JP7623870B2 - Method for producing heat-treated wheat bran and method for producing processed foods - Google Patents

Description

The present invention relates to a method for producing heat-treated wheat bran and a method for producing processed foods.

In recent years, with the rise in health consciousness, wheat bran, which is rich in nutrients such as dietary fiber, vitamins, and minerals, as well as functional ingredients and has a good flavor, is being used to manufacture secondary processed products such as bread and noodles.

Patent Document 1 discloses a wheat bran processed product in which the ratio of soluble protein to the total protein mass is 3 to 15% and the gelatinized starch content is 1 to 10% by mass, with the aim of obtaining a processed product that has the original flavor of wheat bran and reduced harshness and odor.

JP 2017-225423 A

However, the technology in Patent Document 1 had poor secondary processability when using wheat bran, and the texture of the secondary processed products using wheat bran was also unsatisfactory.

Therefore, the object of the present invention is to provide heat-treated wheat bran that is highly suitable for secondary processing and can be processed into secondary processed products with excellent flavor and texture.

The present invention relates to a method for producing wheat bran from Australian Standard White, the method comprising the steps of contacting the wheat bran with superheated steam to heat treat the wheat bran,
The present invention provides a method for producing heat-treated wheat bran having an average particle size of 30 to 180 μm.

The present invention also provides a method for producing processed foods, in which 1 to 60 parts by mass of heat-treated wheat bran obtained by the above-mentioned production method is used per 100 parts by mass of cereal flour.

The present invention provides heat-treated wheat bran that is highly suitable for secondary processing and can be processed into secondary processed products with excellent flavor and texture.

The method for producing heat-treated wheat bran of the present invention (hereinafter, simply referred to as the "production method") will be described below based on a preferred embodiment. In the following description, when it is stated that "X to Y[Z]" (X and Y are arbitrary numbers and [Z] is an arbitrary unit), it means "X[Z] or more and Y[Z] or less" unless otherwise specified.

In this manufacturing method, wheat bran obtained from Australian Standard White (ASW, for example, produced in Australia), which is classified as a medium-quality wheat among white wheat, a type of white wheat of the genus Triticum, is used as a raw material, and the wheat bran is subjected to a predetermined heat treatment. The raw material wheat bran contains a predetermined amount of dietary fiber and carbohydrates. By using wheat bran derived from ASW as a raw material, it is possible to improve the suitability for secondary processing, and the obtained secondary processed product has a good flavor with reduced unpleasant tastes such as bitterness and astringency derived from wheat bran, a smooth texture, and an excellent appearance. Whether wheat bran is derived from ASW or not can be selected, for example, by genetic characteristics.

Generally, wheat caryopses (wheat kernels) are roughly divided into endosperm, husk (outer skin and seed coat), and germ (embryo). Wheat kernels are crushed, and the husk-derived fraction obtained by removing the endosperm and germ becomes wheat bran. This wheat bran typically has a moisture content of 3 to 15% by mass, and is preferably in powder form.

This manufacturing method includes a step of contacting wheat bran derived from ASW with superheated steam and heat-treating the wheat bran. In the following description, wheat bran that has not been heat-treated is also referred to as "untreated."

First, the endosperm and germ are separated from the raw material untreated ASW grains to obtain untreated wheat bran. The ASW grains can be conditioned by adding water to the grains or can be ground without adding water. There are no particular limitations on the method for extracting wheat bran from the ground grains, and it is possible to use a method in which the ground grains are separated into wheat bran and other components by a known classification method such as sieving, and then the wheat bran is extracted.

The untreated ASW grains can be ground using a grinding method commonly used in this technical field, such as roll grinding, impact grinding, airflow grinding, etc. The grains may be ground once, or multiple times using the same or different grinding methods. For example, roll grinding and impact grinding may be combined and performed in that order, or roll grinding may be performed multiple times in multiple stages. The grinder used for impact grinding is not particularly limited as long as it grinds the grains by mechanical impact between an impact plate and a rotating rotor. It is preferable to use roll grinding from the viewpoint of simultaneously improving the grain grinding efficiency and the bran separation efficiency.

The average particle size of wheat bran refers to the volume cumulative particle size D50 at 50% cumulative volume when measured in a dry state using a laser diffraction scattering type particle size distribution measuring device (for example, the "Microtrack Particle Size Distribution Measuring Device 9200FRA" manufactured by Nikkiso Co., Ltd.). This measurement method is commonly applied throughout this specification.

Next, the untreated wheat bran obtained by the above-mentioned method is brought into contact with superheated steam to heat-treat the wheat bran. By carrying out heat treatment using superheated steam as a heat treatment method, the secondary processability of the heat-treated wheat bran is further improved, and the flavor and texture of the resulting secondary processed product are further improved. In addition, the heat treatment step makes it easier to adjust the particle size of the wheat bran, which is advantageous in that the particle size of the heat-treated wheat bran can be adjusted to a suitable range to increase the productivity of secondary processed products. In addition, the heat treatment step reduces or inactivates the activity of various enzymes such as amylase and protease, which is particularly advantageous in that it can further improve the secondary processability and the texture of the secondary processed product.

The temperature of the superheated steam used in the heat treatment is preferably 150 to 450°C, more preferably 150 to 300°C, and even more preferably 150 to 250°C. The treatment time with the superheated steam is preferably 0.5 to 10 minutes, more preferably 1 to 8 minutes, and even more preferably 2 to 5 minutes, provided that the temperature is within the above-mentioned range. The flow rate of the superheated steam can be appropriately adjusted depending on the equipment used, but in the case of the equipment used in the examples described later (SV Roaster HOTMAX (Nakanishi Manufacturing Co., Ltd.)), for example, it can be preferably set to 30 to 300 kPa.
By contacting the superheated steam under such conditions, the wheat bran to be treated can be heat-treated at a temperature equivalent to that of the superheated steam, and the harshness and odor peculiar to wheat bran can be effectively reduced. In addition, the secondary processing suitability of wheat bran when used as a raw material for processed foods is improved, and the flavor of processed foods containing wheat bran is improved. In addition, the generation of unintended roasted odor can be suppressed, and a secondary processed product that is easy to eat can be obtained.

One method for contacting the wheat bran with superheated steam is, for example, to introduce the wheat bran to be treated into a closed container and allow superheated steam to circulate and remain within the container. If necessary, the wheat bran to be treated may be contacted with the superheated steam while being stirred.

Through the above steps, the desired heat-treated wheat bran can be obtained. This heat-treated wheat bran is preferably in powder form, and its average particle size is preferably 30 to 180 μm, more preferably 45 to 150 μm, and even more preferably 60 to 120 μm. With such an average particle size, it is possible to highly productively produce secondary processed products that are highly suitable for secondary processing and have excellent appearance, flavor, and texture.

In order to obtain heat-treated wheat bran having the above-mentioned preferred average particle size, for example, untreated wheat bran that has been subjected to particle size adjustment such as crushing or classification so as to obtain the desired average particle size of the heat-treated wheat bran before heat treatment, such as when grinding the grains, can be subjected to heat treatment, or after heat treatment, particle size adjustment such as crushing or classification can be performed so as to obtain the desired average particle size of the heat-treated wheat bran.
Alternatively, before the heat treatment, untreated wheat bran may be coarsely ground to an average particle size larger than the average particle size of the desired heat-treated wheat bran, and this wheat bran may be contacted with superheated steam, after which the heat-treated wheat bran may be finely ground and classified to an average particle size of the heat-treated wheat bran described above.
In other words, it is preferable to carry out a step of adjusting the particle size of the wheat bran before or after the heat treatment step with superheated steam, or both before and after the heat treatment step. Note that the average particle size of the wheat bran does not substantially change before and after the heat treatment.

From the viewpoint of efficiently obtaining fine heat-treated wheat bran, it is more preferable to further pulverize the heat-treated wheat bran to obtain a finely pulverized product having the above-mentioned preferable average particle size. This pulverization step is also preferably carried out by impact pulverization. The pulverization process is preferably carried out so that the proportion of the fraction with an average particle size of less than 200 μm relative to the total mass of the wheat bran is about 50 to 100 mass%, and more preferably 70 to 100 mass%.

In order to efficiently obtain heat-treated wheat bran that can be used to produce secondary processed products with a smooth texture and little roughness by making the particle size distribution sharp, it is preferable to classify the finely ground heat-treated wheat bran and separate a fraction having an average particle size of preferably 200 μm or less, more preferably 150 μm or less. This classification process may be performed using a sieve, an air classifier, or both.

When classification is performed using a sieve, the sieve has an opening of preferably 150 to 200 μm, more preferably 150 to 180 μm, and even more preferably 150 μm, and the fraction that has passed through the sieve is collected. When this step is performed using an air classifier, a classifier capable of accurately separating fractions with a particle size boundary of 150 to 200 μm is used, and a fraction with an average particle size of preferably 200 μm or less, more preferably 150 μm or less is collected. From the viewpoint of space saving, it is preferable to perform pulverization and classification using an impact type pulverizer with an air classifier built in. An example of an impact type fine pulverizer with an air classifier built in can be ACM Pulverizer (trade name) manufactured by Hosokawa Micron Corporation.

The heat-treated wheat bran obtained through the heat treatment process using superheated steam has very little condensed water compared to when saturated steam is used, so its moisture content is preferably 15% by mass or less. This moisture content is the same as that of untreated wheat bran, and the moisture content remains almost unchanged before and after heat treatment.

On the other hand, the moisture content may be unintentionally relatively high due to unintentional adhesion of condensed water due to excessive contact with superheated steam, unintentional dripping in the heat treatment environment, etc. If these phenomena occur, the moisture content of the heat-treated wheat bran may exceed 15% by mass.
In this case, from the viewpoint of preventing the proliferation of spoilage bacteria and enhancing the shelf life, it is preferable to carry out a drying treatment after the heat treatment with superheated steam to reduce the moisture content of the heat-treated wheat bran. Specifically, the moisture content of the heat-treated wheat bran is adjusted to preferably 15% by mass or less, more preferably 3 to 15% by mass. The drying treatment may be carried out after the heat treatment with superheated steam and before the particle size adjustment step, or after each of the heat treatment with superheated steam and the particle size adjustment steps. The moisture content can be measured by a heat drying method.

The heat-treated wheat bran obtained through this manufacturing process preferably has a dietary fiber content and carbohydrate content within a specified range. In the following explanation, for convenience of explanation, unless otherwise specified, heat-treated wheat bran, which is a powdered material having a moisture content within the above-mentioned range, is used as an example. Furthermore, when the moisture content of the heat-treated wheat bran is 8 to 9% by mass, it is preferable for the contents of the components described in the following explanation to be as high quality as possible.

The dietary fiber content of the heat-treated wheat bran is preferably 40% by mass or more, more preferably 43% by mass or more, and even more preferably 44% by mass or more, and from the viewpoint of the production efficiency of secondary processed products, 60% by mass or less is realistic. By setting the dietary fiber content in this range, secondary processed products produced using the heat-treated wheat bran will have a good flavor and texture derived from the wheat bran and a good appearance. In addition, the health promotion effect of ingesting dietary fiber can be obtained. The dietary fiber content can be appropriately adjusted by, for example, further subjecting the untreated wheat bran fraction obtained by crushing ASW kernels to at least one of crushing and classification to increase the content of wheat husk.

The dietary fiber content in the present invention is the total value of soluble dietary fiber and insoluble dietary fiber, quantified by the modified Prosky method (analysis method based on the AOAC 985.29 method) based on the Analysis Manual of the Standard Tables of Food Composition in Japan, 2015 Edition (7th Edition). The dietary fiber content can be measured, for example, using a commercially available measurement kit based on the modified Prosky method.

The carbohydrate content of the heat-treated wheat bran is preferably 18% by mass or less, more preferably 17.7% by mass or less, even more preferably 17% by mass or less, and even more preferably 16% by mass or less, and from the viewpoint of the production efficiency of secondary processed products, 10% by mass or more is realistic. By setting the carbohydrate content in this range, the suitability of the heat-treated wheat bran for secondary processing can be improved, and the obtained secondary processed products have excellent appearance and texture. The carbohydrate content can be appropriately adjusted by, for example, further subjecting the untreated wheat bran fraction obtained by crushing ASW kernels to at least one of crushing and classification to increase the content of wheat husk.

The carbohydrate content in the present invention can be the value obtained by subtracting the dietary fiber value from the carbohydrate value determined by a subtraction method based on the Analysis Manual of the 2015 Edition (7th Edition) of the Standard Tables of Food Composition in Japan. In other words, the carbohydrate content in the present invention is the value obtained by subtracting the masses of water, protein, lipid, ash, and dietary fiber from the mass of 100 g of the measurement subject. The masses of water, protein, lipid, ash, and dietary fiber can each be quantified based on the analysis manual.

When such heat-treated wheat bran is used for secondary processing into foods such as bread and noodles, the dough produced has good physical properties such as elasticity, shape retention, and moldability, and is highly suitable for secondary processing. In addition, secondary processed products processed using heat-treated wheat bran have reduced unpleasant tastes such as bitterness and astringency derived from wheat bran, excellent flavor and texture, and good appearance. In detail, starch is contained in the wheat husk and its surroundings, which are the raw material for wheat bran, but few of these starches have a structure suitable for secondary processing, and many of these starches are of poor quality. When wheat bran containing such starches is used for secondary processing, the physical properties of the dough tend to deteriorate, and as a result, the texture and appearance of the secondary processed products tend to deteriorate. In this regard, the heat-treated wheat bran obtained through the manufacturing method of the present invention has a relatively low carbohydrate content, so poor quality starches are less likely to be mixed in. As a result, the suitability for secondary processing is increased, and the appearance and texture of the secondary processed products are good. In addition, because heat-treated wheat bran is made from ASW, it can produce a good flavor in secondary processed products with less bitterness and harshness compared to products made from other wheat. In a preferred embodiment of heat-treated wheat bran, it contains a specified amount of dietary fiber, which improves secondary processing suitability, appearance, flavor, and texture, and can efficiently achieve the health-promoting effects of dietary fiber intake.

The heat-treated wheat bran obtained by this manufacturing method can be mixed with flour other than wheat bran, such as wheat flour or wheat germ, to produce a processed food, which is a secondary processed product of heat-treated wheat bran. The content of each raw material can be adjusted appropriately depending on the desired processed food, but the content of heat-treated wheat bran relative to the total mass of the flour (the total mass of heat-treated wheat bran and flour other than wheat bran) is preferably 1 to 60 mass%, more preferably 1 to 45 mass%, and even more preferably 1 to 30 mass%. By including heat-treated wheat bran in the flour within such a range, it is possible to improve the suitability for secondary processing, appearance, and texture, and to impart a good flavor with reduced bitterness and harshness to the processed food, and to efficiently exert the health-promoting effects of ingesting dietary fiber.

The raw materials for processed foods may be used as a flour composition (so-called mix) by further mixing one or more of the following raw materials with the mixed flour: proteins such as gluten; starches such as unmodified starch and modified starch (acetylated starch, etherified starch, cross-linked starch, oxidized starch, etc.); sugars such as sugar and oligosaccharides; fats and oils such as shortening, butter and margarine; fermentation bacteria such as yeast and lactic acid bacteria; salt; skim milk powder; thickeners; emulsifiers; leavening agents; etc.

One embodiment of the process for producing a processed food is as follows. In detail, heat-treated wheat bran alone or mixed flour or a flour composition is mixed with a dough preparation liquid such as water, milk, whole eggs, egg whites, egg yolks, fresh cream, or kansui water to produce a clay-like dough (so-called dough) or a paste-like dough (so-called batter). The dough is then shaped to have the desired shape of the processed food, and the dough is dried, cooled or fermented as necessary, or the dough is subjected to a heat treatment such as baking, steaming, boiling or frying to produce the processed food.

When a mixed flour or flour composition containing heat-treated wheat bran is used to produce processed foods, the amount of dough preparation liquid added to the mixed flour or flour composition is 100% when water is used as the dough preparation liquid and the dough to be prepared is dough.
It is preferably about 50 to 100 parts by mass per 100 parts by mass of the mixed flour or flour composition, and when the dough to be prepared is a batter, it is preferably about 90 to 300 parts by mass per 100 parts by mass of the mixed flour or flour composition.

The mixed flour or flour composition containing heat-treated wheat bran has good dough moldability and good suitability for secondary processing, and can be suitably used to produce various processed foods such as breads such as sliced bread and rolls, bakery foods such as waffles, crepes, pancakes, hotcakes, sponge cakes, okonomiyaki, takoyaki, obanyaki, and taiyaki, noodles such as udon, somen, hiyamugi, soba, Chinese noodles, and pasta, noodle skins such as gyoza skins and spring roll skins, and fried foods such as tempura, fried chicken, tatsuta-age, and fritters. The processed foods obtained are excellent in appearance, flavor, and texture. In detail, if the processed food is bread, it will have an excellent appearance, a good flavor with little bitterness or harshness, and a soft and good texture. If the processed food is noodles, it will be white, have an excellent appearance, have a good flavor with little bitterness or harshness, and have a strong elasticity and good texture.

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.
The heat-treated wheat bran in each of the Examples and Comparative Examples was a powder consisting only of wheat bran, and the moisture content of the wheat bran was in the range of 8 to 9% by mass in all cases.
The dietary fiber and carbohydrate contents (mass%) of the heat-treated wheat bran in each Example and Comparative Example were measured based on the above-mentioned method. The results are shown in Table 1 below.

[Examples 1 to 6]
The raw wheat used was white wheat and medium quality wheat, ASW, which was refined and pulverized in a roll mill. The pulverized material was classified using a sieve with a mesh size of 200 μm, and untreated wheat bran was collected as the residue on the sieve.

Next, the collected untreated wheat bran was subjected to impact pulverization using a turbo mill (manufactured by Tokyo Flour Mills, Ltd.) to coarsely pulverize the bran to an average particle size of about 240 μm. The coarsely pulverized material was subjected to heat treatment by contacting it with superheated steam at a steam flow rate of 100 kPa at the temperature and time shown in Table 1 below using an SV Roaster HOTMAX (manufactured by Nakanishi Seisakusho).
The heat-treated wheat bran was then pulverized using an impact mill (ACM Pulverizer, manufactured by Hosokawa Micron Co., Ltd.), and the pulverized product was classified using a sieve with a mesh size of 150 μm. The bran fraction passing through the sieve and having a particle size of less than 150 μm was collected to obtain the desired heat-treated wheat bran. The average particle size of this heat-treated wheat bran was 90 μm.
Fractions with different dietary fiber and carbohydrate contents were obtained by appropriately adjusting the grinding conditions for roll grinding and impact grinding.

Comparative Example 1
The heat-treated wheat bran was contacted with superheated steam under the same conditions as in Example 3, except that the heat-treated wheat bran was not pulverized, to obtain the desired heat-treated wheat bran. The average particle size of this heat-treated wheat bran was 240 μm. Fractions with different dietary fiber and carbohydrate contents were obtained by adjusting the milling conditions for the roll milling and impact milling.

Comparative Examples 2 to 3
Instead of ASW, No. 1 Canadian Western Red Spring (1CW, produced in Canada), which is red wheat and hard wheat, was used as the raw wheat. In addition, instead of heat treatment with superheated steam, a device having a similar configuration to the heat treatment stirring device described in JP-A-2004-9022 was used to heat the product to a temperature of 120° C. for 25 minutes to perform dry heat treatment. Heat-treated wheat bran was obtained in the same manner as in Example 1.

Comparative Example 4
Heat-treated wheat bran was obtained in the same manner as in Example 1 except that 1CW was used as raw wheat.

Comparative Examples 5 to 6
Heat-treated wheat bran was obtained in the same manner as in Example 1, except that Western White (WW, produced in the United States), which is white wheat and soft wheat, was used as the raw wheat.

[Evaluation 1: Bread production]
The heat-treated wheat bran of each Example and Comparative Example was mixed with the following raw materials in the ratios shown below to prepare dough, and bread, which is a secondary processed product (processed food), was produced through the following bread production process. Ten expert panelists produced and ate the bread to evaluate the workability (secondary processability) of the dough during bread production, as well as the flavor and texture of the resulting bread. The panelists evaluated each Example and Comparative Example by setting the evaluation score for Comparative Example 2 as the "control example" and the evaluation score for the bread produced and eaten using this as "2 points," and evaluated according to the evaluation criteria shown below. The results are shown in Table 1 below as arithmetic mean values.

<Bread ingredients> (The units of ingredients shown below are "parts by mass.")
・Wheat flour (strong flour): 80
・Heat-treated wheat bran: 20
Gluten: 7
・Fabric improver: 0.1
・Yeast: 3
・Salt: 2
・White sugar: 6
・Skimmed milk powder: 2
・Shortening: 5
Water: 81
(Gluten: H-10, manufactured by Ogawa Flour Mills. Dough improver: C Food, manufactured by Oriental Yeast Co., Ltd.)

<Bread manufacturing process>
Each raw material was put into a mixing device (Kanto Mixing Machine Co., Ltd., vertical mixer HPi-20M) and mixed at a product temperature of 28 ° C. in the order of 7 minutes at low speed, 10 minutes at medium-low speed, and 2.5 minutes at medium-high speed to prepare a dough. This dough was left to stand for 60 minutes under conditions of 27 ° C. and 75% RH. The fermented dough was divided into 450 g portions and left to stand for 20 minutes with a bench time. These doughs were formed into rolls and placed in a one-loaf bread mold, and left to stand for 50 minutes under conditions of 32 ° C. and 85% RH to perform a proofing process. Finally, the dough after the proofing process was baked at 210 ° C. for 30 minutes to obtain bread containing the heat-treated wheat bran of the examples and comparative examples.

<Evaluation of secondary processing of bread>
5 points: The fabric is much easier to organize than the control (Comparative Example 2) and has very good secondary processability.
4 points: The fabric is easier to gather than the control example, and has good secondary processability.
3 points: The fabric is somewhat easier to hold together than the control, and secondary processability is somewhat better.
2 points: secondary processability equivalent to that of the control example.
1 point: The fabric is less easily gathered than the control example, and secondary processability is poor.

<Bread texture (roughness)>
5 points: Much smoother in the mouth than the control example (Comparative Example 2), and has an excellent texture.
4 points: Smoother than the control, with excellent texture.
3 points: Taste is better than the control, and the texture is slightly better.
2 points: The texture is the same as the control example.
1 point: Rougher than the control, with a poor texture.

<Bread texture (crunchiness)>
5 points: Much crisper than the control example (Comparative Example 2) and has an excellent texture.
4 points: Crisper than the control, with better texture.
3 points: Crisper than the control, with a slightly better texture.
2 points: The texture is the same as that of the control.
1 point: Less crisp and has a worse texture than the control.

<Bread flavor (bitterness)>
5 points: Compared with the control example (Comparative Example 2), there is no bitterness or it is very weakly bitter, and the flavor is very excellent.
4 points: Less bitter than the control, and has an excellent flavor.
3 points: The bitterness is slightly weaker than that of the control, and the flavor is quite good.
2 points: Flavor equivalent to the control.
1 point: Compared to the control, it has a strong bitter taste and a bad flavor.

As shown in Table 1, by contacting wheat bran derived from ASW with superheated steam, it is possible to obtain heat-treated wheat bran that is excellent in secondary processability and can be used to produce processed foods that have excellent flavor and texture.

Claims (4)

A method for producing heat-treated wheat bran, comprising contacting wheat bran derived from Australian Standard White with superheated steam to heat-treat the wheat bran,
In the step of heat treating the wheat bran, the superheated steam having a temperature of 150 to 300 ° C. is contacted for 1 to 8 minutes,
The method for producing heat-treated wheat bran, wherein the heat-treated wheat bran has an average particle size of 60 to 120 μm. The manufacturing method according to claim 1, which obtains the heat-treated wheat bran having a dietary fiber content of 40% by mass or more and a carbohydrate content of 20% by mass or less. The method according to claim 1 or 2, wherein the wheat bran is pulverized before the step of heat-treating the wheat bran, or the wheat bran is heat-treated to obtain the heat-treated wheat bran and then the heat-treated wheat bran is pulverized. A method for producing processed foods, using 1 to 60 parts by mass of heat-treated wheat bran obtained by the method according to any one of claims 1 to 3 per 100 parts by mass of cereal flour.