Manufacturing method of gelatinized grain flour

Abstract

To provide pregelatinized starches which have excellent resistance to starch retrogradation and can be used to produce starch-containing foods having good texture. [Solution] The method for producing gelatinized cereal flour of the present invention comprises a heating step of heating a mixture containing 100 parts by mass of raw cereal flour, 1 part by mass or more of sugar, and 30 parts by mass or more of water, and a drying step of drying the mixture that has undergone the heating step to obtain a solid product. In the heating step, either Method A or B below is carried out. (Method A) When the raw material cereal flour is starch, the mixture is heated under conditions such that the product temperature is 90°C or higher and 160°C or lower. (Method B) When the raw material cereal flour is cereal flour, the mixture is heated under conditions such that the product temperature is higher than 120°C and not higher than 160°C.

Description

[Technical Field]

[0001] The present invention relates to a method for producing gelatinized cereal flour suitable for food applications. [Background technology]

[0002] Pregelatinized starch is produced by heating raw starch in the presence of water to pregelatinize (gelatinize). Pregelatinization disrupts the molecular arrangement inside the starch granules, resulting in irreversible changes in properties such as swelling of the starch granules, loss of birefringence, melting of natural microcrystals, and solubilization of the starch. For this reason, pregelatinized starch exhibits unique properties different from those of raw starch, and is widely used in food and industrial applications. Conventional methods for producing pregelatinized starch include drying starch slurry using a spray dryer, drum dryer, etc. Other known methods include adding water to starch and heating it while kneading it in an extruder, and heating and humidifying it by passing superheated steam through a container containing the starch.

[0003] Patent Documents 1 and 2 disclose methods for producing heat-treated wheat flour, which include a step of heating a mixture of wheat flour and sugars. The method for producing heat-treated wheat described in Patent Document 1 includes the steps of mixing wheat flour with one or more carbohydrates selected from the group consisting of oligosaccharides and sugar alcohols, and subjecting the mixture to a moist heat treatment. The moist heat treatment involves adding water to the mixture and storing the mixture in an airtight container at an ambient temperature of 100 to 120°C for 3 to 60 seconds, with the amount of water added being 5 to 20% by mass of the mixture. The heat-treated wheat produced by the method described in Patent Document 1 is said to be capable of producing bakery foods that are less likely to lose texture over time. The method for producing heat-treated wheat described in Patent Document 2 involves mixing 100 parts by mass of wheat flour, a secondary ingredient, and more than 30 parts by mass and not more than 40 parts by mass of water at 70°C to 100°C, and heating the mixture at an ambient temperature of 100°C to less than 120°C for 3 to 60 seconds. The secondary ingredient is one or more selected from a pH-adjusting ingredient, sugar and / or sugar alcohol, and enzymes. The heat-treated wheat produced by the method described in Patent Document 2 is said to be capable of producing bakery foods that maintain a moist and chewy texture even when stored frozen for long periods. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-175954 [Patent Document 2] International Publication No. 2023 / 149267 Summary of the Invention [Problem to be solved by the invention]

[0005] Starch retrogradation is a problem in starch-containing foods. Starch retrogradation is a phenomenon in which pregelatinized starch releases the moisture it has incorporated and transforms into beta crystals. For example, some bakery foods, which are a type of starch-containing food, are desired to have a moist and soft texture (moistness). However, the starch contained in such bakery foods retrogrades during transportation, sale, and storage, and the original moistness is lost, resulting in a dry, undesirable texture. There is a demand for technology that can provide starch-containing foods with excellent shelf life.

[0006] An object of the present invention is to provide a pregelatinized starch that has excellent resistance to starch retrogradation and can be used to produce starch-containing foods that have a good texture. [Means for solving the problem]

[0007] The present invention is a method for producing gelatinized grain flour, which comprises a heating step of heating a mixture containing 100 parts by mass of raw grain flour, 1 part by mass or more of sugar, and 30 parts by mass or more of water, and a drying step of drying the mixture that has undergone the heating step to obtain a solid, wherein the heating step involves carrying out either method A or B below. (Method A) When the raw material cereal flour is starch, the mixture is heated under conditions such that the product temperature is 90°C or higher and 160°C or lower. (Method B) When the raw material cereal flour is cereal flour, the mixture is heated under conditions such that the product temperature is higher than 120°C and not higher than 160°C.

[0008] The present invention also relates to a method for producing processed foods or bakery foods using the gelatinized grain flour produced by the production method of the present invention. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide pregelatinized grain flours that have excellent resistance to starch retrogradation and can be used to produce starch-containing foods that have a good texture. DETAILED DESCRIPTION OF THE INVENTION

[0010] The method for producing gelatinized cereal flour of the present invention comprises a step of heating a mixture containing raw cereal flour, sugars, and water (heating step), and a step of drying the mixture that has been heated to obtain a solid (drying step). The heating step causes the starch contained in the raw cereal flour in the mixture to be gelatinized, and the raw cereal flour becomes gelatinized cereal flour. Therefore, the heating step can also be considered a gelatinization step.

[0011] The method for producing gelatinized grain flour of the present invention typically includes a step of preparing a mixture to be heated in the heating step (preparation step). That is, the method for producing gelatinized grain flour of the present invention typically includes a preparation step, a heating step (gelatinization step), and a drying step, each of which is carried out in this order.

[0012] As the raw material flour used in the preparation step, basically, any flour that can be used in food production can be used without particular restrictions. In this specification, "flour" refers to a substance derived from a grain that is powdery at room temperature and normal pressure, and is a concept that includes grain flour and starch. "Starch" as used here refers to "pure starch" isolated from plants such as wheat, and is distinguished from starch that is inherently contained in grain flour or whole grain flour. Furthermore, the grains from which "flour" is derived include not only cereals (seeds of grass plants), but also pseudocereals (seeds of dicotyledonous plants), pulses (seeds of legumes), and potatoes (edible tuberous roots or stems), etc., as long as they contain starch as an ingredient.

[0013] The raw material flour (grain flour, starch) used in the preparation step may be any material containing starch, regardless of the amylose content, and in the case of grasses, may be either non-glutinous or glutinous. The raw material flour used in the preparation step may be one type or two or more types. Specific examples of flour include flours primarily composed of the endosperm, such as wheat flour (specifically, for example, strong flour, medium flour, soft flour, durum wheat flour, and durum semolina), rice flour, buckwheat flour, rye flour, soy flour, barley flour, and corn flour, as well as flours containing at least the outer skin and / or germ, such as "bran" primarily composed of the outer skin, and "whole wheat flour" containing the three main components of the endosperm, outer skin, and germ. Specific examples of bran and whole wheat flour include wheat bran and whole wheat flour, which are derived from wheat. However, bran has a relatively low starch content and is somewhat less suitable as a raw material for the gelatinized flours targeted in the present invention, so it is preferable to use flours other than bran as the raw material flours used in this process. Specific examples of starch include unmodified starches such as potato starch, wheat starch, corn starch, waxy corn starch, rice starch, and tapioca starch; and modified starches obtained by subjecting unmodified starch to one or more of the following treatments: oil / fat processing, etherification, esterification, acetylation, cross-linking, and oxidation.

[0014] The raw flour used in the preparation step is typically unprocessed flour that has not been subjected to pretreatment such as heating, but pretreated raw flour can also be used. Examples of the pretreatment include adding various flour modifiers to the raw flour. The flour modifiers are agents that can modify the properties of the flour to desired properties, and examples of such agents 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 preparation step, a mixture is prepared by adding 30 parts by mass or more of water to 100 parts by mass of raw grain flour. That is, the water content in the mixture is 30 parts by mass or more per 100 parts by mass of raw grain flour contained in the mixture. If the amount of water added in the preparation step is less than 30 parts by mass per 100 parts by mass of raw grain flour, the retrogradation resistance of the starch contained in the mixture will be poor, and the desired effect of the present invention may not be achieved. In the preparation step, the amount of water added per 100 parts by mass of the raw material cereal flour is preferably 35 to 60 parts by mass, more preferably 45 to 60 parts by mass. If the amount of water added is too much, a lot of time and energy will be required to obtain a solid product in the subsequent drying step, which may increase production costs and reduce production efficiency.

[0016] In the preparation process, a specific amount of sugars is also added to a mixture containing raw cereal flour and water. When the mixture contains a specific amount of sugars, it is thought that when the starch in the cereal flour is gelatinized by heating, the amylose and amylopectin in the starch interact with the polysaccharides, resulting in a superior effect in improving the starch's resistance to retrogradation compared to when the mixture does not contain sugars. When pregelatinized flour is obtained from the sugar-free mixture and then used in combination with sugars in the production of processed foods, the significant effects obtained when pregelatinized flour obtained from the sugar-containing mixture are not obtained.

[0017] Specific examples of sugars include monosaccharides, disaccharides, trisaccharides, oligosaccharides, dextrins, and sugar alcohols. In the preparation step, these sugars can be used alone or in combination of two or more. Specific examples of monosaccharides include glucose, fructose, galactose, xylose, and arabinose. Specific examples of disaccharides include sucrose, maltose, isomaltose, and trehalose. A specific example of a trisaccharide is maltotriose. A specific example of an oligosaccharide is maltooligosaccharide. Specific examples of sugar alcohols include reduced maltose, reduced starch syrup, reduced palatinose, xylitol, erythritol, sorbitol, mannitol, and lactitol.

[0018] In the preparation step, the amount of sugar added is 1 part by mass or more, preferably 2 to 10 parts by mass, and more preferably 3 to 5 parts by mass, per 100 parts by mass of the raw material flour. If the amount of sugar added is too small, the intended effect of the present invention may not be fully achieved. From the perspective of improving the retrogradation resistance of starch and enhancing the quality of pregelatinized grain flour, the greater the amount of sugar added, the better. However, if the amount of sugar added is too high, the stickiness of the pregelatinized grain flour increases, reducing the handleability of the pregelatinized grain flour and potentially reducing the production efficiency of the pregelatinized grain flour itself or processed foods using it.

[0019] The mixture prepared in the preparation step typically contains only raw flour, sugar, and water as a solvent, but may contain other ingredients, such as a flour modifier that can be used in the pretreatment of the raw flour, as necessary. In this case, 1) a mixture containing flour pretreated with a flour modifier may contain a flour modifier that is the same as or different from the flour modifier, or 2) a mixture containing unprocessed flour may contain a flour modifier. In a mixture containing a flour modifier, a reaction involving the flour modifier, such as an enzymatic reaction, occurs, and this reaction may be completed before the slurry is subjected to the subsequent drying step, or may occur during the drying step.

[0020] In the heating step, the method for heating the mixture is not particularly limited. A typical heating method is to place a mixture containing raw grain flour and sugar in a container and heat the container. The mixture may be heated batchwise or continuously. Examples of the container for holding the mixture when heated include a pressure cooker when a batchwise method is used and a line mixer such as a static mixer when a continuous method is used. The heating means is also not particularly limited, and examples include electric, gas, and steam types, and these can be used alone or in combination of two or more. An example of a method for heating the mixture using steam heating means is to directly introduce saturated steam or superheated steam into a container containing the mixture.

[0021] A preferred example of a method for heating the mixture in the heating step is a heating method using an extruder. An extruder is a type of food processing equipment that is configured to convey a material to be treated (the mixture) inside the extruder, subject the material to treatment, such as kneading, pressurization, and heating, and then extrude the material to the outside of the extruder. An extruder typically includes a hollow cylindrical barrel having an internal flow path for the material to be treated, a screw disposed in the flow path and driven to rotate by a drive source such as a motor, and a feeder that supplies the material to the flow path. A heating means such as a cartridge heater is attached around the barrel, and the interior of the barrel can be heated by the heating means. In an extruder configured as described above, the material to be treated is supplied into the barrel by the feeder and then conveyed by the screw toward the tip of the barrel (the end of the barrel downstream in the direction of conveyance of the material to be treated). During conveyance within the barrel, the material is kneaded and heated, and finally extruded to the outside from the outlet of the extruder. When the material to be treated is pressurized in the barrel, the material to be treated may expand to become an expanded material when extruded from the outlet of the extruder into a normal pressure environment.

[0022] The "extruder outlet" differs depending on whether the extruder is equipped with a die. A die is a component that constitutes the downstream side of the extruder in the conveying direction of the material to be processed, and is connected to the tip of the barrel when in use. It has an inlet opening into which the material to be processed that has passed through the barrel is introduced, an outlet opening from which the material to be processed is extruded, and a flow path connecting these openings. When a die is connected to the tip of the barrel, the extruder outlet is the outlet opening of the die. On the other hand, when a die is not connected to the tip of the barrel, the extruder outlet is the opening at the tip of the barrel (the open end of the barrel flow path downstream in the conveying direction of the material to be processed).

[0023] There are various extruders, including single-screw extruders having one of the above screws, twin-screw extruders having two of the above screws, and multi-screw extruders having three or more of the above screws, and any of these can be used in the present invention. From the viewpoints of achieving the desired effects of the present invention and improving the efficiency of the production process, a twin-screw extruder is preferred.

[0024] The heating conditions for the mixture in the heating step vary depending on the type of raw material flour used to prepare the mixture. Specifically, the heating conditions are as follows: When the raw material flour is starch, the mixture is heated under conditions such that the product temperature is 90°C or higher and 160°C or lower (Method A). In Method A, the product temperature of the mixture during heating is preferably higher than 120°C and 160°C or lower, more preferably 130°C or higher and 160°C or lower, and even more preferably 150°C or higher and 160°C or lower. When the raw material cereal flour is cereal flour (for example, wheat flour), the mixture is heated under conditions such that the product temperature is higher than 120°C and not higher than 160°C (Method B). In Method B, the product temperature of the mixture during heating is preferably 130°C or higher and 160°C or lower, more preferably 150°C or higher and 160°C or lower.

[0025] The higher the heating temperature of the mixture, the more the starch modification progresses and the more likely the desired effects of the present invention are to be achieved. However, if the heating temperature is too high, the amount of heat applied to the mixture increases, making it difficult to control the pressure inside the container containing the mixture, which may lead to increased production costs or decreased productivity. The heating conditions (product temperature of the mixture when heated) in Methods A and B were determined taking these factors into consideration. Heating under conditions that raise the product temperature of the mixture to above 100°C can be achieved, for example, by heating the mixture in a pressurized atmosphere.

[0026] When the heating step (method A or B) is carried out using an extruder, the product temperature (heating temperature) of the mixture in the heating step can be the outlet temperature of the extruder. The "extruder outlet temperature" refers to the temperature of the components at the extruder outlet or in the vicinity thereof, or the ambient temperature. As mentioned above, the "extruder outlet" differs depending on whether or not the extruder is equipped with a die; if the extruder is equipped with a die, it is the "exit opening of the die," and if the extruder is not equipped with a die, it is the "opening at the tip of the barrel." The "vicinity of the extruder outlet" may be, for example, a portion within 1 / 3 of the total length of the extruder upstream from the extruder outlet (the outlet opening of the die or the opening at the tip of the barrel) in the conveying direction of the material to be treated. The "temperature of a component" is the temperature of a component that defines the outlet of the extruder or its vicinity, and may be, for example, the temperature of a wall that defines the flow path of a die or barrel. The "ambient temperature" may be the temperature of the atmosphere at the outlet of the extruder or in the flow path nearby.

[0027] The heating time of the mixture in the heating step (the time for maintaining the product temperature) is preferably 20 to 90 seconds, more preferably 30 to 60 seconds, regardless of the type of raw grain flour, i.e., regardless of whether method A or B is performed, from the standpoint of more reliably achieving the desired effects of the present invention and from the standpoint of production efficiency, etc.

[0028] In the heating step, the mixture is preferably heated in a pressurized atmosphere, i.e., the mixture is heated under an atmospheric pressure exceeding 1 atmosphere. This has the effect of promoting gelatinization of the starch contained in the raw material cereal flour. The pressure of the pressurized atmosphere (the atmospheric pressure of the environment in which the mixture exists) can be adjusted appropriately depending on the amount of solvent contained in the mixture and the heating temperature (product temperature of the mixture). When the mixture is heated in a pressurized atmosphere, the upper limit of the product temperature (heating temperature) of the mixture is affected by the pressure of the pressurized atmosphere, so it is preferable to adjust the pressure of the pressurized atmosphere so that the heating temperature is within the desired temperature range. When the mixture is heated in a pressurized atmosphere, the pressure of the pressurized atmosphere is preferably 0.2 to 2 MPa, more preferably 0.5 to 1.5 MPa.

[0029] When the mixture is heated in a pressurized atmosphere using an extruder, the pressure (atmospheric pressure) of the pressurized atmosphere can be the outlet pressure of the extruder. The "extruder outlet pressure" refers to the pressure at or near the extruder outlet. The "extruder outlet or its vicinity" is as described above. The extruder outlet pressure is measured using a pressure gauge installed at or near the extruder outlet. From the viewpoint of more reliably achieving the desired effects of the present invention, the extruder outlet pressure is preferably 0.2 to 2 MPa, more preferably 0.5 to 1.5 MPa.

[0030] In the drying step, the mixture heated in the heating step is dried to obtain a solid material containing pregelatinized cereal flours. The method for drying the mixture is not particularly limited, and known drying methods can be used. For example, drying can be carried out in a conventional manner using a known dryer such as a tray dryer or a fluidized bed dryer. The degree of drying of the mixture is not particularly limited, but typically, the mixture is dried until the moisture content of the solid material obtained by drying is approximately the same as the moisture content of the raw cereal flours used in the preparation step, more specifically, until it is approximately 15% by mass.

[0031] The solid matter of the mixture obtained through the 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 coffee 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.

[0032] The degree of gelatinization (gelatinization degree) of the obtained pregelatinized flours can be preferably 90% or more, more preferably 95% or more. By incorporating pregelatinized flours with such a high degree of gelatinization into foods, the taste and texture of the food are significantly improved, and the food is also endowed with excellent resistance to aging. In this specification, the 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).

[0033] [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)

[0034] (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.

[0035] (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

[0036] Pregelatinized cereal flours (hereinafter also referred to as "specific pregelatinized cereal flours") produced by the production method of the present invention can be used in place of known pregelatinized cereal flours or pregelatinized starches, and can typically be used in the food industry to produce processed foods. The processed foods referred to here are starch-containing foods produced using cereal flours as a raw material, and examples include bakery foods; noodles such as udon, somen, hiyamugi, Chinese noodles, pasta, and instant noodles (including non-fried); fried foods such as tempura, fried chicken, tatsuta-age, and fritters; and powdered foods such as instant soups. Processed foods may also be frozen foods.

[0037] Specific pregelatinized cereal flours are particularly suitable for bakery foods. In this specification, "bakery foods" refers to foods obtained by subjecting dough made from cereal flour as the main ingredient to which, as needed, auxiliary ingredients such as yeast or leavening agents (e.g., baking powder), water, salt, and sugar are added, and then subjecting the resulting dough to heat treatments such as baking, steaming, and frying. Specific examples of bakery foods include breads; pizzas; cakes; Western-style baked goods such as waffles, choux pastries, biscuits, cookies, and crepes; Japanese-style baked goods such as taiyaki, imagawayaki, dorayaki, and ningyoyaki; fried sweets such as cake donuts and ponde rings; and flour-based foods such as okonomiyaki and takoyaki.

[0038] Specific pregelatinized flours are particularly useful for bakery foods that are required to have a moist texture, and examples of such bakery foods include breads, pizzas, cakes, Japanese and Western baked goods such as waffles, choux pastries, biscuits, and baked buns, fried sweets such as donuts, takoyaki, okonomiyaki, and chijimi. Examples of breads include bread (e.g., rolls, white bread, brown bread, French bread, hardtack, buns, and croissants), cooked bread, and sweet buns. Examples of cakes include sponge cakes, butter cakes, roll cakes, hotcakes, bouche, Baumkuchen, pound cakes, cheesecakes, snack cakes, muffins, bars, cookies, pancakes, and crepes.

[0039] A method for producing bakery foods using specific gelatinized grain flours typically includes the steps of preparing a mix containing the specific gelatinized grain flours, adding water to the mix to prepare dough, and subjecting the dough to a heat treatment (baking, steaming, frying, etc.). These steps can be carried out according to conventional methods. The content of the specific gelatinized cereal flour in the mix is ​​preferably 1 to 10% by mass, more preferably 3 to 5% by mass, based on the total mass of the mix. The mix usually contains other cereal flours in addition to the specific gelatinized cereal flours, and as such other cereal flours, any cereal flour that can be used as the cereal flour for the raw cereal flours can be used without any particular restrictions, and wheat flour is typically used. The content of the other cereal flour in the mix is ​​preferably 1 to 10% by mass, more preferably 3 to 5% by mass, based on the total mass of the mix. [Example]

[0040] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0041] [Examples 1 to 18 and Comparative Examples 1 to 7: Production of Pregelatinized Grain Flours] The raw material cereal flour (starch or flour) and sugar were mixed and then water was added to prepare a mixture having the composition shown in Table 1 below (preparation step). With regard to the raw material cereal flour, the starch used was tapioca starch ("Native Tapioca Starch" manufactured by Siam Modified Starch Corporation Co., Ltd.), and the cereal flour used was wheat flour ("Chikugo Mugihata" manufactured by Nisshin Flour Milling Co., Ltd.). Next, the mixture was heated using a twin-screw extruder under conditions that the product temperature of the mixture would be the temperature (extruder outlet temperature) shown in the "Mixture heating temperature (°C)" column in Table 1 below (heating step). The time for which the mixture was maintained at that temperature (heating time) in the heating step was within the range of 15 to 60 seconds. The mixture extruded from the extruder outlet had a long, elongated shape extending in the extrusion direction, and the mixture was cut in the longitudinal direction to obtain a plurality of short mixtures. Next, the short mixture was dried to obtain a solid (drying step). The method of drying the mixture was either 1) using a tray dryer to leave the mixture in an environment with an ambient temperature of 90°C for 8 hours, or 2) using a fluidized bed dryer to dry the mixture under conditions of an internal fluidized bed temperature of 135°C and a residence time of 8 minutes. The choice of 1) or 2) was determined depending on factors such as the amount of the mixture to be dried. Note that there is no substantial difference in the impact on the quality of the resulting product (gelatinized cereal flour) between 1) and 2). Next, the solid was coarsely pulverized using a roll mill, and further pulverized using a pin mill so that the fraction remaining on a 100 μm mesh sieve was approximately 20% by mass, thereby producing the desired gelatinized cereal flour.

[0042] [Table 1]

[0043] [Production Examples 1 to 36: Production of pancakes] Pancakes, a type of bakery food (processed food), were produced using the pregelatinized grain flours of each Example and Comparative Example. Specifically, a pancake mix was first prepared containing essential ingredients accounting for 96.2% by mass of the total mass and selected ingredients accounting for 3.8% by mass of the total mass. The essential ingredients consisted of 73.2% by mass of plain flour, 19.2% by mass of sugar, and 3.8% by mass of baking powder. The selected ingredients consisted of either the pregelatinized grain flours of the Examples or Comparative Examples alone, or the pregelatinized grain flours and sugars of the Comparative Examples (see the "Composition of Selected Ingredients in Mix" column in Table 2 below). Next, 100 parts by mass of the mix, 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 batter with a viscosity of 5 to 10 Pa·s as measured by a B-type viscometer at a product temperature of 25°C. After preparing the batter, the batter was allowed to rest for 10 minutes, and then 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 upside down and baked on the other side for 2 minutes to produce the desired pancakes.

[0044] [Production Examples 37 and 38: Production of donuts] Donuts, a type of bakery food (processed food), were produced using the pregelatinized flours of each Example and Comparative Example. Specifically, a donut mix was first prepared containing essential ingredients accounting for 96.2% by mass of the total mass and selected ingredients accounting for 3.8% by mass of the total mass. The essential ingredients consisted of 73.2% by mass of processed tapioca starch, 19.2% by mass of sugar, and 3.8% by mass of baking powder. The selected ingredients consisted of either the pregelatinized flours of the Examples or Comparative Examples alone, or the pregelatinized flours and sugars of the Comparative Examples (see the "Composition of Selected Ingredients in Mix" column in Table 3 below). Next, 100 parts by mass of the mix, 15 parts by mass of margarine, and an appropriate amount of water were added to a mixer (N50, manufactured by Hobart Japan Co., Ltd.) and mixed at first speed for 120 seconds using a beater to prepare a dough at a product temperature of 25°C. The dough was then divided into 15g portions per donut and shaped into balls. The balls were then dropped into a fryer heated to 180°C and deep-fried for 5 minutes while pressing down with a wire rack to ensure the dough was completely submerged, producing the desired donuts.

[0045] (Evaluation test) For each type of bakery food product (pancakes and donuts) of the Production Examples, two states, "immediately after production" and "after refrigerated storage," were prepared, and 10 expert panelists tasted each product and scored the texture (moistness) according to the following evaluation criteria. Specifically, the bakery food products of the Production Examples were divided into several groups, and one Production Example was selected from each group as a control. The expert panelists were asked to evaluate the texture of the control example immediately after production relative to the other products in the same group, using the texture of the control example immediately after production as the standard and assigning a score of 2 out of 5. The arithmetic mean values ​​of the scores of the 10 panelists are shown in Tables 2 and 3 below as the evaluation results for the texture of the Production Examples. Production examples with evaluation scores exceeding 2 points were deemed to have acceptable texture.

[0046] The "bakery food immediately after production" is a bakery food that has been left in a room temperature environment for 20 minutes immediately after production. The "bakery food after refrigerated storage" is a bakery food that has been left to cool immediately after production, stored in a refrigerator at an internal temperature of 4°C for 3 days, and then removed from the refrigerator and left in a room temperature environment for 20 minutes. The "bakery food after refrigerated storage" is a sample for so-called accelerated deterioration test, and is intended to evaluate the bakery food's resistance to quality deterioration over time (starch retrogradation resistance).

[0047] <Texture evaluation criteria> 5 points: Extremely moist and soft compared to the control, extremely good. 4 points: Moist and soft compared to the control, good. 3 points: Slightly moister and softer than the control, and somewhat better. 2 points: Equivalent to the control case, slightly poor. 1 point: Dry or hard compared to the control, poor quality.

[0048] [Table 2]

[0049] As shown in Table 2, pancakes made using the pregelatinized grain flours of the Examples had a superior texture both immediately after production and after refrigerated storage compared to pancakes made using the pregelatinized grain flours of the Comparative Examples. As shown in Table 1, the pregelatinized grain flours of the Examples were obtained by heating a mixture containing raw grain flours, sugars, and water, whereas the pregelatinized grain flours of the Comparative Examples were obtained by heating a mixture containing raw grain flours and water but no sugars. For example, referring to the Group A column in Table 2, Production Example 1 and Production Example 4 have in common the fact that the selected ingredients in the mix contain approximately the same amount of sucrose. However, Production Example 1 differs in that the selected ingredients contain pregelatinized grain flours and sucrose as separate ingredients, whereas Production Example 4 contains sucrose as part of the pregelatinized grain flours (the raw grain flours and sucrose are integrated). Due to this difference, the pancakes of Production Example 4 have a superior texture compared to Production Example 1. Similar trends to those of Group A are also observed in the other groups. This shows that the use of gelatinized flour obtained by heating raw material flour and sugars in the presence of water is effective in obtaining starch-containing foods (pancakes) that have excellent resistance to aging and a good texture. Production Examples 8 and 10 differ in the sugar content in the mixture, which is a production intermediate of the gelatinized grain flour, with Production Example 10 having a higher sugar content than Production Example 8 (see the columns for Examples 3 and 4 in Table 1), and the texture of the pancakes produced in Production Example 10 was rated higher than that of Production Example 8. However, the gelatinized grain flour of Example 4 used in Production Example 10 was more sticky than the gelatinized grain flour of Example 3 used in Production Example 8 due to its higher sugar content, and the gelatinized grain flour of Example 3 was rated higher in terms of handleability in the gelatinization treatment step.

[0050] [Table 3]

[0051] As shown in Table 3, the donuts made using the gelatinized grain flour of the example had a superior texture both immediately after production and after refrigerated storage compared to the donuts made using the gelatinized grain flour of the comparative example.

Claims

1. a heating step of heating a mixture containing 100 parts by mass of raw grain flour, 1 part by mass or more of sugar, and 30 parts by mass or more of water; a drying step of drying the mixture that has been subjected to the heating step to obtain a solid product, A method for producing gelatinized grain flour, comprising carrying out the following method A or B in the heating step. (Method A) When the raw material cereal flour is starch, the mixture is heated under conditions such that the product temperature is 90°C or higher and 160°C or lower. (Method B) When the raw material cereal flour is cereal flour, the mixture is heated under conditions such that the product temperature is higher than 120°C and not higher than 160°C.

2. The method for producing gelatinized grain flour according to claim 1, wherein in the method A, the mixture is heated under conditions such that the product temperature is higher than 120°C and not higher than 160°C.

3. The method for producing gelatinized grain flour according to claim 1 or 2, wherein the sugar is one or more selected from the group consisting of monosaccharides, disaccharides, trisaccharides, oligosaccharides, dextrins, and sugar alcohols.

4. The method for producing gelatinized grain flour according to claim 1 or 2, wherein the mixture is heated in a pressurized atmosphere in the heating step.

5. A method for producing processed foods, which uses gelatinized grain flour produced by the method according to claim 1 or 2.

6. A method for producing bakery foods, which uses gelatinized grain flour produced by the method according to claim 1 or 2.

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