Pregelatinized cereal flour and manufacturing method thereof

Abstract

The pregelatinized cereal flour of the present invention has a mechanical loss tangent of less than 1 at a strain rate of 268% or less in a strain-dependent measurement of dynamic viscoelasticity at a temperature of 25°C and a frequency of 1 Hz in the state of being mixed with water in an amount 10 times as much as the own weight thereof. The manufacturing method of the pregelatinized cereal flour of the present invention includes a step for adding and mixing 500 parts by mass or more of water to 100 parts by mass of a starting cereal flour to obtain a slurry, and then heating and drying the slurry in a drum dryer. Preferably, in the manufacturing method of the pregelatinized cereal flour, the starting cereal flour is prepared from a waxy species.

Description

Pregelatinized grain flour and its manufacturing method

[0001] The present invention relates to gelatinized flours that are useful as raw materials for processed foods.

[0002] Pregelatinized flours are produced by heat-treating raw material flours in the presence of moisture to gelatinize (gelatinize) the starch contained in the flour, and are used in food applications, industrial applications, etc. Known methods for producing pregelatinized flours include drying a slurry containing flour using a spray dryer, drum dryer, etc., adding water to flour and heating it while kneading it in an extruder, and heating and humidifying it by passing superheated steam through a container containing flour.

[0003] Patent Document 1 describes a food-grade pregelatinized starch that can impart a good texture to wheat flour-containing foods, which is obtained by pregelatinizing a starch-wheat flour blend obtained by blending wheat flour with starch in a drum dryer. Patent Document 2 describes a wheat flour for breadmaking that can produce bread with a good texture and flavor and slow staling, which contains pregelatinized wheat flour and α-amylase and / or pullulanase, and cites an example of the pregelatinized wheat flour that is obtained by mixing raw wheat flour with 1 to 3 times the amount of water and drying it in a drum dryer.

[0004] Patent Document 3 describes a shape-retaining food that contains a starch-containing substance with a degree of gelatinization of 30% or more and a sweetener, and that has a storage modulus G' and a loss modulus G" that are each within a specific range as determined by a dynamic viscoelasticity measurement method at an angular frequency of 1 rad / sec and a temperature of 25°C. The shape-retaining food described in Patent Document 3 is specifically a jelly confectionery that is said to be smooth and able to maintain a self-standing shape.

[0005] JP 2007-169442 A JP 2004-129607 A JP 2019-216677 A

[0006] Starch retrogradation is a problem in foods that contain a relatively large amount of starch. For example, in processed foods that are primarily made from wheat flour, retrogradation of the starch in the wheat flour progresses during storage, resulting in a problem of texture deterioration over time, such that a food that was moist, soft, and had a good texture immediately after production becomes dry and hard after storage for a certain period of time, and this tendency is particularly noticeable when stored in a refrigerator. There has yet to be provided a pregelatinized flour that has excellent resistance to starch retrogradation and can be used to produce processed foods such as cooked dough foods that have an excellent texture not only immediately after production but also when stored in a refrigerator after production.

[0007] An object of the present invention is to provide a gelatinized grain flour that can be used to produce processed foods that have a good texture and can maintain that good texture even when stored in a refrigerator.

[0008] The present invention relates to gelatinized grain flours that, when mixed with 10 times their own weight in water and the strain dependency of their dynamic viscoelasticity is measured at a temperature of 25°C and a frequency of 1 Hz, have a mechanical loss tangent of less than 1 at a strain rate of 268% or less.

[0009] The present invention also provides a method for producing gelatinized grain flour, which, when mixed with 10 times its own weight of water and the strain dependence of its dynamic viscoelasticity is measured at a temperature of 25°C and a frequency of 1 Hz, has a mechanical loss tangent of less than 1 at a strain rate of 268% or less, the method comprising the steps of adding and mixing 500 parts by mass or more of water to 100 parts by mass of raw grain flour to obtain a slurry, and then heating and drying the slurry in a drum dryer.

[0010] The present invention also relates to a mix for processed foods containing pregelatinized grain flour. The present invention also relates to a processed food produced using the pregelatinized grain flour of the present invention and / or the mix of the present invention.

[0011] Figure 1 is a graph showing an example of a "strain rate-G', G", tan δ curve" for gelatinized flour obtained by measuring the strain dependency of dynamic viscoelasticity according to the present invention. Figures 2(a) to 2(h) are each a schematic diagram of an example of a drum dryer that can be used in the method for producing gelatinized flour of the present invention.

[0012] The gelatinized flours of the present invention are flours that have been subjected to gelatinization treatment. In this specification, the term "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 herein 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, grains from which "flours" are 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), as long as they contain starch as an ingredient.

[0013] As used herein, "gelatinization treatment" refers to a treatment in which raw material grain flour is heated in the presence of moisture. The gelatinized grain flour of the present invention may be subjected to one or more types of processing treatment other than gelatinization treatment. Examples of processing treatment other than gelatinization treatment include cross-linking treatment, phosphorylation treatment, acetylation treatment, etherification treatment, and oxidation treatment. When the gelatinized grain flour of the present invention has been subjected to multiple processing treatments including gelatinization treatment, the order of these multiple processing treatments during the production of the gelatinized grain flour is not particularly limited.

[0014] When the strain dependency of dynamic viscoelasticity of the gelatinized grain flour of the present invention is measured at a temperature of 25°C and a frequency of 1 Hz while mixed with water in an amount 10 times its own weight, the mechanical loss tangent at a strain rate of 268% or less is less than 1. Due to this characteristic, the gelatinized grain flour of the present invention can provide processed foods that have a good texture and can maintain that good texture even when stored in a refrigerator.

[0015] The mechanical loss tangent (tan δ) is calculated using the storage modulus (G') and loss modulus (G") of the substance (gelatinized flour) in question using the following formula: tan δ = G" / G'. G' is an index of the strength of the elasticity (solid properties) of the substance in question, and G" is an index of the strength of the viscosity (liquid properties) of the substance in question; the larger the value of tan δ, the stronger the liquid properties of the substance. Generally, if tan δ > 1, the substance is considered to be a sol, if tan δ < 1, the substance is considered to be a gel, and if tan δ = 1, the substance is considered to be at the sol-gel transition point.

[0016] The strain-dependence measurement of dynamic viscoelasticity according to the present invention will now be described. As described above, the sample is a mixture of the gelatinized cereal flour to be measured and water in an amount 10 times its own weight. Specifically, for example, a mixture of 100 parts by mass of gelatinized cereal flour and 1,000 parts by mass of water can be used as the sample. The sample is measured 10 minutes after its preparation is complete. An example of a dynamic viscoelasticity measuring device is the dynamic viscoelasticity measuring and analyzing device "MC302" manufactured by Anton Paar Japan Co., Ltd. The procedure for measuring the strain-dependence of dynamic viscoelasticity according to the present invention will be described using the MC302 as an example. The sample is placed on the lower disc (φ57 mm) of the MC302 and sandwiched between the upper disc (φ25 mm) and the lower disc. The gap between the two discs is 1 mm, and the temperature of the lower disc is controlled at 25°C during measurement. Then, with the frequency held constant at 1 Hz (6.28 rad / s), G' and G" are continuously measured while the strain rate (shear force) is gradually increased from 0.1 to 1000%. Specifically, for example, 29 measurement points (preferably 20 or more) are set between strain rates of 0.1 to 1000%, and G' and G" are measured at the strain rates associated with these measurement points. In this case, the spacing between adjacent measurement points is set so that they are equally spaced when the common logarithm of the strain rate is taken. For example, when 29 measurement points are set between strain rates of 0.1 to 1000%, the interval 4 between log 0.1 and log 1000 is equally divided into 28 (= 29 - 1), so the spacing between adjacent measurement points is approximately 0.143 (= 4 / 28).

[0017] FIG. 1 shows an example of a "strain rate - G', G", tan δ curve" for pregelatinized flours obtained by measuring the strain dependency of dynamic viscoelasticity according to the present invention. For the pregelatinized flours in FIG. 1, when the strain rate is relatively small, G' and G" change very little, and therefore tan δ also changes very little. However, when the strain rate reaches a certain level, G' decreases and G" increases as the strain rate increases, and since the decrease in G' is greater at this time, the value of tan δ increases as the strain rate increases. This tendency for tan δ to increase as the strain rate increases is common to many pregelatinized flours. For the pregelatinized flours in FIG. 1, tan δ is less than 0.5 at a strain rate of 268%, and tan δ = 1 when the strain rate is over 370%, so tan δ is less than 1 at strain rates of 268% or less.

[0018] From the viewpoint of improving the texture of processed foods and further improving the retrogradation resistance of starch, it is preferable that the gelatinized grain flour of the present invention has a tan δ of less than 1 at a strain rate of 268% or less, and further has a tan δ of less than 1 at a strain rate of 373% or less, when the strain dependence of dynamic viscoelasticity is measured at a temperature of 25°C and a frequency of 1 Hz while mixed with water in an amount 10 times its own weight.

[0019] The tan δ of gelatinized grain flours can be adjusted by appropriately adjusting the type of grain flour used as the raw material for the gelatinized grain flour, the conditions of the gelatinization treatment (heating means, heating conditions) applied to the grain flour in the production process of the gelatinized grain flour, etc.

[0020] The gelatinized cereal flour of the present invention may be either non-glutinous or glutinous (waxy) flour, but is preferably glutinous from the viewpoints of improving the texture of processed foods and further improving the retrogradation resistance of starch. That is, the gelatinized cereal flour of the present invention is preferably a gelatinized product of glutinous cereal flour. Examples of the gelatinized cereal flour of the present invention that is glutinous include pregelatinized glutinous wheat flour, pregelatinized glutinous rice flour, pregelatinized waxy cornstarch, and pregelatinized glutinous tapioca starch.

[0021] The degree of gelatinization (degree of gelatinization) of the pregelatinized grain flours of the present invention is not particularly limited, but is preferably 90% or higher, more preferably 95% or higher. The degree of gelatinization of pregelatinized grain flours can be adjusted by appropriately adjusting the conditions (heating means, heating conditions) of the gelatinization treatment applied to the grain flour in the production process of the pregelatinized grain flour. As used herein, "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 ( Home Economics Journal 32(9), 653-659, 1981).

[0022] [Method for measuring the degree of gelatinization by the β-amylase-pullulanase method] (A) Reagents The reagents used are as follows. 1) 0.8 M acetic acid-Na acetate buffer solution 2) 10 N sodium hydroxide solution 3) 2 N 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 reagent and Nelson reagent (reagents for measuring the amount of reducing sugars)

[0023] (B) Measurement Method B-1) The sample (gelatinized cereal flour) is pulverized using a homogenizer to a mesh size of 100 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, obtaining a dispersion. B-3) 2 mL of the dispersion from B-2) is placed in each of two 25 mL graduated test tubes, and one of the two tubes is made to volume with 0.8 M acetic acid-Na acetate buffer to serve as the test group. B-4) 0.2 mL of 10 N sodium hydroxide solution is added to the other of the two tubes, and the mixture is allowed to react at 50°C for 3 to 5 minutes to completely gelatinize the dispersion from B-2). Next, 1.0 mL of 2N acetic acid solution was added to the other tube, the pH was adjusted to around 6.0, and the volume was adjusted to the required volume with 0.8M acetic acid-Na acetate buffer to create the gelatinized section. B-5) 0.4 mL of each of the test and gelatinized sections prepared in B-3) and B-4) was taken, and 0.1 mL of enzyme solution was added to each. The enzyme reaction was carried out at 40°C for 30 minutes to obtain a reacted solution. At the same time, a blank was prepared by adding 0.1 mL of inactivated enzyme solution instead of the enzyme solution. The enzyme reaction was carried out while occasionally stirring the reaction solution during the reaction. B-6) 0.5 mL of Somogyi reagent was added to 0.5 mL of the reacted solution and the blank, and the mixture was boiled in a boiling bath for 15 minutes. After boiling, the mixture was cooled in running water for 5 minutes, and then 1.0 mL of Nelson's reagent was added, stirred, and left to stand 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.

[0024] (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 completely gelatinized test solution)} x 100 = {(A-a) / (A'-a')} x 100 In the formula, A, A', a, and a' are as follows: A = absorbance of test group A' = absorbance of gelatinized group a = absorbance of blank of test group a' = absorbance of blank of gelatinized group

[0025] Next, the method for producing the gelatinized grain flour of the present invention will be described. For points not specifically described regarding the method for producing the gelatinized grain flour of the present invention, the above description of the gelatinized grain flour of the present invention will be applied as appropriate.

[0026] The method for producing gelatinized cereal flour of the present invention comprises a step of preparing a slurry containing raw cereal 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 raw cereal flour in the slurry to be gelatinized, thereby obtaining the desired gelatinized cereal flour.

[0027] The raw cereal flour may be cereal flour or starch, and may be either non-glutinous or glutinous. In the present invention, one type of raw cereal flour may be used, or two or more types of raw cereal flour may be used. Of the three main components constituting a cereal caryopsis (endosperm, husk, and embryo), cereal flours that can be used as raw cereal flours include those primarily composed of the endosperm (e.g., wheat flour) and those containing the husk and / or embryo. Specific examples of the latter include "bran" primarily composed of the husk, and "whole wheat flour" containing the three main components of endosperm, husk, and embryo. Specific examples of bran and whole wheat flour include wheat bran and whole wheat flour, which are derived from wheat. Specific examples of flour include wheat flour, rice flour, barley flour, rye flour, oat flour, corn flour, soy flour, and buckwheat flour. Specific examples of wheat flour include strong flour, medium flour, soft flour, durum wheat flour (crushed durum wheat flour with an average particle size of less than 250 μm), and durum semolina (crushed durum wheat flour with an average particle size of 250 μm or more). As mentioned above, starch that can be used as raw grain flour refers to "pure starch" isolated from plants such as wheat. Specific examples of starch include unprocessed starch such as potato starch, wheat starch, corn starch, rice starch, and tapioca starch; and processed starch obtained by subjecting unprocessed starch to one or more processing treatments other than gelatinization (e.g., cross-linking, phosphorylation, acetylation, etherification, and oxidation).

[0028] A preferred example of the raw material flour is glutinous grain flour. When the raw material flour is waxy, it becomes easier to obtain gelatinized grain flour having the above-mentioned dynamic viscoelasticity (mechanical loss tangent less than 1 at a strain rate of 268% or less), that is, the desired effects of the present invention are more easily achieved. Specific examples of glutinous grain flour include glutinous wheat flour, glutinous rice flour, waxy cornstarch, and glutinous tapioca starch. Glutinous grain flour may be flour derived from grains that lack expression of amylose synthesis genes and whose starch is composed substantially almost exclusively of amylopectin.

[0029] The method for producing pregelatinized cereal flour of the present invention is characterized by: 1) the slurry preparation step, in which 500 parts by mass or more of water are added and mixed with 100 parts by mass of raw cereal flour to obtain a slurry; and 2) the slurry drying step, in which the slurry is heated and dried in a drum dryer. By satisfying both 1) and 2), pregelatinized cereal flours with the dynamic viscoelasticity described above can be obtained. While the reason for this is unclear, it is presumed that preparing a highly hydrated slurry as in 1) above facilitates opening of the starch side chains contained in the cereal flours in the subsequent drying step of the slurry, resulting in superior effects compared to conventional production methods in terms of improving starch retrogradation resistance and viscoelasticity. Furthermore, it is presumed that heating and drying this highly hydrated slurry in a drum dryer as in 2) above makes it possible to produce high-quality pregelatinized cereal flours while minimizing heat damage to the opened starch side chains.

[0030] In the slurry preparation step, if the amount of water added is less than 500 parts by mass per 100 parts by mass of raw material flour, it will be difficult to obtain gelatinized flour with the above-mentioned dynamic viscoelasticity. On the other hand, if the amount of water is too much, a lot of time and energy will be required to obtain a solid in the subsequent slurry drying step, which may result in increased production costs and reduced 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.

[0031] The slurry may contain other components in addition to the raw grain flour and water. Specific examples of other components that can be contained in the slurry include one or more enzymes selected from the group consisting of lipase and amylase. Heating and drying a slurry containing the enzymes in addition to the raw grain flour and water in a drum dryer makes it easier to obtain pregelatinized grain flours that have the dynamic viscoelasticity described above and are useful for improving the texture of processed foods and further improving the retrogradation resistance of starch. The content of the enzymes (lipase, amylase) in the slurry is preferably 0.001 to 10 parts by mass, more preferably 0.005 to 1 part by mass, per 100 parts by mass of the raw grain flour in the slurry.

[0032] The slurry prepared in the slurry preparation step is heated and dried using a drum dryer in the slurry drying step. Figure 2 shows several examples of drum dryers that can be used in the present invention. Figures 2(a) to 2(f) are single-drum types, Figure 2(g) is a double-drum type, and Figure 2(h) is a twin-drum type. Figures 2(a) to 2(f) differ in the method of supplying the material to be dried (slurry) to the drum: Figure 2(a) is a splash feed method, Figure 2(b) is a dip feed method, Figure 2(c) is a lower roll transfer method, Figure 2(d) is an upper roll feed method, Figure 2(e) is a side roll feed method, and Figure 2(f) is 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-mentioned systems can be used, but the basic configuration (type) is preferably that shown in Figure 2(d), Figure 2(e), Figure 2(f), or Figure 2(g), and the operating pressure is preferably the atmospheric pressure type.

[0033] As shown in Figure 2, 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 as described above 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 and forms 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.

[0034] The heating conditions in the slurry drying step vary depending on the configuration of the drum dryer used, the state of the material to be dried, and the like. From the viewpoint of more reliably achieving the desired effects of the present invention, however, the temperature of the heating section of the drum dryer (the temperature of the outer peripheral surface of the drum) is preferably 100 to 150°C, more preferably 110 to 150°C, and even more preferably 130 to 150°C.

[0035] Furthermore, from the viewpoint of more reliably achieving the desired effects of the present invention, 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 zone (temperature of the outer peripheral surface of the drum) and the moisture content (target moisture content) of the material to be dried after drying are determined, the amount of material to be dried supplied to the heating zone and the rotation speed of the drum dryer (contact time between the heating zone and the material to be dried) are automatically determined. Therefore, the degree of drying of the slurry, which is the material to be dried, can be adjusted by adjusting the temperature of the heating zone and the target moisture content.

[0036] 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 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.

[0037] The present invention includes a processed food mix (hereinafter also simply referred to as a "mix") containing the pregelatinized grain flour of the present invention. The mix of the present invention contains at least the pregelatinized grain flour of the present invention. The mix of the present invention is typically in the form of a powder or granules at room temperature and normal pressure. The content of the pregelatinized grain flour of the present invention in the mix of the present invention can be adjusted appropriately depending on the type of processed food, etc., and is not particularly limited, but is preferably 1 to 50% by mass, more preferably 5 to 20% by mass, based on the total mass of the mix.

[0038] The mix of the present invention may contain ingredients other than the pregelatinized cereal flour of the present invention. Examples of the other ingredients include cereal flours other than the pregelatinized cereal flour of the present invention, specifically cereal flours or starches that can be used as the raw cereal flours; leavening agents such as sodium bicarbonate (baking soda), baking powder, ammonium carbonate, ammonium bicarbonate, and ammonium chloride, or yeast; fats and oils such as salad oil; sugars such as sugar; eggs such as whole eggs, egg whites, and egg yolks; dairy products such as milk, skim milk powder, and butter; salts such as salt; and additives such as emulsifiers, thickeners, acidulants, flavorings, spices, colorings, fruit juice, and vitamins, and these can be used alone or in combination of two or more.

[0039] The gelatinized cereal flours and mixes of the present invention can be used to produce processed foods. As used herein, "processed foods" refers to secondary processed foods produced using cereal flours (cereal flour or starch) as raw materials, including refrigerated or frozen foods. Processed foods are typically heated dough foods. The term "heated dough foods" refers to foods in which a fluid dough is prepared by adding water to and mixing a raw material flour containing cereal flour, and then baking the dough to set its shape. Specific examples include bakery foods, takoyaki, and okonomiyaki. Examples of processed foods include bakery foods; noodles such as udon, somen, hiyamugi, Chinese noodles, pasta, and instant noodles (including non-fried); 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 the bakery foods include breads, pizzas, cakes, Japanese and Western baked goods such as waffles, choux pastries, biscuits, and pan-fried buns, and fried goods such as donuts. Examples of the breads include bread (e.g., rolls, white bread, brown bread, French bread, hardtack, buns, and croissants), cooked bread, and sweet buns. Examples of the cakes include sponge cakes, butter cakes, roll cakes, hotcakes, bouche, Baumkuchen, pound cakes, cheesecakes, snack cakes, muffins, bars, cookies, and pancakes.

[0040] The gelatinized flours and mixes of the present invention are particularly suitable for producing bakery foods. When the gelatinized flours or mixes of the present invention are used in the production of bakery foods, they have the effect of imparting a desirable moist texture to the food and improving its resistance to aging, and the desirable texture of the bakery foods immediately after production is maintained, not only immediately after production but also after some time has passed since production or even after refrigerated storage after production.

[0041] The method for producing processed foods using the pregelatinized cereal flour or mix of the present invention can be similar to known methods for producing such processed foods. For example, a method for producing bakery foods typically comprises the steps of adding water to a raw material flour containing the pregelatinized cereal flour of the present invention or a mix of the present invention to prepare dough, fermenting the dough as necessary, and then baking the dough. Furthermore, a method for producing noodles typically comprises the steps of adding water to a raw material flour containing the pregelatinized cereal flour of the present invention or a mix of the present invention 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 normal pressure, and typically includes cereal flours (cereal flour, starch), wheat protein, and other vegetable proteins, but does not include auxiliary raw materials such as salt, sugar, baking powder, or oils and fats. The proportion by mass of the gelatinized grain flour of the present invention to the total mass of the raw material flour (hereinafter also referred to as "gelatinized grain flour proportion") 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% by mass, more preferably 2 to 30% by mass, and even more preferably 5 to 20% by mass.

[0042] 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.

[0043] Examples 1 to 9, Comparative Example 1 Raw flours (glutinous wheat flour, glutinous rice flour) or raw starches (waxy corn starch, glutinous tapioca starch, tapioca starch) shown in Table 1 were used as raw flours. The raw flours were mixed with water in the amounts shown in Table 1 to prepare a slurry (slurry preparation step). The slurry was then heated and dried in a drum dryer (single drum type, manufactured by Katsuragi Kogyo Co., Ltd.) to obtain a solid (slurry drying step). The solid was then pulverized in a grinder (Ultracentrifugal grinder ZM200, manufactured by Retsch) to produce gelatinized flours (gelatinized flour, gelatinized starch) with a moisture content of 6% by mass. In the slurry drying step, the temperature of the heating zone of the drum dryer (temperature of the outer peripheral surface of the drum) was 130°C.

[0044] [Production Example: Pancake Production] Pancakes, a type of bakery food, were produced using any one of the pregelatinized flours from the Examples and Comparative Examples. Specifically, 45 g of non-heat-treated wheat flour ("Flour" manufactured by Nisshin Flour Milling Co., Ltd.), 5 g of pregelatinized flour, 12.5 g of white sugar, and 2.5 g of baking powder were first introduced into a bowl and mixed to prepare a mix. The pregelatinized flour content in the mix was 7.7% by mass. Next, 5 g of salad oil, 15 g of whole egg liquid, 40 g of milk, and an appropriate amount of water were added to the mix in the bowl as liquid ingredients, and the mixture was hand-mixed using a whisk at 120 revolutions per minute to prepare a pancake batter with a viscosity of 5 to 10 Pa·s as measured by a B-type viscometer at a product temperature of 25°C. The amount of water added was adjusted so that the viscosity of the pancake batter would fall within the above range. After the pancake batter was prepared, it 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 turned upside down and baked on the other side for 2 minutes to produce pancakes.

[0045] [Evaluation of Pancakes] The prepared pancakes were tasted by 10 expert panelists, who rated the texture according to the following evaluation criteria. For each type of pancake, two types were prepared and evaluated: 1) immediately after preparation, and 2) after refrigerated storage for two days. Table 1 shows the arithmetic mean of the ratings by the 10 expert panelists. 1) was the result of leaving the pancakes in an ambient temperature of 27°C for 30 minutes immediately after baking. 2) was the result of leaving the pancakes in an ambient temperature of 27°C for 30 minutes immediately after baking, then wrapping the entire pancake in food wrap film and storing it in a refrigerator at an internal temperature of 4°C for two days, and then removing it from the refrigerator and leaving it in an ambient temperature of 27°C for 30 minutes. Note that the "refrigerated storage for two days" in 2) was conducted to accelerate the deterioration of the pancakes in order to evaluate their resistance to quality deterioration over time (starch retrogradation resistance), and 2) was a sample for a so-called accelerated deterioration test.

[0046] <Evaluation criteria for pancake texture> 5 points: Very moist and chewy, very good texture. 4 points: Moist and chewy, good texture. 3 points: Somewhat moist and chewy, somewhat good texture. 2 points: Somewhat brittle and dry, somewhat undesirable texture. 1 point: Very brittle and dry, very undesirable texture

[0047]

[0048] As shown in Table 1, in each Example, the gelatinized flour used as a raw material had a mechanical loss tangent (tan δ) of less than 1 at a strain rate of 268% or less in the strain dependence measurement of dynamic viscoelasticity described above, and therefore the pancakes had a superior texture both immediately after production and after refrigerated storage compared to Comparative Example 1, which did not meet this requirement. Comparing Examples 7 and 8, Example 7, which used glutinous rice as the raw material flour, received a higher rating, demonstrating the usefulness of using glutinous rice as the raw material flour. Comparing Examples 1, 3, and 4, Examples 3 and 4, in which enzymes were added to the slurry, received a higher rating, demonstrating the usefulness of adding enzymes to the slurry to be heated and dried (gelatinized).

[0049] According to the present invention, there is provided a gelatinized cereal flour that can be used to produce processed foods that have a good texture and that can maintain that good texture even when stored in a refrigerator. For example, when the gelatinized cereal flour provided by the present invention is used to produce bakery foods, which are a type of processed food, bakery foods that are fluffy, soft, moist, and chewy can be obtained, and the good texture can be maintained for a long period of time.

Claims

1. When the strain dependency of dynamic viscoelasticity is measured at a temperature of 25°C and a frequency of 1 Hz while mixed with 10 times its own weight of water, the mechanical loss tangent at a strain rate of 268% or less is less than 1.

2. The gelatinized flour according to claim 1, which is glutinous rice flour.

3. A method for producing gelatinized grain flour, wherein, when the strain dependency of dynamic viscoelasticity is measured at a temperature of 25°C and a frequency of 1 Hz in a state where the flour is mixed with water in an amount 10 times its own weight, the mechanical loss tangent is less than 1 at a strain rate of 268% or less, A method for producing gelatinized grain flour, comprising the steps of adding and mixing 500 parts by mass or more of water to 100 parts by mass of raw grain flour to obtain a slurry, and then heating and drying the slurry in a drum dryer.

4. The method for producing gelatinized grain flour according to claim 3, wherein the raw grain flour is glutinous rice.

5. The method for producing gelatinized grain flour according to claim 3 or 4, wherein the slurry contains at least one of lipase and amylase.

6. A processed food mix comprising the gelatinized grain flour according to claim 1.

7. A processed food produced using the gelatinized grain flour according to claim 1 or 2 and / or the mix according to claim 6.