Method for producing buckwheat-containing food

Abstract

To provide methods for producing buckwheat-containing food or processed buckwheat grain food with enhanced properties.SOLUTION: The present invention provides a method for producing buckwheat-containing food, characterized by using buckwheat flour made from a Fagopyrum plant with an amylose content of less than 20.0 mass% as its raw material. The present invention also provides a method for producing processed buckwheat grain food, characterized by using buckwheat grains made from a Fagopyrum plant with an amylose content of less than 20.0 mass% as its raw material.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a method for producing a buckwheat-containing food or a buckwheat grain processed food, characterized in that buckwheat flour or buckwheat grains obtained from a Fagopyrum plant having a low amylose content are used as a raw material. The present invention also relates to a method for improving the physical properties of a buckwheat-containing food, characterized in that buckwheat flour obtained from a Fagopyrum plant having an amylose content of less than 20.0% by mass is used as a raw material. The present invention also relates to a buckwheat-containing food with improved physical properties. [Background technology]

[0002] Cultivated species of the genus Fagopyrum, classified in the Polygonaceae family, include buckwheat (Fagopyrum esculentum) (hereafter referred to as "common buckwheat"), Tartary buckwheat (F. tataricum), and perennial buckwheat (F. cymosum). In Japan, common buckwheat and Tartary buckwheat are primarily used as food. When using buckwheat kernels, texture and workability during food manufacturing (dough consistency, stretchiness, etc.) are important factors, and starch has a major impact on these. Starch is broadly divided into amylose, which is a linear polymerized form of glucose, and amylopectin, which is branched.

[0003] The amylose content of buckwheat is approximately 20-30% in whole wheat flour (Non-Patent Document 1), which is higher than that of the major varieties of rice and wheat currently used. In Japan, buckwheat is commonly used to make noodles, but as mentioned above, due to its high amylose content, the dough does not hold together well, there are limited variations in texture, and the physical properties become brittle when stored in a refrigerator. In order to improve these problems, auxiliary ingredients such as wheat flour and physical property-preserving agents such as processed starch are added to the raw material for buckwheat noodles, but this does not sufficiently solve the above problems, and the quality of the "buckwheat aroma" and other aspects declines as the blending ratio of buckwheat decreases. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] Suzuki T, Noda T, Morishita T, Ishiguro K, Otsuka S, Andrea B. (2019) Present status and future perspectives of breeding for buckwheat quality. Breed. Sci. 70: 48-66. Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a method for producing a buckwheat-containing food or a processed buckwheat food with improved physical properties. Specifically, an object of the present invention is to provide a method for producing a buckwheat-containing food or a processed buckwheat food that is less likely to become hard and / or brittle. [Means for solving the problem]

[0006] According to the present invention, the following inventions are provided. [1] A method for producing a buckwheat-containing food product, using buckwheat flour milled from a buckwheat plant having an amylose content of less than 20.0% by mass as a raw material. [2] A method for producing a buckwheat grain processed food, using buckwheat grains obtained from a buckwheat plant having an amylose content of less than 20.0% by mass as a raw material. [3] A method for improving the physical properties of a buckwheat-containing food, characterized in that buckwheat flour obtained from a buckwheat plant having an amylose content of less than 20.0% by mass is used as a raw material, and when the food is refrigerated for 72 hours after production and the maximum load is measured when the food is compressed to 50% of its thickness, the increase in the physical properties of the food compared to the maximum load measured immediately after production is 100% or less. [4] The method for improving physical properties according to [3], wherein the buckwheat-containing food is boiled noodles or boiled noodles stored in a refrigerator. [5] A food containing 50% by mass or more of buckwheat flour milled from a plant of the genus Fagopyrum having an amylose content of less than 20.0% by mass, and the maximum load when the food is compressed to 50% of its thickness is 6.0 N or less. [6] A food containing 50% by mass or more of buckwheat flour milled from a plant of the genus Fagopyrum having an amylose content of less than 20.0% by mass, and when the food is refrigerated for 72 hours after manufacture and then compressed to 50% of its thickness, the increase in the maximum load measured is 100% or less compared to the maximum load measured immediately after manufacture. [7] Bread, confectionery, or rice cakes characterized by a chewy texture, produced by the method described in [1] or [2]. Effect of the Invention

[0007] According to the present invention, by using buckwheat flour or buckwheat grains from a low-amylose Fagopyrum plant, it is possible to maintain the physical properties of foods with different amounts of water added and protein contents and to prevent them from becoming hard. According to the present invention, it is possible to provide buckwheat-containing foods and buckwheat grain processed foods that are characterized by a soft and chewy texture. [Brief description of the drawings]

[0008] [Figure 1] Figure 1 is a graph showing the results of a sensory evaluation test of boiled noodles immediately after production. *, **: There is a significant difference in the average rank at the 5% and 1% levels in the Mann-Whitney U test. [Diagram 2] Figure 2 is a graph showing the results of a sensory evaluation test of boiled noodles that had been refrigerated for 72 hours after production. *, **: There is a significant difference in the average rank at the 5% and 1% levels in the Mann-Whitney U test. [Diagram 3] Figure 3 is a graph showing the maximum load when a noodle band of 2.0 mm thickness is compressed by 50% for noodle bands that were refrigerated for 72 hours after production. Noodle bands A to D have different water content during production. [Figure 4] FIG. 4 is a graph showing the change over time in noodle band hardness in wild-type buckwheat and GBSSa-deficient buckwheat lines. [Diagram 5] Figure 5 is a graph showing the change in bread hardness over time. The hardness of the bread made from the GBSSa-deficient buckwheat line is shown as a relative value when the load of the wild-type buckwheat bread on each day was set at 100. [Figure 6] FIG. 6 shows photographs of mountain-shaped bread made from wild-type buckwheat flour (left) and GBSSa-deficient buckwheat flour (right). [Figure 7] FIG. 7 shows photographs of cooked wild-type buckwheat grains (left) and GBSSa-deficient buckwheat grains (right). [Figure 8] Figure 8 shows photographs of heated wild-type buckwheat rice cake (left) and GBSSa-deficient buckwheat rice cake (right). [Figure 9] Figure 9 shows photographs of fried wild-type buckwheat rice crackers (left) and GBSSa-deficient buckwheat rice crackers (right). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The following description of the present invention may be based on representative embodiments and specific examples, but the present invention is not limited to such embodiments. In this specification, a numerical range expressed using "~" means a range including the numerical values ​​before and after "~" as the lower and upper limits. In this specification, "%" and the like are based on mass unless otherwise specified.

[0010] <Manufacturing method for buckwheat-containing foods> The present invention relates to a method for producing a buckwheat-containing food, using buckwheat flour milled from a plant of the genus Fagopyrum having an amylose content of less than 20.0% by mass as a raw material.

[0011] (Amylose content) The method for producing a buckwheat-containing food of the present invention uses, as a raw material, buckwheat flour milled from seeds (grains) of a plant of the genus Fagopyrum having an amylose content of less than 20.0% by mass.

[0012] According to the study by the present inventors, the amylose content of Hitachi Aki Soba, a wild-type buckwheat, was 22.6% to 28.7% in buckwheat flour (whole grain flour) of the seeds after removing the husk. Therefore, the amylose content of "less than 20.0%" is a lower amylose content than that of conventional wild-type buckwheat plants. In this specification, a low amylose content compared to conventional wild-type buckwheat plants, particularly an amylose content of less than 20.0%, is referred to as low amylose. Furthermore, a buckwheat plant having a low amylose content compared to conventional wild-type buckwheat plants, particularly an amylose content of less than 20.0%, is referred to as a low amylose buckwheat plant.

[0013] In the present invention, the raw buckwheat flour can be milled from seeds (grains) of Fagopyrum plants having an amylose content of less than 20.0%, preferably 19.5% or less, 19.0% or less, 18.9% or less, 18.8% or less, 18.7% or less, 18.6% or less, 18.5% or less, 18.4% or less, 18.3% or less, 18.2% or less, 18.1% or less, or 18.0% or less. In the present invention, the lower limit of the amylose content of Fagopyrum plants may be 0%, but from the viewpoint of the texture of the buckwheat-containing food, it may be 1% or more, 2% or more, 3% or more, 4% or more, 5% or more, 6% or more, 7% or more, 8% or more, 9% or more, 10% or more, 11% or more, 12% or more, 13% or more, 14% or more, or 15% or more.

[0014] In the present invention, the amylose content is expressed as the percentage (mass%) of amylose in the starch of the whole grain flour, unless otherwise specified. In the present invention, the whole grain flour for which the amylose content is measured is prepared by grinding the seeds in a mortar after removing the husk.

[0015] The amylose content (mass%) of starch in buckwheat flour (endosperm) obtained by milling buckwheat seeds in a flour mill according to a conventional method can be calculated from the amylose content of whole wheat flour. For example, if the starch content of buckwheat flour milled in a flour mill is 85.7% and the starch content of whole wheat flour is 65.8% (Izydorczyk, MS and D. Head (2010) Characterization and potential uses of functional buckwheat fractions obtained by roller milling of new Canadian buckwheat genotypes. The European Journal of Plant Science and Biotechnology 4: 71-81, Koto), the amylose content of starch in whole wheat flour can be calculated by multiplying the amylose content of starch in whole wheat flour by 85.7 / 65.8.

[0016] Amylose in starch can be quantified by colorimetry of the iodine-starch reaction on starch solubilized with dimethyl sulfoxide (DMSO), for example, by the external standard method described below. Weigh out 20 mg of buckwheat flour, add 1 mL of dimethyl sulfoxide, and boil for 15 minutes while stirring. After returning to room temperature, add 6 mL of ethanol, mix by inversion, and leave at room temperature overnight. Centrifuge at 2000 × g for 5 minutes, discard the supernatant, dry the precipitate at 25 ° C for 10 minutes, add 2 mL of DMSO, and boil for 15 minutes while stirring. After returning to room temperature, add 200 μL of 50-fold diluted iodine solution (2% (w / v) potassium iodide, 1% (w / v) iodine) to 20 μL of 20-fold diluted DMSO, and measure the absorbance at 690 nm. Calculate the amylose content from the standard line (a combination of commercially available amylose + amylopectin with a known amylose content).

[0017] In the present invention, the raw buckwheat flour can be milled from the grains of any Fagopyrum plant as long as it has low amylose content. Fagopyrum genus plants include common buckwheat (Fagopyrum esculentum), Tartary buckwheat (Fagopyrum tataricum), perennial buckwheat (Fagopyrum cymosum), Dibotrys buckwheat (Fagopyrum dibotrys), wild relatives of buckwheat (Fagopyrum homotropicum), Fagopyrum giganteum, which is a hybrid of Tartary buckwheat and perennial buckwheat, and Fagopyrum tatari-cymosum. Other buckwheat plants include Fagopyrum megaspartanium, Fagopyrum pillus, Fagopyrum macrocarpum, Fagopyrum callianthum, Fagopyrum urophyllum, Fagopyrum gilesii, Fagopyrum statice, Fagopyrum leptopodum, Fagopyrum gracilipes, Fagopyrum capillatum, Fagopyrum pleioramosum, Fagopyrum lineare, Fagopyrum Rubifolium is included.

[0018] In the present invention, the genus Fagopyrum is not particularly limited, but examples of preferred species include common buckwheat, Tartary buckwheat, perennial buckwheat, or wild buckwheat, or a hybrid of any of them (for example, F. giganteum, which is a hybrid of Tartary buckwheat and perennial buckwheat), and an example of a more preferred species is common buckwheat.

[0019] In the present invention, the raw buckwheat flour can be milled from the grains of low amylose buckwheat plants bred or selected from existing varieties and lines. There are no particular limitations on the wild species, varieties and lines used for breeding or selection. Examples of buckwheat varieties include Kitawase buckwheat, Botan buckwheat, Kitayuki, Hashikami Wase, Iwate Wase, Mogami Wase, Hashikami Wase, Hitachi Aki Soba, Shinano Ichigo, Shinshu Dai Soba, Shinano Natsu Soba, Fukui native species, Kochi native species, Miyazaki Daitsubu, AOI, KOMA, NARO-FE-1, Akiakane, Gamma no Irodori, Kitano Mashu, Kita Mitsuki, Great Ruby, Cobalt no Chikara, Sachi Izumi, San Examples of varieties of tartary buckwheat include Rutin, Buckwheat Nakama Mother No. 1, Tachiakane, Dewakaori, Toyomusume, Natsumi, Nijiyutaka, Horominori, Miyazaki Ootsubu, Rutiking, Relanokaori, Natsuyoshi, Aizu no Kaori, Kaida Wase, Miyazaki Wase Kaori, Takamine Ruby, Takamine Ruby 2011, Yamagata BW5, Izumo no Mai, Haru no Ibuki, Shinenaga Red, Nagano S11, Nagano S8, Shimada Scarlet, Hietsu 1, and Hokkai 3. Examples of varieties of tartary buckwheat include Shinenaga Yellow, Hokkai T8, Hokkai T9, Hokkai T10, Hokuriku 4, Ki no Chikara, Ki no Takara, Ki no Toyo, Daizen, Shinano Kurotsubu, Daruma Datttan, Aeon no Kisai, Manten Kirari, Nishi no Haruka, and Aeon no Kisai. Many of these are available from seed companies or seed-related carriers.

[0020] A method for producing a low-amylose buckwheat plant is disclosed in JP 2022-44024 A, and a person skilled in the art can breed a low-amylose buckwheat plant based on the description in JP 2022-44024 A to obtain a buckwheat plant. Specifically, the method for producing a low-amylose buckwheat plant includes a step of mutating the GBSS gene of the buckwheat plant and / or a step of propagating a buckwheat plant having a mutated GBSS gene.

[0021] In the present invention, the low amylose buckwheat plant may be a buckwheat plant having a mutation in an active starch synthase (GBSS) gene. The GBSS gene mutation may be a mutation in at least one of the GBSSa gene and the GBSSb gene, but preferably has a mutation in the GBSSa gene. In one preferred embodiment, the mutation includes a mutation accompanied by an amino acid mutation (amino acid substitution, stop codon insertion), a splicing mutation (splicing signal mutation, genomic mutation accompanied by splicing mutation due to an intron mutation), a mutation in the expression level of a gene transcript due to a mutation in a non-translated region (including methylation of nucleic acid), and the like. A specific example is a gene mutation in which a mutation occurs in the splicing signal site of GBSSa, a stop codon is inserted in the gene transcript, and the accumulation of the GBSS protein is reduced, resulting in a decrease in the amylose content.

[0022] In one embodiment of the present invention, the low-amylose buckwheat plant is a buckwheat plant having a GBSSa gene mutation, and the buckwheat plant having a GBSSa gene mutation may have a polynucleotide consisting of the base sequence of SEQ ID NO: 1, or a polynucleotide having 80% or more, 85% or more, 90% or more, 95% or more, 97.5% or more, or 99% sequence identity to a polynucleotide consisting of the sequence of SEQ ID NO: 1, in which the nucleotide corresponding to position 1846 of SEQ ID NO: 1 is not A.

[0023] In one embodiment of the present invention, the low-amylose buckwheat plant is a low-amylose buckwheat plant in which the activity of the following proteins is suppressed: (A) a protein consisting of any one of the amino acid sequences of SEQ ID NOs: 2 to 7; (B) a protein consisting of an amino acid sequence having 90% or more, 95% or more, 97.5% or more, or 99% identity with any one of the amino acid sequences of SEQ ID NOs: 2 to 7, and having a function of controlling the amylose content of the buckwheat plant; (C) a protein consisting of an amino acid sequence in which 1 to 60 amino acids are deleted, substituted, or added in any one of the amino acid sequences of SEQ ID NOs: 2 to 7, and having a function of controlling the amylose content of the buckwheat plant. Buckwheat plants having a mutation in the GBSS gene are disclosed in JP 2022-44024 A, and a person skilled in the art can obtain a buckwheat plant having a mutation in the GBSS gene based on the description of JP 2022-44024 A.

[0024] In the present invention, when the term "sequence identity" is used in relation to a base sequence or an amino acid sequence, it means the percentage of the number of identical nucleotides or amino acids shared between two sequences when the two sequences are aligned in an optimal manner, unless otherwise specified. That is, identity can be calculated as follows: (number of identical positions / total number of positions) x 100, and can be calculated using a publicly available algorithm. In addition, such an algorithm is incorporated in the NBLAST and XBLAST programs described in Altschul et al., J. Mol. Biol. 215 (1990) 403-410. More specifically, searches and analyses regarding the identity of base sequences or amino acid sequences can be performed using algorithms or programs (e.g., BLASTN, BLASTP, BLASTX, ClustalW) well known to those skilled in the art. When using a program, the parameters can be appropriately set by those skilled in the art, and the default parameters of each program may be used. Specific techniques for these analysis methods are also well known to those skilled in the art.

[0025] Furthermore, in one embodiment of the present invention, the low amylose buckwheat plant is a GBSSa-deficient line "18N de 6". The GBSSa-deficient line "18N de 6" is disclosed in JP 2022-44024 A and is available from the National Agriculture and Food Development Organization.

[0026] In the present invention, examples of buckwheat-containing foods include noodles (raw noodles, boiled noodles, etc.), breads (e.g., sliced ​​bread, sweet buns, bagels, steamed bread, and butter rolls), pizza, mixed flours (e.g., fried chicken flour, tempura flour, bread mix flour, pancake mix flour, okonomiyaki mix flour, and takoyaki mix flour), confectioneries (cookies, biscuits, crackers, boro, snacks, sponge cakes, manju, dango, rice crackers, arare, and okaki), and rice cakes.

[0027] One aspect of the present invention relates to breads, confectioneries, or rice cakes characterized by a chewy texture, which are produced by a method for producing a buckwheat-containing food using buckwheat flour milled from a plant of the genus Fagopyrum with an amylose content of less than 20.0% by mass as a raw material. In the examples described below, it is shown that the breads, confectioneries, or rice cakes produced by the method for producing the present invention are softer, chewier, tastier, and less likely to harden than those produced by using wild-type buckwheat flour.

[0028] One aspect of the present invention relates to a method for producing noodles with an improved texture, characterized in that buckwheat flour milled from a Fagopyrum plant with an amylose content of less than 20.0% by mass is used as a raw material. In the Examples described later, it is shown that by using buckwheat flour obtained from a Fagopyrum plant with an amylose content of less than 20.0% by mass as a raw material, the noodles immediately after production have a softer texture and are more chewy than when buckwheat flour from wild-type buckwheat is used.

[0029] One aspect of the present invention is a method for producing a buckwheat-containing food using buckwheat flour milled from a Fagopyrum plant having an amylose content of less than 20.0% by mass as a raw material, and is characterized in that the maximum load when the buckwheat-containing food is compressed by 50% of its thickness is 6.0 N or less.

[0030] One aspect of the present invention is a method for producing a buckwheat-containing food product that uses buckwheat flour milled from a Fagopyrum plant having an amylose content of less than 20.0% by mass as a raw material, and is characterized in that when the food is refrigerated for 72 hours after production and then compressed to 50% of its thickness, the maximum load measured shows an increase of 100% or less compared to the maximum load measured immediately after production.

[0031] One aspect of the present invention is a food product containing 50% by mass or more of buckwheat flour milled from a Fagopyrum plant having an amylose content of less than 20.0% by mass, and having a maximum load of 6.0 N or less when the thickness of the food product is compressed by 50%. The buckwheat flour content in the food product is the content of buckwheat flour in the entire flour raw material.

[0032] One aspect of the present invention is a food product containing 50% by mass or more of buckwheat flour milled from a Fagopyrum plant having an amylose content of less than 20.0% by mass, and when the food product is refrigerated for 72 hours after production and the maximum load measured when the food product is compressed to 50% of its thickness is measured, the increase in the maximum load measured immediately after production is 100% or less. The buckwheat flour content in the food product is the content of buckwheat flour in the entire flour raw material.

[0033] One aspect of the present invention relates to a method for producing bread or confectionery, characterized in that buckwheat flour milled from a Fagopyrum plant having an amylose content of less than 20.0% by mass is used as a raw material. According to the present invention, it is possible to produce bread or confectionery that does not contain wheat flour as a raw material. Wheat-free bread and confectionery are in high demand because they can be eaten by patients with wheat allergy or gluten intolerance. In one embodiment, according to the present invention, it is possible to provide bread and confectionery that does not contain wheat flour as a raw material, is soft, has an increased chewy texture, and tastes delicious. In the examples described later, it is shown that by using buckwheat flour obtained from a Fagopyrum plant having an amylose content of less than 20.0% by mass as a raw material, it is possible to produce buckwheat bread that is soft, has an increased chewy texture, and tastes delicious, compared to the case of using wild-type buckwheat flour.

[0034] One aspect of the present invention relates to a method for producing rice cakes, characterized by using buckwheat flour milled from a Fagopyrum plant having an amylose content of less than 20.0% by mass as a raw material. In the examples described below, it is shown that by using buckwheat flour obtained from a Fagopyrum plant having an amylose content of less than 20.0% by mass as a raw material, rice cakes that are softer, more chewy, and more delicious can be produced compared to when wild-type buckwheat flour is used. One aspect of the present invention relates to a method for producing rice crackers, characterized by using buckwheat flour milled from a Fagopyrum plant having an amylose content of less than 20.0% by mass as a raw material. In the examples described below, it is shown that by using buckwheat flour obtained from a Fagopyrum plant having an amylose content of less than 20.0% by mass as a raw material, rice crackers that are softer, more crispy, and more delicious can be produced compared to when wild-type buckwheat flour is used.

[0035] One aspect of the present invention relates to a method for producing chilled noodles, characterized in that buckwheat flour milled from a Fagopyrum plant having an amylose content of less than 20.0% by mass is used as a raw material. Chilled noodles are noodles that are distributed or stored in the chilled temperature range, and may be fresh noodles, semi-fresh noodles, or boiled noodles. In a specific aspect, chilled noodles are preferably boiled noodles that are distributed and stored in the chilled temperature range. The "chilled temperature range" refers to a temperature condition in which the average temperature is within the range of 0°C to 10°C.

[0036] Chilled boiled noodles are in high demand because they can be easily eaten by pouring on noodle soup (hot or cold) or by pouring on water to loosen the noodles and dipping them in noodle soup (hot or cold). However, there is a problem that buckwheat noodles become hard and dry when stored at chilled temperatures. In the examples described later, it is shown that by using buckwheat flour obtained from a buckwheat plant with an amylose content of less than 20.0% by mass as a raw material, the noodles have a soft texture, an increased chewiness, a decreased dryness, and a delicious taste even after 72 hours of refrigerated storage, compared to when buckwheat flour from wild-type buckwheat is used. By using buckwheat flour obtained from a buckwheat plant with an amylose content of less than 20.0% by mass as a raw material, it is possible to prevent deterioration of the texture after refrigerated storage at chilled temperatures.

[0037] One aspect of the present invention relates to a method for producing a buckwheat-containing food, characterized in that buckwheat flour milled from a Fagopyrum plant with an amylose content of less than 20.0% by mass is used as a raw material, and the maximum load when the food is compressed to 50% of its thickness after refrigerated storage for 84 hours after production is 6.5 N or less. In the Examples described below, the hardness of the noodles when stored in a refrigerator tended to differ depending on the hydration rate, but it was revealed that noodles made from buckwheat flour obtained from a Fagopyrum plant with an amylose content of less than 20.0% by mass tended to maintain their softness more easily than noodles made from wild-type buckwheat, regardless of the hydration rate.

[0038] Buckwheat-containing foods can be produced by conventional methods, except that buckwheat flour milled from a plant of the genus Fagopyrum having an amylose content of less than 20.0% by mass is used as a raw material.

[0039] One aspect of the present invention relates to a method for producing thick buckwheat noodles, characterized in that buckwheat flour milled from a Fagopyrum plant having an amylose content of less than 20.0% by mass is used as a raw material. In one embodiment, the shape of the thick buckwheat noodles is a noodle string, the cross section perpendicular to the noodle string direction is a rectangle, and the length of one side is 3 mm or more, for example, in the range of 3 to 10 mm, or in the range of 3 to 8 mm. In another embodiment, the shape of the thick buckwheat noodles is a noodle string, the cross section perpendicular to the noodle string direction is a circle, and the diameter is 3 mm or more, for example, in the range of 3 to 10 mm, or in the range of 3 to 8 mm. The thick buckwheat noodles may be boiled noodles or dried noodles. The thick buckwheat noodles may be cut by cutting the rolled out dough with a knife, or the dough may be extruded. In the examples described later, it is shown that by using buckwheat flour obtained from a Fagopyrum plant with an amylose content of less than 20.0% by mass as a raw material, thick buckwheat noodles can be produced that are softer, more chewy, and tastier than when wild-type buckwheat flour is used. The thick buckwheat noodles of the present invention can be said to have a new characteristic because they are chewy and have a strong aroma due to the use of buckwheat flour obtained from a Fagopyrum plant with an amylose content of less than 20.0% by mass as a raw material.

[0040] (Protein content) In the manufacturing method of the present invention, the protein content of the raw buckwheat flour may be 11% or less. Generally, whole buckwheat flour contains 12% protein (Ministry of Education, Culture, Sports, Science and Technology, "Standard Tables of Food Composition in Japan 2015 Edition (7th Edition)"). The main types of protein are albumin, gliadin, and fibrin.

[0041] The protein content can be calculated by measuring the total nitrogen content in buckwheat flour using the dry combustion method, and multiplying the measured value by 6.31 as the nitrogen-protein conversion factor to calculate the protein content (dry matter equivalent).The protein content in buckwheat grains can be calculated by drying and preparing unpolished buckwheat, removing the husks, finely pulverizing it, measuring the total nitrogen content using the dry combustion method, and multiplying the measured value by 6.31 as the nitrogen-protein conversion factor to calculate the protein content (dry matter equivalent).

[0042] It is known that it is difficult to produce buckwheat noodles from buckwheat flour with a low protein content, and that the buckwheat noodles after production tend to harden. According to the study by the present inventors, when 100% wild-type buckwheat flour is used for production, the boiled noodle band produced from buckwheat flour with a protein content of 20% or more showed almost no increase in maximum load when compressed to 50% of the noodle band thickness (2.0 mm) even after 72 hours of refrigeration compared to immediately after production, and the hardness was almost unchanged, but when boiled noodle bands produced from buckwheat flour with a protein content of 11% or less were refrigerated for 72 hours after production, the maximum load when compressed to 50% of the noodle band thickness (2.0 mm) increased from 4.3 N to 10.0 N (increase rate of 135%), and the noodle bands became harder when stored in a refrigerator for 72 hours after production compared to immediately after production.

[0043] However, the present inventors surprisingly found that by using buckwheat flour milled from low-amylose buckwheat plants, buckwheat noodles made from buckwheat flour with a low protein content are less likely to become hard. According to the inventors' research, when buckwheat noodles were made using 100% buckwheat flour milled from buckwheat plants with an amylose content of less than 20.0%, the maximum load of boiled noodle sheets with a protein content of 11% or less increased from 3.5N to 5.9N after 72 hours of refrigerated storage compared to immediately after production. This increase rate was 67%, which was suppressed compared to the increase rate (135%) when wild-type buckwheat was used. It was revealed that by using buckwheat flour milled from low-amylose buckwheat plants as a raw material, even buckwheat flour with a low protein content can be used to suppress hardening of buckwheat-containing foods, especially hardening due to refrigerated storage.

[0044] The buckwheat-containing food produced by the present invention has a rate of increase in maximum load when refrigerated for 72 hours after production compared to immediately after production ((maximum load after refrigerated storage for 72 hours / maximum load immediately after production-1) x 100) of 100% or less, and preferably 90% or less, 80% or less, 70% or less, 60% or less, or 50% or less. Here, the maximum load is when the noodle sheet thickness (2.0 mm) is compressed by 50%, and the buckwheat-containing food is boiled noodles produced using 100% buckwheat flour.

[0045] One aspect of the present invention is a method for producing a buckwheat-containing food from buckwheat flour having a protein content of 11% by mass or less, which uses buckwheat flour milled from a Fagopyrum plant having an amylose content of less than 20.0% by mass as a raw material.

[0046] One aspect of the present invention is a method for producing a buckwheat-containing food using buckwheat flour milled from a Fagopyrum plant having an amylose content of less than 20.0% by mass as a raw material, characterized in that the protein content of the buckwheat flour is 11% by mass or less, and the maximum load when the buckwheat-containing food is compressed to 50% of its thickness is 6.0 N or less. In a specific aspect of the present invention, the maximum load when the thickness is compressed to 50% may be less than 6.0 N, for example, 5.5 N or less, 5.0 N or less, 4.5 N or less, 4.0 N or less, 3.5 N or less, or 3.0 N or less.

[0047] One aspect of the present invention is a method for producing a buckwheat-containing food product that uses buckwheat flour milled from a Fagopyrum plant having an amylose content of less than 20.0% by mass as a raw material, the buckwheat flour having a protein content of 11% by mass or less, and when the food is refrigerated for 72 hours after production and the maximum load is measured when the food is compressed to 50% of its thickness, the increase in the maximum load measured immediately after production is 100% or less.

[0048] One aspect of the present invention is a food product containing 50% by mass or more of buckwheat flour milled from a Fagopyrum plant having an amylose content of less than 20.0% by mass, the buckwheat flour having a protein content of 11% by mass or less, and a maximum load of 6.0 N or less when the food product is compressed to 50% of its thickness. The buckwheat flour content in the food product is the content of buckwheat flour in the entire flour raw material.

[0049] One aspect of the present invention is a food product containing 50% by mass or more of buckwheat flour milled from a Fagopyrum plant having an amylose content of less than 20.0% by mass, the buckwheat flour having a protein content of 11% by mass or less, and when the food product is refrigerated for 72 hours after production and the maximum load measured when the food product is compressed to 50% of its thickness is measured, the increase in the maximum load measured immediately after production is 100% or less. The buckwheat flour content in the food product is the content of buckwheat flour in the entire flour raw material.

[0050] In the present invention, the buckwheat-containing food may be 100% buckwheat flour except for the auxiliary materials, or may contain other flour ingredients besides buckwheat flour in addition to buckwheat flour. The flour ingredients other than buckwheat flour are 60% or less of the total flour ingredients, and preferably 55%, 50%, 45%, 40%, 35%, 30%, 25% or less, 20% or less, 15% or less, 10% or less, or 5% or less in order not to impair the physical property improvement effect due to the low amylose content. Examples of the flour ingredients other than buckwheat flour include wheat flour, rice flour, starch powder, etc. Examples of the auxiliary materials include water, whole eggs, egg whites, egg yolks, seaweed binders, yam binders, oils and fats, milk, dairy products, etc. Depending on the type of buckwheat-containing food produced by the method of the present invention, the type and amount of the auxiliary materials can be selected and adjusted within a range that does not impair the physical property improvement effect of the present invention. The final moisture content of the entire flour raw material can be in the range of about 35-98%, about 40-98%, about 50-98%, or about 60-98%, assuming that the moisture content of the entire flour raw material is 0%. Note that, in the present invention, the protein content of buckwheat flour does not include proteins derived from other flour raw materials, such as wheat flour.

[0051] Buckwheat flour is generally produced by rolling buckwheat (seeds) and separating the ground material with a sieve. In the roll milling process, the flour is made from the center of the buckwheat, and the flour that comes out is called No. 1 flour, No. 2 flour, and No. 3 flour, in that order.

[0052] In the present invention, the protein content of buckwheat flour can be made 11% or less by blending No. 1 flour, No. 2 flour, and No. 3 flour, in particular, by blending No. 1 flour, which has a high starch ratio and a low protein ratio, with No. 2 flour, which has a high protein ratio.

[0053] <Method for improving physical properties> The present invention provides a method for improving the physical properties of buckwheat-containing foods, which is characterized by using buckwheat flour obtained from a Fagopyrum plant having an amylose content of less than 20.0% by mass as a raw material. In this specification, with respect to processed buckwheat foods, physical properties refer to physical properties related to texture (hardness, elasticity, chewy texture, gritty texture, etc.), quality (shelf life, hardening due to refrigerated storage, etc.), and appearance (luster, color, etc.). In a specific embodiment, the physical property of the processed buckwheat food is hardening after refrigerated storage.

[0054] The physical properties of buckwheat-containing foods, especially hardness, can be measured as the maximum load when the thickness of the noodle sheet (2.0 mm) is compressed by 50% over 2 seconds (0.5 mm / sec). The maximum load can be measured, for example, using a physical property testing system (Yamaden RE2-3305C-1). The temperature during measurement can be 25°C.

[0055] One aspect of the present invention is a method for improving the physical properties of a buckwheat-containing food, characterized in that buckwheat flour obtained from a plant of the genus Fagopyrum having an amylose content of less than 20.0% by mass is used as a raw material, and when the food is refrigerated for 72 hours after production and the maximum load measured when the food is compressed to 50% of its thickness is measured, the increase in the maximum load measured immediately after production is 100% or less. Here, the maximum load is measured when the noodle sheet thickness (2.0 mm) is compressed to 50%, and the boiled noodle sheet is produced using 100% buckwheat flour.

[0056] The present inventors have demonstrated that by using buckwheat flour milled from low-amylose Fagopyrum plants as a raw material, it is possible to suppress hardening of buckwheat-containing foods, particularly hardening due to refrigerated storage, even when buckwheat flour with a low protein content is used. Specifically, the present inventors have found that boiled noodle sheets made from buckwheat flour milled from low-amylose Fagopyrum plants are less likely to harden even after 72 hours of refrigerated storage, compared to boiled noodle sheets made from buckwheat flour from wild-type Fagopyrum plants.

[0057] In the method for improving physical properties of the present invention, the buckwheat-containing food is one described above in the section "Protein Content." In a specific embodiment, the buckwheat-containing food is boiled noodles.

[0058] The method for improving the physical properties of a processed buckwheat food of the present invention may also be a method for improving the physical properties of boiled noodles that have been refrigerated and stored in the chilled temperature range.

[0059] The present invention further provides a method for preventing deterioration in the texture of boiled noodles, comprising using buckwheat flour obtained from a plant of the genus Fagopyrum having an amylose content of less than 20.0% by mass as a raw material. The texture of boiled noodles can be evaluated by sensory evaluation by a panel.

[0060] In the examples described later, it has been shown that by using buckwheat flour obtained from a Fagopyrum plant with an amylose content of less than 20.0% by mass as a raw material, the noodles immediately after production have a softer texture and are more chewy than when wild-type buckwheat flour is used, and further, even after 72 hours of refrigerated storage, the noodles have a softer texture, more chewy texture, less dry texture, and taste better. By using buckwheat flour obtained from a Fagopyrum plant with an amylose content of less than 20.0% by mass as a raw material, it is possible to prevent deterioration of the texture after refrigerated storage.

[0061] <Method of manufacturing buckwheat processed food> The present invention is a method for producing a processed buckwheat food using buckwheat grains obtained from a Fagopyrum plant having an amylose content of less than 20.0% by mass as a raw material.

[0062] In the context of the present invention, buckwheat grain is unmilled buckwheat kernel, specifically hulled buckwheat kernel. Buckwheat grain may include the husk, endosperm and germ. In some embodiments, the buckwheat grain may be husk-free.

[0063] In the present invention, the processed buckwheat grain foods include boiled buckwheat grains, cooked buckwheat grains, buckwheat grain porridge (e.g., kasha), and whole buckwheat grains for mixed grain rice. In the examples described later, it is shown that the processed buckwheat grain foods produced by the production method of the present invention have an improved soft, delicious, and chewy texture immediately after production, compared to buckwheat grain processed foods made from wild-type buckwheat. Buckwheat is used as grains (kasha) in Russia, for example, but there is a problem that the starch is easily retrograded over time after cooking due to its high amylose content, resulting in a poor texture (hard and brittle). However, in the present invention, buckwheat grains from a low-amylose buckwheat plant are used, so that the texture is less likely to deteriorate even after time has passed after cooking. In the examples described later, it has been shown that the buckwheat grain processed food produced by the production method of the present invention has an improved soft, tasty and chewy texture compared to the buckwheat grain processed food made from wild-type buckwheat, even after refrigerated storage for 72 hours after production.

[0064] The processed buckwheat food produced by the production method of the present invention may have a maximum load of 3.5 N or less, 3.0 N or less, 2.5 N or less, or 2.0 N or less when compressed to 75% of its thickness. The processed buckwheat food produced by the production method of the present invention may have a maximum load of 3.5 N or less, 3.0 N or less, 2.5 N or less, or 2.0 N or less when compressed to 75% of its thickness after refrigerated storage for 72 hours after production.

[0065] Buckwheat grains used in the buckwheat grain processed food can be collected from a low-amylose Fagopyrum plant described in the above section on amylose content. In the production method of the present invention, the protein content of the raw buckwheat grains may be 11% or less. Buckwheat grains with a protein content of 11% or less by mass can be collected from a strain of Fagopyrum plant with a low protein content. EXAMPLES

[0066] The present invention will be described more specifically based on the following examples, but the present invention is not limited to these examples.

[0067] Example 1: Sensory evaluation test of boiled noodles immediately after production Test Method: In this example, GBSSa-deficient buckwheat was used as a low-amylose buckwheat plant. The GBSSa-deficient buckwheat is 18N de6. The protein content (measured by dry combustion method) was 14.2% for the GBSSa-deficient buckwheat and 14.5% for the wild-type buckwheat. The GBSSa-deficient and wild-type buckwheat were dehulled, milled using a low-temperature flour milling buckwheat manufacturing device (Chihoda Seiko Co., Ltd., CGM-200M), and noodles were made from 100% buckwheat flour. A sensory evaluation test was conducted on the boiled noodles immediately after production. Regarding the difference in texture, six panelists each voted one vote as either "quite different," "different," "slightly different," "almost the same," or "the same." Regarding the comparison of noodle hardness, the six panelists evaluated the "wild-type score" with "soft" being 1 point, "hard" being 7 points, and "GBSSa-deficient buckwheat" being 4 points. To compare the chewiness of the noodles, a panel of six members scored the "wild-type buckwheat" with "not chewy" being given 1 point, "chewy" being given 7 points, and the "GBSSa-deficient line" being given 4 points.

[0068] result: Of the six panelists, four judged the texture of the GBSSa-deficient buckwheat noodles to be "significantly different" from that of the wild-type buckwheat noodles, one judged it to be "different," and one judged it to be "slightly different" (Fig. 1A). Compared to the wild-type buckwheat noodles, the GBSSa-deficient buckwheat noodles had a significantly "softer texture" (Fig. 1B) and "chewy texture" (Fig. 1C). Consideration: When compared immediately after production, the buckwheat noodles made from the GBSSa-deficient buckwheat line had a different texture than those made from wild-type buckwheat, which may be due to differences in softness and chewiness.

[0069] Example 2: Test method: Sensory evaluation test of buckwheat noodles 72 hours after production The GBSSa-deficient and wild-type buckwheat were dehulled and milled using a low-temperature soba milling machine (CGM-200M, Chihoda Seiko Co., Ltd.), and made into noodles using 100% buckwheat flour. The boiled noodles immediately after production were stored at 5°C for 72 hours, and then a sensory evaluation test was conducted. The panel consisted of seven members. Regarding the difference in texture, each person voted for either "quite different," "different," "slightly different," "almost the same," or "the same." The hardness of the noodles was compared by rating the "GBSSa-deficient buckwheat" with "soft" given 1 point, "hard" given 7 points, and "wild type" given 4 points. The chewiness of the noodles was compared by rating the "GBSSa-deficient buckwheat" with "not chewy" given 1 point, "chewy" given 7 points, and "wild type" given 4 points. The dry texture of the noodles was compared by rating the GBSSa-deficient buckwheat noodles on a scale of 1 to 4, with "not dry" being given 1 point, "dry" being given 7 points, and "wild type" being given 4 points. The deliciousness of the noodles was compared by rating the GBSSa-deficient buckwheat noodles on a scale of 1 to 4, with "not tasty" being given 7 points, and "wild type" being given 4 points. The protein content of the GBSSa-deficient buckwheat noodles was 14.2%, while that of the wild type was 14.5%.

[0070] result: All seven panelists rated the texture of GBSSa-deficient buckwheat noodles as "significantly different" from that of wild-type buckwheat (Fig. 2A). The texture of GBSSa-deficient buckwheat noodles was significantly more "soft," "chewy," and "not dry" than that of wild-type buckwheat (Fig. 2B-D), and was also rated as "delicious" (Fig. 2E). Consideration: The texture of the buckwheat noodles made from GBSSa buckwheat was different from that of the wild-type buckwheat after refrigerated storage, which may be due to differences in softness, chewiness, and dryness. In addition, the deliciousness was maintained, which suggests that the noodles are suitable for chilled storage.

[0071] Example 3: Physical property testing Test Method: The GBSSa-deficient strain and wild-type buckwheat were dehulled and milled using a low-temperature buckwheat milling machine (CGM-200M, Chihoda Seiko Co., Ltd.). Noodle sheets were made from 100% buckwheat flour (thickness 2.0 mm). The boiled noodle sheets immediately after production were stored at 5°C for 84 hours, and the maximum load when the noodle sheets were compressed by 50% for 2 seconds was measured using a physical property testing system (Yamaden RE2-3305C-1). The temperature during measurement was 25°C. Since the softness differs depending on the amount of water added, the final water content when the water content of the buckwheat flour was set to 0% was 62.7% (lower limit of water content for hand-made buckwheat), 74.4% (water content for hard hand-made buckwheat), 86.0% (standard water content for hand-made buckwheat), and 97.7% (upper limit of water content for hand-made buckwheat). The protein content was 14.2% in the GBSSa-deficient strain and 14.5% in the wild type. result: The results are shown in Figure 3. The higher the hydration rate, the smaller the maximum load. When comparing GBSSa-deficient buckwheat and wild-type buckwheat at the same hydration rate, the maximum load of the GBSSa-deficient buckwheat noodles when stored in a refrigerator tended to be smaller than that of the wild-type. The difference was small at the highest hydration rate of 97.7%. Consideration: Although the hardness of the noodles when stored in a refrigerator tended to vary depending on the water content, it appears that GBSSa-deficient buckwheat noodles tend to maintain their softness more easily than wild-type buckwheat noodles.

[0072] Example 4: Protein content test Test Method: GBSSa-deficient buckwheat and wild-type buckwheat were dehulled and milled using a low-temperature buckwheat milling device (Chihoda Seiko Co., Ltd., CGM-200M). Buckwheat flours with different protein contents were prepared by changing the blend ratio of first flour (high starch content) and second flour (high protein content). Noodle sheets were produced (2.0 mm thick) using a blend of 100% buckwheat flour and 50% commercially available wheat flour (medium-strength flour). The final water content was 83.0% when the moisture content of the buckwheat flour was 0%. The boiled noodle sheets immediately after production were stored at 5°C for 3 days (72 hours) after production, and the maximum load when the noodle sheets were compressed to 50% of their thickness over a period of 2 seconds was measured using a physical property testing system (Yamaden RE2-3305C-1, Yamaden Corporation). The temperature during measurement was 25°C. The protein and starch contents of the produced noodle sheets are shown in Table 1.

[0073] result: The results are shown in Table 1 and Figure 4. When comparing noodle bands with similar protein contents (comparison between solid lines, between medium dashed lines, and between thin dashed lines), buckwheat had a lower maximum load in all samples compared to wild-type buckwheat. When comparing noodle bands made from 100% buckwheat flour with those made from 50% wheat flour, the latter had a lower maximum load. When noodle sheets were made using wild-type buckwheat flour with a protein content of 9.6% and a starch content of 61%, their hardness increased when they were refrigerated for three days (72 hours) after production (maximum load increased from 4.3 N to 10.0 N). When noodle sheets were made using wild-type buckwheat flour with a protein content of 20% or more, the increase in hardness was small even when they were refrigerated for three days after production. When GBSSa-deficient buckwheat with a protein content of 10.8% and a starch content of 61% was refrigerated for three days after production, the hardness did not change much (maximum load increased from 3.5 N to 5.9 N). The same tendency was observed when 50% buckwheat flour and 50% wheat flour were used. [Table 1] Consideration: It has been reported that the higher the protein content, the softer the noodles will be, so it was unclear whether low-amylose noodles would actually be softer. In this test, even when the protein content was increased to 30%, the maximum load of the noodle band of the GBSSa-deficient buckwheat strain was smaller than that of wild-type buckwheat, suggesting that the physical properties can be softened. The same tendency was observed when wheat flour was added at 50%, suggesting that the GBSSa deficiency in buckwheat flour can soften the physical properties even in dough containing gluten.

[0074] Example 5: Measurement of amylose content To investigate seasonal and variety-specific changes in amylose content, the amylose content was measured in Hitachiaki buckwheat, the breeding parents of the GBSSa-deficient line, and GBSSa-deficient lines 1 to 4 sown in spring 2021, summer 2021, spring 2022, summer 2022, and spring 2023. [Method for measuring amylose content] The following tests were performed in triplicate. For the seeds of outcrossing buckwheat lines cultivated and harvested under isolated conditions at maturity, 10 g of seeds after removing the husks were ground in a mortar, and 20 mg of buckwheat flour was measured into a plastic tube. 1 ml of dimethyl sulfoxide (DMSO) was added and boiled for 15 minutes while stirring. After returning to room temperature, 6 ml of ethanol was added, mixed by inversion, and left at room temperature overnight. Centrifuge at 2000 x g for 5 minutes, discard the supernatant, and dry the precipitate at 25°C for 10 minutes, add 2 ml of DMSO, and boil for 15 minutes while stirring. After returning to room temperature, 200μL of 50-fold diluted iodine solution (2% (w / v) potassium iodide, 1% (w / v) iodine) was added to 20μL of the solution diluted 20-fold with DMSO, and the absorbance at 690nm was measured, and the amylose content was calculated from a standard line (a combination of commercially available amylose + amylopectin with a known amylose content). The starch content in buckwheat flour, which is necessary for calculating the amylose content, was measured using a MEGAZYME kit (amylose / amylopectin analysis kit). The amylose content in starch varied from 22.6% to 28.7% in the wild type and from 15.6% to 18.5% in the GBSSa-deficient line during the last season. [Table 2]

[0075] Example 6: Preparation of various foods In Example 6, various foods were produced using flour from normal amylose buckwheat (wild type) or low amylose buckwheat (GBSSa-deficient line). The amylose content of the flour used in Example 6 is as follows: Wild buckwheat: 20.6% GBSSa-deficient buckwheat: 16.3% The method of the sensory evaluation test carried out in Example 6 is as follows. Various foods were prepared using flour from wild-type or GBSSa-deficient strains, and a panel of six members evaluated the food products on both subjective and objective criteria. The subjective evaluation items were color, aroma, softness, texture, and deliciousness. The score for the wild type was fixed at 4 points, and the GBSSa-deficient line was scored as follows, compared to the wild type: very poor (1 point), slightly poor (2 points), slightly poor (3 points), normal (4 points), slightly good (5 points), slightly good (6 points), and very good (7 points). The subjective evaluation is an evaluation that takes into account the "preferences" of the panel. For example, when evaluating "hard noodles," a "panel that likes hard noodles" will give the noodles a "very good" rating, and conversely, a "panel that dislikes hard noodles" will give the noodles a "very bad" rating. The objective evaluation items were hardness and texture. The score for the wild type was fixed at 4 points, and the GBSSa-deficient line was scored for hardness from hard (1 point) to soft (7 points) and for texture from crumbly (1 point) to chewy (7 points) in comparison with the wild type. The texture of the "arare" was scored from crumbly (1 point) to crispy (7 points). The objective evaluation was whether the rice crackers were hard or soft, crumbly or chewy (crispy), regardless of preference.

[0076] 6-1: Mountain-shaped bread Bread production Materials and Methods The recipe for the mountain-shaped bread ingredients is as follows: Ingredients: 160g buckwheat flour, 12g sugar, 3.2g salt, 184g water, 3.2g commercial yeast powder Mix the ingredients for the mountain bread and knead to make dough. · Let the dough rise at 35℃ for 30 minutes, then bake in a 200℃ oven for 28 minutes.

[0077] Evaluation method The specific volume of baked bread was measured using the rapeseed substitution method and compared. The physical properties of the inner layer of the baked bread were measured by cutting it into pieces 10 mm in length and width and 15 mm in thickness, and measuring the load when compressed to 75% using a physical property testing system (Yamaden RE2-3305C-1, Yamaden Corporation). Measurements were taken from the day of baking until two days later, and the values ​​for the GBSSa-deficient buckwheat bread on each day were shown as relative values, with the load for the wild-type buckwheat bread set at 100.

[0078] result The results of the sensory evaluation test are shown in Table 3. [Table 3] In the sensory evaluation, the GBSSa-deficient line had improved "softness" and "tastiness" on the day of baking, and a "chewy texture" compared to the wild type. The improved "softness" and "tastiness" and the chewy texture tended to be maintained even in the GBSSa-deficient line bread one day after baking. Since the "softness, texture, and taste" were evaluated as positive, it was thought that more satisfactory bread could be produced by using buckwheat flour from the GBSSa-deficient line as an ingredient.

[0079] Comparison of specific volume of baked bread: ·Wild type: 2.47±0.21mL / g GBSSa-deficient strain: 2.57±0.15mL / g (No significant difference in the mean values ​​in the t-test) Since there was almost no difference in the specific volume of baked bread between the wild type and the GBSSa-deficient strain, it was thought that the GBSSa-deficient strain would not pose a problem in terms of the rise of buckwheat bread.

[0080] The results of the physical property tests are shown in FIG. Instrumental analysis showed that bread made from GBSSa-deficient buckwheat flour required a smaller load to compress it to 75% compared to bread made from the wild-type buckwheat, suggesting that the bread maintained its softness.

[0081] A photograph of the bread is shown in Figure 6. The bread made from the GBSSa-deficient buckwheat flour showed no significant differences in appearance or inner layer compared to bread made from the wild-type, suggesting that there are no problems with the appearance or inner layer of buckwheat bread.

[0082] 6-2: Grain rice cooking test [method] The grains were cooked using the following composition and evaluated. 100g of buckwheat grains were mixed with 200g of water, left for 2 hours, and then cooked in a commercially available rice cooker. The physical properties were measured using a physical property testing system (Yamaden RE2-3305C-1) at the load when the rice grains were compressed to 75% after cooking.

[0083] A photograph of cooked grains is shown in Figure 7. Since no particular difference was observed in appearance, it was considered that the GBSSa-deficient line had no problem with the appearance of buckwheat grains.

[0084] The results of the physical property tests are shown in Table 4. [Table 4] Instrumental analysis of cooked rice grains showed that the load required to compress the GBSSa-deficient rice by 75% was smaller than that of the wild-type rice up to three days after cooking, suggesting that the rice retained its softness.

[0085] The results of the physical property tests are shown in Table 5. [Table 5] In a sensory evaluation of the cooked rice grains, the GBSSa-deficient line had improved "softness" and "taste" on the day of cooking, and a "chewy texture" compared to the wild type. The improved "softness" and "taste" as well as the "chewy texture" were maintained even after three days of refrigerated storage. Since the "softness, texture, and taste" were evaluated as positive, it is believed that more desirable cooked rice grains can be produced.

[0086] 6-3: Mochi production test [method] 20g of buckwheat flour was mixed with 40g of water and heated in a microwave oven. After the dough started to solidify, it was mixed well and rolled into balls. After heating at 180℃, the expansion volume was investigated using the rapeseed displacement method.

[0087] The results of the sensory evaluation test of mochi are shown in Table 6. [Table 6] In a sensory evaluation of the mochi, the GBSSa-deficient line maintained its "softness" and "chewy texture" compared to the wild type on the day of production and three days later, and the evaluation of "softness, texture, and flavor" was positive, suggesting that more desirable mochi can be produced.

[0088] A photograph of mochi after heating is shown in Figure 8. Volume after heating (on the day of manufacture) When the volume before heating is set to 1.00 Wild type: 1.03 GBSSa-deficient strain: 1.76 Mochi made from buckwheat flour from the GBSSa-deficient line expanded to a greater extent than wild-type mochi, suggesting that the flour has favorable properties for mochi.

[0089] 6-4: Arare production test [method] 20g of buckwheat flour was mixed with 40g of water and heated in a microwave oven. Once the solidification had started, the dough was kneaded thoroughly, cut into 7x7x12mm pieces, dried for a day, and then heated in oil at 180°C for 6 minutes. The volume after heating was measured using the rapeseed displacement method. The results of the sensory evaluation test are shown in Table 7. [Table 7] In a sensory evaluation of the arare crackers, the GBSSa-deficient line maintained its "softness" and "crispy texture" compared to the wild-type, and since the "softness, texture, and flavor" were rated positively, it is believed that more desirable arare crackers can be produced. A photograph of the arare after heating is shown in Figure 9. If the volume before heating is 1.00: Wild type: 1.18 GBSSa-deficient strain: 1.64 In the investigation of the volume after heating, the GBSSa-deficient strain expanded to a greater extent than the wild type, which suggests that the strain has favorable properties for use as arare.

[0090] 6-5: Noodle manufacturing test [method] 100g of buckwheat flour was mixed with 45g of water, kneaded for 2 minutes, and made into noodles of 2mm, 4mm, and 5mm squares. After making the noodles, they were boiled for 1.5, 7, and 10 minutes, respectively, and then subjected to sensory evaluation. The results of the sensory evaluation test are shown in Table 8. [Table 8] For 2mm, 4mm, and 5mm square noodles, the GBSSa-deficient line had improved "softness" and "tastiness" and a more "chewy texture" compared to the wild type. In particular, in the sensory evaluation of the 5mm square thick noodles, the GBSSa-deficient line was highly rated for its "aroma," "softness," "tastiness," and "chewy texture." When the GBSSa-deficient line noodles are made thicker, they have a stronger chewiness and a stronger aroma, suggesting that it may be possible to produce a food with new characteristics. Although the sensory evaluation test was performed using cold noodles, it was thought that the chewy texture of the GBSSa-deficient line was stronger with warm noodles, bringing out their characteristics even more.

[0091] Sequence Listing SEQ ID NO: 1: Buckwheat GBSSa (mutant) gene (same as the sequence described in SEQ ID NO: 2 of JP 2022-44024) ttgatttatt tgttatatag catactaatt acttactttg tgttactcta tgtaggcatt 60 ttgcaatgac gtcactcaca atcacaagta gcttgcctgc agtgagcacc gtagcaggag 120 ccacatcttc aagcaaggca atgttcttgc aaaatagtct caaaagcact gcagggctcc 180 gacctttcaa cgacgtcgat atgctcaaat gcggggccaa ctcaaataac gcaccttcca 240 agttaccaac aatggaaccc aagagatccg caaataattc tgtggaatca agagttatcc 300 gatgtgggat gaacttggtc tttgtaggag ctgaggtagc tccatggagc aaaaccggtg 360 gccttggaga cgttcttgcc ggcctcccgc ctgcaatggc ggtatgtcat taatcctacc 420 atcttattgt taattggttt taggatagaa ctcattgagt ttatgcgttg aactggagtc 480 taacgtgtgt gacctcgtga ggatcaggcg aatgggcacc gagtgatgac agtctccccg 540 cgttatgatc agtaccaaga cgcttgggac acaagcgtgc aagctgaggt aaaagtggga 600 gataagacgg aaactgtgcg atttttcac tcttataagc gcggggtcga tcgcgtcttt 660 gttgatcatc ctttgttctt agccaaggta tagtatacat cttcgcatta taacgttacc 720 tgcaagattt gagatgaatt gtttgattaa tttacgttac gtgtatgata tcgaaggtat 780 ggggaaaaac tggattcaaa atctatggtc caagagccgg cgaagattat gaagacaacc 840 aacttcggtt tagcctctta gcacaggtca atataacgtg tataagatca tagtatatac 900 atagtttatc ttttatatcc gataggtata agacgggagg gtatgcacta ctaggggtga 960 gcaaaaatat ccgatttgac taatccgaag atccggttcg aaaaaatccg aatccgaaga 1020 tatccgacaa ttggtgatcc gatctgatcc agacatattt ttcggatcag atatggatcg 1080 gggtgtggag aaaaaagtga gatcggatcg gatagatccg actagtctaa gaataaatac 1140 ccggatcgga tcttcggatc agatatctgt ccggataaaa ctgcggata tccgcatcct 1200 ctcggaacgg atagattcga ctattctaag aataaatacc cggatcggat cggatcaaat 1260 ctttggatcg gatatatgtc aggataaaac tgtcagatat ccgggttctc tcggatcaga 1320 ttcgaatcgg acttttctaa gattgtcgga tcggatatcc ggaaatgccc atccctatgc 1380 actaggcacc caagactttc gggttccaga gtagtagcac taagacttat tggttcacgt 1440 gttatcatat tgtcgatgtg aaacatttc acactcaaca ctcccctcaa gtgcaaatat 1500 catggctgac acttgaccca aaaccttaag gccggcttag tcaaacggac tggataacat 1560 atttcgcta atcacagccc aaacccgtga tcgactcctc attatcatgt taatttattt 1620 tttatactgg gatgagacat tttcacattt ggacaataac tataatatta catgttttta 1680 tatatggttg tgttgcatgg atttcaggca gctttggaag caccaaggat tcttaatctc 1740 agcaacaagt tctttcagg accttatggt ttgtgcatat gatttaagta ttgtacttat 1800 gattgttttg ttctactaat actaatcata tgcatatatg tacgttggtg agatgttgt 1860 atttatcgcc aatgattgc acactgcact gctgccatgc tacctgaaaa ccatgtacaa 1920 atcgagagga atacaca atgcaaggt ataccaatct ttcatatcta ctgtcactct 1980 tcctcttaat atctaggtta ttaagatgct ttgttgtgat tctaggtggc gttttgcatt 2040 cacaatactct cttaccaagg acgatttgcc cgatctgact acaatctct caatttgccc 2100 gagaattac ttagatcttt caatttca gacgggtatt ctattctaaa attackattac 2160 aaagtaat gttgctgaat tcatgatat tacataatt aacaggtag atacgccggt 2220 ggaagggcct aagatcact ggatgcaagc aggaatactc gatccgaca aggttgtgac 2280 tgtgagcccg tattatgcgg agagctgat tcgggtgca gaagaggag tcgagttaga 2340 cactgtgatt cgatcaccg gattacagg gatcttgaat ggcatggaca aacaagagtg 2400 gatccttta actgataac acatcactta tcaatgat gttcaatg taatgcataa 2460 gtcgtcttta attaaaaca tatgcttaat aaaagtgt tgaaatactg aaatctaa 2520 cacttatttt gtgattttag gtgatggagg caaggcttt gaacaggaa gccttgcaag 2580 ctgaggtggg attgcctgtt gataggaaca tacctcttat aggattcatt ggaaggctag 2640 aggagcaaaa gggttcggat attctcgtcg aatcaattcc tcaatgcatc aatgagaacg 2700 tccagcttct tgttttggta agcttaatga attgaaactt gtttgatcta ataagggtca 2760 atctctttgc tgctattaaa aaaaaaacat gttgtggcct ataaagggaa ccggaaagaa 2820 gaaattcgag aaagaaatcg aagaactcga aaatctgtat ccaaacaagg ttagaggagt 2880 gaccaagttt aacccagcccc tagctcacaa gatcattgca ggggctgatt tcatgctcat 2940 accaagccga ttcgagccat gcgggcttat ccaactacat gccatgcttt atggaacggt 3000 acgacgttat agaacaagtc tatcatataa ggttggtggg ttatttcacg gattctaatt 3060 ttgcatcaca atttgtgtg gttcctatgt gtgcctcaac tggaggactt gttgactgcg 3120 tcaaagaagg cattacagga ttccacatgg gccgattcgg agcccaggta tatagtata 3180 aattgaattt gcttatgtta aataatttg tgagtatttt agttggtgac tgaacaaagt 3240 cttgatttgt aacagtgcaa agctgtagat gcggctgatg ttgcagctgt gacatcgact 3300 gtgaggaggg cagttgcagt gcatggtaca cctgctatga gagacatgat tctcaattgc 3360 atgtatcaag acctttcatg gaaggcaagt cctattgaat ttcccttttc gtttcggttt 3420 tgacctgaac taacttcgaa acgtacttgc atgaatgtaa acaatgaata tacaggagcc 3480 tgcaaggaaa tgggaagaga tgctacttgg aatgcaggtg gctgggagcg ggcctgggat 3540 caagggcgaa gaaattgcgc cgttagctgc ggaaaacatc gccactccat aatcaggagg 3600 gttcatgtac ctgcagaaca gtataaggtg tatgactgta tgtcattact agcatgacct 3660 tatatatctt gtcaatgcta ctatattgtg aaccgaatat ggatctatct tccatatctg 3720 ttgcatgaat aaagttcaca tctttgtttg tcaagtatct attttgttca acaacagt 3778 SEQ ID NO: 2: Common buckwheat GBSSa (same as the sequence described in SEQ ID NO: 8 of JP 2022-44024) MTSLTITSSL PAVSTVAGAT SSSKAMFLQN SLKSTAGLRP FNDVDMLKCR ANSNNAPSKL 60 PTMEPKRSAN NSVESRVIRC GMNLVFVGAE VAPWSKTGGL GDVLAGLPPA MAANGHRVMT 120 VSPRYDQYQD AWDTSVQAEV KVGDKTETVR FFHSYKRGVD RVFVDHPLFL AKVWGKTGFK 180 IYGPRAGEDY EDNQLRFSLL AQAALEAPRI LNLSNKFFSG PYGEDVVFIA NDWHTALLPC 240 YLKTMYKSRG IYNNAKVAFC IHNISYQGRF ARSDYNSLNL PEELLRSFKF QDGYDTPVEG 300 PKINWMQAGI LESDKVVTVS PYYAEELISG AERGVELDTV IRSTGITGIL NGMDKQEWNP 360 LTDKHITYQY DVSNVMEAKA LNKEALQAEV GLPVDRNIPL IGFIGRLEEQ KGSDILVESI 420 PQCINENVQL LVLGTGKKKF EKEIEELENL YPNKVRGVTK FNPALAHKII AGADFMLIPS 480 RFEPCGLIQL HAMLYGTVPM CASTGGLVDC VKEGITGFHM GRFGAQCKAV DAADVAAVTS 540 TVRRAVAVHG TPAMRDMILN CMYQDLSWKE PARKWEEMLL GMQVAGSGPG IKGEEIAPLA 600 AENIATP 607 SEQ ID NO: 3: Common buckwheat GBSSb (same as the sequence described in SEQ ID NO: 9 of JP 2022-44024) MASLNTAVCM ASSGGTTTGS DASKVVSLQN GLRNHTGLRP LNRVDMLKWR ANTSKLPRME 60 EKRVVTSPSF KKGVIQCGMN LVFVSAEVAP WSKTGGLGDV LAGLPPAMAA NGHRVMTISP 120 RYDQYQDAWD TSVEAEVKVG DKTETVRFFH SYKRGVDRVF VDHPLFLAKV WGKTGFQIYG 180 PRAGEDYEDN QLRFSVLSQA ALEAPRILNL NNKFFSGPYG EDVLFVANDW HSALLPCYLK 240 SMYKSRGIYK NAKVAFCIHN ISYQGRFAPT DFKALNLPNE FLKSFEFFDG YDTPITGDKI 300 NWMQAGILES DKVVTVSPYY AEELVSGAER GVELEKIIRK TGVIGILNGM DKQEWNPSSD 360 KFINYKYDVS TVMEAKPLIK ESLQAELGLP VDRNIPLIGF IGRLEEQKGS DILVESIPEF 420 INENVQIVIL GTGKKRFEKQ IEDLEALYPD KARGVAAFNP SMAHKINAGV DFMLIPSRFE 480 PCGLTQLHAM LYGTIPICAS TGGLVDCVKE GITGFQMGKF SAECKAVDPT DVAAVTRTVR 540 KAVGLHGTPA MREMILNCMY QDLTWKEPAK KWEEMLLGLQ VAGSGPGIEG EEIAPLAVEN 600 VAAP 604 SEQ ID NO: 4: Tartary buckwheat GBSSa (same as the sequence described in SEQ ID NO: 10 of JP 2022-44024) MTSLTITSSL PAVSTVAGAT SSSKAMFLQN SLKSTAGLRP FNDVDMLKCG ANSNNAPSKL 60 PTMEPKRSAN NSAQPGVIRC GMNLVFVGAE VAPWSKTGGL GDVLAGLPPA MAANGHRVMT 120 ISPRYDQYQD AWDTSVQAEV KVGDKTETVR FFHSYKRGVD RIFVDHPLFL AKVWGKTGFK 180 IYGPRAGEDY EDNQLRFSLL AQAALEAPRI LNLSNKFFSG PYGEDVVFIA NDWHTALLPC 240 YLKTMYKSRG IYNNAKVAFC IHNISYQGRF AQSDFISLNL PEELLRSFEF QDGYDTPVEG 300 PKINWMQAGI LESDKVVTVS PYYAEELISG AERGVELDKV IGSTGITGIL NGMDKQEWNP 360 LTDKHITYQY DVSNVMEAKA LNKEALQAEV GLPVDRNIPL IGFIGRLEEQ KGSDILVESI 420 PQCINENVQF LVLGTGKKKF EKEIEELENL YPNKIRGVTK FNPALAHKII AGADFMLIPS 480 RFEPCGLIQL HAMLYGTVPM CASTGGLVDC VKEGITGFHM GRFGAQCKAV DPADVAAVTS 540 TVRRAVAVHG TPAMRDMILN CMYQDLSWKE PAKKWEEMLL GMQVAGSGSG FKGEEIAPLA 600 AENIATP 607 SEQ ID NO: 5: Tartary buckwheat GBSSb (same as the sequence described in SEQ ID NO: 11 of JP 2022-44024) MASLNTAVCM ASSGGTTTGS DASKVVLLQN GLRNHTGLRP LNRVDMLKWR ANTSKLPRME 60 EKRVVTSPSF KKGVIQCGMN LVFVSAEVAP WSKTGGLGDV LAGLPPAMAA NGHRVMTISP 120 RYDQYQDAWD TSVEAEVKVG DKTETVRFFH SYKRGVDRVF VDHPLFLAKV WGKTGFQIYG 180 PRAGEDYEDN QLRFSVLSQA ALEAPRILNL SNKFFSGPYG EDVLFVANDW HSALLPCYLK 240 SMYKSRGIYK NAKVAFCIHN ISYQGRFAPT DFGALNLPNE FLKSFEFFDG YDTPITGDKI 300 NWMQAGILES DKVVTVSPYY AEELVSGAER GVELEKIIRK TGVIGILNGM DKQEWDPSSD 360 KFINYKYDVS TVMEAKPLIK ESLQAELGLP VDRNIPLIGF IGRLEEQKGS DILVESIPEF 420 INENVQIVIL GTGKKRFEKQ IEELEALYPN KARGVAAFNP SMAHKINAGV DFMLIPSRFE 480 PCGLTQLHAM LYGTIPICAS TGGLVDCVKE GITGFHMGKF NAECKAVDPA DVAAVTSTVR 540 KAVTLHGTPA MREMILNCMY QDLTWKEPAK KWEEMLLGLQ VVGSGPGIEG EEIAPLAMEN 600 VAAP 604 SEQ ID NO: 6: Perennial buckwheat GBSSa (same as the sequence described in SEQ ID NO: 12 of JP 2022-44024) MTSLTITSSL PAVSTAGGAT SSSKAMFLQN SLKSTAGLRP LNDVDMLKCR ANSNNAPSKL 60 PTMEVKRSAN NYAEPGVIRC GMNLVFVGAE VAPWSKTGGL GDVLAGLPPA MAANGHRVMT 120 ISPRYDQYQD AWDTSVQAEV KVGDKTETVR FFHSYKRGVD RIFVDHPLFL AKVWGKTGFK 180 IYGPRAGEDY EDNQLRFSLL AQAALEAPRI LNLSNKFFSG PYGEDVVFIA NDWHTALLPC 240 YLKTMYKSRG IYNNAKVAFC IHNISYQGRF AQSDFISLNL PEELLRSFEF QDGYDTPVEG 300 PKINWMQAGI LESDKVVTVS PYYAEELISG AERGVELDKV IRSTGITGIL NGMDKQEWNP 360 LTDKHITYQY DVSNVMEAKA LNKEALQAEV GLPVDRNIPL IGFIGRLEEQ KGSDILVESI 420 PQCINENVQF LVLGTGKKKF EKEIEELENL YPNKIRGVTK FNPALAHKII AGADFMLIPS 480 RFEPCGLIQL HAMLYGTVPM CASTGGLVDC VKEGITGFHM GRFGAQCKAV DPADVAAVTS 540 TVRRAVAVHG TPAMRDMILN CMYQDLSWKE PARKWEEMLL GMQVAGSGPG FKGEEIAPLA 600 AENIPTP 607 SEQ ID NO: 7: Perennial buckwheat GBSSb (same as the sequence described in SEQ ID NO: 13 of JP 2022-44024) MASLNTAVCM ASSGGTTTGS DASKVVSLQN GLRNHTGLRP LNRVDMLKWR ANTSKLPRME 60 EKRVVTSPSF KKGVIQCGMN LVFVSAEVAP WSKTGGLGDV LAGLPPAMAA NGHRVMTISP 120 RYDQYQDAWD TSVEAEVKVG DKTETVRFFH SYKRGVDRVF VDHPLFLAKV WGKTGFQIYG 180 PRAGEDYEDN QLRFSVLSQA ALEAPRILNL NNKFFSGPYG EDVLFVANDW HSALLPCYLK 240 SMYKSRGIYK NAKVAFCIHN ISYQGRFAPT DFKALNLPNE FLKSFEFFDG YDTPITGDKI 300 NWMQAGILES DKVVTVSPYY AEELVSGAER GVELEKIIRK TGVIGILNGM DKQEWDPSSD 360 KFINYKYDVS TVMEAKPLIK ESLQAELGLP VDRNIPLIGF IGRLEEQKGS DILVESIPEF 420 INENVQIVIL GTGKKRFEKQ IEELEALYPD KARGVAAFNP SMAHKINAGV DFMLIPSRFE 480 PCGLTQLHAM LYGTVPICAS TGGLVDCVKE GVTGFHMGKF SAECKAVDPT DVAAVTSTVR 540 KAVALHGTPA MQEMILNCMY QDLTWKEPAK KWEEMLLGLQ VAGSGPGIEG EEIAPLAVEN 600 VAAP 604

Claims

1. A method for producing a buckwheat-containing food product, comprising using, as a raw material, buckwheat flour milled from a plant of the genus Fagopyrum having an amylose content of less than 20.0% by mass.

2. A method for producing a processed buckwheat food, using buckwheat grains obtained from a buckwheat plant having an amylose content of less than 20.0 mass% as a raw material.

3. A method for improving the physical properties of a buckwheat-containing food, characterized in that buckwheat flour obtained from a buckwheat plant having an amylose content of less than 20.0% by mass is used as a raw material, and when the food is refrigerated for 72 hours after production and the maximum load is measured when the food is compressed to 50% of its thickness, the increase in the physical properties of the food compared to the maximum load measured immediately after production is 100% or less.

4. 4. The method for improving physical properties according to claim 3, wherein the buckwheat-containing food is boiled noodles or boiled noodles stored in a refrigerator.

5. The food contains 50% by mass or more of buckwheat flour milled from a plant of the genus Fagopyrum having an amylose content of less than 20.0% by mass, and the maximum load when the food is compressed to 50% of its thickness is 6.0 N or less.

6. A food product containing 50% by mass or more of buckwheat flour milled from a buckwheat plant having an amylose content of less than 20.0% by mass, wherein when the food product is refrigerated for 72 hours after production and the maximum load is measured when the food product is compressed to 50% of its thickness, the increase in the maximum load measured immediately after production is 100% or less.

7. 3. Bread, confectionery, or rice cake, characterized by a chewy texture, produced by the method according to claim 1 or 2.

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