JP7746262B2 - Method for producing heat-treated wheat flour - Google Patents

Description

The present invention relates to a method for producing heat-treated wheat flour used in the production of bakery foods such as bread and sweets, and noodles.

Conventionally, the method for producing heat-treated wheat flour used in bakery products, etc. has been known to involve adding water and heating wheat flour (e.g., Patent Document 1).

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 products with a moist and chewy texture (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.

Japanese Patent Application Laid-Open No. 2003-061600 WO2021/095827A1

However, while the prior art, including Patent Documents 1 and 2, achieves a moist and chewy texture, it has not fully addressed the issue of deterioration in texture due to long-term freezing of some types of bakery foods, or the deterioration in texture due to refrigeration of noodles.

The objective of the present invention is to provide heat-treated wheat flour that can be used efficiently to produce bakery foods such as bread that have a moist and chewy texture (hereinafter simply referred to as "moist and chewy"), while easily maintaining the texture of relatively fragile bakery foods such as pancakes even when frozen for long periods of time, and that can also be suitably used to produce noodles.

The present invention is a method for producing heat-treated wheat flour, which involves combining 100 parts by weight of wheat flour having an amylose content of 25% or less with 30 to 45 parts by weight of water at 70°C or higher to obtain a mixture, and heating it at an ambient temperature of 100°C or higher but less than 120°C for 3 to 60 seconds to obtain heat-treated wheat flour having a degree of gelatinization of 50% to 95%.

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.

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

One feature of the heat-treated wheat flour manufacturing method of the present invention is the use of wheat flour with an amylose content of 25% or less as a raw material. Through extensive research, the inventors have found 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 mitigate 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 obtained with this invention has a particularly excellent moist and chewy texture. For example, as shown in a comparison between Comparative Example 6 and Example 1, this manufacturing method exhibits excellent effects by using wheat flour with an amylose content of 25% or less, even at a similar degree of gelatinization, but with a predetermined value or less of amylose.

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 wheat flour milled from low-amylose wheat varieties such as "Tsurupikari,""Chikugoizumi,""Nebarigoshi,""Nishihonami,""Ayahikari,""Iwainodaichi,""Yumeseiki,""Kinuazuma," and "Kanto 107." Examples of wheat flour from these low-amylose wheat varieties include wheat flour derived from wheat lacking expression of any two of the amylose synthesis genes Wx-A1, Wx-B1, and Wx-D1. As wheat flour with an amylose content of 25% or less, one or a suitable mixture of two or more of these low-amylose wheat-derived wheat flours can be used.

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. Further crossing this with non-waxy wheat and subsequent selection according to conventional methods results in waxy wheat with an amylose content of 10% or less. In the present invention, wheat flour derived from waxy wheat with an amylose content of 10% or less may be used as the 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.

In the present invention, the proportion of wheat flour of a wheat variety having an amylose content of 25% or less among the wheat flour used as the raw material for the heat-treated wheat flour is preferably 50% by mass or more, particularly preferably 75% by mass or more, and may be 100% by mass, from the viewpoint of improving the texture described above.

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, and the mixture 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 pre-heat-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 adjusting the temperature of the water mixed with wheat flour to 70°C or higher, bakery foods can have an excellent moist and chewy texture, and also the freezing resistance of hotcakes and the refrigeration resistance of noodles can be easily achieved. The water temperature referred to in this specification is the water temperature under normal pressure, and the upper limit is usually 100°C.

In the mixing process, the mixture of wheat flour and water at or above a predetermined temperature does not need to be a homogenous mixture; it is sufficient if the mixture 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 or above a predetermined temperature does not require a homogenization procedure, such as stirring. However, homogenization procedures, such as stirring, when obtaining a mixture of wheat flour and water are not excluded from the present invention and can be performed as appropriate depending on the intended use and quality of the heat-treated wheat flour. 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.

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 mixed with wheat flour must be 30 to 45 parts by weight per 100 parts by weight of wheat flour. Adding 30 parts by weight 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 weight or less prevents a decrease in productivity due to the wheat flour becoming doughy, suppresses the occurrence of stickiness during breadmaking due to excessive gelatinization of the starch in the wheat flour, and has the advantage of excellent workability. The amount of water mixed with wheat flour is more preferably 30 to 40 parts by weight per 100 parts by weight of wheat flour, and even more preferably 32 to 38 parts by weight.

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, the amount of emulsifier, fatty acid, oil and fat used is preferably very small, i.e., less than 0.05% by mass, more preferably less than 0.01% by mass, and even more preferably less than 0.005% by mass, of 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.

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 process will be referred to simply as "heat treatment"). The "ambient temperature" here refers to the air temperature surrounding the mixture (wheat flour), which is the object to be heated, and not the temperature of the object 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, the 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.

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. By maintaining the temperature of the mixture during the heat treatment at greater than 100°C and less than 110°C, wheat flour with the gelatinization degree described below can be successfully obtained, and the flour also exhibits 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 temperature of the mixture 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 have found that, for wheat with a specific amylose content, a particularly excellent texture improvement effect can be obtained 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 more than 100°C and not more than 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 more than 100°C and not more than 110°C, as long as it reaches more than 100°C and not more than 110°C at least once during the heat treatment. To control the temperature of the mixture within the above range, the temperature and amount of water combined with 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.

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

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 heats it is used. Heat treatment can be carried out using known heating devices, such as an autoclave or steam oven. One example of the heat treatment according to the present invention is a process in which wheat flour and water at or above the predetermined temperature are sealed in an airtight container, such as an aluminum pouch or a heat jacket, and heated under pressure. The atmosphere inside the airtight container may be preheated to the desired temperature before the introduction of the wheat flour and water. A suitable stirring mechanism may also be provided inside the airtight container. Pressurization may also 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, while stirring the mixture as needed, saturated steam is introduced into the container simultaneously with, before, or after (preferably simultaneously with, or before) the introduction of the mixture, and the mixture is heated under pressure (in this case, the amount of saturated steam is not included in the amount of water at 70°C or above added to the wheat flour). These processes can be carried out, for example, using a single-screw or twin-screw extruder.

When steam is introduced into a container and heating is performed under pressure, the flow rate of steam is usually adjusted to within the range of 40 to 130 kg/h, and preferably within the range of 70 to 100 kg/h. "Under pressure" here primarily refers to a pressurized state caused by steam filling the container, and does not refer to a pressurized state of the raw wheat being brought into contact with an object such as a pusher (a component equivalent to the screw provided in an extruder)

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 process of granulating the heated mixture into dough particles. Examples of granulation steps include granulation processes using an extrusion granulator, a mixer granulator, etc. Other examples include a process in which the heated mixture is stretched between two rolls and then the stretched dough is cut into granules, or a process in which the mixture extruded from a kneader is cut into small pieces and granulated when a kneader is used for the heat treatment described above. 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 production time and saving space for production equipment.

When grinding the heat-treated wheat flour obtained by heat treatment, there are no particular limitations on the grinding method, and any known method can be used, such as roll grinding, impact grinding, airflow grinding, and pin mill grinding. Of these, pin mill grinding and airflow grinding are preferably used.

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 efficient milling. Drying can be performed by known methods such as shelf drying, hot air drying, and fluidized bed drying. Drying can 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 enhance 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 to 24 hours is preferred. High-temperature drying at 100°C to 180°C is preferred for 5 to 120 seconds. 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.

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, and has the advantage of preventing deterioration in texture during frozen storage in dough products such as pancakes, as well as preventing aging resistance in 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.

<Method for measuring gelatinization degree>
(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 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)

(B) Measurement method 1. Pulverize wheat flour using a homogenizer to a size of 100 mesh or less. Place 0.08 to 0.10 g of this pulverized wheat flour in 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 create a 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. After that, 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 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.

(C) Calculation of Gelatinization Degree The gelatinization degree is calculated using the following formula.
Degree of gelatinization (%) = (decomposition rate of test solution) / (decomposition rate of completely gelatinized test solution) × 100
=(A-a)/(A'-a')×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

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.

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.

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 manufacturing 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 that has not been heat-treated, such as strong wheat flour, semi-strong wheat flour, medium-strength wheat flour, weak 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.

When the bakery food mix and noodle mix obtained by the present invention contain non-heat-treated wheat flour, the amount of 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 incorporating 1 part by mass or more of the heat-treated wheat flour obtained by the present invention, the texture improvement effect in bakery foods and noodles is more easily achieved. By incorporating 40 parts by mass or less of the heat-treated wheat flour, the confectionery, bread-making, and noodle-making properties are improved. From these perspectives, the amount of 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.

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 applications, confectionery applications such as pancakes, and noodle applications, because they are highly effective in improving workability, texture, appearance, and internal structure.

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 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, colorings, fruit juice, 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.

The present invention has been described above based on its preferred embodiments, but the preferred configurations described in the examples above or below 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 configuration at any stage.

The following examples are provided to specifically explain the present invention, but the present invention is not limited to these examples. In each example and comparative example, the steam temperature inside the container was in the range of 90 to 130°C, the gauge pressure inside the container was in the range of 10 to 100 kPa, and the steam flow rate was within the above ranges.

(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."

(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.
Thereafter, wheat flour was prepared by milling the varieties and brands of wheat listed in Table 1. The amylose contents of the wheat flour were 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 dried at 50°C for 12-24 hours by shelf drying without a granulation step to a moisture content of 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.

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.

(Test Example 1)
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 1, bread, a type of bakery food, was produced by the following method.

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 a mixing step was carried out to prepare bread dough.
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 dough thus obtained 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 a loaf shape and packed into a loaf mold. The dough was then proofed for 60 minutes (in an atmosphere of 38°C and 85% relative humidity) and baked at 200°C for 30 minutes to obtain loaf bread.

The resulting bread was left to stand at 4°C for 1 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, it has a moist and chewy texture overall, and there are no problems with the taste or texture.
3 points: A slight moist and chewy feeling is felt.
2 points: Overall, it is not very moist or chewy, and is a bit dry.
1 point: The whole product is too hard or has a dry texture, and the taste and texture are poor.

(Test Example 2)
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 2, hot cakes, 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 the heat-treated wheat flour to be evaluated or 10 g of the 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 mixed by hand using a whisk at 120 rpm for 1 minute and then 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, packaged, and stored at -5°C for 30 days before being used to evaluate the texture.

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 evaluation criteria. The average evaluation scores of the panelists are shown in Table 1.
(Evaluation criteria for hotcake texture)
5 points: Very moist and chewy, very good texture 4 points: Moist and chewy, good texture 3 points: Slightly moist and chewy, somewhat good texture 2 points: Slightly brittle and dry, somewhat undesirable texture 1 point: Very brittle and dry, very undesirable texture

(Test Example 3)
Noodles were produced by the following method 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.
20 parts by mass of the wheat flour to be tested 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 (manufactured by Hobart) for 5 minutes. The resulting crumbly noodle dough was gathered together in a noodle roller, combined, rolled, and made into noodle strands measuring 3 mm in thickness and 4 mm in width. 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, good texture 3 points: Slightly chewy, slightly smooth, somewhat good texture 2 points: Slightly brittle, slightly smooth, somewhat unpleasant texture 1 point: Very brittle, not smooth, very unpleasant texture

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 stored frozen for a long time had a brittle and dry texture, and the noodles also had a brittle texture, especially when the hydration was insufficient. 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 hydration was insufficient, and the hotcakes stored frozen for a long time had a slightly brittle and dry texture, and the noodles were brittle and less smooth.

Claims (2)

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. 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.