Pregelatinized grain flour manufacturing method

Abstract

The method for producing a pregelatinized grain flour according to the present invention includes a step for thermally drying a slurry, which contains 100 parts by mass of grain flour and 500-1500 parts by mass of water, using a drum dryer. Preferably, the grain flour contains wheat flour. Preferably, the grain flour contains one or more selected from low-amylose wheat flour and a glutinous grain flour. Preferably, the temperature of the heating section of the drum dryer is 100-150°C. A method for producing a processed food according to the present invention is characterized in that a pregelatinized grain flour produced by the aforesaid production method is used as a starting material.

Description

[Technical Field]

[0001] The present invention relates to pregelatinized grain flour that can be used as a food ingredient. [Background technology]

[0002] Pregelatinized flour is produced by heating cereal flour such as wheat flour in the presence of moisture to pregelatinize (gelatinize) the starch contained in the cereal flour, and is widely used in food applications, industrial applications, etc. Known methods for producing pregelatinized flour include drying a slurry containing cereal flour using a spray dryer, drum dryer, etc., adding water to cereal flour and heating it while kneading it in an extruder, and heating and humidifying it by passing superheated steam through a container containing cereal flour.

[0003] Patent Document 1 describes a method for producing corn powder with excellent suitability for drying in a drum dryer and excellent water dispersibility, which includes a step of blending α-amylase-treated corn paste with high amylose starch and drying it in a drum dryer. Furthermore, regarding the drying process using such a drum dryer, drum It describes a dryer surface temperature of 100 to 180°C and a drying time of 2 to 240 seconds, but does not specifically describe the amount of water to be added to the material to be dried (a mixture of corn paste and high-amylose starch). Patent Document 2 describes a food-grade gelatinized starch that can impart a good texture to wheat-flour-containing foods, obtained by pregelatinizing a starch-flour mixture in a drum dryer, in which wheat flour is blended with starch. It also describes that, with regard to the gelatinization treatment using a drum dryer, the concentration of the starch-flour mixture in the aqueous suspension dropped into the heating section of the drum dryer is 30 to 50% by mass. Patent Document 3 describes wheat flour for bread that can be used to produce bread with good texture and flavor and slow staling. It also describes that the pregelatinized wheat flour used in the bread flour is obtained by mixing raw wheat flour with 1 to 3 times the amount of water and drying the mixture in a drum dryer. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-198243 [Patent Document 2] Japanese Patent Application Laid-Open No. 2007-169442 [Patent Document 3] Japanese Patent Application Laid-Open No. 2004-129607 Summary of the Invention

[0005] Starch retrogradation is a problem in foods containing a relatively large amount of starch. For example, in bakery foods that are primarily made from wheat flour, retrogradation of the starch in the wheat flour progresses during storage, resulting in a problem of deterioration of taste and texture over time, such that a food that is moist, soft, and has a good taste and texture immediately after production becomes dry and hard after storage for a certain period of time. There has yet to be provided a pregelatinized flour that has excellent resistance to starch retrogradation and that can be used to produce secondary processed products that have excellent taste and texture not only immediately after production but also after storage after production.

[0006] An object of the present invention is to provide a gelatinized grain flour that can be used to produce secondary processed products that have a good taste and texture and are resistant to deterioration over time.

[0007] The present inventors have conducted extensive research into technologies that can improve the retrogradation resistance of starch, and have found that gelatinized flour obtained by adding a relatively large amount of water (500 parts by mass or more) to 100 parts by mass of flour to prepare a slurry and then heating and drying the slurry in a drum dryer has excellent starch retrogradation resistance and can solve the above-mentioned problems. Methods for producing gelatinized flour using a drum dryer are described in Patent Documents 1 to 3 and are publicly known, but in such cases the amount of water added to the raw material flour is usually at most about 300 parts by mass per 100 parts by mass of flour, and it was not known that increasing this to 500 parts by mass or more could improve starch retrogradation resistance.

[0008] The present invention was made based on the above findings and is a method for producing gelatinized grain flour, which comprises a step of heat-drying a slurry containing 100 parts by mass of grain flour and 500 to 1500 parts by mass of water in a drum dryer. The present invention also relates to a method for producing processed foods, which uses as a raw material the gelatinized grain flour produced by the production method of the present invention. [Brief explanation of the drawings]

[0009] [Figure 1] 1(a) to 1(h) are each a schematic diagram of an example of a drum dryer that can be used in the method for producing pregelatinized grain flour of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] The method for producing gelatinized flour of the present invention comprises a step of preparing a slurry containing flour and water (slurry preparation step), and a step of heating and drying the slurry (slurry drying step). The slurry drying step causes the starch contained in the flour in the slurry to be gelatinized, thereby obtaining the desired gelatinized flour.

[0011] The flour used in the slurry preparation step may be any flour containing starch, regardless of the amylose content, and may be non-glutinous or glutinous. The term "flour" as used herein refers not only to flours that are primarily composed of the endosperm (e.g., wheat flour), one of the three main components that make up a grain caryopsis (endosperm, husk, and germ), but also to flours that contain the husk and / or germ, such as whole grain flour (wheat whole grain flour in the case of wheat). Specific examples of flour include wheat flour, rice flour, buckwheat flour, rye flour, and soy flour. Examples of wheat flour include hard flour, all-purpose flour, soft flour, durum wheat flour, and durum semolina. In the present invention, one type of flour may be used as the raw material for the gelatinized flour, or two or more types of flour may be used in combination.

[0012] The flour used in the slurry preparation step preferably contains wheat flour. By using wheat flour as a raw material for gelatinized flour, it is possible to more reliably impart a wheat-like flavor to bakery foods, noodles, and other secondary processed products, particularly compared to when starch is used.

[0013] The flour used in the slurry preparation step preferably comprises one or more selected from low-amylose wheat flour and glutinous wheat flour. By using low-amylose wheat flour or glutinous wheat flour as the raw material for pregelatinized flour, the desired effects of the present invention can be more reliably achieved. Here, "low-amylose wheat flour" refers to wheat flour derived from wheat that lacks expression of any two or all of the three amylose synthesis genes Wx-A1, Wx-B1, and Wx-D1, and "glutinous wheat flour" refers to flour derived from grains other than wheat that lack expression of amylose synthesis genes and whose starch is composed essentially almost exclusively of amylopectin. Low-amylose wheat flour can be obtained, for example, by milling the grain caryopsis of Japanese wheat varieties such as "Tsurupikari," "Chikugoizumi," "Nebarigoshi," and "Nishihonami" (all of which lack two of the three amylose synthesis genes) and "Mochihime" (which lacks all three amylose synthesis genes).

[0014] The flour used in the slurry preparation step is typically unprocessed flour that has not been subjected to pretreatment such as heating, but pretreated flour can also be used. Examples of the pretreatment include adding various flour modifiers to the flour. The flour modifiers are agents that can modify the flour to desired properties, and examples include enzymes, acid or alkali agents, emulsifiers, catalysts, sugars, amino acids, peptides, thickening agents such as thickening polysaccharides, and the like. Examples of the enzymes include amylase and protease that degrades proteins contained in flour.

[0015] In the slurry preparation step, 500 to 1500 parts by mass of water is added to 100 parts by mass of flour to prepare a slurry. By adding such a relatively large amount of water to the flour-containing slurry, the side chains of the starch contained in the flour are more likely to open during the subsequent drying step of the slurry. As a result, it is believed that superior effects are achieved compared to conventional manufacturing methods in terms of improving the starch's retrogradation resistance and viscoelasticity. If the amount of water added is less than 500 parts by mass per 100 parts by mass of flour, the desired effects of the present invention are not achieved. If the amount of water added is more than 1500 parts by mass, the subsequent slurry drying step requires a lot of time and energy to obtain a solid, which may increase production costs and reduce production efficiency. The amount of water added is preferably 600 to 1500 parts by mass, more preferably 800 to 1500 parts by mass, per 100 parts by mass of flour.

[0016] The slurry prepared in the slurry preparation step typically contains only flour and water as a solvent, but may contain other ingredients, such as a flour modifier that can be used in the pretreatment of the flour, as needed. In this case, 1) a flour modifier that is the same as or different from the flour modifier may be added to a slurry containing flour pretreated with a flour modifier, or 2) a flour modifier may be added to a slurry containing raw flour. In addition, in a slurry containing a flour modifier, a reaction involving the flour modifier, such as an enzymatic reaction, occurs. This reaction may be completed before the slurry is subjected to the subsequent drying step, or may occur during the drying step.

[0017] The slurry prepared in the slurry preparation step is heated and dried using a drum dryer in the slurry drying step. Figure 1 shows several examples of drum dryers that can be used in the present invention. Figures 1(a) to 1(f) show a single-drum type, Figure 1(g) shows a double-drum type, and Figure 1(h) shows a twin-drum type. Figures 1(a) to 1(f) differ in the method of supplying the material to be dried (slurry) to the drum: Figure 1(a) shows a splash feed method, Figure 1(b) shows a dip feed method, Figure 1(c) shows a lower roll transfer method, Figure 1(d) shows an upper roll feed method, Figure 1(e) shows a side roll feed method, and Figure 1(f) shows a multi-roll feed method. Other methods include a spray method in which the slurry is supplied to the outer peripheral surface of the drum by spray atomization. Drum dryers are also available in atmospheric and vacuum types, depending on the operating pressure. In the present invention, any of the above systems can be used, but the basic configuration (type) is preferably that shown in Figure 1(d), Figure 1(e), Figure 1(f), or Figure 1(g), and the operating pressure is preferably the atmospheric pressure type.

[0018] As shown in Figure 1, a drum dryer typically comprises one or more cylindrical drums 1 rotatably supported around a rotation axis, a scraper 2 disposed opposite the outer peripheral surface 1a of the drum 1 and scraping off solid matter from the slurry S (material to be dried) formed on the outer peripheral surface 1a, and a receiver 3 for receiving the solid matter scraped off by the scraper 2, with the outer peripheral surface 1a functioning as a heating section that comes into contact with the slurry S and heats it. Heat drying of a slurry using a drum dryer configured in this way is carried out by introducing a heat medium such as steam into the interior of the drum 1 to heat the outer peripheral surface 1a, and supplying the slurry S to the rotating and heated outer peripheral surface 1a. The slurry S dries during the rotation of the drum 1, forming a thin layer, which is scraped off by the scraper 2 and collected inside the receiver 3. This collected solid matter is the target product, pregelatinized grain flour.

[0019] The heating conditions in the slurry drying step will vary depending on the configuration of the drum dryer used, the state of the material to be dried, etc., but from the perspective of more reliably achieving the desired effects of the present invention, the temperature of the heating section of the drum dryer (the temperature of the outer surface of the drum) is preferably 100 to 150° C., more preferably 100 to 120° C., and even more preferably 100 to 115° C. As described above, in the present invention, a highly hydrated slurry is prepared by adding 500 parts by mass or more of water to 100 parts by mass of flour, which is thought to contribute significantly to making the side chains of the starch contained in the flour more easily open, and in turn to improve the retrogradation resistance and viscoelasticity of the starch. By heat-drying this highly hydrated slurry in the heating section of a drum dryer whose surface temperature is set within the above-mentioned preferred range, it is possible to produce high-quality pregelatinized flour while minimizing heat-induced damage to the open starch side chains.

[0020] Furthermore, from the viewpoint of ensuring that the desired effects of the present invention are achieved more reliably, the heat drying of the slurry in the slurry drying step is preferably carried out under conditions such that the moisture content (target moisture content) of the solid matter of the slurry (gelatinized flour) obtained by the slurry drying step is 15% by mass or less, more preferably 5 to 15% by mass, even more preferably 5 to 12% by mass, and even more preferably 5 to 10% by mass. Generally, in a drum dryer, once the temperature of the heating section (the temperature of the outer peripheral surface of the drum) and the moisture content of the material to be dried after drying (target moisture content) are determined, the amount of material to be dried supplied to the heating section and the rotation speed of the drum dryer (contact time between the heating section and the material to be dried) are automatically determined. Therefore, by adjusting the temperature and target moisture content of the heating section, it is possible to adjust the degree of drying of the slurry, which is the material to be dried.

[0021] The solid matter of the slurry obtained through the slurry drying step may be used as is as gelatinized flour, or may be pulverized into powder. The pulverization of the solid matter can be carried out in a conventional manner using a household pulverizer such as a Corby mill or a juicer, or an industrial pulverizer such as a hammer mill, a pin mill, or a jet mill, and the solid matter may be pulverized to the desired particle size.

[0022] The degree of gelatinization (gelatinization degree) of the gelatinized flour produced by the production method of the present invention is preferably 90% or more, more preferably 95% or more. Incorporation of such high-degree gelatinized flour into foods significantly improves the taste and texture of the food, and furthermore, imparts resistance to aging to the food. As used herein, the term "degree of gelatinization" refers to the degree of gelatinization measured by the BAP method (β-amylase-pullulanase method). Measurement of the degree of gelatinization by the BAP method can be carried out as follows, in accordance with a previous report ( Journal of Home Economics 32(9), 653-659, 1981).

[0023] [Method for measuring the degree of gelatinization using the β-amylase-pullulanase method] (A) Reagents The reagents used are as follows: 1) 0.8M acetic acid-Na acetate buffer 2) 10N sodium hydroxide solution 3) 2N acetic acid solution 4) Enzyme solution: 0.017 g of β-amylase (Nagase ChemteX Corporation, #1500S) and 0.17 g of pullulanase (Hayashibara Biochemical Laboratories, No. 31001) were dissolved in the 0.8 M acetic acid-Na acetate buffer solution to make 100 mL. 5) Inactivated enzyme solution: Prepared by boiling the enzyme solution for 10 minutes. 6) Somogyi and Nelson reagents (reagents for measuring reducing sugars)

[0024] (B)Measurement method B-1) The sample (gelatinized flour) is pulverized using a homogenizer to a size of 100 mesh or less. 0.08 to 0.10 g of this pulverized sample flour is placed in a glass homogenizer. B-2) 8.0 mL of demineralized water is added to the contents of the glass homogenizer, and the glass homogenizer is moved up and down 10 to 20 times to disperse the contents, thereby obtaining a dispersion. B-3) Place 2 mL of the dispersion liquid from B-2) into each of two 25 mL graduated test tubes, and dilute one of the tubes to the volume with 0.8 M acetic acid-Na acetate buffer to use as the test area. B-4) To the other of the two tubes, add 0.2 mL of 10 N sodium hydroxide solution and react at 50°C for 3 to 5 minutes to completely gelatinize the dispersion from B-2). Then, add 1.0 mL of 2 N acetic acid solution to the other tube to adjust the pH to around 6.0, and then make up to volume with 0.8 M acetic acid-Na acetate buffer to create a gelatinized sample. B-5) Take 0.4 mL of each of the test solutions prepared in B-3) and B-4) above from the test group and the gelatinized group, add 0.1 mL of enzyme solution to each, and carry out the enzyme reaction at 40°C for 30 minutes to obtain a reacted solution. At the same time, prepare a blank by adding 0.1 mL of inactivated enzyme solution instead of the enzyme solution. The enzyme reaction is carried out while occasionally stirring the reaction solution during the reaction. B-6) Add 0.5 mL of Somogyi reagent to 0.5 mL of the reaction mixture and the blank, and boil in a boiling bath for 15 minutes. After boiling, cool in running water for 5 minutes, then add 1.0 mL of Nelson reagent, stir, and leave for 15 minutes. B-7) Then, 8.00 mL of demineralized water is added to each of the reacted solution and the blank, and the mixture is stirred, and the absorbance at 500 nm is measured.

[0025] (C) Calculation of the degree of gelatinization The degree of gelatinization is calculated using the following formula. Degree of gelatinization (%) = {(decomposition rate of test solution) / (decomposition rate of fully gelatinized test solution)} × 100 ={(Aa) / (A'-a')}×100 In the above formula, A, A', a, and a' are as follows. A = absorbance of test area A' = absorbance of gelatinized sample a = absorbance of the test blank a' = absorbance of the gelatinized blank

[0026] The gelatinized flour produced by the production method of the present invention can be used to produce processed foods. Using the gelatinized flour in the production of processed foods can improve the taste and texture of the processed food, as well as the starch's resistance to retrogradation. When the processed food is instant noodles, further improvement in hot water reconstitution is expected. The term "processed food" as used here refers to a secondary processed food produced using flour as a raw material, including refrigerated or frozen foods. Examples of processed foods include bakery foods; noodles such as udon, somen, hiyamugi, Chinese noodles, pasta, and instant noodles (including non-fried noodles); noodle wrappers such as gyoza wrappers, shumai wrappers, and spring roll wrappers; deep-fried foods such as tempura, fried chicken, tatsuta-age, and fritters; hot snacks such as okonomiyaki, takoyaki, and chijimi; and powdered foods such as instant soups. Specific examples of bakery foods include breads, pizzas, cakes, Japanese and Western baked goods such as waffles, choux pastries, biscuits, and pan-fried buns; and deep-fried goods such as donuts. Examples of the breads include bread (e.g., rolls, white bread, brown bread, French bread, hardtack, roll bread, croissants, etc.), cooked bread, and sweet bread. Examples of the cakes include sponge cakes, butter cakes, roll cakes, hotcakes, bouche, Baumkuchen, pound cakes, cheesecakes, snack cakes, muffins, bars, cookies, and pancakes.

[0027] The gelatinized flour produced by the production method of the present invention is particularly suitable for producing bakery foods, noodles, and hot snacks. When the gelatinized flour is used in bakery foods, it imparts a desirable moist texture and improves aging resistance, and when used in noodles, it imparts a desirable viscoelasticity to the texture. Furthermore, when the gelatinized flour is used in hot snacks, the desirable texture (e.g., the fluffy texture of okonomiyaki or the thickness of takoyaki) is maintained immediately after production, not only immediately after production but also over time, or even after refrigerated or frozen storage, and the shape retention of takoyaki is also improved.

[0028] The method for producing processed foods using the pregelatinized grain flour as a raw material can be similar to known methods for producing such processed foods. For example, a method for producing bakery foods typically includes the steps of adding water to raw material flour containing the pregelatinized grain flour to prepare dough, fermenting the dough as necessary, and then baking the dough. Furthermore, a method for producing noodles typically includes the steps of adding water to raw material flour containing the pregelatinized grain flour to prepare dough, shaping the dough into a predetermined shape such as noodle strands, and drying the shaped dough as necessary. The term "raw material flour" as used herein refers to a powdered raw material at room temperature and pressure, and typically includes flour (including the pregelatinized grain flour), starch (collectively referred to as "flours"), and vegetable proteins such as wheat protein, but does not include auxiliary ingredients such as salt, sugar, baking powder, or oils and fats. Furthermore, unless otherwise specified, the term "starch" as used herein refers to "pure starch" isolated from plants such as wheat, and is distinguished from starch inherently present in grain flour. The proportion of the mass of gelatinized grain flour to the total mass of the raw material flour (hereinafter also referred to as "gelatinized grain flour occupancy rate") is not particularly limited and can be adjusted appropriately depending on the type of processed food, etc., but for example, when producing bakery foods or noodles, it is preferably 0.5 to 50 mass%, more preferably 2 to 30 mass%, and even more preferably 5 to 20 mass%. [Example]

[0029] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples. Examples 1 to 11, 13 and 14 are reference examples.

[0030] [Examples 1 to 16, Comparative Examples 1 to 4] Unprocessed wheat flour or whole wheat flour was used as the raw flour, and a predetermined amount of water was added to the raw flour to prepare a slurry. The slurry was heated and dried in a drum dryer (single drum type, manufactured by Katsuragi Kogyo Co., Ltd.) to obtain a solid, which was then pulverized in a grinder (Ultracentrifugal grinder ZM200, manufactured by Retsch) to produce a gelatinized flour (gelatinized wheat flour or gelatinized whole wheat flour) with a moisture content of 8% by mass.

[0031] [Control Examples 1 to 3] Unprocessed wheat flour or whole wheat flour was used as the raw flour, and 40 parts by mass of water was added to 100 parts by mass of the raw flour to prepare a mixture. The mixture was then heated and dried using an extruder while maintaining the mixture at a temperature of 95°C for 3 minutes to obtain a solid. The solid was pulverized in the same manner as in the previous examples to produce a gelatinized flour (gelatinized wheat flour or gelatinized whole wheat flour) with a moisture content of 8% by mass.

[0032] The wheat flour used as the raw material flour in the above Examples, Comparative Examples, and Control Examples was prepared as follows: The caryops of raw wheat were pulverized in a pulverizer (Test Mill, manufactured by Buhler Co., Ltd.), and the pulverized material was divided into three fractions: high-grade flour, low-grade flour, and bran. The raw material flour was prepared so that 60% by mass of the total pulverized material was high-grade flour. If there was a shortage of high-grade flour, the shortage was made up with low-grade flour. The raw wheat used was "Kitahonami," "Satonosora," and "Chikugoizumi" (all produced in Japan), "Western Red Spring 1 (1CW)" (produced in Canada), or "Western White (WW)" (produced in the United States). Of these five types of raw wheat, only flour derived from "Chikugoizumi" is low-amylose wheat flour, while flour derived from the other wheat varieties is non-low-amylose wheat flour. The whole wheat flour used as the raw material flour in the above Examples, Comparative Examples and Control Examples is "Super Fine Soft" manufactured by Nisshin Flour Milling Co., Ltd.

[0033] [Production Example 1: Production of pancakes] A raw material flour was prepared containing 5 to 20% by mass of any one type of pregelatinized wheat flour from the Examples, Comparative Examples, and Control Examples, with the remainder being soft flour ("Flour" manufactured by Nisshin Flour Milling, Inc.). 100 parts by mass of the raw material flour, 25 parts by mass of sugar, 5 parts by mass of baking powder, 10 parts by mass of salad oil, 30 parts by mass of whole eggs, 50 parts by mass of milk, and an appropriate amount of water were placed in a container, and the mixture was manually stirred at 120 rpm to prepare a pancake batter with a viscosity of 5 to 10 Pa·s at a product temperature of 25°C, as measured by a Brookfield viscometer. The amount of water added was adjusted so that the viscosity of the pancake batter would fall within the above range. After allowing the pancake batter to rest for 10 minutes, 55 g of the batter was poured onto a griddle and baked on one side for 3 minutes at a griddle temperature of 180°C. The batter was then flipped over and baked on the other side for 2 minutes to produce pancakes.

[0034] [Production Example 2: Production of whole wheat pancakes] Whole wheat flour pancakes were produced in the same manner as in Production Example 1, except that gelatinized wheat whole wheat flour of any one of the Examples, Comparative Examples, and Control Examples was used instead of gelatinized wheat flour.

[0035] [Production Example 3: Bread Production] A raw material flour was prepared containing 10% by mass of any one type of gelatinized wheat flour from the Examples, Comparative Examples, and Control Examples and 90% by mass of strong flour ("Camellia" manufactured by Nisshin Flour Milling Co., Ltd.) by weight. 100 parts by mass of the raw material flour, 4 parts by mass of butter, 6.8 parts by mass of sugar, 2.4 parts by mass of skim milk, 2 parts by mass of salt, and 1.1 parts by mass of dry yeast were placed in a bread maker (manufactured by Panasonic Corporation, product name "SD-BM103"), and bread was made by selecting the "standard course" provided by the bread maker.

[0036] [Production Example 4: Production of cold boiled udon noodles] A raw material flour was prepared containing 10% by mass of any one type of gelatinized wheat flour from the Examples, Comparative Examples, and Control Examples described above, 45% by mass of all-purpose flour ("Kunpu" manufactured by Nisshin Flour Milling, Inc.), 40% by mass of acetylated tapioca starch ("Ajisai" manufactured by Matsutani Chemical Industry Co., Ltd.), and 5% by mass of wheat protein ("A-Glu G" manufactured by Glico Nutrition Foods Co., Ltd.). An appropriate amount of water in which 3 parts by mass of salt had been dissolved was added to 100 parts by mass of the raw material flour, and the mixture was kneaded under a reduced pressure of -90 kPa to prepare a noodle dough. The noodle dough was then rolled and cut into noodle strands 3 mm thick using a cutting blade (#10 angle). The noodle strands were then boiled in water, washed with water, and cooled. 3 parts by mass of a loosening agent ("Soya Up M3000" manufactured by Fuji Oil Co., Ltd.) was uniformly sprayed onto 100 parts by mass of the cooled noodle strands to produce boiled udon noodles. The boiled udon was stored in a refrigerator at an internal temperature of 5°C for 24 hours to produce cold boiled udon.

[0037] [Pancake and bread evaluation] The prepared pancakes and breads were tasted by 10 expert panelists and rated for texture according to the following criteria. For each type of pancake or bread, two types were prepared and evaluated: 1) immediately after preparation and 2) after refrigerating for one day. Sample 1) was baked and then left at room temperature for 20 minutes. Sample 2) was baked, cooled, then stored in a refrigerator at 4°C for one day, and then removed from the refrigerator and left at room temperature for 20 minutes. Sample 2) "refrigerated for one day" was used to accelerate the deterioration of the pancakes and bread over time (starch retrogradation resistance). Sample 2) was used for the accelerated deterioration test. Tables 1 and 2 show the arithmetic mean values ​​of the scores given by the 10 expert panelists. The control example for each example and comparative example in Table 1 is Control Example 1, and the control example for each example in Table 2 is Control Example 2. <Evaluation criteria for pancake and bread texture> 5 points: Very moist and soft compared to the control. 4 points: Moist and softer than the control. 3 points: Slightly moister and softer than the control. 2 points: Equivalent to the control. 1 point: Dry and hard compared to the control.

[0038] [Evaluation of cold boiled udon noodles] The cold boiled udon noodles stored in the refrigerator were taken out of the refrigerator and immediately eaten by 10 expert panelists, who then rated the texture according to the following evaluation criteria. Table 1 shows the arithmetic mean values ​​of the scores given by the 10 expert panelists. <Evaluation criteria for texture of cold boiled udon noodles> 5 points: Viscoelasticity is significantly superior to the control. 4 points: Superior viscoelasticity compared to the control example. 3 points: Slightly better viscoelasticity than the control example. 2 points: Equivalent to the control. 1 point: Viscoelasticity is inferior to the control.

[0039] [Evaluation of whole wheat pancakes] After baking, the whole wheat pancakes were cooled and then stored in a refrigerator at 4°C for one day. They were then removed from the refrigerator and left at room temperature for 20 minutes. They were then cut into bite-sized pieces and eaten by 10 expert panelists. They were asked to rate the texture according to the "Evaluation Criteria for Pancake and Bread Texture" above, and the flavor according to the following evaluation criteria. Table 3 shows the arithmetic mean values ​​of the scores given by the 10 expert panelists. Control Example 3 is the control example for each of the Examples and Comparative Examples in Table 3. <Evaluation criteria for the flavor of whole wheat pancakes> 5 points: The bran smell and harshness are very weak compared to the control. 4 points: The bran smell and harshness are weaker than the control. 3 points: The bran smell and harshness are slightly weaker than the control. 2 points: Equivalent to the control. 1 point: The bran smell and harshness are stronger than the control sample.

[0040] [Table 1]

[0041] As shown in Table 1, in each example, a slurry was prepared by adding 500 or more parts by mass of water to 100 parts by mass of raw grain flour, and the slurry was then heated and dried in a drum dryer to produce gelatinized grain flour.As a result, the texture of processed foods (pancakes, bread, udon) was superior to that of comparative examples and control examples that did not meet these requirements, and products stored in the refrigerator for one day were highly rated, indicating that the starch had excellent resistance to aging and that quality deterioration over time was suppressed.

[0042] [Table 2]

[0043] As shown in Table 2, Example 12, which used low-amylose wheat flour as the raw flour for the gelatinized flour, had superior texture and starch retrogradation resistance compared to other Examples that did not use low-amylose wheat flour.

[0044] [Table 3]

[0045] As shown in Table 3, in each example, a slurry was prepared by adding 500 or more parts by mass of water to 100 parts by mass of raw grain flour, and the slurry was then heated and dried in a drum dryer to produce gelatinized grain flour.Therefore, compared to the comparative examples and control examples that did not meet these requirements, the texture of the processed food (pancakes) and the starch's resistance to aging were superior, and furthermore, despite the use of whole wheat flour as the raw grain flour, the unpleasant bran odor and acrid taste were sufficiently reduced. [Industrial Applicability]

[0046] According to the present invention, there is provided a gelatinized grain flour that can be used to produce secondary processed products that have a good taste and texture and are excellent in resistance to deterioration over time. More specifically, for example, when the gelatinized flour provided by the present invention is used to produce bakery foods, bakery foods that are fluffy, soft, moist, and chewy can be obtained, and when it is used to produce noodles, noodles with excellent viscoelasticity and a good texture can be obtained, and in either case, the good taste and texture can be maintained for a long period of time. Furthermore, when the gelatinized flour provided by the present invention is gelatinized whole wheat flour made from whole wheat flour, the characteristic odor and harshness caused by the bran in the whole wheat flour can be reduced, and secondary processed products that can exhibit the above-mentioned excellent effects can be produced.

Claims

1. The method includes a step of heating and drying a slurry containing 100 parts by mass of flour and 500 to 1500 parts by mass of water in a drum dryer, The flour is at least one selected from low-amylose wheat flour and whole wheat flour, The method for producing gelatinized flour, wherein the low-amylose wheat flour is wheat flour derived from wheat lacking expression of any two or all of the three amylose synthesis genes Wx-A1, Wx-B1, and Wx-D1.

2. The method for producing gelatinized grain flour according to claim 1, wherein the temperature of the heating section of the drum dryer is 100 to 150°C.

3. A method for producing gelatinized grain flour as described in claim 1, wherein the water content in the slurry is 800 to 1,500 parts by mass per 100 parts by mass of the grain flour.

4. A method for producing gelatinized grain flour as described in claim 1, wherein the gelatinized grain flour is for use in bakery foods.

5. A method for producing a processed food, using as a raw material the gelatinized grain flour produced by the method according to any one of claims 1 to 4.

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