using a normal pressure drying method (e.g., heating at 135°C for 3 hours) or a halogen moisture meter (e.g., heating at 135°C with a weight change of 0.05% or less set to constant weight).

[0041] Additionally, the viable count of undried buckwheat seeds at 0 hours after pressure treatment (0 hours after completion of pressure treatment) can be suppressed to 1.0E+04 cfu / g or less. The "viable count" here refers to the sample taken by quickly opening vacuum-packed or otherwise sealed buckwheat seeds after pressure treatment. 90 ml of phosphate-buffered saline is added to 10 g of sample and stirred to obtain a sample solution. 1 ml of this sample solution is serially diluted and inoculated onto a standard agar medium. The sample medium is cultured in an incubator at 35°C for 48 hours, and the viable count (cfu / g) is calculated from the number of colonies that appear.

[0042] [Method for producing buckwheat flour and processed buckwheat products with high gamma-aminobutyric acid content] The dried buckwheat seeds thus obtained can be distributed as they are, but they can also be milled to produce buckwheat flour with a high content of γ-aminobutyric acid (S206). Milling can be performed by a known method using a millstone or a dedicated mill, or by other known methods or methods equivalent thereto.

[0043] Furthermore, buckwheat processed products with a high content of γ-aminobutyric acid can be produced by processing undried buckwheat seeds after pressure treatment or dried buckwheat seeds after pressure treatment to a degree that does not reduce the amount of γ-aminobutyric acid to an extent that is contrary to the object of the present invention (S307). "Processing" here includes grinding, heating, seasoning, etc., and also includes milling. Therefore, "buckwheat processed products" here refer to buckwheat foods or buckwheat dishes made with buckwheat seeds. Examples include kasha and other porridges, mixed rice or mixed rice with cooked rice, and snack foods to which sugar, salt, or other seasonings are applied. [Example]

[0044] Buckwheat seeds (buckwheat seeds) from the buckwheat variety "Natsuyoshi" (trade name: Nagakaori) grown in Nagano, Matsumoto City, Nagano Prefecture, were used. In Examples 1-1 to 1-9, 50 g of buckwheat was mixed with 50 ml of water, placed in a rectangular nylon plastic bag (15 cm x 25 cm), and vacuum-packed. Immediately after vacuum packaging, the buckwheat was pressurized according to the conditions shown in Table 1. After pressure treatment, a portion of the sample was taken for a general viable count test and dried in a dryer at 70°C for 2.5 to 3 hours. After drying, the sample was pulverized using a mill to prepare a sample for γ-aminobutyric acid analysis. The general viable count of the sample before drying was tested, and the free amino acid (free γ-aminobutyric acid) of the dried sample was analyzed. In Comparative Example 1-1, the raw material (pulverized product) of dried buckwheat without adding water or pressure was also tested and analyzed for the general viable count and the amount of free γ-aminobutyric acid. The results are shown in Figure 2 and Table 1.

[0045] The equipment used is shown below, and the equipment was used for the same operations in all examples. Vacuum packaging: TOSEI V-602GII Vacuum Packaging Machine, Stationary Tilt Type Pressure treatment: Toyo Koatsu Co., Ltd., thermal pressure processing device TFS2-50 Drying: Kihara Manufacturing Co., Ltd., wet-bulb controlled dryer SM7S-EH Grinding: Iwatani Corporation, Crush Mill IFM-C20G

[0046] The test and analysis methods are shown below, and these methods were applied to the tests and analyses in all examples. (General live bacteria count test) 90 ml of phosphate-buffered saline (sold by AS ONE Corporation, Sanispek sterilized dilution water OR-90) was added to 10 g of sample and stirred to obtain a sample solution. This sample solution was serially diluted and inoculated into standard agar medium (Shimadzu Diagnostics, Acudia® standard agar medium granules) in 1 ml aliquots. The sample medium was cultured in an incubator at 35°C for 48 hours, and the viable bacterial count (cfu / g) was calculated from the number of colonies that appeared.

[0047] (Free amino acid (free γ-aminobutyric acid) analysis) One gram of sample was weighed into a 15 ml centrifuge tube, and 10 ml of 2% (w / v) sulfosalicylic acid solution (sulfosalicylic acid: 5-sulfosalicylic acid dihydrate, Kanto Chemical Co., Ltd.) was added and stirred using a vortex mixer. Extraction was then performed by ultrasonic cleaning using an ultrasonic cleaner (SND Corporation, US-10KS) at 25°C, 38 kHz, and 240 W for 15 minutes. The sample was then centrifuged at 3000 rpm for 5 minutes, and 1 ml of the supernatant was filtered (pore size: 0.45 μm) to obtain the analytical sample. This analytical sample was analyzed using an amino acid analyzer (Hitachi High-Technologies Corporation, L-8900BH) using the standard program for post-column derivatization (using ninhydrin reagent). The amount of free γ-aminobutyric acid (mg / 100 g dry matter) was calculated from the analytical results. The moisture content of the sample required for calculation was measured by drying at normal pressure using a constant temperature air blast dryer (Tokyo Rikakikai, WFO-700) at 135°C for 3 hours, or by using a halogen moisture meter (Shimadzu, MOC63u) at 135°C with a weight change of 0.05% or less set to a constant mass.

[0048] [Table 1]

[0049] As shown in Figure 2 and Table 1, it was shown that by continuously exposing buckwheat seeds to pressurized conditions under hydrated conditions, the amount of γ-aminobutyric acid increased and the number of bacteria decreased compared to untreated seeds (Comparative Example 1-1) (Examples 1-1 to 1-9). The increase in the amount of γ-aminobutyric acid is thought to be due to the fact that the pressure causes water to penetrate into the buckwheat seed cells, which quickly progresses the glutamic acid decarboxylation reaction by GAD, and at the same time, the pressure is thought to have a bactericidal and bacteriostatic effect.

[0050] Over time, γ-aminobutyric acid increased sharply at a relatively early stage of 15 minutes after the start of pressure application (Examples 1-1, 1-4, and 1-7). Within the pressure range of 20 to 50 MPa, γ-aminobutyric acid continued to increase favorably, albeit relatively slowly (Examples 1-2 to 1-3, 1-5, and 1-6). On the other hand, at a pressure of 100 MPa, the amount of γ-aminobutyric acid remained almost unchanged or showed a relatively slow, but decreasing tendency (Examples 1-8 to 1-9). This is thought to be because GAD is damaged and inactivated when a relatively high pressure of 100 MPa is continuously applied. The general viable cell count tended to decrease with increasing pressure and longer treatment time (Examples 1-1 to 1-9). [Example]

[0051] Buckwheat seeds (buckwheat seeds) from the buckwheat variety "Natsuyoshi" (trade name: Nagakaori) grown in Nagano, Matsumoto City, Nagano Prefecture, were used. In Examples 2-1 to 2-5, 50 g of buckwheat was mixed with 50 ml of water, placed in a rectangular nylon plastic bag (15 cm x 25 cm), and vacuum-packed. Immediately after vacuum packaging, the buckwheat was pressurized according to the conditions shown in Table 2. After pressure treatment, a portion of the sample was taken for a general viable count test and dried in a dryer at 70°C for 2.5 to 3 hours. After drying, the sample was pulverized using a mill to prepare a sample for γ-aminobutyric acid analysis. The general viable count of the sample before drying was tested, and the free amino acid (free γ-aminobutyric acid) of the dried sample was analyzed. In Comparative Example 2-1, the raw material (pulverized product) of dried buckwheat without adding water or pressure was also tested and analyzed for the general viable count and the amount of free γ-aminobutyric acid. Note that Example 2-1 uses the results of Example 1-2, Example 2-3 uses the results of Example 1-5, and Example 2-5 uses the results of Example 1-8. Comparative Example 2-1 uses the average value of Comparative Example 1-1 and the results of testing and analyzing the population used this time. The results are shown in Figure 3 and Table 2.

[0052] [Table 2]

[0053] As shown in FIG. 3 and Table 2, bactericidal and bacteriostatic effects were obtained for untreated seeds (Comparative Example 2-1) at any pressure range from 20 to 100 MPa (Examples 2-1 to 2-5). The general viable cell count did not change significantly at pressures of 20 to 80 MPa (Examples 2-1 to 2-4), but was slightly reduced at a pressure of 100 MPa (Example 2-5). Considering the results of Example 1 together, it can be said that, overall, the higher the pressure, the greater the bactericidal and bacteriostatic effects tended to be. Furthermore, although the enrichment effect was obtained for the amount of γ-aminobutyric acid at any pressure range from 20 to 100 MPa (Examples 2-1 to 2-5) compared to untreated seeds (Comparative Example 2-1), the amount of γ-aminobutyric acid enriched at a pressure of 100 MPa (Example 2-5) was slightly lower than the amount of γ-aminobutyric acid at a pressure of 20 to 80 MPa (Examples 2-1 to 2-4). This is thought to be because GAD is damaged and inactivated when a relatively high pressure of 100 MPa is continuously applied. [Example]

[0054] Buckwheat seeds (buckwheat seeds) from the buckwheat variety "Natsuyoshi" (trade name: Nagakaori) grown in Nagano, Matsumoto City, Nagano Prefecture, were used. In Examples 3-1 to 3-4, 50 g of buckwheat was mixed with 50 ml of water and placed in a rectangular nylon plastic bag (15 cm x 25 cm) and vacuum-packed. Immediately after vacuum packaging, the buckwheat was pressurized according to the conditions shown in Table 3. After the pressurization, a portion of the sample was taken for a general viable count test and dried in a dryer at 70°C for 2.5 to 3 hours. After drying, the sample was pulverized using a mill to prepare a sample for γ-aminobutyric acid analysis. The general viable count of the sample before drying was tested, and the free amino acid (free γ-aminobutyric acid) of the dried sample was analyzed. In Comparative Example 3-1, the raw material (pulverized product) of dried buckwheat without adding water or pressure was also tested and analyzed for the general viable count and the amount of free γ-aminobutyric acid. The results are shown in Figure 4 and Table 3.

[0055] [Table 3]

[0056] As shown in FIG. 4 and Table 3, the bactericidal and bacteriostatic effects were observed for untreated seeds (Comparative Example 3-1) at any temperature range from 25 to 60°C, and the general viable cell count tended to decrease as the treatment temperature increased (Examples 3-1 to 3-4). In particular, at temperatures above 50°C (Comparative Examples 3-3 and 3-4), extremely high bactericidal and bacteriostatic effects were observed, at least three orders of magnitude higher than those for untreated seeds (Comparative Example 3-1). Furthermore, although the enrichment effect for γ-aminobutyric acid was observed for untreated seeds (Comparative Example 3-1) at any temperature range from 25 to 60°C (Examples 3-1 to 3-4), the enrichment amount was slightly lower in the 50 to 60°C temperature range (Examples 3-3 and 3-4) than in the 25 to 40°C temperature range (Examples 3-1 and 3-2). This is thought to be because, when GAD is continuously exposed to a relatively high temperature of 50°C or higher, it is thermally denatured and inactivated, or the reaction rate slows down due to being outside the optimal temperature range for GAD. [Example]

[0057] Buckwheat seeds (buckwheat seeds) from the buckwheat variety "Natsuyoshi" (trade name: Nagakaori) grown in Nagano, Matsumoto City, Nagano Prefecture, were used. 50 g of buckwheat was mixed with 50 ml of water and placed in a rectangular nylon plastic bag (15 cm x 25 cm) and vacuum-packed. In Examples 4-1 to 4-6, pressure treatment was performed immediately after vacuum packaging according to the conditions shown in Table 4. In Comparative Examples 4-1 to 4-12, samples were stored in a constant-temperature water bath according to the conditions shown in Table 4 immediately after vacuum packaging. After pressure treatment or constant-temperature storage, a portion of each sample was taken for general viable cell count testing and dried in a dryer at 70°C for 2.5 to 3 hours. After drying, the sample was pulverized using a mill to prepare a sample for γ-aminobutyric acid analysis. The general viable cell count of the sample before drying was tested, and the free amino acid (free γ-aminobutyric acid) of the dried sample was analyzed. In addition, as Comparative Example 4-13, the raw material (ground material) of the dried, unhydrated, unpressurized, unpulverized fruit was also tested and analyzed for the general viable cell count and the amount of free γ-aminobutyric acid. The results are shown in Figure 5 and Table 4.

[0058] [Table 4]

[0059] As shown in Figure 5 and Table 4, the amount of γ-aminobutyric acid is enriched compared to untreated seeds (Comparative Example 4-13) not only in Examples 4-1 to 4-6 that were subjected to pressure treatment, but also in Comparative Examples 4-1 to 4-12 that were simply stored after adding water. However, the amount of enrichment was significantly higher in Examples 4-1 to 4-6 that were subjected to pressure treatment than in Comparative Examples 4-1 to 4-12 that were simply stored after adding water, regardless of the treatment time setting, and was also clearly higher than in Comparative Examples 4-1 to 4-6 that were kept at the same temperature of 40°C.

[0060] Over time, in Examples 4-1 to 4-6 where pressure treatment was performed, γ-aminobutyric acid increased sharply at a relatively early stage, 5 minutes after the start of pressure application, compared to untreated seeds (Comparative Example 4-13) (Example 4-1), and this sharp increase continued for 30 minutes after the start of pressure application (Example 4-2). After that, γ-aminobutyric acid showed an overall tendency to increase, albeit at a relatively slower rate (Examples 4-3 to 4-6). On the other hand, in Comparative Examples 4-1 to 4-12 where water was added and the seeds were simply stored, although a certain degree of enrichment effect was obtained compared to untreated seeds (Comparative Example 4-13) 5 minutes after the start of pressure application, the effect quickly slowed down, resulting in a large difference in the amount of enrichment compared to Examples 4-1 to 4-6 where pressure treatment was performed. This difference is thought to be due to the fact that in Examples 4-1 to 4-6, which were pressurized, the added water quickly penetrated into the buckwheat seed cells within about 30 minutes of the start of pressurization, enabling a more widespread glutamic acid decarboxylation reaction at an earlier stage, whereas in Comparative Examples 4-1 to 4-12, which were added with water but not pressurized, GAD performed a certain amount of work due to the water that penetrated near the surface at the beginning of the addition of water, but the penetration of water into the interior of the cells was extremely weak and slow, resulting in a limited reaction field.

[0061] Furthermore, in Examples 4-1 to 4-6, in which pressure treatment was performed, sterilization and bacteriostasis effects were obtained on untreated seeds (Comparative Example 4-1) regardless of the pressure treatment time, from 5 minutes to 4 hours. Considering the results of Example 1 together, the general viable cell count showed an overall tendency to decrease over the course of 3 hours from the start of pressure application (Examples 4-1 to 4-5), but at 4 hours after the start of pressure application, the general viable cell count was slightly higher than at 3 hours, which was the peak of the decrease (Example 4-6). This is thought to be because resistant bacteria begin to grow in the pressurized environment. However, 4 hours after the start of pressure application is thought to be the time when resistant bacteria have just begun to grow, and the general viable cell count was suppressed to a certain acceptable level.

[0062] In addition, the results of Example 3 showed that the general viable bacterial count when pressure treatment was performed tended to decrease as the treatment temperature increased (Examples 3-1 to 3-4). However, in Comparative Examples 4-1 to 4-12, in which water was simply added, the general viable bacterial count tended to be lower in Comparative Examples 4-7 to 4-12, which were stored at a lower temperature (25°C), than in Comparative Examples 4-1 to 4-6, which were stored at a higher temperature (40°C).

[0063] The results of Examples 1 to 4 above demonstrate that pressurization is effective in achieving sufficient γ-aminobutyric acid enrichment in a short period of time, while simultaneously achieving bactericidal and bacteriostatic effects. On the other hand, excessive pressure and temperature can easily inactivate GAD, and excessively long treatment times can lead to an increase in resistant bacteria. Considering the balance between the γ-aminobutyric acid enrichment effect and the bactericidal and bacteriostatic effects, the pressure of the pressurization treatment is, for example, preferably in the range of 20 to 80 MPa, also preferably in the range of 20 to 70 MPa, also preferably in the range of 20 to 60 MPa, also preferably in the range of 20 to 50 MPa, also preferably in the range of 20 to 40 MPa, also preferably in the range of 20 to 30 MPa, also preferably in the range of 30 to 80 MPa, also preferably in the range of 30 to 70 MPa, also preferably in the range of 30 to 60 MPa, also preferably in the range of 30 to 50 MPa, also preferably in the range of 30 to 40 MPa, also preferably in the range of 40 to 80 MPa, also preferably in the range of 40 to 70 MPa, also preferably in the range of 40 to 60 MPa, also preferably in the range of 40 to 50 MPa, and also preferably in the range of 50±5 MPa.

[0064] The temperature for the pressure treatment is preferably in the range of 20 to 60°C, more preferably in the range of 20 to 50°C, more preferably in the range of 20 to 45°C, and more preferably in the range of 20 to 40°C. Alternatively, the range of 25 to 60°C is also preferred, more preferably in the range of 25 to 50°C, more preferably in the range of 25 to 45°C, and more preferably in the range of 25 to 40°C. Alternatively, the range of 30 to 60°C is also preferred, more preferably in the range of 30 to 50°C, more preferably in the range of 30 to 45°C, and more preferably in the range of 30 to 40°C. Alternatively, the range of 40±5°C is also preferred.

[0065] The time for the pressure treatment is preferably in the range of 5 minutes to 4 hours, more preferably in the range of 15 minutes to 4 hours, more preferably in the range of 30 minutes to 4 hours, more preferably in the range of 1 hour to 4 hours, and more preferably in the range of 2 hours to 4 hours. Alternatively, it is also preferably in the range of 5 minutes to 3.5 hours, more preferably in the range of 15 minutes to 3.5 hours, more preferably in the range of 30 minutes to 3 hours, more preferably in the range of 1 hour to 3 hours, and more preferably in the range of 2 hours to 3 hours. Alternatively, it is also preferably in the range of 3 hours ± 30 minutes. Furthermore, the pressure treatment is particularly preferably in the range of 50 ± 5 MPa, 40 ± 5°C, and 3 hours ± 30 minutes. [Example]

[0066] Buckwheat seeds (buckwheat seeds) from the buckwheat variety "Natsuyoshi" (trade name: Nagakaori) grown in Nagano, Matsumoto City, Nagano Prefecture, were used. In Example 5-1, 300 ml of water was added to 500 g of the buckwheat. 323.8 g of the buckwheat for Comparative Example 5-1 was extracted from the buckwheat, and the remaining buckwheat was placed in a rectangular nylon plastic bag (30 cm x 43 cm) and vacuum-packed. A total of five bags were prepared for the mass production test, and samples were taken from one of the bags. Immediately after vacuum packaging, the sample was subjected to a pressure treatment under the conditions of 50 MPa, 40°C, and 3 hours shown in Table 4. Meanwhile, in Comparative Example 5-1, the extracted 323.8 g was vacuum-packaged in the same manner and then immediately stored in a constant-temperature water bath at room temperature (25°C) shown in Table 5 for 3 hours. After the pressure treatment or constant-temperature storage, both samples were dried in a dryer at 70°C for 17 hours. After drying, the samples were pulverized using a mill to prepare samples for general viable cell count testing and γ-aminobutyric acid analysis, which were then tested and analyzed. Furthermore, as Comparative Example 5-2, a dried, unpressurized, unpulverized raw material was used, and as Reference Example 5-1, a product containing commercially available germinated grains (excluding buckwheat) was also pulverized, and general viable cell count testing (not performed for Reference Example 5-1) and free amino acid content were tested and analyzed. The results are shown in Figures 6A, 6B, 7, and Table 5.

[0067] [Table 5]

[0068] For a 2.3 kg sample (500 g each of five bags of pulp, minus approximately 200 g for Comparative Example 5-1, taking into account moisture addition), the final yield was approximately 2 kg, resulting in a yield of approximately 87%, and it was determined that mass production was possible. As shown in Figure 6A, the amount of γ-aminobutyric acid was highest in Example 5-1, which underwent pressure treatment, at a high content of 49.2 mg / 100 g dry matter. Furthermore, as shown in Figure 6B, the general viable cell count was lowest in Example 5-1, which underwent pressure treatment, and was 1.1E+02 cfu / g, due in part to sterilization by drying.

[0069] Furthermore, as shown in Figure 7, the amount of free amino acids other than γ-aminobutyric acid (GABA) also tended to be higher overall in Example 5-1, which was subjected to pressure treatment, than in Comparative Examples 5-1, 5-2, and Reference Example 5-1. This indicates that pressure treatment decomposes proteins and increases various amino acids. As a result, modified buckwheat seeds were obtained that had improved nutritional value overall, not just γ-aminobutyric acid, compared to untreated seeds (Comparative Example 5-2). Note that pressure treatment promoted the conversion of glutamic acid to γ-aminobutyric acid by GAD, but ultimately the production of glutamic acid by protein degradation exceeded this, resulting in an increase in the amount of glutamic acid (Glu). [Explanation of symbols]

[0070] S101 Preparation of dehulled buckwheat seeds S102 Added water S103 Vacuum packaging S104 Pressure treatment S105 Drying S206 Flour Milling S307 processing

Claims

1. Buckwheat seeds are dehusked, water is added, and the seeds are pressurized and then dried. The method for producing buckwheat seeds having a high content of γ-aminobutyric acid is characterized by the following.

2. The pressure treatment is carried out in the range of 20 to 80 MPa.

2. The method for producing buckwheat seeds with a high content of γ-aminobutyric acid according to claim 1,

3. The pressure treatment is carried out for a period of 5 minutes to 4 hours.

3. The method for producing buckwheat seeds with a high content of γ-aminobutyric acid according to claim 2,

4. The pressure treatment is carried out at a temperature in the range of 20 to 60°C.

4. The method for producing buckwheat seeds with a high content of γ-aminobutyric acid according to claim 3,

5. The buckwheat seeds from which the husks have been removed are vacuum-packed after adding water, and then the pressure treatment is carried out. Alternatively, the unpackaged buckwheat seeds from which the husks have been removed are placed in a pressure vessel of a pressure device, and the pressure vessel is filled almost completely with water to carry out the pressure treatment. The method for producing buckwheat seeds with a high content of γ-aminobutyric acid according to any one of claims 1 to 4, characterized by:

6. the amount of free γ-aminobutyric acid in the buckwheat seeds dried after the pressure treatment is 30 mg / 100 g dry matter or more; The general viable cell count of the undried buckwheat seeds 0 hours after the pressure treatment is 1.0E+04 cfu / g or less. The method for producing buckwheat seeds with a high content of γ-aminobutyric acid according to any one of claims 1 to 4, characterized by:

7. Buckwheat seeds are dehusked, water is added, and they are pressurized, dried, and then milled. The method for producing buckwheat flour having a high content of γ-aminobutyric acid is characterized by the following.

8. Buckwheat seeds are dehusked, water is added, and the seeds are pressurized before being processed. The method for producing a buckwheat processed product having a high content of γ-aminobutyric acid is characterized by the following.

9. Buckwheat seeds are dehusked and then water is added to them to make a pressure treatment. A method for enriching buckwheat seeds with γ-aminobutyric acid, comprising:

10. Water is added to the buckwheat seeds from which the husks have been removed, and the pressure treatment is carried out at a pressure range of 20 to 80 MPa and a temperature range of 20 to 60°C for 5 minutes to 4 hours. The method for enriching buckwheat seeds with γ-aminobutyric acid according to claim 9,

11. Buckwheat seeds that have been pressure-treated together with water, the amount of free γ-aminobutyric acid in the buckwheat seeds dried after the pressure treatment is 30 mg / 100 g dry matter or more; The buckwheat seeds have a general viable cell count of 1.0E+04 / g or less in the undried buckwheat seeds 0 hours after the pressure treatment.

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