Method for producing heat-treated wheat flour

Abstract

The present invention is a heat-treated wheat flour manufacturing method wherein: 100 parts by mass wheat flour having 25% or less amylose content, and 30-45 parts by mass water having a temperature of 70°C or greater are mixed and a mixture is obtained; and the mixture is heated for 3-60 seconds at an ambient temperature of 100°C or more and less than 120°C, and heat-treated wheat flour having a degree of gelatinization of 50-95% is obtained. Preferably, the mixture of wheat flour and water of the stated temperature is made hotter than 100°C, and not hotter than 110°C, by the heat treatment. Preferably, as the heat-treated wheat flour, heat-treated wheat flour for bakery products or for noodles is manufactured.

Description

[Technical Field]

[0001] The present invention relates to a method for producing heat-treated wheat flour used in the production of bakery foods such as breads and confectioneries, and noodles. [Background technology]

[0002] Conventionally, heat-treated wheat flour used in bakery products and the like has been produced by adding water to wheat flour and heating it (see, for example, Patent Document 1).

[0003] Due to diversifying tastes, bakery products such as breads and confectioneries are commercially available with a variety of flavors and textures. Among these, there has been an increasing demand in recent years for moist and chewy textures (hereinafter also referred to as "moist and chewy"). BACKGROUND ART Various methods have been proposed for imparting a moist or chewy texture to bakery foods such as breads and confectioneries. For example, Patent Document 2 describes a method for producing pulverized heat-treated wheat flour that can be used to produce bakery foods that have a moist and / or chewy texture and are resistant to deterioration over time, by combining 20 to 55 parts by mass of water and / or steam at 70°C or higher with 100 parts by mass of wheat flour to obtain a mixture, heating the mixture at an ambient temperature of 80 to 120°C for 3 to 60 seconds, reducing the temperature of the mixture to 80 to 100°C, and then pulverizing the mixture. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-061600 [Patent Document 2] WO2021 / 095827A1 Summary of the Invention

[0005] However, in the prior art including Patent Documents 1 and 2, while a moist and chewy texture is obtained, the deterioration of texture due to long-term freezing depending on the type of bakery food, and the deterioration of texture due to refrigeration of noodles have not been fully considered.

[0006] The object of the present invention is to provide heat-treated wheat flour that can be used to efficiently produce bakery foods such as bread that have a moist and chewy texture (hereinafter also referred to simply as "moist and chewy") and that easily maintain their texture even when relatively fragile bakery foods such as pancakes are stored in a frozen state for a long period of time, and that can also be suitably used to produce noodles.

[0007] The present invention is a method for producing heat-treated wheat flour by combining 100 parts by mass of wheat flour having an amylose content of 25% or less with 30 to 45 parts by mass of water at 70°C or higher to obtain a mixture, and heating the mixture at an ambient temperature of 100°C or higher but lower than 120°C for 3 to 60 seconds to obtain heat-treated wheat flour having a degree of gelatinization of 50% to 95%. DETAILED DESCRIPTION OF THE INVENTION

[0008] The present invention will be described below based on preferred embodiments. In this specification, heat-treated wheat flour refers to wheat flour that has been subjected to heat treatment.

[0009] First, the method for producing the heat-treated wheat flour of the present invention will be described. The method for producing the heat-treated wheat flour of the present invention involves combining 100 parts by mass of wheat flour having an amylose content of 25% or less with 30 to 45 parts by mass of water at 70°C or higher to obtain a mixture, which is then heated at an ambient temperature of 100°C to less than 120°C for 3 to 60 seconds to obtain a heat-treated wheat flour having a degree of gelatinization of 50% to 95%.

[0010] One feature of the heat-treated wheat flour production method of the present invention is the use of wheat flour with an amylose content of 25% or less as a starting material. The inventors' extensive research has revealed that using wheat flour with an amylose content of 25% or less and heat-treating it with a predetermined amount of water at a predetermined temperature or higher for a predetermined time to achieve a degree of gelatinization within a predetermined range can suppress the problem of texture deterioration caused by long-term freezing, even in bakery foods that tend to become brittle, such as pancakes, and can also improve the texture of refrigerated noodles. Furthermore, the bread produced by the present invention has a particularly excellent moist and chewy texture. For example, as shown in a comparison between Comparative Example 6 and Example 1, this production method exhibits excellent effects by using wheat flour with an amylose content of 25% or less, even at a similar degree of gelatinization.

[0011] The wheat flour used in the present invention has an amylose content of 25% or less, from the viewpoint of the moist and chewy texture of starch with low amylose content and the ease of gelatinization by heat treatment. The amylose content refers to the amylose content in the starch of the wheat flour. Examples of wheat flour with an amylose content of 25% or less include flour milled from low-amylose wheat varieties such as "Tsurupikari," "Chikugoizumi," "Nebarigoshi," "Nishihonami," "Ayahikari," "Iwainodaichi," "Yumeseiki," "Kinuazuma," and "Kanto 107." flour Examples of such low-amylose wheat flour include wheat flour derived from wheat lacking expression of any two of the amylose synthesis genes Wx-A1, Wx-B1, and Wx-D1. Wheat flour with an amylose content of 25% or less can be obtained by mixing one or more of these low-amylose wheat flours.

[0012] Another example of wheat flour with an amylose content of 25% or less is waxy wheat flour. The wheat used for waxy wheat flour is produced, for example, according to the method described in Japanese Patent Application Laid-Open No. 6-125669, by crossing a hexaploid lacking expression of the Wx-A1 and Wx-B1 genes but maintaining the ability to express the Wx-D1 gene with a hexaploid lacking expression of only the Wx-D1 gene to obtain a first-generation hybrid, which is then self-fertilized to produce a second-generation hybrid, from which individuals lacking expression of the three genes are selected. This hybrid has an amylose content of 0. Waxy wheat with an amylose content of 10% or less can be obtained by crossing this with non-waxy wheat and selecting it according to standard methods. In the present invention, wheat flour with an amylose content of 10% or less derived from waxy wheat may also be used as wheat flour with an amylose content of 25% or less. The amylose content of the wheat flour used in the present invention is preferably 0 to 25%, more preferably 0 to 20%, from the viewpoints of a chewy and moist texture, freezing resistance, refrigeration resistance, etc.

[0013] In the present invention, the wheat flour used as the raw material for the heat-treated wheat flour has an amylose content of 25% or more. under From the viewpoint of improving the texture described above, the proportion of wheat flour of this wheat variety is preferably 50% by mass or more, particularly preferably 75% by mass or more, and may be 100% by mass.

[0014] In the present invention, water heated to a predetermined temperature or higher is combined with wheat flour having the above-mentioned specific amylose content to obtain a mixture, which is then heat-treated. Hereinafter, the process of combining water and wheat flour to obtain a mixture is also referred to as a mixing process. For example, Patent Document 1 describes heat-treating a mixture of water and wheat flour, but does not describe preheat-treating the water to be mixed with wheat flour. In contrast, in the present invention, heat-treating a mixture of wheat flour and water heated to a predetermined temperature or higher significantly promotes gelatinization of the starch in the wheat flour in a shorter time than when mixing with unheated water. This is then applied to heating wheat flour with a specific amylose content under predetermined conditions, resulting in an excellent effect of achieving a moist and chewy texture in bread, freezing resistance in pancakes, and refrigeration resistance in noodles. Specifically, the water added to wheat flour is heated to 70°C or higher, preferably 75°C or higher, and more preferably 80°C or higher. By mixing the water with wheat flour at a temperature of 70°C or higher, bakery foods can have a moist and chewy texture, and pancakes and other foods can be frozen with ease, and noodles can be frozen with ease. storehouse The water temperature referred to in this specification is the water temperature under normal pressure, and the upper limit is usually 100°C.

[0015] In the mixing process, the mixture of wheat flour and water at a predetermined temperature or higher does not need to be a homogenous mixture, as long as it is in a mixed state. Furthermore, in this specification, the process of combining wheat flour and water to obtain a mixture of wheat flour and water at a predetermined temperature or higher does not necessarily require a homogenization operation such as stirring. However, homogenization operations such as stirring when obtaining the mixture of wheat flour and water are not excluded from the present invention and can be performed appropriately depending on the intended use and quality of the heat-treated wheat flour required. The mixture of wheat flour and water may be obtained by adding the water to wheat flour, or by adding wheat flour to the water. However, adding the water to wheat flour is advantageous in terms of uniformity and ease of mixing and stirring.

[0016] In the method for producing heat-treated wheat flour of the present invention, the amount of water mixed with wheat flour in the mixing step is a predetermined amount. The amount of water at 70°C or higher to be mixed with wheat flour must be 30 to 45 parts by mass per 100 parts by mass of wheat flour. Adding 30 parts by mass or more of water ensures sufficient gelatinization of the starch in the wheat flour, resulting in a moist, chewy, and favorable texture. On the other hand, adding 45 parts by mass or less prevents a decrease in productivity due to the wheat flour becoming doughy, and suppresses the occurrence of stickiness during breadmaking due to excessive gelatinization of the starch in the wheat flour, resulting in excellent workability. The amount of water mixed with wheat flour is preferably 30 to 40 parts by mass, more preferably 32 to 38 parts by mass per 100 parts by mass of wheat flour.

[0017] In the present invention, there is no need to use emulsifiers, fatty acids, oils and fats during the heat treatment of wheat flour. If they are added, it is preferable to use only trace amounts of emulsifiers, fatty acids and oils, each of which is less than 0.05% by mass, more preferably less than 0.01% by mass, and even more preferably less than 0.005% by mass, based on the wheat flour. In the mixture, the total amount of components other than wheat flour and water is preferably 2.0% by mass or less, more preferably 1.0% by mass or less, based on the wheat flour.

[0018] As described above, a mixture of water and wheat flour at a predetermined temperature is heated at an ambient temperature of 100°C to 120°C for 3 to 60 seconds (hereinafter, this treatment is also referred to simply as "heat treatment"). The "ambient temperature" here refers to the air temperature of the space surrounding the mixture (wheat flour), which is the object to be heated, and not the temperature of the object to be heated itself (the temperature of the mixture). An ambient temperature of 100°C or higher and a heating time of 3 seconds or longer facilitates sufficient gelatinization of the starch in the wheat flour. Furthermore, an ambient temperature of less than 120°C and a heating time of 60 seconds or shorter has the advantage of suppressing excessive starch gelatinization and protein denaturation. From this perspective, the heating time is preferably 4 to 30 seconds, or 4 to 15 seconds. Furthermore, the ambient temperature is preferably 100°C to 110°C. In the present invention, mixing of wheat flour and water and heating may be performed simultaneously, or heating may be performed after mixing. For example, by adding flour and water to a container whose internal atmosphere has been heated in advance, the flour and water can be mixed simultaneously with heating. In this case, the heating time starts when the flour and water are added to the container.

[0019] In the method for producing heat-treated wheat flour of the present invention, the temperature of the mixture during the heat treatment is preferably greater than 100°C and less than 110°C, more preferably greater than 101°C and less than 110°C. Heating the mixture at a temperature greater than 100°C and less than 110°C not only successfully produces wheat flour with the gelatinization degree described below, but also results in a moist and chewy texture, excellent freezing resistance for pancakes, and excellent refrigeration resistance for noodles. Patent Document 2 states in paragraph

[0018] that "By maintaining the mixture temperature at 100°C or less, a moist and chewy texture can be obtained, and bakery products with excellent workability, appearance (volume), and internal structure can also be obtained." However, the present inventors' investigations have revealed that for wheat with a specific amylose content, a particularly excellent texture improvement effect can be achieved when the mixture is heated to a temperature greater than 100°C and less than 110°C to achieve a predetermined gelatinization degree. In the method for producing heat-treated wheat flour of the present invention, the temperature of the mixture only needs to reach greater than 100°C and less than or equal to 110°C at least once during the heat treatment. For example, the temperature of the mixture can be measured at the completion of the heat treatment. As described above, the temperature of the mixture at the completion of the heat treatment may be outside the range of greater than 100°C and less than or equal to 110°C, as long as it reaches greater than 100°C and less than or equal to 110°C at least once during the heat treatment. To achieve the temperature of the mixture within the above range, the temperature and amount of water added to the wheat flour during the mixing treatment may be set within the above range, the time from when the wheat flour and water are mixed to when the heat treatment is started may be adjusted, the ambient temperature and heating time during the heat treatment may be set within the above range, and the flow rate of heated steam circulating inside the container during the heat treatment may be adjusted.

[0020] It is preferable to continuously mix wheat flour with water at a predetermined temperature and heat the mixture so that the temperature of the mixture at the completion of heating falls within the range described below. "Continuously" refers to, for example, mixing wheat flour with water at a predetermined temperature and starting heating within a few seconds, including the case where wheat flour and water are separately introduced into a container whose internal atmosphere has been heated in advance. When measuring the temperature of the mixture in a heat treatment device, for example, when a device is used for heat treatment that heats the contents while transferring them from the inlet to the outlet in a container using an internal extruder, the temperature of the mixture can be the temperature of the mixture at the outlet.

[0021] The heat treatment according to the present invention can be carried out using any known heating device, but preferably, a device that adds water to gelatinize the starch in the wheat flour and performs the heat treatment can be used. The heat treatment can be carried out using known heating devices such as an autoclave or a steam oven. One example of the heat treatment according to the present invention is a process in which wheat flour and water at a temperature above the predetermined temperature are sealed in an airtight container, such as an aluminum pouch or a heatable container using a heat jacket, and heated under pressure. The atmosphere inside the airtight container may be preheated to a desired temperature before the introduction of the wheat flour and water. A suitable stirring mechanism may also be provided inside the airtight container. The pressurization may be achieved by heated steam in the airtight container. Another example of the heat treatment according to the present invention is a process in which wheat flour and water are introduced into an airtight container, and the mixture is stirred as needed. Then, saturated steam is introduced into the container simultaneously with, before, or after the introduction (preferably simultaneously with, or before the introduction) and the mixture is heated under pressure (the amount of saturated steam in this case is not included in the amount of water at 70°C or higher added to the wheat flour). These processes can be carried out, for example, using a single-screw or twin-screw extruder.

[0022] When steam is introduced into a vessel and heating is performed under pressure, the flow rate of steam is usually adjusted within the range of 40 to 130 kg / h, preferably within the range of 70 to 100 kg / h. Here, "under pressure" mainly refers to a pressurized state caused by steam filling the vessel, and does not refer to a pressurized state of the raw material wheat brought into contact with an object such as an extrusion tool (a component equivalent to the screw provided in an extruder) or the like.

[0023] In the method for producing heat-treated wheat flour of the present invention, it is preferable to heat-treat a mixture containing wheat flour and heated water as described above, and then pulverize the resulting heat-treated wheat flour. In the present invention, it is preferable to pulverize the heated mixture after heat treatment without a granulation step. The granulation step refers to a step of granulating the heated mixture to form dough particles. Examples of granulation steps include a granulation step using an extrusion granulator, a mixer granulator, etc. Other examples include a step of stretching the heated mixture between two rolls and cutting the stretched dough into granules, or a step of cutting the mixture extruded from a kneader into small pieces when a kneader is used for the heat treatment. The particle diameter of the dough particles can be 1 mm to 50 mm, preferably 5 mm to 20 mm. In the present invention, pulverizing the heated mixture without a granulation step has the advantages of shortening the production time and saving the space required for production equipment.

[0024] When the heat-treated wheat flour obtained by the heat treatment is pulverized, the pulverization method is not particularly limited and any known method can be used, for example, roll pulverization, impact pulverization, airflow pulverization, pin mill pulverization, etc., among which pin mill pulverization and airflow pulverization are preferably used.

[0025] In the present invention, the heat-treated wheat flour may be dried prior to milling. As mentioned above, heat-treated wheat flour is usually wet, so drying before milling allows for more appropriate milling. Drying can be performed by known methods such as shelf drying, hot air drying, and fluidized bed drying. Drying may also be performed simultaneously with milling. If the heat-treated wheat flour is not dried before milling, it is preferable to dry it after milling to improve its shelf life. Regarding the drying temperature, to prevent starch gelatinization and protein denaturation in the heat-treated wheat flour, low-temperature drying at 30°C to 70°C for 6 hours to 24 hours is preferred, while high-temperature drying at 100°C to 180°C for 5 seconds to 120 seconds is preferred. Low-temperature drying at 40°C to 60°C is more preferred, and high-temperature drying at 120°C to 160°C is more preferred.

[0026] The heat-treated wheat flour obtained by the present invention has a degree of gelatinization of 50% or more and 95% or less. Heat-treated wheat flour with a degree of gelatinization of 50% or more provides a moist and chewy texture to breads, prevents texture deterioration during frozen storage in dough products such as pancakes, and improves the aging resistance of noodles. Heat-treated wheat flour with a degree of gelatinization of 95% or less has the advantage of preventing stickiness caused by excessive starch gelatinization, thereby preventing a decrease in productivity and bread-making workability. From this perspective, the heat-treated wheat flour preferably has a degree of gelatinization of 50% or more and 95% or less, and more preferably 65% ​​or more and 90% or less. The degree of gelatinization is measured by the β-amylase-pullulanase method, specifically as follows.

[0027] <Method for measuring gelatinization degree> (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 Biochemical Industries, Ltd. #1500) and 0.17 g of pullulanase (Hayashibara Biochemical Laboratories, 31001) were dissolved in the above 0.8 M acetic acid-Na acetate buffer solution to make 100 ml. 5. Inactivated enzyme solution: Prepare by boiling the above enzyme solution for 10 minutes. 6. Somogyi and Nelson reagents (reagents for measuring reducing sugars)

[0028] (B)Measurement method 1. Pulverize the wheat flour using a homogenizer to a size of 100 mesh or less. Add 0.08-0.10 g of this pulverized flour to a glass homogenizer. 2. Add 8.0 ml of demineralized water to this and disperse by moving the glass homogenizer up and down 10 to 20 times. 3. Place 2 ml of the dispersion liquid from step 2 above into two 25 ml graduated test tubes, and dilute one tube to the required volume with 0.8 M acetic acid-Na acetate buffer to use as the test group. 4. To the other tube, add 0.2 ml of 10 N sodium hydroxide solution and react at 50°C for 3 to 5 minutes to completely gelatinize. Then, add 1.0 ml of 2 N acetic acid solution to adjust the pH to around 6.0, and then make the volume to the constant level with 0.8 M acetic acid-sodium acetate buffer to create the gelatinized sample. 5. Take 0.4 ml of each of the test and gelatinized test solutions prepared in steps 3 and 4 above, add 0.1 ml of enzyme solution to each, and allow the enzyme reaction to occur at 40°C for 30 minutes. 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. 6. Add 0.5 ml of Somogyi reagent to 0.5 ml of the above reaction mixture 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's reagent, stir, and leave for 15 minutes. 7. Then, add 8.00 ml of demineralized water, stir, and measure the absorbance at 500 nm.

[0029] (C) Calculation of gelatinization degree 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 formula, A, A', a and a' are as follows. A = absorbance of test area A' = absorbance of gelatinized sample a = blank absorbance of test area a' = absorbance of the gelatinized blank

[0030] The heat-treated wheat flour of the present invention can be used in various food applications after secondary processing, with bakery foods being a typical example. Bakery foods, as used herein, refer to foods obtained by subjecting fermented or unfermented dough, primarily made from cereal flour, to which, as needed, secondary ingredients such as yeast, leavening agents, water, salt, and sugar are added, to heat treatments such as baking, steaming, and frying. Examples of bakery foods to which the present invention can be applied include breads and confectioneries. Examples of breads include white bread, French bread, rolls, buns, croissants, and pizza. Examples of confectioneries include donuts, dorayaki, sponge cakes, butter cakes, hotcakes, pancakes, muffins, and cookies. Examples of bakery foods that tend to become brittle when frozen include breads such as white bread, French bread, rolls, buns, and pizza, and confectioneries such as hotcakes, dorayaki, sponge cakes, butter cakes, hotcakes, pancakes, and muffins. Examples of noodles include udon, Chinese noodles, and pasta.

[0031] The heat-treated wheat flour obtained by the present invention is preferably used for bakery foods or noodles, and can be used, for example, as a raw material for bakery food mixes or noodle mixes. The bakery food mixes and noodle mixes obtained by the present invention contain heat-treated wheat flour obtained by the heat-treated wheat flour manufacturing method of the present invention. The inventors have found that by using the heat-treated wheat flour obtained by the heat-treated wheat flour manufacturing method of the present invention, bakery foods such as breads with a moist and chewy texture and hotcakes with high freezing resistance can be obtained. Furthermore, by using the heat-treated wheat flour obtained by the heat-treated wheat flour manufacturing method of the present invention, noodles with excellent refrigeration resistance can be obtained.

[0032] The bakery food mixes and noodle mixes obtained by the present invention preferably contain non-heat-treated wheat flour in addition to the heat-treated wheat flour obtained by the heat-treated wheat flour production method of the present invention, as this facilitates improving workability, texture, appearance, and internal structure. Non-heat-treated wheat flour can be untreated wheat flour, such as hard wheat flour, semi-hard wheat flour, medium-strength wheat flour, soft wheat flour, and durum wheat flour. These can be used alone or in combination of two or more. Wheat flour made from either imported or domestically produced wheat can be used as the non-heat-treated wheat flour. In particular, when domestically produced wheat flour is used as the raw material for the heat-treated wheat flour, it is preferable to use wheat flour made from imported wheat as the non-heat-treated wheat flour in terms of ease of availability.

[0033] When the bakery food mix and noodle mix obtained by the present invention contain non-heat-treated wheat flour, the blending amount of the heat-treated wheat flour obtained by the present invention is preferably 1 part by mass or more and 40 parts by mass or less, based on 100 parts by mass of the total of the heat-treated wheat flour and non-heat-treated wheat flour. By blending the heat-treated wheat flour obtained by the present invention in an amount of 1 part by mass or more, the texture improvement effect in bakery foods and noodles is more easily achieved. By blending the heat-treated wheat flour in an amount of 40 parts by mass or less, the confectionery, bread-making, and noodle-making properties are improved. From these viewpoints, the blending amount of the heat-treated wheat flour obtained by the present invention in the bakery food mix and noodle mix is ​​more preferably 5 parts by mass or more and 40 parts by mass or less, and even more preferably 10 parts by mass or more and 40 parts by mass or less, based on 100 parts by mass of the total of the heat-treated wheat flour and non-heat-treated wheat flour.

[0034] In the bakery food mix and noodle mix of the present invention, out of a total of 100 parts by mass of the heat-treated wheat flour and non-heat-treated wheat flour obtained by the present invention, the amount of non-heat-treated wheat flour blended is preferably 60 parts by mass or more and 99 parts by mass or less, more preferably 65 parts by mass or more and 95 parts by mass or less, and even more preferably 70 parts by mass or more and 90 parts by mass or less, from the viewpoint of its high effect of improving workability, texture, appearance, and internal structure. Furthermore, the total amount of the heat-treated wheat flour and non-heat-treated wheat flour obtained by the present invention in the bakery food mix and noodle mix is ​​preferably 50% by mass or more, more preferably 55% by mass or more, and particularly preferably 60% by mass or more. In particular, the above amounts are preferred for general bread, confectionery such as pancakes, and noodles, as they are highly effective in improving workability, texture, appearance, and internal structure.

[0035] Bakery food mixes and noodle mixes can also contain ingredients other than the heat-treated wheat flour and non-heat-treated wheat flour obtained by the present invention. Examples of such ingredients include cereal flours other than wheat flour, such as rye flour, barley flour, buckwheat flour, rice flour, soy flour, and corn flour; potato starch, corn starch, waxy starch, wheat starch, and modified starches obtained by pregelatinizing, etherifying, esterifying, crosslinking, or oxidizing these; leavening agents or yeast, such as sodium bicarbonate, baking powder, ammonium carbonate, ammonium bicarbonate, and ammonium chloride; 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; emulsifiers, thickeners, acidulants, flavorings, spices, coloring agents, fruit juices, fruits, vitamins, and brine. These ingredients can be used alone or in combination. These other ingredients may be mixed together when the heat-treated wheat flour and non-heat-treated wheat flour obtained by the present invention are mixed, or may be mixed in advance with one of the heat-treated wheat flour and non-heat-treated wheat flour, or may be further mixed after the heat-treated wheat flour and non-heat-treated wheat flour are mixed.

[0036] The present invention has been described above based on its preferred embodiments, but the preferred configurations described in the above or below examples can be combined with any other preferred configurations described above or below. Note that the preferred configurations referred to here are not limited to more preferred, particularly preferred, etc., and can be combined with any other configurations at any stage. [Example]

[0037] Examples are given below to specifically explain the present invention, but the present invention is not limited to the following examples. In each example and comparative example, the steam temperature in the vessel was in the range of 90 to 130°C, the gauge pressure in the vessel was in the range of 10 to 100 kPa, and the steam flow rate was within the above ranges.

[0038] (Comparative Examples 1 to 3) The ground wheat flour of the brands shown in Table 1 was used as is as the comparative wheat flour. Note that "1CW" stands for "No. 1 Canada Western," "WW" stands for "Western White," and "ASW" stands for "Australian Standard White."

[0039] (Examples 1 to 4, 6, Comparative Examples 4 to 7) A sealed container equipped with a heat jacket and a single-screw extruder was heated in advance to the ambient temperature shown in Table 1. Specifically, the sealed container was heated from the outside by a heat jacket using steam as a heat source, and the ambient temperature inside the container was heated to the temperature shown in Table 1. Then, wheat varieties and brands listed in Table 1 were milled to prepare flour. The amylose content of the flour was as shown in Table 1. Water heated to 80°C was prepared in the amount shown in Table 1 relative to the amount of wheat flour. The wheat flour and the heated water were mixed in the sealed container, heated for 5 seconds in the sealed container set to the predetermined ambient temperature, and then discharged from the sealed container. The temperature of the mixture at the completion of heating (the temperature of the mixture at the outlet of the sealed container) was the temperature shown in Table 1. The heat-treated mixture was shelf-dried at 50°C for 12-24 hours without undergoing a granulation process to reduce the moisture content to 10% to 14% by mass. The heat-treated wheat flour was then pulverized in a pin mill, and the resulting mixture particles were recovered as pulverized heat-treated wheat flour. The degree of gelatinization of the resulting pulverized heat-treated wheat flour was measured using the method described above. During the heat treatment, saturated steam was introduced into the container to heat the mixture under pressure. The flow rate of the steam in the container was adjusted to achieve the temperature shown in Table 1 at the completion of heating.

[0040] Example 5 The procedure was the same as in Example 1, except that the temperature of the mixture at the end of heating (temperature of the mixture at the outlet of the sealed container) was changed to 100°C or lower (95°C) by adjusting the steam flow rate inside the container. The degree of gelatinization of the obtained pulverized heat-treated wheat flour was measured by the above-mentioned method.

[0041] (Test Example 1) Using the ground and heat-treated wheat flours of Examples 1 to 6 and Comparative Examples 4 to 7 or the wheat flour of Comparative Example 1, bread, which is a type of bakery food, was produced by the following method.

[0042] Into the mixing bowl of a commercially available bread mixer (Dalton Co., Ltd., universal mixer model 5DM-03-r), 320 g of non-heat-treated strong flour Million (Nissin Flour Milling, Inc.), 80 g of the heat-treated wheat flour to be evaluated or 80 g of the wheat flour of Comparative Example 1, 8 g of salt, 32 g of sugar, 9.2 g of fresh yeast (Oriental Yeast Co., Ltd., "Oriental Yeast"), 0.4 g of yeast food (Oriental Yeast Co., Ltd., "C Yeast Food"), and an appropriate amount of water were added, and the bread dough was prepared by a mixing process. Specifically, the dough was mixed at low speed for 4 minutes, then at high speed for 2 minutes, and then 16 g of oil was added and mixed at low speed for 4 minutes, followed by kneading at high speed for 1 minute (kneading temperature: 27°C). The resulting dough was fermented for 1 hour at 27°C and 75% relative humidity, then divided into 450 g portions and rolled into balls. After 30 minutes of bench time, the dough was rolled into loaf shapes and packed into loaf pans. The dough was then proofed for 60 minutes (in an atmosphere of 38°C and 85% relative humidity) and baked for 30 minutes at 200°C to obtain loaf bread.

[0043] The resulting bread was left to stand at 4°C for one day, and then the texture of the resulting bread was evaluated by 10 expert panelists based on the following evaluation criteria. The average evaluation scores of the panelists are shown in Table 1. (Evaluation criteria for bread texture) 5 points: The whole product has a sufficiently moist and chewy texture, and the taste and texture are good. 4 points: Although it may lack moistness or softness in some areas, overall it has a moist and chewy texture and there are no problems with the taste or texture. 3 points: Feels slightly moist and chewy. 2 points: Overall, it is not very moist or chewy, and is a bit dry. 1 point: Overall, the product is too hard or has a dry texture, and the taste and texture are poor.

[0044] (Test Example 2) Using the ground and heat-treated wheat flour of Examples 1 to 6 and Comparative Examples 4 to 7 or the wheat flour of Comparative Example 2, pancakes, which are a type of bakery food, were produced by the following method. As powder ingredients, 40 g of non-heat-treated flour (Nissin Flour Milling Co., Ltd.), 10 g of heat-treated wheat flour to be evaluated or 10 g of wheat flour of Comparative Example 2, 12.5 g of caster sugar, and 2.5 g of baking powder were mixed, and then 5 g of salad oil, 15 g of whole egg liquid, 40 g of milk, and 30 g of water were added to a bowl as liquid ingredients. The mixture was hand-mixed using a whisk for 1 minute (120 rp After stirring at 100°C, the dough was baked at 180°C for 3 minutes on the front and 2 minutes on the back. The baked product was allowed to cool at 27°C for 30 minutes, then packaged and stored at -5°C for 30 days before being used to evaluate the texture.

[0045] The frozen hotcakes were left to thaw for 2 hours at 27°C. Then, the brittle texture of the hotcakes was evaluated by 10 expert panelists based on the following criteria. The average evaluation scores of the panelists are shown in Table 1. (Evaluation criteria for hotcake texture) 5 points: Very moist and chewy, with a very good texture 4 points: Moist and chewy, good texture 3 points: Slightly moist and chewy, with a fairly good texture 2 points: Slightly brittle and dry, slightly undesirable texture 1 point: Very brittle and dry, very undesirable texture

[0046] (Test Example 3) Using the ground, heat-treated wheat flour of Examples 1 to 6 and Comparative Examples 4 to 7, or the wheat flour of Comparative Example 3, noodles were produced by the following method. 20 parts by mass of the test wheat flour was mixed with 80 parts by mass of Menhachishu (Nissin Flour Milling Co., Ltd.), a non-heat-treated medium-strength flour, to which 1 part by mass of salt and 40 parts by mass of water were added and mixed at low speed in a mixer (Hobart) for 5 minutes, and the resulting crumbly noodle dough was gathered together in a noodle roller, combined, rolled, and made into noodle strands 3 mm thick and 4 mm wide. The noodle strands were boiled for 11 minutes, cooled in cold water, and stored in a sealed container at 4°C for 2 days, after which the aging resistance of the noodles was evaluated. (Evaluation criteria for noodle texture) 5 points: Very chewy, very smooth, very good texture 4 points: Chewy, smooth, and has a good texture 3 points: Slightly chewy, slightly smooth, and has a fairly good texture 2 points: Slightly brittle, slightly smooth, slightly unpleasant texture 1 point: Very brittle, not smooth, very undesirable texture

[0047] [Table 1]

[0048] As shown in Table 1, in each example in which wheat flour with a predetermined amylose content was hydrated with a predetermined amount of water at a predetermined temperature and heat-treated for a predetermined time to achieve a specific degree of gelatinization, a moist and chewy texture was obtained for bread, pancakes were less likely to become brittle after long-term freezing, and noodles had a chewy and smooth texture after refrigeration. In particular, when the mixture temperature was set above 100°C, an excellent texture improvement effect was obtained. On the other hand, with the wheat flours of Comparative Examples 4 to 6, which had a relatively high amylose content, the bread had an inferior texture, and the hotcakes and noodles that had been frozen for a long time had a brittle and dry texture, especially when the flour was insufficiently hydrated. Furthermore, when Chikugoizumi wheat flour with an amylose content of 25% or less was used as in Comparative Example 7, the bread had an inferior texture compared to the Examples when the flour was insufficiently hydrated. Furthermore, the hotcakes and noodles that had been frozen for a long time had a brittle and dry texture, and the noodles were brittle and less smooth.

Claims

1. A method for producing heat-treated wheat flour, comprising: combining 100 parts by mass of wheat flour having an amylose content of 25% or less with 30 to 45 parts by mass of water at 70°C or higher to obtain a mixture; and heating the mixture at an ambient temperature of 100°C or higher but lower than 120°C for 3 to 60 seconds to obtain heat-treated wheat flour with a gelatinization degree of 50% to 95%; The method for producing heat-treated wheat flour, wherein the temperature of the mixture of wheat flour and water at the completion of the heat treatment is higher than 100°C and not higher than 110°C by the heat treatment.

2. 2. The method for producing heat-treated wheat flour according to claim 1, wherein the heat-treated wheat flour is heat-treated wheat flour for bakery foods or noodles.

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