JP5187739B2 - Rice flour composition suitable for bread production and use thereof - Google Patents

Description

  The present invention relates to a rice flour composition suitable for the manufacture of breads, a food using the rice flour composition as a main ingredient, and a method for producing the same. More specifically, the present invention relates to a rice flour composition obtained by improving the rice flour produced from improved rice containing more glutelin precursor in the endosperm compared to the wild type alone or mixed with wheat flour, and the rice flour composition described above. The present invention relates to breads made mainly of foods and a method for producing the same.

  So far, flour has been used as the main ingredient of breads such as bread and chopped bread. The reason for using flour is due to the viscoelasticity of gluten in bread dough obtained by adding water to the flour and mixing it. Gluten's viscoelasticity is caused by the formation of a new disulfide-bonded cross-linked structure under the water conditions of two proteins, gliadin and glutenin. Due to the viscoelasticity of gluten, a skeleton that encloses large bubbles and a unique texture are formed in spite of thinning of the bread dough wall due to carbon dioxide bubbles generated during the fermentation process using yeast. The structure is kept without being crushed.

  In Asian countries including Japan, rice has traditionally been used as a staple food. However, in Japan, the amount of rice consumed has been decreasing year by year, and as a countermeasure, it has been attempted not only to make rice a grain meal but also to consume it as a powdered meal. Such expanded use and increased consumption of rice are attracting attention as a way to solve the problem of food shortages expected in the future.

As one attempt to consume rice as a flour meal, research on rice flour bread made mainly from rice flour obtained by pulverizing rice has been accumulated. For example, rice flour bread manufactured by adding gluten or non-fermentable sugar (Patent Document 1), rice flour bread manufactured by adding pregelatinized rice flour or pregelatinized starch (Patent Document 2), and reducing the viscosity Rice flour bread (Patent Document 3) and the like produced using fresh bread dough have been developed so far.
JP 2004-65250 A JP 2005-323536 A JP 2003-189786 A

  However, even the above-mentioned rice flour bread has not yet solved the fundamental problem caused by the property of rice flour that does not contain a gluten component unlike wheat flour. In particular, when bread is produced using rice flour instead of wheat flour as a raw material for bread, in the kneading process in which the raw materials are kneaded, the kneaded bread dough easily sticks to utensils and the workability is very poor. However, although bread dough swells to some extent by fermentation, the swelled structure cannot be maintained, and there is a problem that it dents over time. Furthermore, all the rice flours so far are obtained by using grain edible rice varieties for flour edible, and little consideration is given to the suitability of rice varieties as rice flour.

  Therefore, this invention made it the subject which should be solved to eliminate the problem of the above-mentioned prior art. That is, the present invention should solve the problem of providing a rice flour composition, which is a raw material for bread made from rice varieties suitable for flour meal, having good workability in the manufacturing process, and excellent extensibility and plasticity. It was an issue. Furthermore, this invention made it the subject which should be solved to provide the manufacturing method of bread | pans with good working efficiency using rice flour as a raw material, and bread | pans which have the quality equivalent to or higher than wheat flour.

  In order to solve the above-mentioned problems, the present inventors diligently studied a protein corresponding to a gluten component of wheat flour in rice flour. As a result, it was found that a glutelin precursor that accumulates in the endosperm as such a protein can be used. Furthermore, the present inventors have found that improved rice containing a relatively large amount of glutelin precursor in endosperm and having a protein disulfide isomerase (PDI) deletion mutation is a rice variety suitable for flour meal, By using the produced rice flour as a raw material for breads, we succeeded in obtaining breads with good workability in the kneading process and excellent extensibility and plasticity. Surprisingly, the breads thus obtained were rice flour breads with excellent texture and no change over time.

  That is, according to this invention, the rice flour composition for bread | pans containing rice flour produced from the improved rice which contains more glutelin precursors in endosperm compared with a wild type is provided.

  Preferably, the rice flour composition of the present invention is 1 to 150 parts by weight of wheat flour, more preferably 30 parts by weight of rice flour produced from improved rice containing more glutelin precursor in the endosperm than the wild type. Contains 30-70 parts by weight of flour.

  Preferably, in the rice flour composition of the present invention, the improved rice is an improved rice having a protein disulfide isomerase-deficient mutation.

  Preferably, in the rice flour composition of the present invention, the protein disulfide isomerase is PDIL1-1 described in SEQ ID NO: 1.

Preferably, in the rice flour composition of the present invention, the improved rice having the PDIL1-1 deletion mutation is esp2 ( Accession No. FERM P-21508 ).

  Preferably, in the rice flour composition of the present invention, the wheat flour is a strong flour.

  Furthermore, according to another aspect of the present invention, there is provided a method for producing breads, a kneading step of adding water and yeast to the rice flour composition of the present invention and kneading, fermentation for fermenting bread dough obtained by the kneading step The said manufacturing method including the cooking process which shape | molds and cooks the fermentation dough obtained by the process and the said fermentation process is provided.

  Further, according to another aspect of the present invention, there is provided bread characterized by using at least the rice flour composition of the present invention as a main raw material when producing bread.

  Preferably, the breads of the present invention are bread, coppe bread, butter roll, fried bread, sweet bread, French bread, German bread, bagels, Danish bread, Chinese bun, East donut, pretzel, pizza or naan.

  According to the rice flour composition of the present invention, it is possible to provide a raw material for producing a rice flour bread having high mechanical suitability with reduced adhesive strength as compared with conventional rice flour bread raw materials. Furthermore, according to the rice flour composition of the present invention, it is possible to provide a raw material for producing rice flour bread in the same equipment and process as a bread production line using wheat flour as a raw material.

  According to the production method of the present invention, by using the rice flour composition of the present invention as a raw material, the texture is excellent, and the appearance, inner phase, and flavor are equal to or better than conventional rice flour bread and bread made from wheat flour. , And breads with excellent shelf life can be produced.

  The breads of the present invention can expand distribution channels by having the properties described above, contribute to the expansion of rice use and consumption, and can help solve the food problems that are expected to be faced in the future. .

Hereinafter, embodiments of the present invention will be described in detail.
The rice flour composition of the present invention is a rice flour composition for breads containing rice flour produced from improved rice containing more glutelin precursors in the endosperm than in the wild type.

The “glutelin precursor” as used herein is a precursor of glutelin having a molecular weight of 57 kDa, which can be confirmed by the following method:
The total protein obtained by finely pulverizing the mature rice seeds was extracted with a buffer (50 mM Tris-HCl, pH 6.8, 8 Murea, 4% SDS, 20% glycerol, 5% β-mercaptoethanol). When the protein is separated by PAGE and stained with Coomassie Brilliant Blue (CBB), the protein in the band at 57 kDa is the glutelin precursor.

  As used herein, “improved rice” refers to rice obtained by improving rice using wild-type rice as seeds. The method for improving rice is not particularly limited as long as rice can be improved. For example, artificial selection, hybridization, mutation, gene recombination and the like can be mentioned. Among them, the method of inducing mutation in rice is preferable. The wild-type rice is not particularly limited as long as it is not improved so as to contain more glutelin precursors in the endosperm. For example, NIAS Genebank (http: //www.gene.affrc.go. jp / index_j.php) and rice obtained from grasses registered in the Ministry of Agriculture, Forestry and Fisheries.

As used herein, "improved rice containing more glutelin precursor in endosperm compared to wild type" means that the amount of glutelin precursor present in the endosperm of wild type rice is improved as described above. It means improved rice containing a larger amount of glutelin precursor in the endosperm. Here, “containing more” is not particularly limited as long as it contains a little more than the wild type, but for example, more than twice, preferably more than 3 times, more preferably more than the wild type. It means to contain more than 5 times. Further, the upper limit is not particularly limited, and may be 10 times, 100 times, 1000 times, or 10000 times. The comparison of the content of glutelin precursor in the endosperm between such wild-type rice and improved rice can be performed, for example, according to the following scheme.

  1 ripe brown rice of wild-type rice and 1 ripe brown rice of improved rice improved from wild-type rice are placed in a 2 ml tube and ground finely with metal corn. Add 0.7 ml of SDS solution (50 mM Tris-HCl, pH 6.8, 0.5% (w / v) SDS) and stir at room temperature for about 2 hours. Remove the metal cone from the tube and stir for an additional hour. Centrifuge (13,000 × g, 10 minutes, room temperature), add 1 ml of the SDS solution to the pellet, and stir until there are no large lumps. Centrifuge (13,000 xg, 10 minutes, room temperature) and discard the supernatant. Repeat this operation once more. Next, 0.7 ml of urea / SDS / DTT solution (50 mM Tris-HCl, pH 6.8, 4 Murea, 2% (w / v) SDS, 50 mM DTT) is added to the pellet and stirred for 1 hour. Centrifugation (13,000 × g, 10 minutes, room temperature) and the supernatant is converted to urea / SDS / DTT soluble protein (U). About 100 μl each of gel loading buffer (75 mM Tris-HCl, pH 6.8, 4% (w / v)) for wild-type rice U (hereinafter referred to as WU) and modified rice U (hereinafter referred to as IU) Add SDS, 20% (v / v) glycerol, 10% (v / v) 2-mercaptoethanol, 0.01% (w / v) bromophenol blue), mix, and heat at 85 degrees for 3 minutes. 6 μl of each sample of WU and IU is applied to an SDS-PAGE gel, stained with CBB after electrophoresis. Compare the amount of glutelin precursor (57 kDa) between WU and IU with an image analyzer. Rice with more IU glutelin precursor than WU has more glutelin precursor in endosperm than wild type Including improved rice. For example, when the improved rice is an improved rice having a protein disulfide isomerase-deficient mutation, the amount of glutelin precursor contained in the endosperm of the improved rice is 5 times or more compared to the wild type.

  As a specific example of the improved rice production method, a method of inducing mutation in rice using wild-type rice as a seed can be mentioned. Methods for inducing mutations in rice are not particularly limited. For example, chemical mutagen treatment or irradiation treatment such as N-methyl-N-nitrosourea on fertilized eggs of rice, virus treatment, Infection, transposon transfer, spontaneous mutation, etc.

A specific example of the improved rice resulting from the mutation is an improved rice in which a protein disulfide isomerase (PDI) deletion mutation, which is an enzyme that catalyzes the formation of disulfide bonds (hereinafter referred to as “PDI deletion mutant rice”). There are various family proteins as shown in Table 1 (Houston, NL et al., (2005), Plant Physiology, 137, 762-778) in the PDI family. Rice having at least a part of the base sequence encoding PDIL1-1 (Accession No. of cDNA; AK068268) described in 3 is preferred. Examples of the base sequence of the PDIL1-1 gene can include the base sequence described in SEQ ID NO: 1 in the sequence listing, and the coding region thereof can include the base sequence described in SEQ ID NO: 2. These sequences can also be obtained using the Internet (http://cdna01.dna.affrc.go.jp/cDNA/report/KOME_J013147I21.html).

  The method for producing a PDI-deficient mutant rice is not particularly limited as long as it can produce an improved rice substantially deficient in the expression of the PDI gene or the function of the PDI protein. , Disruption of the PDI gene by introducing DNA fragments, suppression of PDI gene expression by the RNAi method, and the like. Examples of the method for confirming that the rice is a PDI-deficient mutant include, for example, a method for confirming the glutelin precursor in the endosperm as described above, a method for confirming the presence or absence of amplification of the PDI gene region by the PCR method, and a DNA sequence in the region. There are methods for confirming PDI protein by immunofluorescence methods such as blotting and ELISA.

Specific examples of PDI-deficient mutant rice include, for example, Kumamaru T et al., (1987), Jpn J Genet, 62, 333-339 and Kumamaru et al., (1988), Theor Appl Genet 76, 11-16. Name esp2 (Takemoto et al. (2002) Plant Phys. 128, 1212-1222;), which is a gold-minus-style PDI-deficient mutant rice obtained by N-methyl-N-nitrosourea fertilized egg treatment Can do. This esp2 is, accession number FERM P to the National Institute of Advanced Industrial Science and Technology, International Patent Organism Depositary (Yubinbango305-8566 center Higashi, Tsukuba, Ibaraki, 1-1-1 Tsukuba Center 6) of the Institute on February 14, 2008 -21508 . The taxonomic position of esp2 is Oryza sativa L, which is cultivated rice. The esp2 seed can be stored, for example, at −10 ° C. and a humidity of 30%. The germination test of esp2 can be performed under conditions of 25 ° C., 0 to 1000 lux, and 2 weeks, after immersing the seeds with a disinfectant for paddy rice such as benrate. The germination rate under the above conditions is about 80%. Other features of esp2 are shown below using FIGS.

  FIG. 1 shows that ripened seeds of wild type (Ginnan style) and esp2 are pulverized, and the total protein is buffered (50 mM Tris HCl, pH 6.8, 8 Murea, 4% SDS, 20% glycerol, 5% β- The results of protein separation by SDS-PAGE after extraction with mercaptoethanol) and staining with CBB are shown. In addition, the said buffer solution was added to commercially available wheat strong flour, wheat thin flour, and upper fresh flour, and the whole protein extracted similarly was made into control. As is apparent from FIG. 1, esp2 has a 5-fold accumulation of glutelin precursor in the endosperm compared to the wild-type Kinnan style, and the protein composition is also wild-type and superfine powder. And different. Furthermore, the protein composition of esp2 is different from that of wheat flour and flour.

  FIG. 2 shows the results of staining an endosperm section of a mature seed of wild type (Ginnan style) and esp2 with the fluorescent reagent rhodamine and observing with a confocal laser microscope. In the left panel of FIG. 2 (wild type, WT), spherical and highly fluorescent protein granules (PB-I) and large and irregularly shaped protein granules (PB-II) are clearly separated and shown. Yes. On the other hand, the right panel (esp2 mutant) shows that the development of PB-II is inhibited and small granules are developed to fill the whole cell. These results indicate that the accumulation state of the storage protein is greatly different from the wild type in the endosperm cells of esp2. FIG. 1 and FIG. 2 reveal that esp2 is significantly different from the wild type in the composition of the storage protein and the accumulation state in the cell.

  The cultivated species of wild-type rice is not particularly limited as long as it is a plant belonging to the genus Gramineae, and for example, japonica species, indica species, javanica species, graverima species and the like can be used. Furthermore, the wild type rice may be either sticky rice or sticky rice.

  The “rice flour produced from improved rice” in the present specification is not particularly limited as long as the raw rice of the improved rice is pulverized and powdered. Moreover, there is no restriction | limiting in particular also about the raw rice before grinding | pulverization, You may use any raw rices, such as polished rice, brown rice, waste rice, and old rice.

  The grain size of the rice flour is not particularly limited as long as the surface of the bread dough obtained by the kneading process is not roughened, but usually has an average particle size of 1 to 100 μm, preferably 1 to 75 μm, more preferably 1 to 45 μm.

  The rice flour composition of the present invention is, for example, breads containing 1 to 150 parts by weight of wheat flour with respect to 30 parts by weight of rice flour produced from improved rice containing more glutelin precursor in the endosperm than in the wild type. It can be a rice flour composition.

  The “wheat flour” referred to in the present specification is not particularly limited as long as it is a wheat flour containing a gluten component, and examples thereof include strong flour, medium flour, thin flour, whole wheat flour, and strong flour is preferable.

  The ratio of flour is 1-150 mass parts with respect to 30 mass parts of rice flour. However, 30 to 70 parts by weight of wheat flour is preferable to 30 parts by weight of rice flour if the workability of the kneading process in bread production and the extensibility and plasticity of bread are to be increased. If the workability, extensibility and plasticity are further increased, 50 to 70 parts by weight of flour is more preferable with respect to 30 parts by weight of rice flour, and 60 to 70 parts by weight of flour is optimally preferable with respect to 30 parts by weight of rice flour. .

  In addition to rice flour and wheat flour, necessary components can be added to the rice flour composition of the present invention depending on the type of bread. Examples of such components include gluten such as active gluten; sugars such as sucrose, glucose, fructose, lactose, sugar, maltose, isomaltose, and trehalose; sugar alcohols such as sorbitol, maltitol, paratinite, and hydrogenated syrup Salt such as refined salt, sun salt and crude salt with 99% or more of sodium chloride; gums such as alginic acid, xanthan gum, dextrin and cellulose; milk components such as powdered milk, skim milk powder and soy milk powder; egg yolk, egg white, whole egg, etc. Egg components: Fats and oils such as butter, margarine, shortening, lard, olive oil; ammonium chloride, magnesium chloride, ammonium carbonate, ammonium bicarbonate, sodium bicarbonate, potassium carbonate, calcium carbonate, ammonium sulfate, calcium sulfate, magnesium sulfate, phosphorus Inorganic salts such as tricalcium, diammonium hydrogen phosphate, ammonium dihydrogen phosphate, calcium monohydrogen phosphate, calcium dihydrogen phosphate, calcined calcium, ammonium alum; vitamin C (alcorbic acid), vitamin B1, vitamin B2, Vitamins such as vitamin D, vitamin E, and carotene; flour such as rye flour and pigeon flour; plant components such as plant fruits, seeds, and leaves; yeast food; emulsifiers and the like.

  The content of these components in the rice flour composition can be appropriately set according to the type of bread.

  The production method of the present invention is a method for producing breads, a kneading step of adding water and yeast to the rice flour composition of the present invention and kneading, a fermentation step of fermenting bread dough obtained by the kneading step, and the above It includes a cooking process in which the fermented dough obtained by the fermentation process is molded and cooked.

  In the kneading step in the production method of the present invention, in addition to the rice flour composition of the present invention, water and yeast, other raw materials can be added as desired. The water used in the kneading step is not particularly limited, and may be liquid such as milk as well as tap water and distilled water. The yeast is not particularly limited as long as it is a yeast usually used in the manufacture of breads and confectionery, but Saccharomyces cerevisiae baker's yeast is preferable, and either live yeast or dry yeast may be used. As other raw materials, necessary ingredients (for example, sugar, salt, egg ingredients, etc.) are used depending on the type of bread to be added to the above-described rice flour composition.

  Kneading is performed manually or with a commercially available kneader or the like by setting the temperature, humidity, time, etc. according to the type of bread to be produced. As a specific method of kneading, for example, it is carried out at room temperature of 25 to 30 ° C. for 8 to 20 minutes. If necessary, the bread dough obtained in the kneading step can be subjected to a fermentation step after being left for a while under a temperature condition such as 0 to 5 ° C. where the bread dough does not ferment.

  The fermentation process can be performed indoors or in a thermostatic chamber at a temperature of 25 to 35 ° C., preferably 27 to 30 ° C., for 30 to 120 minutes, preferably 40 to 60 minutes. The fermented dough obtained by the fermentation process preferably has a bench time of 15 to 20 minutes.

  In the cooking step, the fermented dough may be formed and then continuously cooked, or stored refrigerated or frozen, and heated and thawed as necessary. The “molding” in the present specification is not particularly limited as long as it can be arbitrarily formed, and may be appropriately divided, and the means may be mechanically performed as well as manual.

  The term “cooking” as used herein refers to cooking by a well-known method such as baking, frying, steaming, microwave heating, or pressure heating after the fermentation dough is formed.

  As the firing method, for example, an oven for heating from the upper surface and / or the lower surface, or a method of heating by directly contacting a preheated furnace surface or the like can be used. As a frying method, for example, a cooking method in which cooking oil is used for heating, a so-called weirding method, a frying method, or the like can be used. As the steaming method, for example, a steamer that generates and heats steam by heating on a flame, or a method of heating steam generated in advance using a boiler can be used. . As a method using a microwave, for example, a method such as heating using a device or apparatus having a function capable of generating and irradiating a microwave can be used. As a pressure heating method, for example, a pressure heating method using a pressure cooker or apparatus that can be heated under high temperature and high pressure conditions can be used.

  The fermented dough can be provided with proof time before being molded and then cooked. In order to obtain a good fermentation state, the proof time is preferably 30 minutes or more, and more preferably 40 to 50 minutes.

  When forming the fermented dough, it can be advantageously carried out by wrapping ingredients such as Ann, curry and various side dishes and finishing them into an bread, curry bread, side dish bread, Chinese buns, and the like.

  The breads of the present invention are breads characterized by using at least the rice flour composition of the present invention as a main raw material when producing breads. The “main raw material” as used herein refers to a raw material that must be included in the manufacture of breads. Therefore, the breads of the present invention are not particularly limited as long as they are breads produced using the rice flour composition of the present invention.

  The breads of the present invention include a wide variety of bread, cupe bread, butter roll, fried bread, sweet bread, French bread, German bread, bagels, Danish bread, Chinese buns, East donuts, pretzel, pizza or naan. If it is manufactured using the rice flour composition of, it will not be limited to these.

  The rice flour bread thus obtained has a long shelf life, can be easily refrigerated or frozen, and can be advantageously carried out by heating, thawing and eating the flavor as needed.

  The following examples further illustrate the present invention, but the present invention is not limited to the examples.

(1) Comparison of proteins contained in gluten A rice flour was prepared by finely pulverizing a rice-grown rice of Kinnan style and Esp2 ( Accession No. FERM P-21508 ) with a laboratory mill 3100 manufactured by Perten. Wheat flour and rice flour (Ginnam-style or esp2) are mixed at a ratio of 7: 3 (left panel) or 1: 1 (right panel), and 0.7x (v / w) distilled water is added and mixed. The formation of a crosslinked structure was promoted, and gluten was formed. The dough was washed with water, and starch particles and proteins that were not incorporated into gluten were removed, and a portion of the remaining gluten was photographed (FIG. 3, upper panel). When the proportion of rice flour was increased from 30% (left panel) to 50% (right panel), the original gluten formation of wheat flour was inhibited, and papasa gluten with weak viscoelasticity was formed. Proteins were extracted from these gluten with a buffer (50 mM Tris HCl pH 6.8, 2% SDS, 100 mM DTT, 10% glycerol), separated by SDS-PAGE and stained with CBB. As a control, a buffer solution was directly added to a flour (mix) obtained by mixing strong flour, rice flour and two, and proteins were extracted and compared. By comparing the protein composition of the mix and gluten, the polypeptide derived from strong flour concentrated in gluten is indicated by arrows. In the polypeptide derived from rice flour, glutelin precursor (proglutelin) and β-glutelin (β-glutelin) are concentrated in gluten. When dough was made by mixing rice flour and wheat flour, it became clear that in addition to wheat-derived protein, rice-derived protein was also incorporated into gluten.

  The above results show that rice flour-derived protein is incorporated into gluten when rice flour and wheat flour are mixed to form gluten. In addition, when esp2 rice flour was used, it was revealed that a large amount of glutelin precursor was incorporated into gluten, unlike the wild type. Next, as shown in Examples 2 and 3, with wild-type (Ginnan style) or esp2 rice flour as the main ingredient, sugar, salt, dry yeast, ascorbic acid, and water are added in appropriate amounts, The dough was prepared by the method described above, and both were compared in a fermentation test. As pointed out in the past, wild-type rice flour dough has strong adhesion to instruments and fingers, and it has been confirmed that workability is poor. On the other hand, it became clear that the fabric of esp2 has weak adhesion to instruments and fingers, it is easy to collect as a fabric, and the workability is remarkably improved.

  Furthermore, when the dough produced as described above was fermented at room temperature (28 ° C.), it became clear that the dough of esp2 swelled larger than the Kinnan style, and that the extensibility of the dough was good. It was. Next, the esp2 fabric was characterized by small dents after swelling. In addition, this feature was maintained after baking in an oven. These results indicate that the dough of esp2 has a high property that the dough swelled by fermentation is maintained in its form (hereinafter referred to as “plasticity”).

(2) Characteristic test of 100% rice flour rice flour bread 50g wild-type (Ginnan style) or esp2 rice flour, 3g sucrose (reagent special grade), 1g sodium chloride (reagent special grade), ascorbic acid (reagent special grade) 10ppm, tap water 35 ml of water was mixed and mixed with a spatula for about 6 minutes until the raw material was evenly dispersed. Next, 1 g of commercially available dry yeast (trade name “Super Camellia Dry Yeast”, sold by Nisshin Foods Co., Ltd.) was dissolved in 5 ml of tap water in advance, and this solution was added to the dough. At this time, the room temperature was about 28 ° C. and the kneading time was 16 minutes. 25 g of dough was weighed (25 g × 3), rounded and shaped, transferred to a 50 ml beaker, covered with parafilm and covered with a 28 ^° C. fermentation test. The dough fermentation process was photographed from right next to the beaker 0.5 hours, 1 hour, 2 hours, and 3 hours after the start of fermentation (FIG. 4). Based on the photographed image, the height at which the fabric swelled was measured and averaged to obtain a graph (FIG. 5). In the wild type (Ginnan style), the height of the dough swells from 1.46 cm to 2.84 cm 30 minutes after the start of fermentation (194%), then withered, and 1.79 cm in height 1 hour after the start of fermentation. The height became 2.49 cm after 3 hours, and the height decreased by about 12% between 30 minutes and 3 hours after the start of fermentation. In contrast, esp2 was 2.98 cm in height 30 minutes after the start of fermentation, swelled to 3.01 cm in height after 1 hour, and swelled 203% compared to 0 hour. The height after 2 hours from the start of fermentation was 2.79 cm, the height after 3 hours was 2.76 cm, and the height decreased by about 8% in 2 hours.

(3) 70% rice flour characteristic test of rice flour bread 35g of rice flour, 15g of commercially available strong flour (Nisshin Foods Co., Ltd., trade name "Nisshin Camellia Strong Wheat Flour"), 3g of sucrose (special grade reagent), sodium chloride ( 1 g of reagent special grade, 10 ppm of ascorbic acid (special grade reagent), and 33 ml of tap water were mixed and mixed in the same manner as in Example 1 for about 5 minutes using a spatula until the raw materials were uniformly dispersed. Next, 1 g of commercially available dry yeast (trade name “Super Camellia Dry Yeast”, sold by Nisshin Foods Co., Ltd.) was dissolved in 5 ml of tap water in advance, and this solution was added to the dough. At this time, the room temperature was about 28 ° C., and the kneading time was 9 minutes. 25 g of dough was weighed (25 g × 3), the beaker was covered with parafilm, and a fermentation test was conducted at 28 ^° C. The dough fermentation process was photographed from right next to the beaker 0.5 hours, 1 hour and 3 hours after the start of fermentation. Due to the addition of strong powder, the dough is easy to bundle, and the dough is not in contact with the wall surface at 0 hours (FIG. 6). Based on the photographed image, the height at which the fabric swelled was measured and averaged to obtain a graph (FIG. 7). When 30% of the strong powder was added, the swelling increased, and in one hour after the start of fermentation, the wild type (Ginnam-style) swelled to 3.42 cm (144%). In esp2, the height swelled to 3.49 cm in 1 hour from the start of fermentation (140%). In Kinnan style, the height dropped to 2.92 cm in 3 hours after the start of fermentation, and it fell about 15% in 2 hours, whereas in esp2, the height of 3 hours after the start of fermentation was 3.44 cm, the same for 2 hours. There was only 1% wilting in between.

(Discussion)
The reasons for the improved extensibility and plasticity of the fabric of esp2 are that a large molecular weight glutelin precursor was incorporated into the gluten-like protein complex, and that the shape and distribution of esp2 protein granules differed greatly from the wild type. In the case where the dough is prepared using esp2 as a main raw material, it is considered that a cross-linked structure between proteins different from the wild type is formed.

  Promoting the use of rice flour, including rice flour bread, leads to an increase in rice consumption. According to the production method of the present invention using the rice flour composition of the present invention, a large amount of rice flour bread having stable quality and high production efficiency can be produced. Furthermore, since the breads of the present invention are rice flour breads having excellent texture and no change with time, it can be expected not only to contribute to the expansion of consumption of rice flour and rice, but also to increase the demand for breads.

FIG. 1 shows the results of SDS-PAGE analysis of the whole protein of Kinnan style wild type and esp2. FIG. 2 shows the results of observing the difference in the distribution of protein granules of Kinnan style wild type (WT) and esp2. FIG. 3 shows the results of SDS-PAGE analysis of the protein contained in gluten after mixing Kimnan style wild type or esp2 and strong flour. FIG. 4 shows the results of a bulge test by yeast fermentation of a golden-style wild-type and esp2 rice flour (100%) dough. FIG. 5 shows a graph of the average value and standard deviation of the bulge test results of FIG. FIG. 6 shows the results of a bulging test by yeast fermentation of the Kimnan style wild-type and esp2 rice flour (70%) dough. FIG. 7 shows a graph of the average value and standard deviation of the bulge test results of FIG.

Claims (8)

Breads containing rice flour made from improved rice containing more glutelin precursor in the endosperm than wild type and containing 30/7 parts by weight of flour to 30 parts by weight of the rice flour A rice flour composition for bread , wherein the improved rice is an improved rice having a protein disulfide isomerase-deficient mutation . The rice flour composition for bread according to claim 1, comprising 30 to 70 parts by mass of wheat flour relative to 30 parts by mass of rice flour produced from improved rice containing more glutelin precursor in the endosperm compared to the wild type. object. The rice flour composition according to claim 1 or 2 , wherein the protein disulfide isomerase is PDIL1-1 described in SEQ ID NO: 1. The PDIL1-1 improved rice deficient mutant has occurred, a ESP2 (consignment number FERM P -21508), rice flour composition of claim 3. The rice flour composition according to any one of claims 1 to 4 , wherein the wheat flour is a strong flour. It is a manufacturing method of breads, Comprising: The kneading process which adds water and yeast to the rice flour composition of Claims 1-5 , kneading, the fermentation process of fermenting the bread dough obtained by the kneading process, and the fermentation process The said manufacturing method including the cooking process which shape | molds and cooks the fermented dough obtained by this. Bread characterized by including the rice flour composition according to any one of claims 1 to 5 as a main ingredient. The bread is bread, hot dog bun, a butter roll, fried bread, sweet buns, French bread, Germany bread, bagels, Danish pastry, Chinese buns, yeast donut, pretzels, pizza or Nan, breads according to claim 7 .