Method for manufacturing heat-treated wheat flour

Abstract

The present invention relates to a manufacturing method of heat-treated wheat flour, wherein 100 parts by mass of wheat flour having a content of amylose of 25% or less is mixed with 30 to 45 parts by mass of water at 70°C or more to obtain a mixture, and the mixture is heated at an atmosphere temperature of 100°C or more and less than 120°C for 3 seconds to 60 seconds to obtain heat-treated wheat flour having a degree of gelatinization of 50 to 95%. It is preferable that the mixture of the wheat flour and the water at the above temperature is heated to a temperature of more than 100°C and 110°C or less by the above heating treatment. It is preferable that heat-treated wheat flour for bakery or for noodles is manufactured as the heat-treated wheat flour.

Description

Technical Field

[0001] This invention relates to a method for manufacturing heat-treated wheat flour used in the manufacture of baked goods such as bread and pastries, as well as flour. Background Technology

[0002] Previously, the production of heat-treated wheat flour used in baked goods and the like was known to be carried out by adding water to wheat flour and heating it (for example, Patent Document 1).

[0003] Regarding baked goods such as bread and pastries, products featuring a variety of flavors and textures are being sold on the market due to the diversification of tastes. In recent years, the desire for a moist and chewy texture (hereinafter referred to as "moist and chewy") has been rising.

[0004] In the past, various methods have been proposed to give baked goods such as bread and pastries a moist or chewy texture.

[0005] For example, Patent Document 2 describes a method for manufacturing pulverized heat-treated wheat flour, which includes the following steps: as pulverized heat-treated wheat flour capable of producing baked goods with a moist and / or chewy texture and not easily deteriorating over time, 20 to 55 parts by mass of water and / or steam at a temperature of 70°C or higher are mixed with 100 parts by mass of wheat flour to obtain a mixture; the mixture is heated at an atmosphere temperature of 80°C to 120°C for 3 to 60 seconds to bring the temperature of the mixture to 80°C to 100°C, and then pulverized.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2003-061600

[0009] Patent Document 2: WO2021 / 095827A1 Summary of the Invention

[0010] However, in the prior art, including patent documents 1 and 2, there has been insufficient research on the aspects of obtaining a moist and chewy texture, such as the decrease in texture due to long-term freezing depending on the type of baked goods, and the decrease in texture due to refrigeration of the dough.

[0011] The subject of this invention relates to providing a heat-treated wheat flour that can efficiently produce a moist and chewy texture (hereinafter also referred to as "moist and chewy") in bread and the like, and that can easily maintain its texture even when the relatively crisp baked goods such as biscuits are frozen for a long time. Moreover, this heat-treated wheat flour is also suitable for use in the manufacture of noodles.

[0012] This invention relates to a method for manufacturing heat-treated wheat flour, wherein 100 parts by weight of wheat flour with an amylose content of less than 25% are mixed with 30 to 45 parts by weight of water at a temperature of 70°C or higher to obtain a mixture, and the mixture is heated for 3 to 60 seconds at an atmosphere temperature of 100°C or higher and less than 120°C to obtain heat-treated wheat flour with a gelatinization degree of 50% to 95%. Detailed Implementation

[0013] The present invention will now be described based on its preferred embodiments. In this specification, heat-treated wheat flour refers to wheat flour that has undergone heat treatment.

[0014] First, the method for manufacturing the heat-treated wheat flour of the present invention will be described. The method for manufacturing the heat-treated wheat flour of the present invention involves mixing 100 parts by weight of wheat flour with an amylose content of 25% or less with 30 to 45 parts by weight of water at a temperature of 70°C or higher to obtain a mixture, and heating the mixture at an atmosphere temperature of 100°C or higher and less than 120°C for 3 to 60 seconds to obtain heat-treated wheat flour with a gelatinization degree of 50% to 95%.

[0015] A feature of the method for manufacturing heat-treated wheat flour according to the present invention is the use of wheat flour with an amylose content of 25% or less as raw material. The inventors have conducted in-depth research and discovered that when wheat flour with an amylose content of 25% or less is used, and when water at a specified temperature or higher is used in a specified amount, and heat treatment is performed for a specified time to achieve a gelatinization degree within a specified range, the problem of reduced texture due to prolonged freezing, even in easily brittle baked goods such as biscuits, is suppressed, and the texture of refrigerated dough is improved. Furthermore, the bread obtained in the present invention has a particularly excellent moist and chewy texture. For example, as shown in the comparison between Comparative Example 6 and Example 1, according to this method, even at the same gelatinization degree, excellent results are achieved by using wheat flour with an amylose content of 25% or less.

[0016] For the wheat flour used in this invention, from the viewpoint of the properties of starch with low amylose content, such as being moist and chewy, and easily gelatinized by heat treatment, the amylose content is 25% or less. Furthermore, amylose content refers to the amylose content in the starch of the wheat flour.

[0017] Wheat flour with an amylose content of 25% or less can be obtained by milling 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 from wheat varieties where the expression of any two of the amylose synthesis genes Wx-A1, Wx-B1, and Wx-D1 is deleted. Wheat flour with an amylose content of 25% or less can be used by appropriately mixing one or more of these low-amylose wheat varieties.

[0018] In addition to wheat flour with an amylose content of 25% or less, there is also glutinous wheat flour. The wheat used for this glutinous wheat flour is produced, for example, as described in Japanese Patent Application Publication No. 6-125669: a hexaploid with the Wx-A1 and Wx-B1 genes absent but maintaining the expression ability of the Wx-D1 gene is crossed with a hexaploid with only the Wx-D1 gene absent, resulting in a first-generation hybrid. This first-generation hybrid is then self-fertilized to produce a second-generation hybrid, from which individuals with the absence of expression of the aforementioned three genes are selected, resulting in a glutinous wheat with an amylose content of 0. Furthermore, after crossing this with japonica wheat using conventional methods, and then screening, glutinous wheat with an amylose content of 10% or less is obtained. In this invention, wheat flour with an amylose content of 25% or less can be produced from glutinous wheat with an amylose content of 10% or less.

[0019] From the perspectives of chewy and moist texture, freeze resistance, and refrigeration resistance, the amylose content of the wheat flour used in this invention is preferably 0-25%, and more preferably 0-20%.

[0020] In this invention, from the perspective of improving the taste, the proportion of wheat flour from wheat varieties whose amylose content is less than 25% is preferably 50% by mass or more, particularly preferably 75% by mass or more, and may also be 100% by mass.

[0021] In this invention, water heated to a predetermined temperature or higher is mixed with wheat flour of a specific amylose content to obtain a mixture, which is then subjected to heat treatment. Hereinafter, the process of mixing water and wheat flour to obtain a mixture will also be referred to as a mixing process. For example, while Patent Document 1 describes heat treatment of a mixture of water and wheat flour, it does not describe pre-heating the water mixed with the wheat flour. On the other hand, in this invention, by heat-treating the mixture of water heated to a predetermined temperature or higher with wheat flour, compared to mixing with unheated water, the α-oxidation of starch in the wheat flour is significantly promoted in a short time. Since this is applied under predetermined conditions to the heating of wheat flour with a specific amylose content, excellent results are obtained in achieving a moist and chewy texture in bread and excellent freeze resistance and refrigeration resistance in baked goods. Specifically, the water added to the wheat flour is heated to 70°C or higher, preferably to 75°C or higher, and more preferably to 80°C or higher. By setting the water temperature mixed with wheat flour to above 70°C, baked goods achieve an excellent moist and chewy texture, and also improve the freeze resistance of biscuits and the refrigeration resistance of dough. The water temperature mentioned in this instruction manual refers to the water temperature under normal pressure, with an upper limit typically of 100°C.

[0022] In the mixing process, the mixture of wheat flour and water at a specified temperature or above does not need to be a homogeneous mixture; it is sufficient that it exists in a mixed state. Furthermore, in this specification, the process of mixing wheat flour and water to obtain the mixture does not necessarily require stirring or other homogenization operations. However, homogenization processes such as stirring when obtaining the mixture of wheat flour and water are not excluded from this invention and can be appropriately performed depending on the intended use and quality of the heat-treated wheat flour. The mixture of wheat flour and water can be obtained by adding the aforementioned water to wheat flour, or by adding wheat flour to the aforementioned water; however, adding the aforementioned water to wheat flour is advantageous from the perspectives of uniformity and ease of mixing and stirring.

[0023] In the method for manufacturing heat-treated wheat flour according to the present invention, the amount of water mixed with the wheat flour in the above-described mixing process is a predetermined amount. The amount of water at a temperature of 70°C or higher mixed with the wheat flour must be 30 to 45 parts by weight relative to 100 parts by weight of wheat flour. By setting the amount of water to 30 parts by weight or more, the α-gelatinization of starch in the wheat flour is sufficiently carried out, resulting in a moist and chewy texture. On the other hand, by setting it to 45 parts by weight or less, it is possible to prevent a decrease in productivity caused by the wheat flour becoming doughy, and to suppress the stickiness that occurs during bread making due to excessive gelatinization of starch in the wheat flour, thus providing the advantage of excellent operability. The amount of water mixed with the wheat flour is more preferably 30 to 40 parts by weight relative to 100 parts by weight of wheat flour, and even more preferably 32 to 38 parts by weight.

[0024] Furthermore, in this invention, emulsifiers, fatty acids, oils, etc. are not required during the heat treatment of wheat flour. If added, the emulsifiers, fatty acids, and oils are preferably used in extremely small amounts relative to the wheat flour, less than 0.05% by mass, more preferably less than 0.01% by mass, and even more preferably less than 0.005% by mass, respectively.

[0025] In the mixture, the components other than wheat flour and moisture are preferably 2.0% by mass or less, more preferably 1.0% by mass or less, relative to the total amount of wheat flour.

[0026] As described above, a mixture of water and wheat flour at a specified temperature is heated at an atmosphere temperature of 100°C to 120°C for 3 to 60 seconds (hereinafter, this process is sometimes simply referred to as "heat treatment"). The "atmosphere temperature" referred to here is the air temperature of the space surrounding the mixture (wheat flour), which is the object being heated, not the temperature of the object itself (the temperature of the mixture). By setting the atmosphere temperature to 100°C or higher and the heating time to 3 seconds or higher, the α-reduction of starch in the wheat flour can be easily and sufficiently carried out. Furthermore, by setting the atmosphere temperature to less than 120°C and the heating time to less than 60 seconds, it is advantageous to suppress excessive gelatinization of starch and denaturation of proteins. From this viewpoint, a heating time of 4 to 30 seconds or 4 to 15 seconds is preferred. Additionally, an atmosphere temperature of 100°C to 110°C or lower is preferred. Furthermore, in this invention, the mixing of wheat flour and water can be carried out simultaneously with heating, or heating can be performed after mixing. For example, by separately adding wheat flour and water into a container with a preheated internal atmosphere, the mixing of wheat flour and water can be carried out simultaneously with heating. The heating process begins when wheat flour and water are added to the container.

[0027] The method for manufacturing heat-treated wheat flour of the present invention preferably involves setting the temperature of the mixture to a temperature exceeding 100°C and below 110°C during heat treatment, more preferably to a temperature between 101°C and 110°C. By setting the temperature of the mixture to a temperature exceeding 100°C and below 110°C during heat treatment, wheat flour with the gelatinization degree described later can be readily obtained, and the moist and chewy texture, freeze resistance of biscuits, and cold storage resistance of the flour are also particularly excellent. Patent Document 2, paragraph

[0018] , states that "by setting the temperature of the mixture to 100°C or below, baked goods that are excellent in terms of workability, appearance (volume), and internal phase, in addition to obtaining a good moist and chewy texture, can be obtained." However, the present inventors have found through research that, for wheat with a specific amylose content, a particularly excellent improvement in texture can be obtained by heating the mixture at a temperature exceeding 100°C and below 110°C to achieve a specified gelatinization degree.

[0028] In the method for manufacturing heat-treated wheat flour according to the present invention, the temperature of the mixture only needs to reach more than 100°C and less than 110°C even once during the heat treatment. For example, the temperature of the mixture can be measured at the end of the heat treatment, but as described above, as long as it reaches more than 100°C and less than 110°C even once during the heat treatment, the temperature of the mixture at the end of the heat treatment can also be outside the range of more than 100°C and less than 110°C. In order to set the temperature of the mixture within the above range, the temperature and amount of water mixed with wheat flour can be set within the above range during the above mixing treatment, and the time from the moment the wheat flour and water are mixed to the moment the heat treatment begins can be adjusted, thereby setting the atmosphere temperature and heating time during the heat treatment within the above range. In addition, the flow rate of heated water vapor flowing inside the container can be adjusted during the heat treatment.

[0029] To ensure that the temperature of the mixture at the end of heating is within the range described later, it is preferable that the mixing of wheat flour and water at a predetermined temperature and the heating treatment are carried out continuously. Continuous, for example, means that the mixing of wheat flour and water at a predetermined temperature takes place within a few seconds from the start of heating, including the aforementioned case where wheat flour and water are added separately into a container with a preheated internal atmosphere. Furthermore, when measuring the temperature of the mixture in the heating treatment apparatus, for example, when using an apparatus that heats the mixture while simultaneously transferring the contents from the inlet to the outlet in a container via an internal extruder during heating treatment, the temperature of the mixture can be set to the temperature of the mixture at the outlet.

[0030] The heat treatment of the present invention can be carried out without particular limitation using any known heating device, but it is preferable to use a device that adds water to the wheat flour for heating treatment in order to gelatinize the starch. The heat treatment can be carried out using known heating devices such as autoclaves and steam furnaces. As an example of the heat treatment of the present invention, a process in which wheat flour and water at a temperature above the aforementioned predetermined temperature are sealed in a heatable sealed container such as an aluminum bag or a heat-jacketed container, and heated under pressure. Before introducing the wheat flour and water, the internal atmosphere of the sealed container can be preheated to a desired temperature. Furthermore, a stirring mechanism can be appropriately provided inside the sealed container. Additionally, pressurization can be achieved using heated steam within the sealed container. Another example of the heat treatment according to the present invention is a process in which wheat flour and water are introduced into a sealed container, the mixture is stirred as needed, and saturated steam is introduced into the container and heated under pressure at the same time as, before, or after the introduction (preferably at the same time as or before the introduction) (the amount of saturated steam in this case is not included in the amount of water added to the wheat flour at a temperature of 70°C or higher). These processes can be carried out, for example, using a single-screw or twin-screw extruder.

[0031] Furthermore, when steam is introduced into the container and heated under pressure, the steam flow rate is typically adjusted within the range of 40–130 kg / h, preferably within the range of 70–100 kg / h. Here, "under pressure" refers primarily to a pressurized state achieved by steam filling the container, not to a state achieved by bringing the raw wheat into contact with an object such as an extrusion tool (equivalent to the screw of an extruder).

[0032] In the method for manufacturing heat-treated wheat flour according to the present invention, it is preferable to pulverize the heat-treated wheat flour after heat-treating a mixture comprising wheat flour and heated water as described above. In the present invention, it is preferable to pulverize the heated mixture without a granulation step after heat treatment. A granulation step refers to the process of forming the heated mixture into granules to produce dough particles. Examples of granulation steps include granulation processes using extrusion granulators, mixing granulators, etc. Alternatively, examples include stretching the heated mixture through two rollers and then cutting the stretched dough to granulate it, or, if a mixing mill was used in the heat treatment described above, cutting the mixture extruded from the mixing mill into smaller granules. Examples of dough particle size include 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 manufacturing time and saving space in manufacturing equipment.

[0033] When pulverizing heat-treated wheat flour obtained through heat treatment, there are no particular limitations on the pulverization method. Known methods can be used, such as roller milling, impact milling, airflow milling, and needle milling. However, needle milling or airflow milling is preferred.

[0034] Furthermore, in this invention, the heat-treated wheat flour can be dried before pulverizing. As mentioned above, heat-treated wheat flour is usually in a moist state, so drying before pulverizing allows for more appropriate pulverization. The drying process can be carried out using known methods such as rack drying, hot air drying, and fluidized bed drying. Additionally, drying can be performed simultaneously with pulverization. Furthermore, if drying of the heat-treated wheat flour is not performed before pulverization, drying after pulverization is preferable to improve shelf life. From the viewpoint of suppressing starch gelatinization and protein denaturation of the heat-treated wheat flour, the drying temperature is preferably 6 hours to 24 hours for low-temperature drying (30°C to 70°C), 5 seconds to 120 seconds for high-temperature drying (100°C to 180°C), more preferably 40°C to 60°C for low-temperature drying, and more preferably 120°C to 160°C for high-temperature drying.

[0035] The heat-treated wheat flour obtained in this invention has a gelatinization degree of 50% to 95%. Heat-treated wheat flour with a gelatinization degree of 50% or higher has the advantages of providing a moist and chewy texture for breads and preventing texture deterioration during freezing for dough products such as biscuits. Furthermore, it also prevents dough from staling. Heat-treated wheat flour with a gelatinization degree of 95% or less has the advantage of preventing a decrease in productivity and bread-making operability by preventing stickiness caused by excessive starch gelatinization. From this viewpoint, the gelatinization degree of heat-treated wheat flour is preferably 50% to 95%, more preferably 65% ​​to 90%. The gelatinization degree is determined by the β-amylase-branched amylase method, specifically by the following method.

[0036] <Method for Determination of Gelatinization>

[0037] (A) Reagent

[0038] The reagents used are as described below.

[0039] 1. 0.8M Acetic Acid-Na Acetic Acid Buffer

[0040] 2. 10N sodium hydroxide solution

[0041] 3. 2N acetic acid solution

[0042] 4. Enzyme solution: The substance was obtained by dissolving 0.017 g of β-amylase (Nagase Chemtex Corp. #1500) and 0.17 g of amylopectin (Hayahara Biochemical Research Institute, 31001) in the above 0.8 M acetate-Na acetate buffer solution and preparing 100 ml.

[0043] 5. Inactivated enzyme solution: Prepared by boiling the above enzyme solution for 10 minutes.

[0044] 6. Somogyi reagent and Nelson reagent (reagents for determining reducing sugar content)

[0045] (B) Determination Method

[0046] 1. Grind the wheat flour using a homogenizer to a fineness of less than 100 mesh. Take 0.08–0.10 g of the ground wheat flour in a glass homogenizer.

[0047] 2. Add 8.0 ml of desalinated water and homogenize the glass homogenizer up and down 10 to 20 times to disperse it.

[0048] 3. Take 2 ml of the above-mentioned dispersion from two graduated 25 ml test tubes, and dilute one tube to volume with 0.8 M acetic acid-Na acetic acid buffer to serve as the test area.

[0049] 4. Add 0.2 ml of 10N sodium hydroxide solution to another tube and react at 50°C for 3–5 minutes to allow it to gelatinize completely. Then, add 1.0 ml of 2N acetic acid solution, adjust the pH to around 6.0, and bring the volume to a final volume with 0.8M acetic acid-Na-acetic acid buffer solution to create the gelatinization zone.

[0050] 5. Take 0.4 ml of the test solution prepared in steps 3 and 4 above, and add 0.1 ml of enzyme solution to each. Incubate the enzyme reaction at 40°C for 30 minutes. Simultaneously, prepare a blank sample containing 0.1 ml of inactivated enzyme solution instead of the enzyme solution. The enzyme reaction is carried out while the reaction solution is stirred continuously.

[0051] 6. Add 0.5 ml of hematoxylin and eosin to 0.5 ml of the liquid after the above reaction is complete, and boil in a boiling bath for 15 minutes. After boiling, cool under running water for 5 minutes, add 1.0 ml of Nelson's reagent and stir, then let stand for 15 minutes.

[0052] 7. Then, after adding 8.00 ml of deionized water, the mixture was stirred and the absorbance at 500 nm was measured.

[0053] (C) Calculation of the degree of gelatinization

[0054] The degree of gelatinization is calculated using the following formula.

[0055] Degree of gelatinization (%) = (Decomposition rate of test solution) / (Decomposition rate of fully gelatinized test solution) × 100 = (Aa) / (A' - a') × 100

[0056] In the formula, A, A', a, and a' are described below.

[0057] A = Absorbance of the test area

[0058] A' = Absorbance of the gelatinized region

[0059] a = Absorbance of the blank in the test area

[0060] a' = Absorbance of the blank space in the gelatinized region

[0061] The heat-treated wheat flour of this invention can be further processed for various food applications, with baked goods being a representative example. Baked goods as described in this invention refer to foods made from wheat flour as the main ingredient, with yeast or leavening agents, water, salt, sugar, and other auxiliary materials added as needed to obtain fermented or non-fermented dough. This dough is then subjected to heat treatments such as baking, steaming, or frying. Examples of baked goods to which this invention is applicable include breads and pastries. Examples of breads include staple breads, French breads, sausage breads, French rolls, croissants, and pizzas. Examples of pastries include donuts, dorayaki, sponge cakes, butter cakes, scones, pancakes, muffins, and small cookies. Furthermore, examples of baked goods that easily become crispy when frozen include staple breads, French breads, sausage breads, French rolls, pizzas, and pastries such as scones, dorayaki, sponge breads, butter cakes, scones, pancakes, and muffins.

[0062] In addition, examples of noodles include udon noodles, Chinese noodles, and Italian pasta.

[0063] The heat-treated wheat flour obtained in this invention is preferably used for baking foods or for flour, for example, it can be used as a raw material for baking food mixtures or flour mixtures.

[0064] The baking food mixtures and dough mixtures obtained in this invention contain heat-treated wheat flour obtained by the method for manufacturing heat-treated wheat flour according to this invention. The inventors have discovered that by using the heat-treated wheat flour obtained by the method for manufacturing heat-treated wheat flour according to this invention, baked goods with a moist and chewy texture for bread and high freeze resistance for biscuits and the like can be obtained. Furthermore, by using the heat-treated wheat flour obtained by the method for manufacturing heat-treated wheat flour according to this invention, dough with excellent cold-resistant properties can be obtained.

[0065] The baking and dough mixtures obtained in this invention contain not only heat-treated wheat flour obtained by the method for manufacturing heat-treated wheat flour according to this invention, but also non-heat-treated wheat flour. This is preferred from the perspective of ease of handling, good taste, appearance, and internal phase. As the non-heat-treated wheat flour, untreated wheat flour that has not undergone heat treatment can be used, such as strong flour, semi-strong flour, medium flour, weak flour, and hard wheat flour. One of these can be used alone, or two or more can be used in combination. The non-heat-treated wheat flour can also be wheat flour made from either foreign or domestic wheat. Particularly when using domestic wheat flour as the raw material for heat-treated wheat flour, from the perspective of ease of acquisition, it is preferable to use wheat flour made from foreign wheat as the non-heat-treated wheat flour.

[0066] When the baking food mixture and dough mixture obtained in this invention contain non-thermal treated wheat flour, the amount of thermally treated wheat flour obtained in this invention is preferably 1 to 40 parts by weight out of a total of 100 parts by weight of the thermally treated wheat flour and non-thermal treated wheat flour. By setting the amount of thermally treated wheat flour obtained in this invention to 1 part by weight or more, it is easier to obtain an improved texture effect in baked goods and dough. By setting the amount of thermally treated wheat flour to 40 parts by weight or less, the properties for making pastries / bread / dough become good. From these viewpoints, for the amount of thermally treated wheat flour obtained in this invention in the baking food mixture and dough mixture, the amount of thermally treated wheat flour out of a total of 100 parts by weight of the thermally treated wheat flour and non-thermal treated wheat flour is more preferably 5 to 40 parts by weight, and even more preferably 10 to 40 parts by weight.

[0067] From the perspective of achieving good operability, taste, appearance, and internal properties, in the baking food mixture and dough mixture of the present invention, in a total of 100 parts by weight of heat-treated wheat flour and non-heat-treated wheat flour obtained in the present invention, the amount of non-heat-treated wheat flour is preferably 60 parts by weight to 99 parts by weight, more preferably 65 parts by weight to 95 parts by weight, and even more preferably 70 parts by weight to 90 parts by weight.

[0068] Furthermore, the total mass ratio of heat-treated wheat flour to non-heat-treated wheat flour obtained in this invention in baking food mixtures and flour mixtures is preferably 50% by mass or more, more preferably 55% by mass or more, and particularly preferably 60% by mass or more. Especially considering the high efficiency in terms of workability, texture, appearance, and internal properties, the above-mentioned amounts are preferred for general bread applications, confectionery applications such as biscuits, and flour applications.

[0069] In baking food mixtures and dough mixtures, other ingredients besides the heat-treated and non-heat-treated wheat flour obtained in this invention may also be included. Examples include: grain flours other than wheat flour such as rye flour, barley flour, buckwheat flour, rice flour, bean flour, and corn flour; potato starch, corn starch, waxy starch, wheat starch, and processed starches that have undergone α-modification, etherification, esterification, cross-linking, oxidation, etc.; leavening agents or yeast such as sodium bicarbonate, baking powder, ammonium carbonate, ammonium bicarbonate, and ammonium chloride; oils such as salad oil; sugars such as granulated 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, spices, flavorings, colorings, fruit juices, fruits, vitamins, brine, etc., and one or more of these ingredients may be used alone or in combination. These other components can be mixed together when the heat-treated wheat flour and non-heat-treated wheat flour obtained in this invention are mixed, or they can be pre-mixed into one of the heat-treated wheat flour and non-heat-treated wheat flour, or they can be mixed after the heat-treated wheat flour and non-heat-treated wheat flour are mixed.

[0070] The present invention has been described above based on its preferred embodiments. However, the preferred configurations described in the above or below embodiments can also be combined with any other preferred configurations described above or below. Furthermore, the preferred configurations described herein do not consider levels of more preferred, particularly preferred, etc., and any level of preferred configuration can be combined with any level of preferred configuration.

[0071] Example

[0072] Examples are given to illustrate the invention in detail, but the invention is not limited to the following examples. Furthermore, in each example and comparative example, the water vapor temperature inside the container is set to a range of 90–130°C, the pressure inside the container is set to a gauge pressure range of 10–100 kPa, and the water vapor flow rate is set to the above range.

[0073] (Comparative Examples 1-3)

[0074] The wheat flour of the names listed in Table 1 was directly used as a comparative example. In addition, "1CW" is an abbreviation for "No.1 Canada Western", "WW" is an abbreviation for "Western White", and "ASW" is an abbreviation for "Australian Standard White".

[0075] (Examples 1-4, 6; Comparative Examples 4-7)

[0076] The sealed container equipped with a heat jacket and a single-screw extruder is preheated to the atmosphere temperature listed in Table 1. Specifically, the sealed container is heated from the outside using a heat jacket with steam as a heat source, so that the atmosphere temperature inside the container reaches the temperature listed in Table 1.

[0077] Next, wheat flour is prepared by milling the wheat varieties and names recorded in Table 1. The amylose content of the wheat flour is shown in Table 1.

[0078] Water was prepared to be heated to 80°C in the amount of wheat flour listed in Table 1. Wheat flour and the heated water were added to the sealed container and mixed. The mixture was heated for 5 seconds in the sealed container at the atmosphere temperature set as specified above, and then discharged from the sealed container. The temperature of the mixture at the end 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 on a rack at 50°C for 12-24 hours without granulation to achieve a moisture content of 10% to 14% by mass. The heat-treated wheat flour was then pulverized using a pin mill, and the mixture particles were recovered as pulverized heat-treated wheat flour. The degree of gelatinization of the obtained pulverized heat-treated wheat flour was measured using the above method. Furthermore, saturated steam was introduced into the container during heat treatment, and the mixture was heated under pressure. The flow rate of the steam in the container was adjusted to achieve the temperature of the mixture at the end of heating as shown in Table 1.

[0079] (Example 5)

[0080] In Example 1, the temperature of the mixture at the end of heating (the temperature of the mixture at the outlet of the sealed container) was changed to below 100°C (95°C) by adjusting the steam flow rate inside the container; otherwise, it was set to be the same as in Example 1. The degree of gelatinization of the obtained pulverized heat-treated wheat flour was measured using the above method.

[0081] (Experimental Example 1)

[0082] Using the pulverized and heat-treated wheat flour of Examples 1-6, Comparative Examples 4-7, or the wheat flour of Comparative Example 1, a type of baked food, namely staple bread, was manufactured by the following method.

[0083] In the mixing bowl of a commercially available bread mixer (Dalton Co., Ltd., universal mixer model 5DM-03-r), 320g of Million (Nisshin Flour Co., Ltd.) as a non-heat-treated strong flour, 80g of the heat-treated wheat flour of the evaluation subject or 80g of the wheat flour of Comparative Example 1, 8g of salt, 32g of sugar, 9.2g of live yeast (Oriental Yeast Industrial Co., Ltd.), 0.4g of fermented food (Oriental Yeast Industrial Co., Ltd.), and an appropriate amount of water were mixed to prepare bread dough.

[0084] Specifically, mix at low speed for 4 minutes, then at high speed for 2 minutes. Next, add 16g of oil and mix at low speed for 4 minutes, then knead at high speed for 1 minute (kneading temperature 27°C). Ferment the resulting dough at 27°C and 75% relative humidity for 1 hour, then divide it into 450g portions and round them. After a 30-minute bench time, shape the dough into sticks and place them into bread molds. Then, perform a final fermentation for 60 minutes (at 38°C and 85% relative humidity), followed by baking at 200°C for 30 minutes to obtain the bread.

[0085] After the obtained staple bread was left to stand at 4°C for one day, 10 specialized judges evaluated its taste based on the following evaluation criteria. The average scores from the judges are shown in Table 1.

[0086] (Evaluation criteria for the texture of staple bread)

[0087] 5 points: Overall, it has a moist and chewy texture, with good taste and texture.

[0088] 4 points: Although it lacks some moisture and softness, it has a moist and chewy texture overall, and the taste and texture are fine.

[0089] 3 points: It feels slightly moist and chewy.

[0090] 2 points: Overall, it lacks moisture and chewiness, and is slightly dry.

[0091] 1 point: The overall texture is too hard or dry, with poor taste and texture.

[0092] (Experimental Example 2)

[0093] Using the pulverized and heat-treated wheat flour of Examples 1-6 and Comparative Examples 4-7, or the wheat flour of Comparative Example 2, a type of baked food, a biscuit was manufactured by the following method.

[0094] As powder raw materials, 40g of non-heat-treated flour (Nisshin Flour Co., Ltd.), 10g of the heat-treated wheat flour of the evaluation object or 10g of wheat flour of Comparative Example 2, 12.5g of white sugar, and 2.5g of baking powder were mixed. Then, 5g of salad oil, 15g of whole egg liquid, 40g of milk, and 30g of water were added to a bowl as liquid raw materials. The mixture was stirred at 120 rpm for 1 minute using a mixer and manually, and then baked at 180°C for 3 minutes on the top and 2 minutes on the bottom. After cooling at 27°C for 30 minutes, the baked product was packaged and stored at -5°C for 30 days for taste evaluation.

[0095] The frozen scones were thawed by placing them at 27°C for 2 hours. Then, 10 expert judges evaluated the crispness of the scones based on the following criteria. The average judges' scores are shown in Table 1.

[0096] (Evaluation criteria for the texture of scones)

[0097] 5 stars: Very moist and chewy, with a very good texture.

[0098] 4 points: Moist and chewy, with a good texture

[0099] 3 points: Slightly moist and chewy, with a slightly good texture.

[0100] 2 points: Slightly crisp and dry, a slightly less desirable texture.

[0101] 1 point: Very crisp and dry, a very undesirable texture.

[0102] (Experimental Example 3)

[0103] Noodles were manufactured using the pulverized and heat-treated wheat flour of Examples 1-6, Comparative Examples 4-7, or the wheat flour of Comparative Example 3 by the following method.

[0104] Twenty parts by weight of wheat flour (the test subject) were mixed with 80 parts by weight of medium-strength flour (Nippon Shoku Flour Co., Ltd., which was not heat-treated). One part by weight of salt and 40 parts by weight of water were added. The mixture was stirred at low speed for 5 minutes using a Hobart mixer. The resulting dough, resembling meat floss, was then shaped, compounded, rolled, and formed into noodles 3 mm thick and 4 mm wide. The noodles were cooked for 11 minutes, cooled in cold water, and then stored in a sealed container at 4°C for 2 days. The aging resistance of the noodles was then evaluated.

[0105] (Evaluation criteria for the texture of noodles)

[0106] 5 stars: Very chewy, very smooth, and has a very good texture.

[0107] 4 points: Chewy, smooth, and with a good texture

[0108] 3 points: Slightly chewy, slightly smooth, and with a slightly good texture.

[0109] 2 points: Slightly crisp, somewhat smooth, slightly less than ideal texture

[0110] 1 point: Very crisp, no smoothness, a very undesirable texture.

[0111]

[0112] As shown in Table 1, in each embodiment where wheat flour with a specified amylose content was heat-treated for a specified time by adding water at a specified temperature and a specified amount to achieve a specific degree of gelatinization, a moist and chewy texture of staple bread, improved crispness of biscuits after long-term freezing, and a chewy and smooth texture of refrigerated dough were all obtained. In particular, excellent texture improvement was achieved when the mixture temperature was set above 100°C.

[0113] On the other hand, for the wheat flours of Comparative Examples 4-6, which have a relatively high amylose content, especially when insufficient water is added, the bread has a poor texture, and the baked biscuits after long-term freezing also have a crisp and dry texture, and the dough also becomes crisp. Similarly, when Chikugoizumi with an amylose content of 25% or less is used, as in Comparative Example 7, compared to the examples, the bread has a poor texture when insufficient water is added, and the baked biscuits after long-term freezing also have a slightly crisp and dry texture, the dough is crisp, and the smoothness is reduced.

Claims

1. A method for manufacturing heat-treated wheat flour, wherein, 100 parts by weight of wheat flour with an amylose content of less than 20% are mixed with 30 to 45 parts by weight of water at a temperature of 70°C or higher to obtain a mixture. The mixture is then heated for 3 to 60 seconds at an atmosphere temperature of 100°C or higher but less than 120°C, so that the temperature of the mixture of wheat flour and water at the end of the heating treatment is 101°C or higher but less than 110°C, to obtain heat-treated wheat flour with a gelatinization degree of 50% to 95%.

2. The method for manufacturing heat-treated wheat flour according to claim 1, wherein, Heat-treated wheat flour is used for manufacturing baked goods or for making dough.

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