Physically-modified wheat flour and method for producing same

Abstract

This physically-modified wheat flour has a damaged starch content of at least 8 mass% and a wet gluten content of not more than 15 mass%.

Description

Physically modified wheat flour and method for producing the same

[0001] The present invention relates to physically modified wheat flour and a method for producing the same.

[0002] Fried foods are often produced by coating ingredients and frying them in oil. Coatings for fried foods generally use starch or wheat flour as the main raw material. Coatings containing wheat flour can have stickiness due to gluten, making it easy to make various forms of coatings such as thin coatings and thick coatings, having a fragrant flavor of grains when fried in oil, and forming coatings with good disintegration and melt-in-the-mouth properties. On the other hand, highly advanced techniques are required to prepare coatings containing wheat flour having such excellent properties.

[0003] Improvement techniques for wheat flour have been proposed in the past. In Patent Document 1, it is described that modified wheat flour obtained by heat-treating raw wheat flour, having an RVA peak viscosity of 3500 to 7000 mPa·s and a gelatinization start temperature 10°C or more lower than that of the raw wheat flour, has good dispersibility in water, good workability, and can provide a fried food coating with a crispy texture. In Patent Document 2, there is described a modified wheat flour obtained by heat-treating wheat flour, wherein the viscosity when a 10% aqueous suspension of the modified wheat flour is heated to 85°C and then cooled to 25°C is 1000 mPa·s or less, and the degree of dispersion when the aqueous suspension is heated to 85°C, cooled to 25°C, and then allowed to stand for 24 hours is 90% or less, and it is described that this is suitable as a raw material powder for bread and noodle doughs, coatings for fried foods, etc. In Patent Document 3, there is described a hydrothermally treated wheat flour having a gelatinization degree of 12.5 to 30% and a viscosity of 1 to 10 Pa·s when added to 300% by mass of the flour, which improves the workability and the fire penetration of the coating when cooking fried foods, and also achieves both further improvement in the crispy and crunchy texture of the coating and improvement in the appearance of the coating such as the volume and blooming of the coating, and provides fried foods having excellent resistance to change over time.

[0004] International Publication No. 2017 / 135353, International Publication No. 2020 / 213117, JP-A-2008-67675

[0005] There remains a high demand for wheat flour with greater utility as a food ingredient. This invention provides modified wheat flour that is useful as a food ingredient.

[0006] The inventors have discovered that by using modified wheat flour, produced by physical modification and having a specific amount of damaged starch and wet gluten, as a coating material for fried foods, it is possible to produce high-quality fried foods with a coating that has improved crispness and melt-in-the-mouth texture.

[0007] The present invention provides the following as representative embodiments: [1] Physically modified wheat flour having a damaged starch content of 8% by mass or more and a wet gluten content of 15% by mass or less. [2] The physically modified wheat flour according to [1], having a damaged starch content of 10 to 23% by mass and a wet gluten content of 10% by mass or less. [3] A frying blade containing the physically modified wheat flour according to [1] or [2]. [4] A method for producing physically modified wheat flour, comprising moist heat treatment of raw wheat flour and then fluid bed drying treatment, wherein the physically modified wheat flour has a damaged starch content of 8% by mass or more and a wet gluten content of 15% by mass or less. [5] The method according to [4], wherein the moist heat treatment comprises heating in a sealed container with steam introduction and stirring. [6] The method according to [4] or [5], wherein the moist heat treatment is performed at a product temperature of 90°C or higher and less than 140°C for 10 seconds to 20 minutes. [7] The method according to any one of [4] to [6], wherein the fluidized bed drying treatment includes drying the flour while it is suspended or flowing in an environment into which hot air at a temperature of 90 to 120°C is introduced.

[0008] The physically modified wheat flour provided in this invention is useful as a material for batter for deep-frying. By using a batter containing the physically modified wheat flour of this invention, it is possible to produce deep-fried food with a batter that is crispy and melts in the mouth.

[0009] In this specification, physically modified wheat flour refers to wheat flour whose properties have been modified by physical treatment of the raw wheat flour. The raw wheat flour for the physically modified wheat flour of the present invention can be any wheat flour milled in the usual way from edible wheat grains without particular limitation. Examples of the raw wheat flour include strong flour, semi-strong flour, medium flour, weak flour, durum wheat flour, semolina flour, whole wheat flour, etc., and any one of these or a combination of two or more can be used. Of these, weak flour is preferred. Furthermore, when the raw wheat flour is treated to modify the raw wheat flour, if other grain flours or starches are present, it becomes difficult to obtain the desired properties. For this reason, the flour to be treated to modify the raw wheat flour preferably contains 5% by mass or less of components other than the raw wheat flour, and more preferably 3% by mass or less.

[0010] The physically modified wheat flour of the present invention has the following properties (A) and (B): (A) Damaged starch content of 8% by mass or more, preferably 8 to 25% by mass, more preferably 10 to 25% by mass, even more preferably 10 to 23% by mass, and even more preferably 12 to 21% by mass; (B) Wet gluten content of 15% by mass or less, preferably 11.5% by mass or less, more preferably 10% by mass or less, even more preferably 6% by mass or less, and even more preferably 4% by mass or less.

[0011] Regarding the above property (A), the amount of damaged starch in wheat flour represents the proportion of starch granules in the wheat flour that are damaged. The amount of damaged starch affects the water absorption and syneresis of starch, and therefore, it is generally considered preferable for wheat flour to have a low amount of damaged starch. On the other hand, the physically modified wheat flour of the present invention has a relatively higher amount of damaged starch than ordinary unmodified wheat flour (0-4% by mass) or heat-treated wheat flour (2-7.5% by mass). The amount of damaged starch in this specification can be determined by a measurement method in accordance with AACC method 76-31. A commercially available kit (for example, Megazyme's "Starch Damage Assay Kit") can be used to measure the amount of damaged starch according to AACC method 76-31.

[0012] Regarding the aforementioned property (B), the wet gluten content of wheat flour represents the amount of gluten produced from gliadin and glutenin contained in the wheat flour. In unmodified wheat flour, the wet gluten content is approximately 40% by mass for strong flour and approximately 25% by mass for weak flour. The wet gluten content of the physically modified wheat flour of the present invention is lower than that of ordinary unmodified wheat flour. The wet gluten content of wheat flour can be determined by a measurement method in accordance with AACC method 38-12. The gluten content based on AACC method 38-12 can be measured using commercially available measuring equipment (for example, Glutomatic 2000 System; manufactured by PerkinElmer).

[0013] A specific example of the procedure for measuring the wet gluten content of wheat flour in this specification is as follows: (1) Weigh 10 g ± 0.1 g of sample wheat flour and place it in a wash chamber containing an 88 μm mesh sheet; (2) Add 4.3 mL of 2% (W / V) saline solution to (1); (3) Mix (2) for 20 seconds to form a dough; (4) Place the formed dough in the wash chamber, add 100 mL of water and wash for 5 minutes, then gently discard the water. Repeat this process three times; (5) After the operation in (4), the remaining dough mass is centrifuged in a gluten index centrifuge (e.g., Pelten Gluten Index Centrifuge 2015; manufactured by Northern Crops Institute) using a dedicated sieve cassette at 6000 ± 5 rpm for 1 minute; (6) The wet gluten remaining in the sieve is collected and its mass is measured; (7) The wet gluten content is calculated using the following formula: Wet gluten content (%) = Wet gluten mass / Sample flour mass × 100

[0014] The amount of damaged starch in wheat flour can be increased by applying physical forces such as pressure, shear force, and heat to the starch granules. On the other hand, the wet gluten content of wheat flour can be decreased by applying acid or heat to the flour. However, generally speaking, chemical treatments such as acid treatment can adjust the wet gluten content through hydrolysis of gluten, but they cannot adjust the amount of damaged starch.

[0015] In this invention, the amount of damaged starch and the wet gluten content of raw wheat flour are adjusted by physical treatment to produce the physically modified wheat flour of the present invention which has both of the properties of (A) and (B) described above. The physical treatment used to produce the modified wheat flour of the present invention includes heat treatment and mechanical treatment, and these can be used individually or in combination. Preferably, the physically modified wheat flour of the present invention is produced by moist heat treatment of the raw wheat flour followed by fluidized bed drying treatment.

[0016] The moist heat treatment used in this invention refers to a heat treatment in which moisture is added as needed to heat the raw wheat flour under conditions that maintain or increase its moisture content. For example, moist heat treatment can be carried out using hot water, saturated steam, or superheated steam as the heating medium. Among these, moist heat treatment using saturated steam or superheated steam as the heating medium is preferred from the viewpoint of being able to reduce the wet gluten from the raw wheat flour evenly and comprehensively while easily adjusting the amount of wet gluten to a desired range. Furthermore, from the viewpoint of being able to easily control the temperature and time conditions when heating, it is even more preferable to put the raw wheat flour into an apparatus that has been preheated to the heating temperature and then introduce saturated steam or superheated steam as the heating medium to perform the moist heat treatment.

[0017] Examples of the aforementioned moist heat treatment methods include heating raw wheat flour in a sealed container while stirring, with the addition of water or steam as needed, and under pressure as needed. For example, the following methods can be used: (1) Adding water to the raw wheat flour as needed in advance, and then heating it in a sealed container while stirring and under pressure as needed; (2) Heating the raw wheat flour in a sealed container while stirring and under pressure as needed, and adding water as needed; (3) Adding water to the raw wheat flour as needed in advance, and then heating it in a sealed container while stirring and introducing saturated steam or superheated steam; or (4) Heating the raw wheat flour in a sealed container while stirring and introducing saturated steam or superheated steam. Moist heat treatment by the above methods can be carried out, for example, using the apparatus described in Japanese Patent Application Publication No. 2009-034038.

[0018] The temperature and time conditions for the aforementioned moist heat treatment are preferably 90°C to less than 140°C for 10 seconds to 20 minutes, more preferably 95°C to 135°C for 10 seconds to 15 minutes, and even more preferably 105°C to 130°C for 10 seconds to 10 minutes, with the temperature conditions expressed in terms of the flour's temperature. To prevent the flour from burning or becoming discolored, it is preferable to shorten the treatment time as the temperature increases within the above temperature and time range.

[0019] The fluidized bed drying process used in this invention refers to a process in which the object is dried while being suspended or flowed by hot air. Starch damage generally occurs when pressure or shear force is applied to wheat flour. By performing fluidized bed drying on wheat flour after moist heat treatment, the wheat flours collide with each other, making it possible to increase the amount of damaged starch. On the other hand, in methods of drying wheat flour by blowing hot air on it while it is standing, such as shelf drying, the progression of starch damage is slow and uneven, and if the temperature is increased, scorching occurs, making it difficult to adjust to the degree of starch damage desired in this invention.

[0020] Preferably, in the fluidized bed drying process used in the present invention, the flour is dried while suspended or flowing in an environment into which hot air at a temperature of 90 to 120°C, preferably 95 to 110°C, is introduced. Preferably, the moisture content of the flour after drying is 5 to 14% by mass. The fluidized bed drying process can be carried out using a commercially available fluidized bed dryer.

[0021] The physically modified wheat flour of the present invention has an average particle size of preferably 30 to 220 μm, more preferably 45 to 190 μm, and even more preferably 60 to 160 μm. The modified wheat flour after the aforementioned physical treatment can be crushed and graded as needed to obtain wheat flour with the above average particle size. In this specification, the average particle size is the volume average diameter (MV) of the particles calculated by the laser diffraction-scattering method, and can be measured using a commercially available laser diffraction-scattering particle size distribution analyzer (for example, Microtrac MT3000II; Microtrac Bell Co., Ltd.).

[0022] The fluidized bed drying process and sizing of the modified wheat flour described above can be carried out, for example, using the "Dry Meister (registered trademark) DMR-H" manufactured by Hosokawa Micron Corporation. This apparatus has a classification section at the top and a grinding section and a hot air introduction section at the bottom, and is configured to circulate hot air from the bottom to the top. Large, heavy particles in the wheat flour introduced into the apparatus are ground in the grinding section at the bottom, dried with hot air, and transported to the top, where small particles are collected in the classification section at the top. Large particles that are not collected fall to the bottom, are ground again in the grinding section, and are then dried with hot air and classified. The hot air temperature in this process is preferably 90 to 120°C, more preferably 95 to 110°C, and the processing time is preferably 5 to 60 minutes, more preferably 8 to 40 minutes.

[0023] If necessary, the flour may be further dried after the aforementioned physical treatment, or after grinding or sizing. The further drying treatment should preferably be performed using a method that does not affect the amount of damaged starch or gluten, such as low-temperature drying. The physically modified flour of the present invention has a moisture content of preferably 2 to 15% by mass, more preferably 5 to 14% by mass. In this specification, the moisture content of the flour refers to the value measured according to the oven-drying method.

[0024] In the production of physically modified wheat flour according to the present invention, in addition to the physical treatment described above, chemical treatment of the wheat flour may also be performed. Examples of such chemical treatments include oxidation treatment, esterification treatment, etherification treatment, crosslinking treatment, etc., and one or more of these can be performed in combination. Such chemical treatment may be performed before, after, or in between the physical treatments.

[0025] The physically modified wheat flour of the present invention is suitable for use as an ingredient in batter for deep-frying. By using a batter for deep-frying containing the physically modified wheat flour of the present invention, it is possible to produce deep-fried food with a good texture, such as crispness and melt-in-the-mouth quality. Therefore, the present invention also provides a batter for deep-frying containing the physically modified wheat flour of the present invention (hereinafter also referred to as "the batter of the present invention").

[0026] The content of the physically modified wheat flour of the present invention in the coating material of the present invention may vary depending on the type of fried food produced using the coating material and is not particularly limited, but may be, for example, 5% by mass or more, 10% by mass or more, 20% by mass or more, or 50% by mass or more, or 100% by mass, of the total mass of the coating material. For example, the content may be in the range of 5 to 100% by mass, 5 to 80% by mass, 5 to 70% by mass, 5 to 60% by mass, or 10 to 40% by mass.

[0027] The coating material of the present invention may contain other components besides the physically modified wheat flour of the present invention. Examples of such other components include, but are not limited to, other grain flours other than the physically modified wheat flour of the present invention; starch; whole egg powder or egg white powder; oils and fats; sugars such as dextrin, starch syrup, and sugar alcohols; salts; seasonings; leavening agents; emulsifiers; thickeners; enzymes, etc. Examples of such other grain flours include other wheat flours other than the physically modified wheat flour of the present invention, barley flour, rye flour, rice flour, corn flour, sorghum flour, and bean flour. Examples of such other wheat flours include unmodified wheat flour that has not undergone any processing other than the usual milling process. Examples of such starch include unprocessed starches such as potato starch, tapioca starch, corn starch, waxy corn starch, and wheat starch, and processed starches therefrom (pregelatinized starch, etherified starch, esterified starch, acetylated starch, cross-linked starch, etc.). The coating material of the present invention may contain one or more of the other components listed above, depending on the type of fried food to be produced using the coating material. The content of the other components in the coating material of the present invention may be the residue of the physically modified wheat flour of the present invention contained in the coating material, for example, 95% by mass or less, 90% by mass or less, 80% by mass or less, or 50% by mass or less. The coating material of the present invention may not contain the other components at all. For example, the content of the other components may be in the range of 0 to 95% by mass, 20 to 95% by mass, 30 to 95% by mass, 40 to 95% by mass, or 60 to 90% by mass.

[0028] The garment material of the present invention can be prepared from the physically modified wheat flour of the present invention, or by mixing it with other components as described above, if necessary. The garment material of the present invention is preferably in powder form.

[0029] In the production of fried foods using the coating material of the present invention, the coating material of the present invention is applied to the ingredients to produce the fried food material. At that time, the coating material of the present invention can be used in powder form or after being prepared as a batter. Examples of powdered coating materials include dusting flour, batter for fried chicken, etc. Examples of batters include batter for tempura, batter for fried chicken, batter for breaded fried foods, etc. Preferably, the coating material of the present invention is used in powder form, and more preferably as a batter.

[0030] In one embodiment, when the coating material of the present invention is used as a batter, a liquid is added to the powdered coating material and mixed to prepare the batter. The liquid can be water, egg wash, etc. The resulting batter can be applied to the ingredients by coating them or other means to produce fried food. In another embodiment, when the coating material of the present invention is used as a dusting powder, the powdered coating material is applied to the ingredients by a normal operation such as sprinkling. Then, other batters or batter can be applied to this to produce fried food. In yet another embodiment, when the coating material of the present invention is used as a batter, the powdered coating material can be applied to the ingredients by a normal operation such as sprinkling to produce fried food.

[0031] The ingredients to which the coating material of the present invention is attached are not particularly limited and include various ingredients such as meats such as chicken, pork, beef, lamb, and goat; seafood such as squid, shrimp, fish, and shellfish; vegetables; and artificial meats such as soy meat. If necessary, the ingredients may be seasoned or dusted with flour before the coating material of the present invention is attached.

[0032] When using the coating material of the present invention as dusting powder, batter, or batter, the coating material may be applied to the ingredients coated with the dusting powder, batter, or batter, if necessary. The coating material applied further may be appropriate depending on the type of fried food being prepared. For example, the coating material applied further may be the coating material of the present invention or a batter containing it, or it may be another batter (e.g., breadcrumbs, fried chicken flour, grain flour, starch, etc.) or another batter (e.g., egg wash, tempura batter, fried chicken batter, breadcrumb batter, etc.).

[0033] The fried food ingredients coated with the coating material of the present invention may be deep-fried immediately, but may be refrigerated or frozen if necessary. Deep-frying the fried food ingredients produces fried food. In the production of fried food using the coating material of the present invention, the procedures for producing the fried food, such as coating the ingredients with the coating material and deep-frying, can be carried out in accordance with the usual procedures for producing fried food. The fried food produced using the coating material of the present invention is not particularly limited, but examples include breaded fried foods such as cutlets, tempura, karaage (Japanese fried chicken), and fried chicken.

[0034] 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.

[0035] (Measurement Method) The average particle size (MV) of wheat flour was measured using a Microtrac MT3000II (manufactured by Microtrac Bell Co., Ltd.) according to the manual. The amount of damaged starch in wheat flour was measured using a "Damaged Starch Analysis Kit" (manufactured by Megazyme) according to the manual. The wet gluten content of wheat flour was measured according to the specific example described above, based on AACC method 38-12. The amount of damaged starch and wet gluten content were measured twice for the same sample, and the average value was calculated.

[0036] (Manufacturing Examples) Production of Physically Modified Wheat Flour (Manufacturing Examples 1-9, Comparative Example 1) Soft flour (moisture content 12% by mass) was used as the raw material wheat flour. 10 parts by mass of water per 100 parts by mass of raw material wheat flour was sprayed onto the raw material wheat flour using a spray bottle and mixed until homogeneous. The apparatus described in Japanese Patent Publication No. 2009-034038 was prepared, and saturated steam was introduced while the apparatus was running to bring the temperature inside the apparatus to Table 1. The raw material wheat flour was then added and heated (moist heat treatment) while stirring for a heating time of 30 seconds. The heated wheat flour was immediately put into Dry Meister (registered trademark) DMR-H (Hosokawa Micron Corporation), and operated for 20 minutes while blowing in 100°C hot air to pulverize, hot air dry and classify the wheat flour while it was flowing, producing physically modified wheat flour (moisture content 12% by mass) with an average particle size (MV) of 90-110 μm.

[0037] (Comparative Examples 2-4) Soft flour (moisture content 12% by mass) was used as the raw material flour for the production of physically modified wheat flour. 10 parts by mass of water per 100 parts by mass of raw material flour was sprayed onto the raw material flour using a spray bottle and mixed until homogeneous. The apparatus described in Japanese Patent Publication No. 2009-034038 was prepared, and saturated steam was introduced while the apparatus was running to bring the temperature inside the apparatus to Table 2. The raw material flour was then added and heated (moist heat treatment) while stirring for a heating time of 30 seconds. The heat-treated flour was then placed in a constant temperature dryer (NDO-420; manufactured by Tokyo Rikakikai Co., Ltd.) and dried at 100°C for 40 minutes. After that, it was crushed with a pin mill and classified to have an average particle size (MV) of 90-110 μm to produce physically modified wheat flour (moisture content 12% by mass).

[0038] The amount of damaged starch and wet gluten content were measured for the physically modified wheat flour produced. The results are shown in Tables 1 and 2.

[0039] (Test Example 1) Preparation of deep-fried chicken: 50 parts by mass of physically modified wheat flour and 50 parts by mass of potato starch from Examples 1 to 9 and Comparative Examples 1 to 4 of fried chicken production were thoroughly mixed to prepare a coating material for fried foods. Chicken thigh meat was cut into pieces so that each piece weighed 30 g and was marinated with a seasoning liquid (a mixture of soy sauce, sake, and ginger juice). Next, the coating material for fried foods was evenly applied to each piece of chicken at a rate of 6 g per piece of chicken, and the mixture was well kneaded to obtain a fried food material. The obtained fried food material was deep-fried in salad oil heated to 170°C for 3 minutes and 30 seconds to produce deep-fried chicken. As a reference example, deep-fried chicken was produced in the same procedure as above using a 1:1 mixed powder of raw wheat flour (weak flour) and potato starch.

[0040] The texture and melt-in-the-mouth of deep-fried chicken immediately after production were evaluated. Ten professional panelists evaluated the deep-fried chicken of the reference example immediately after production as 2 points, and the deep-fried chicken was evaluated according to the following evaluation criteria, and the average score of the 10 evaluations was obtained. The results are shown in Tables 1 and 2.

[0041] <Evaluation Criteria> (Texture) 5: The coating has a very crispy texture, extremely good. 4: The coating has a crispy texture, good. 3: The coating is slightly sticky or slightly soft, but a crispy texture can be felt, slightly good. 2: The coating is slightly sticky or soft, and the crispy texture is somewhat lacking, but within the acceptable range (equivalent to the reference example). 1: The coating is sticky or soft, and no crispy texture is felt, poor. (Melt-in-the-mouth) 5: The melt-in-the-mouth of the coating is very good, extremely good. 4: The melt-in-the-mouth of the coating is good, good. 3: The coating leaves a slightly remaining feeling, but a good melt-in-the-mouth can be felt, slightly good. 2: The coating leaves a remaining feeling, but within the acceptable range (equivalent to the reference example). 1: The coating always leaves a remaining feeling, poor.

[0042]

[0043]

[0044] (Test Example 2) Production of deep-fried chicken: Under the same conditions as in Production Example 6, except that the temperature and operating time conditions of the drying treatment (with hot air flow) were variously changed, physically modified wheat flours of Production Examples 2-1 to 2-8 and Comparative Example 2-1 were produced. Using these physically modified wheat flours, deep-fried chicken was produced and evaluated in the same procedure as in Test Example 1. The results are shown in Table 3.

[0045]

[0046] (Test Example 3) Using the physically modified wheat flour prepared in the same manner as in Production Example 2-4 for fried chicken production, a coating material for fried chicken having the composition shown in Table 4 was prepared. Using this coating material, fried chicken was produced and evaluated in the same procedure as in Test Example 1. The results are shown in Table 4.

[0047]

Claims

1. Physically modified wheat flour having a damaged starch content of 8% by mass or more and a wet gluten content of 15% by mass or less.

2. The physically modified wheat flour according to claim 1, wherein the amount of damaged starch is 10 to 23% by mass and the wet gluten content is 10% by mass or less.

3. A frying blade containing the physically modified wheat flour described in claim 1 or 2.

4. A method for producing physically modified wheat flour, comprising treating raw wheat flour with moist heat and then performing fluidized bed drying, wherein the physically modified wheat flour has a damaged starch content of 8% by mass or more and a wet gluten content of 15% by mass or less.

5. The method according to claim 4, wherein the moist heat treatment includes heating in a sealed container while stirring under the introduction of steam.

6. The method according to claim 4, wherein the moist heat treatment is performed at a product temperature of 90°C or higher and less than 140°C for 10 seconds to 20 minutes.

7. The method according to claim 4, wherein the fluidized bed drying treatment includes drying the flour while it is suspended or fluidized in an environment into which hot air at a temperature of 90 to 120°C is introduced.

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