JP6779536B2 - Method for producing rice flour bread that does not contain gluten and thickener - Google Patents

Description

The present invention relates to a method for producing rice flour bread that does not contain gluten and a thickener.

In recent years, the development of rice flour bread has been encouraged for the purpose of increasing the consumption of rice flour. On the other hand, gluten (wheat gluten) contained in wheat flour bread is known to cause wheat allergy and celiac disease symptoms, so rice flour bread using rice flour as a substitute for wheat flour is a food for those patients. Is also attracting attention.

Gluten is an important ingredient in the production of plump bread. In the production of general wheat flour bread, by adding water to the flour and kneading it, the proteins gliadin and glutenin contained in the flour produce "gluten", which is rich in stickiness and elasticity, and this is the stretchability and elasticity of the bread dough. It is known that the flour bread after fermentation and baking has good swelling and softness by enhancing the properties.

However, in bread dough that uses only rice flour that does not contain gliadin or glutenin as the main ingredient, gluten is not produced even if the dough is mixed. Therefore, in general, it is said that bread using 100% rice flour as grain flour does not swell sufficiently by the same bread manufacturing method as wheat flour bread. Therefore, most of the commercially available rice flour breads and the commercially available rice flours for producing rice flour breads contain wheat flour and gluten. However, such products contain relatively high amounts of wheat gluten and are not available to patients with wheat allergies or celiac disease.

The development of technology for producing gluten-free rice flour bread is also underway. For example, a bread making method using plastic foam molding technology (Patent Document 1), a method using a dough containing pregelatinized rice flour and pregelatinized starch (Patent Documents 2 and 3 etc.), and a method of adding a thickener (Patent Document 1). Document 4 etc.), etc. However, the rice flour bread produced by these methods has a problem that the quality is significantly inferior to that of wheat flour bread and rice flour bread produced by adding gluten in terms of softness and softness.

The present inventor has developed a method for producing fine-grained rice flour bread with good swelling by blending glutathione with rice flour (Patent Document 5). Further, a method for producing rice flour bread using rice flour and sorghum flour has also been developed (Patent Document 6). However, there is still a need for the development of a method capable of producing rice flour bread containing no gluten or thickener by a simpler method without using special auxiliary materials such as glutathione and sorghum flour.

Japanese Unexamined Patent Publication No. 2003-189786 Japanese Unexamined Patent Publication No. 2006-174822 JP-A-2007-215401 Japanese Unexamined Patent Publication No. 2005-245409 International release WO2011 / 033994 Japanese Unexamined Patent Publication No. 2015-107081

An object of the present invention is to provide a simple method for producing rice flour bread having good swelling, which does not contain gluten and a thickener.

As a result of diligent studies to solve the above problems, the present inventor has found that rice flour having a predetermined property can be used to produce rice flour bread having good swelling without using gluten or a thickener. We have found and completed the present invention.

That is, the present invention includes the following.
[1] Rice flour bread containing rice flour, water and yeast showing a damaged starch rate of 5% or less and a water absorption rate of 80% or less, and containing no gluten or thickener, and fermenting and baking. Manufacturing method.
[2] The method according to the above [1], wherein the damaged starch ratio of rice flour is 3% or more and the water absorption rate is 72% or more.
[3] The method according to the above [1] or [2], wherein the bread dough further contains one or more selected from sugar, salt, and fat.
[4] The method according to any one of [1] to [3] above, wherein the bread dough is fermented until the specific volume becomes 4 mL / g or more.
[5] The method according to any one of [1] to [4] above, which comprises a step of preparing the bread dough.
[6] A bread dough containing rice flour, water and yeast showing a damaged starch rate of 5% or less and a water absorption rate of 80% or less, and containing no gluten or thickener.
[7] The bread dough according to the above [6], wherein the damaged starch ratio of rice flour is 3% or more and the water absorption rate is 72% or more.
[8] The bread dough according to the above [6] or [7], further comprising one or more selected from sugar, salt, and fat.
[9] The bread dough according to any one of the above [6] to [8], which has been fermented.
[10] The bread dough according to the above [9], which has a specific volume of 4 mL / g or more.
[11] A rice flour bread containing no gluten and a thickener, produced by using the bread dough according to any one of the above [6] to [10].

According to the present invention, it is possible to easily produce a rice flour bread having good swelling that does not contain gluten and a thickener.

FIG. 1 is a photograph showing a cross-sectional state of rice flour bread produced using rice flour of samples 1 to 9. A: Sample 1, B: Sample 2, C: Sample 3, D: Sample 4, E: Sample 5, F: Sample 6, G: Sample 7, H: Sample 8, I: Sample 9. The graph in FIG. 2 shows the relationship between the damaged starch ratio of rice flour and the specific volume of bread produced. The graph of FIG. 3 shows the relationship between the water absorption rate of rice flour and the specific volume of the produced bread. The graph of FIG. 4 shows the relationship between the mode particle size of rice flour and the specific volume of bread produced.

Hereinafter, the present invention will be described in detail.
The present invention relates to a method for producing rice flour bread using rice flour having predetermined properties without using gluten-constituting proteins, grain flour containing the same (wheat flour, etc.), gluten, thickeners and the like.

In the present invention, rice flour is used as the main raw material for bread. Rice flour refers to powder obtained by crushing rice (Oryza sativa) seeds (raw rice). The rice used as a raw material for rice flour is not limited, but glutinous rice is preferable. The glutinous rice may be, for example, japonica rice, indica rice, or Javanica rice, and may be various varieties of rice belonging to them. The rice varieties are not limited to the following, but may be varieties suitable as rice for rice flour, such as Takanari, Mizuhochikara, and Yumefuwari, and have a high amylose content and are moderate. , Or low varieties. The rice flour may also be a mixture of various varieties of rice flour. The rice flour used as a raw material in the present invention does not need to contain pregelatinized rice flour obtained by pregelatinizing (gelatinizing) rice by heating and then drying and powdering it.

In the present invention, rice flour having a damaged starch rate of 5% or less and a water absorption rate of 80% or less is used. In one preferred embodiment, the damaged starch ratio of the rice flour is preferably 3% or more, for example 4% or more. In one preferred embodiment, the water absorption rate is preferably 72% or more, for example 74% or more. In one preferred embodiment, the rice flour has a damaged starch rate of 3% to 5% and a water absorption rate of 72% to 80%, but is not limited to the following.

The damaged starch ratio of rice flour can be measured by a conventional method. In the present invention, in particular, the properties of rice flour can be determined based on the damaged starch ratio determined by using the damaged starch measurement kit Starch Damage Assay Kit (Megazyme) or an equivalent kit or reagent. Specifically, as described in Examples described later, first, 100 mg of rice flour and an amylase solution (50 U / ml) are pre-incubated in separate containers at 40 ° C. for about 5 minutes, and then 1 mL of amylase solution is added to the rice flour. Is added, mixed with a vortex mixer, and reacted at 40 ° C. for 10 minutes. Then, 8 ml of sulfuric acid solution (0.2% v / v) is added, mixed with a vortex mixer to stop the reaction, and centrifuged at 3,000 rpm for 5 minutes. 0.1 ml of the supernatant is collected, 0.1 ml of an amyloglucosidase solution is added and reacted at 40 ° C. for 10 minutes, then 4 ml of a glucose measuring reagent GOPOD (glucose oxidase and peroxidase) solution is added, and the mixture is added at 40 ° C. Allow to react for 20 minutes. Further, the absorbance of the reaction solution is measured at 510 nm. A GOPOD solution is added to a 150 mg / ml glucose standard solution and a buffer solution (blank) to react, and the absorbance is measured to prepare a calibration curve. The damaged starch ratio (%) of rice flour can be determined based on this calibration curve.

The water absorption rate of rice flour can be measured by a conventional method. In the present invention, in particular, the properties of rice flour can be determined based on the water absorption rate measured as described in Examples described later. Specifically, 10 g of rice flour (dried state) is placed in a 50 mL tube, ion-exchanged water is added to a scale of 50 mL, the mixture is left overnight at room temperature, centrifuged at 3000 rpm for 30 minutes, the supernatant is discarded, and water absorption is performed. After that, the weight of the rice flour (the total weight of the rice flour and the water absorbed by the rice flour) is measured. Based on the measured value, the water absorption rate of rice flour can be calculated by the following formula.
Water absorption rate (%) = (rice flour weight after water absorption-rice flour weight before water absorption (10 g)) / rice flour weight before water absorption (10 g) x 100

The rice flour used in the present invention may have a mode particle size of preferably 200 μm or less, more preferably 70 to 130 μm, for the purpose of producing a well-textured bread, for example. For rice flour, use a particle size distribution measuring device (LS13320 [Beckman Coulter] or an equivalent device) to measure the particle size distribution by the dry method according to the manual, and determine the most frequent particle size of rice flour from the measured particle size distribution. Can be done.

The rice flour used in the present invention is not limited, but is preferably produced by a wet airflow pulverization method. The above rice flour can also be obtained as a commercial product.

In the present invention, rice flour bread is produced using bread dough containing the above-mentioned rice flour, water and yeast, and not containing gluten and a thickener. The amount of water in the bread dough may be a general amount of water used as a raw material in the production of bread using rice flour, and may be, for example, 70 to 120% by weight of the amount of rice flour. The water in the bread dough may be added as water, but may be added as a component of other raw materials. For example, the water in the bread dough may be water derived from beverages such as milk, soy milk, and juice added to the bread dough. Water at room temperature or beverage may be added to the rice flour as a raw material, or heated or cooled water or beverage may be added.

The yeast to be blended in the bread dough may be any yeast that can be used for bread fermentation, but is typically baker's yeast (Saccharomyces cerevisiae strain used in bread making). The yeast used in the present invention does not secrete gluten-constituting proteins. The yeast may be dry yeast or raw yeast. Further, yeast may be contained in a so-called fermented species (starter). The fermented species is a fermented product obtained by fermenting and proliferating yeast existing in the natural world, and may contain various microorganisms such as lactic acid bacteria in addition to baker's yeast. Such fermented seeds may be mixed with bread dough as a source of yeast. However, in order to prepare bread dough that does not contain gluten and thickener, it is necessary to prepare fermented seeds using raw materials that do not contain gluten and thickener. Those skilled in the art can appropriately adjust the amount of yeast suitable for bread production, but in general, yeast in an amount that is 0.5 to 5% by mass of the amount of rice flour by dry weight is used. Just do it. Yeast may be mixed with rice flour from the beginning, or may be added to the dough once mixed and then further mixed. Yeast after pre-fermentation may be added to rice flour or bread dough, or yeast may be added to rice flour or bread dough without pre-fermentation.

The bread dough according to the present invention may contain other raw materials as long as it does not contain gluten and a thickener. The bread dough according to the present invention may further contain, for example, one or more selected from sugars such as sugar, salt, and fats and oils. The fats and oils may be vegetable fats and oils such as olive oil, animal fats and oils such as butter, arbitrary fats and oils such as shortening and margarine, or mixtures thereof, and butter is a preferred example.

In the present invention, the term "salt" shall mean a food grade or pharmaceutical grade salt (mainly composed of sodium chloride). In addition to the main component sodium chloride, the salt may contain other inorganic salts such as potassium chloride, calcium chloride, and magnesium chloride. Any salt product can be used as the salt to be blended in the bread dough according to the present invention. For example, a high-purity salt such as a commercially available refined salt (containing almost only sodium chloride) or an unrefined salt (mainly composed of sodium chloride but containing a larger amount of other inorganic salts) is used. be able to. When refined salt (containing 99% or more sodium chloride by dry weight) is added to bread dough, the amount of refined salt is almost equal to the sodium chloride content, so the salt content in bread dough is the addition of refined salt. It can be calculated based on the quantity. On the other hand, when unrefined salt (containing less than 99% sodium chloride by dry weight) is added to the dough, the salt content in the dough is based on the sodium chloride equivalent calculated from the sodium content of the added unrefined salt. To calculate. The sodium chloride equivalent is calculated by multiplying the sodium content by 2.54.

In the present invention, any sugar such as white sugar, brown sugar, millet sugar and sucrose can be used as the sugar. In addition, other sugars (glucose, fructose, honey, maltose, brown sugar, granulated sugar, etc .; excluding polysaccharides) can also be used.

The bread dough according to the present invention also includes foods such as meat / fish, nuts, mushrooms, fruits, vegetables, herbs, legumes, beverages, dairy products, fermented foods, sweeteners, confectionery, spices, and food materials such as eggs. , Ham, sausage, bacon, almond, carrot, sesame, raisin, apple, edible beans, vegetable juice, rosemary, milk, cheese, yogurt, trehalose, chocolate, cinnamon powder and the like. The bread dough according to the present invention may also contain food additives such as emulsifiers, preservatives, flavors and colorants, as long as they do not contain gluten and thickeners.

The bread dough according to the present invention does not contain gluten-constituting protein or grain flour containing gluten-constituting protein (wheat flour, rye flour, barley flour, oat flour, or flour of a hybrid thereof, etc.). The bread dough according to the present invention preferably contains only rice flour as the grain flour, and particularly preferably contains only rice flour having a damaged starch rate of 5% or less and a water absorption rate of 80% or less. The bread dough according to the present invention also uses any of gluten, gluten-constituting protein, and grain flour containing gluten-constituting protein (wheat flour, limewood flour, barley flour, oats flour, or a hybrid grain flour thereof, etc.) as a raw material. It does not contain gluten because it is made without gluten. Here, when the bread dough "does not contain" these components, it means that these components are not present in the bread dough in an effective amount. If gluten, gluten-constituting proteins, or other flour is not used as a raw material for dough, but is mixed in a very small amount during the dough or bread making process, an effective amount of gluten is contained in the dough. , Gluten-constituting proteins, or other flours are absent, so the dough is determined to be free of them. More specifically, when the amount of gluten mixed in the dough is less than 0.5% by weight (preferably less than 0.1% by weight) of the amount of rice flour, an effective amount of gluten is present in the dough. Instead, such bread dough according to the present invention shall be gluten-free. When the amount of gluten-constituting protein or other grain flour mixed in the bread dough is less than 1.0% by weight (preferably less than 0.1% by weight) of the amount of rice flour, the effective amount is contained in the bread dough. No gluten-constituting protein or other flour is present, and such bread dough according to the present invention is free of gluten-constituting protein or other flour.

In a preferred embodiment, the dough according to the invention may be more strictly "gluten-free". In the present invention, "gluten" includes wheat gluten derived from wheat flour as well as gluten-like proteins derived from other flours. Gluten is produced by the reaction of gluten-constituting proteins (gliadin and glutenin in the case of wheat flour) contained in flour flour in the presence of water. The gluten-constituting proteins that correspond to gliadin in wheat are called holder-in in barley, secalin in rye, and avenin in oats. In the present invention, "gluten-free" means that the content of gluten is 0.002% or less (20 mg / kg or less) of the total weight (total mass) of the food. This is the value set by the Codex Alimentarius in 2008 as a "gluten-free" standard. Typically, by producing the bread dough or the like according to the present invention using a production line dedicated to gluten-free products, it is possible to prevent mixing of wheat flour, gluten and the like, and to produce gluten-free bread dough.

A thickener is usually used in the production of gluten-free rice flour bread, but the bread dough according to the present invention does not contain not only gluten but also a thickener. Examples of the thickener include a wide variety of thickeners that can be used in the food field, such as thickening polysaccharides and gelling agents. Examples of thickeners include alginic acid, arabic gum, carrageenan, carboxymethyl cellulose, guar gum, xanthan gum, locust bean gum, starch, cellulose, tamarind seed gum, psyllium seed gum, glucomannan, gelatin, agar, soybean polysaccharides, tapioca. There are, but are not limited to, starch, corn starch, kudzu starch, carrageenan, potato starch and derivatives thereof (acetylates, esterifieds, degradation products, etc.). Even if a thickening component is produced from rice flour, yeast or other raw materials during the bread dough or bread production of the method of the present invention, such a component shall not be included in the "thickener". .. Here, the phrase "the bread dough according to the present invention does not contain a thickener" means that an effective amount of the thickener is not present in the bread dough. Although the thickener is not used as a raw material for the dough, if it is mixed in a very small amount in the bread dough or the bread manufacturing process, the effective amount of the thickener does not exist in the bread dough. It is determined that such bread dough according to the above does not contain a thickener. More specifically, when the amount of the thickener mixed in the bread dough is less than 0.05% by weight (preferably less than 0.005% by weight) of the amount of rice flour, the effective amount is increased in the bread dough. It is assumed that there is no thickener and such bread dough according to the present invention does not contain a thickener.

In the present invention, the above-mentioned criteria that "free" of gluten, gluten-constituting protein, grain flour other than rice flour, or thickener is applied not only to bread dough but also to rice flour bread.

The bread dough according to the present invention can be prepared from the above-mentioned bread ingredients by a conventional method, and specifically, it is prepared by mixing rice flour, water, yeast, and other ingredients by one or more steps. be able to. In the field of food processing, "mixing" refers to kneading a raw material mixture containing powder and liquid so that its components are uniformly dispersed. In the present invention, mixing can be performed by a stirring function of, for example, a mixing device or a home bakery, or can be performed by hand. Mixing may be performed at a normal temperature used for mixing in bread making, and is not particularly limited, but generally, mixing is performed at about room temperature, for example, about 4 ° C. to 32 ° C., preferably 15 to 30 ° C. Good. The mixing can be carried out in a normal mixing time known to those skilled in the art, for example, about 3 to 40 minutes per mixing step, but preferably about 10 to 30 minutes per mixing step. Mixing may be performed once or multiple times.

The bread dough according to the present invention may be prepared by a method including mixing rice flour, water, yeast, and if necessary, other raw materials into one, and mixing them in one step. Alternatively, the bread dough according to the present invention can be prepared by a method including two or more mixing steps. In one embodiment, for example, rice flour, water, and, if necessary, one or more other ingredients are mixed and mixed, followed by sugars such as yeast, sugar, and, if necessary, another one or more. The bread dough according to the present invention can also be prepared by further adding the raw materials and mixing them. After final mixing, additional ingredients (eg nuts, cheese, fruits, etc.) may be added (eg, mixed, wrapped, toppings or embedded). After mixing rice flour and water, it may be left for a certain period of time to allow a sufficient soaking time, and then other raw materials such as yeast may be added.

The bread dough prepared as described above can be placed in a container, divided or molded as needed, and then fermented by any method used for bread production. The bread dough according to the present invention is usually, for example, usually about 20 minutes to 4 hours (more generally 25 minutes to 2) at a temperature suitable for fermentation (4 to 50 ° C., usually 25 to 45 ° C.). It can be fermented by leaving it for about an hour. Fermentation may be carried out in only one fermentation step or in two or more fermentation steps. For example, a primary fermentation (also called floor time) in which bread dough is fermented by leaving it at a relatively low temperature (for example, 15 to 32 ° C.) for about 15 minutes to 2 hours (more generally, about 30 minutes to 90 minutes) is performed. You may go. At the stage where fermentation has progressed to some extent by the primary fermentation, the temperature is further increased at 4 ° C to 45 ° C (more preferably 25 to 42 ° C) for usually about 15 minutes to 2 hours (more generally about 30 minutes to 90 minutes). It may be fermented (final fermentation called hoilo). The bread dough according to the present invention may be subjected to the fermentation step without interruption until the final fermentation is completed by first placing the dough in a bread forming container (mold) and starting the fermentation step after mixing.

In the present invention, the bread dough according to the present invention can be remarkably inflated at the fermentation stage. In the present invention, in a preferred embodiment, the specific volume of the dough can be 3 mL / g or more, especially 4 mL / g or more at the end of the fermentation stage. In the method of the present invention, it is preferable to ferment the bread dough according to the present invention until the specific volume is 3 mL / g or more, particularly 4 mL / g or more. Here, the specific volume of the bread dough can be calculated by dividing the volume (mL) of the fermented bread dough by the weight of the bread dough.

The bread dough according to the present invention prepared as described above may be packaged by an arbitrary method, for example, in a sealed container or a sealed bag. The bread dough according to the present invention may be subjected to treatments such as sterilization, refrigeration, and freezing.

The present invention provides a method for preparing (manufacturing) bread dough as described above. The method for preparing bread dough according to the present invention is, in addition to the mixing step, one or more optional steps such as a dividing step, a molding step, one or more fermentation steps, a packaging step, a sterilization step, and a refrigeration or freezing step. May include the steps of.

The present invention also provides a bread dough according to the present invention prepared by the method as described above. The bread dough according to the present invention refers to the dough before the completion of baking. The bread dough according to the present invention also includes bread dough that has been subjected to, for example, sterilization, refrigeration, or freezing. The bread dough according to the present invention may be a retort pouch product. The bread dough according to the present invention also includes dough that has been partially baked but has not been baked. The bread dough according to the present invention also includes dough prepared by mixing or the like, which is placed in a container, molded, mixed with other ingredients, wrapped, placed or embedded in the dough as long as it is not baked.

Rice flour bread can be produced by fermenting the bread dough according to the present invention and further baking it. The dough can be baked by a conventional method. Specifically, the baking step may be carried out by heating the dough by any means such as an oven, a microwave oven, and a kettle (for example, heating at 100 ° C. to 240 ° C.). The firing time is generally about 5 to 100 minutes. A person skilled in the art can appropriately adjust the firing temperature and firing time. The bread dough according to the present invention shows good swelling even after baking. The rice flour bread according to the present invention preferably has a specific volume of 3 mL / g or more after baking, particularly 4 mL / g or more. Here, the specific volume of bread (specific volume of bread) can be calculated by dividing the volume (mL) of bread after baking by the weight of bread.

It is also possible to produce sweet bread, cooked bread, etc. by topping nuts, fruits, cream, syrup, etc. on the baked bread, or sandwiching side dishes, ham, etc. Bread processed in this way is also included in the scope of bread according to the present invention. The rice flour bread according to the present invention may be any form of bread such as bread, bread rolls, round bread, delicatessen bread, and sweet bread. The present invention also provides a method for producing rice flour bread as described above using the bread dough according to the present invention. The method for producing rice flour bread of the present invention may further include a step of preparing the bread dough according to the present invention. Therefore, the present invention also provides a method for producing rice flour bread, which comprises preparing bread dough by the method for preparing bread dough of the present invention, fermenting and baking as described above. In the bread production method of the present invention, a series of operations from mixing of raw materials to fermentation and baking may be continuously performed in one home bakery or bread production line.

The rice flour bread produced from the bread dough according to the present invention by the method of the present invention shows good swelling even though it does not contain gluten and a thickener. In the method of the present invention, bread dough and rice flour bread showing good swelling can be produced without adding glutathione to rice flour. The rice flour bread according to the present invention, particularly gluten-free rice flour bread, is produced without using grain flour or gluten containing gluten-constituting protein such as wheat flour as a raw material, and therefore does not contain gluten-constituting protein or gluten. , Especially suitable for people who should avoid gluten intake such as wheat allergy patients and celiac disease patients.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the technical scope of the present invention is not limited to these examples.

In the following examples, as the rice flour, glutinous rice was used as a raw material, and rice flour of Samples 1 to 9 commercially available as rice flour for confectionery and bread making was used. All of Samples 1 to 9 do not contain grain flour containing gluten-constituting protein such as wheat flour, gluten-constituting protein, gluten and thickener. A purified salt having a sodium chloride content of 99% or more was used as the salt.

[Example 1] Manufacture of rice flour bread 160 g of rice flour and 140 g of water from any of Samples 1 to 9 are placed in a bread case of a home bakery (SD-BH105, manufactured by Panasonic Corporation), and the "dry yeast course" program is used. The mixture was mixed by stirring at room temperature for 20 minutes. After adding 15 g of sugar, 5 g of dry yeast for bread (manufactured by Nisshin Foods Inc.), 2 g of butter (manufactured by Calpis Co., Ltd.), and 1.6 g of salt, the program of "Dry yeast course" was used. Further, the mixture was mixed by stirring at room temperature for 20 minutes. 175 g of the dough thus obtained was weighed in a square bread case (capacity 800 mL) and fermented in an oven range (EMO-C16C, Sanyo Electric Co., Ltd.) at 40 ° C. for about 30 minutes. The appearance of the dough was observed at the end of this fermentation stage. Subsequently, the dough (fermented dough) that had completed the fermentation step was baked at 180 ° C. for 24 minutes to produce rice flour bread that did not contain gluten and a thickener.

The day after baking, each bread was subjected to weight measurement and shape measurement by a laser volume meter (SELNAC-WinVM2100A, Astex Co., Ltd.), and the measured value of specific volume (mL / g), which is an index of bread expandability, was measured. Obtained. The specific volume is expressed as the volume of bread (mL / g) per 1 g of bread. The results obtained are shown in Table 1. Table 1 also shows the milling method used for producing each rice flour.

As shown in Table 1, even in the rice flour bread produced by the same production method, the specific volume of the bread produced was different depending on the rice flour used.

Further, the cross section of each bread after cutting was photographed and observed (Fig. 1). In all of the breads (samples 1, 2, and 7) having a bread specific volume of 4 mL / g or more after baking, the dough swelled to the upper part of the square bread case at the end of the fermentation stage before baking. Since the weight of the dough used for fermentation is 175 g and the capacity of the square bread case is 800 mL, the specific volume of the bread using Samples 1, 2 or 7 is already 4 mL / g or more at the end of the fermentation stage. It was shown that It was shown that the bread using wheat flour swells greatly in the baking stage after fermentation, but the rice flour bread according to the present invention swells greatly in the fermentation stage and does not swell so much in the baking stage.

When the rice flour of Sample 7 was used, a well-textured bread similar to bread containing wheat flour or gluten as a raw material was produced (FIG. 1G). Sample 1 provided bread that was softer than Sample 7 and was slightly crushed (FIG. 1A). When sample 2 was used, it was easy for voids to enter the bread (Fig. 1B).

In rice flour bread dough using wheat flour or gluten as a raw material, the bread swells due to the sticky gluten protein network trapping the fermentation gas, but gluten-free rice flour bread does not have such a gluten network. However, the test results in this example showed that by using rice flour showing predetermined properties, it is possible to produce rice flour bread having good swelling without containing gluten. It is considered that the gluten-free rice flour bread using the rice flour of Samples 1, 2 and 7 achieved good swelling by a mechanism different from that of the gluten-containing rice flour bread.

[Example 2] Relationship between evaluation of rice flour properties and bread specific volume In order to examine the properties of rice flour that can increase the specific volume of rice flour bread that does not contain gluten or thickener, the rice flour of samples 1 to 9 is damaged. The starch rate, water absorption rate, and most frequent particle size were measured.

1) Measurement of Damaged Starch Rate The damaged starch rate of each rice flour was determined as follows using a damaged starch measurement kit (Start Damage Assay Kit; Megazyme Co., Ltd.).

First, 100 mg of rice flour was placed in a tube, and the tube and amylase solution (50 U / ml) were pre-incubated at 40 ° C. for about 5 minutes. 1 mL of amylase solution was added to the rice flour in the tube, mixed with a vortex mixer, and reacted at 40 ° C. for 10 minutes. The reaction was stopped by adding 8 ml of a sulfuric acid solution (0.2% v / v) and mixing with a vortex mixer. Then, it was centrifuged at 3,000 rpm for 5 minutes. 0.1 ml of the supernatant was collected, placed in another tube, 0.1 ml of an amyloglucosidase solution was added thereto, and the mixture was reacted at 40 ° C. for 10 minutes. Further, 4 ml of a glucose measuring reagent GOPOD (glucose oxidase and peroxydase) solution was added, and the mixture was reacted at 40 ° C. for 20 minutes. The absorbance of the reaction solution was measured at 510 nm. On the other hand, a GOPOD solution was added to a 150 mg / ml glucose standard solution and a buffer solution (blank) to react, and the absorbance was measured to prepare a calibration curve. The damaged starch ratio (%) of each rice flour was determined based on this calibration curve.
The results are shown in Table 2.

2) Measurement of water absorption rate 10 g of rice flour (dry state) was placed in a 50 mL tube, ion-exchanged water was added up to a scale of 50 mL, and the mixture was left overnight at room temperature. After centrifuging this tube at 3000 rpm for 30 minutes, the supernatant was discarded, and the weight of rice flour after water absorption (total weight of rice flour and water absorbed by the rice flour) was measured. The water absorption rate was calculated by the following formula.
Water absorption rate (%) = (rice flour weight after water absorption-rice flour weight before water absorption (10 g)) / rice flour weight before water absorption (10 g) x 100
Table 2 shows the water absorption rates determined for each rice flour.

3) Measurement of the most frequent particle size If the most frequent particle size is included in the specification information provided by each rice flour manufacturer, it is shown in Table 2. For rice flour for which the most frequent particle size is not disclosed, the particle size distribution is measured by the dry method according to the manual using the particle size distribution measuring device LS13320 (Beckman Coulter), and the most frequent particle size is obtained from the measured value of the particle size distribution. It was. The measurement results are also shown in Table 2.

In addition, graphs showing the relationship between the damaged starch ratio, the water absorption rate, and the most frequent particle size and the bread specific volume shown in Table 1 are shown in FIGS. 2, 3, and 4.

As shown in FIG. 2, the damaged starch ratio of rice flour showed a strong correlation with the specific volume of bread. In particular, it was revealed that the damaged starch ratio of rice flour suitable for obtaining a bread specific volume of 4 mL / g or more is 5% or less.

As shown in FIG. 3, the water absorption rate of rice flour showed a strong correlation with the specific volume of bread. In particular, it was revealed that the water absorption rate of rice flour suitable for obtaining a bread specific volume of 4 mL / g or more is 80% or less.

On the other hand, as shown in FIG. 4, the particle size of rice flour (particularly, the most frequent particle size) showed almost no correlation with the specific volume of bread.

From the above results, by using rice flour showing a damaged starch rate of 5% or less and a water absorption rate of 80% or less in the production of rice flour bread, a rice flour bread with good swelling can be obtained without using gluten or a thickener. It was shown that it can be manufactured. Considering that unlike gluten-containing rice flour bread, gluten-free rice flour bread does not have a gluten network at all, the use of such rice flour makes it possible to use rice flour bread that does not contain gluten or thickeners and has good swelling. It is a surprising result that we were able to manufacture.

According to the present invention, a rice flour bread having good swelling and containing no gluten or thickener can be easily produced.

Claims (10)

A bread dough containing rice flour, water and yeast showing a damaged starch rate of 5% or less and a water absorption rate of 80% or less, and containing no gluten or thickener, which comprises fermenting, swelling and baking. Production method. The method according to claim 1, wherein the damaged starch ratio of rice flour is 3% or more, and the water absorption rate is 72% or more. The method of claim 1 or 2, wherein the dough further comprises one or more selected from sugar, salt, and fats and oils. The method according to any one of claims 1 to 3, wherein the bread dough is fermented until the specific volume becomes 4 mL / g or more. The method according to any one of claims 1 to 4, which comprises the step of preparing the bread dough. Contains rice flour, water and yeast exhibiting a damaged starch rate of 5% or less and a water absorption rate of 80% or less for producing rice flour bread by the method according to any one of claims 1 to 5, and gluten and Fermented and inflated bread dough that does not contain thickeners. The bread dough according to claim 6, wherein the damaged starch ratio of the rice flour is 3% or more, and the water absorption rate is 72% or more. The bread dough according to claim 6 or 7, further comprising one or more selected from sugar, salt, and fats and oils. The bread dough according to any one of claims 6 to 8, which has a specific volume of 4 mL / g or more. A rice flour bread containing no gluten and a thickener, produced by using the bread dough according to any one of claims 6 to 9 .

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