Fried tofu manufacturing method

Abstract

To provide a manufacturing method of fried tofu having a small generation rate of tofu refuse, and rich in soybean dietary fiber.SOLUTION: A manufacturing method of fried tofu containing soybean dietary fiber has a dispersion step for allowing fine air to exist in soybean powder milk obtained by dispersing soybean powder containing dietary fiber into water, and by heating the same, a coagulation step for coagulating the same without being separated from hot water, by adding protein cross-linking enzyme, and a frying step for frying an obtained coagulum without a dehydration step.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a method for producing fried tofu, and more particularly to a method for producing fried tofu rich in soybean dietary fiber. [Background technology]

[0002] Fried tofu is made by heating a mixture of soybeans ground with water, coagulating the soymilk from which the "okara" has been removed, dehydrating it, and then expanding the dough by two-stage frying. If the expansion is insufficient, the skin will harden and the soft texture of the fried tofu will be lost. One of the factors that inhibits the expansion of fried tofu is the presence of soybean dietary fiber. Therefore, when producing fried tofu, a process is carried out in which as much "okara," the main component of which is soybean dietary fiber, as possible is removed from the soymilk.

[0003] In the general production of soy milk and tofu, about 1.5 times the amount of "okara" is generated as the amount of raw soybeans. "Okara" must be disposed of as industrial waste, which places a heavy burden on tofu manufacturers. On the other hand, "okara" contains not only dietary fiber but also the nutritional components of soybeans such as protein. Rather than disposing of "okara" as waste, there are attempts to popularize it as a food ingredient, feed, fertilizer, etc. that is rich in nutrients. For example, efforts are being made to popularize "dried okara", which is made by drying the water content of "okara" (Non-Patent Document 1).

[0004] Patent Document 1 proposes a method for producing tofu that uses whole soybean flour obtained by finely grinding soybeans as a raw material and produces little or no "okara". Thus, tofu that produces significantly less "okara" has been proposed, but in the case of fried tofu, it is difficult to reduce the amount of "okara" produced because the presence of dietary fiber inhibits the swelling of the fried tofu as described above. For example, Patent Document 2 proposes a method for producing fried tofu using whole soybean flour, but the fried tofu obtained by this method does not have a tofu layer and is mainly made of skin, which is different from general thin fried tofu (Patent Document 2, paragraph 0004).

[0005] Patent Document 3 proposes a method for producing fried tofu rich in soybean dietary fiber by forming a paste from tofu that has already been produced, adding soybean powder containing dietary fiber to the paste, homogenizing the dough while adjusting the moisture content, and frying the dough in two stages. However, this method requires a step of forming a paste from tofu that has already been produced, a step of adding soybean powder to adjust the moisture content, and a step of adding other ingredients to homogenize the dough, and the labor required for adjusting the moisture content and the increased number of work steps significantly reduce production efficiency. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2002-345425 A [Patent Document 2] JP 2008-154473 A [Patent Document 3] JP 2010-130961 A [Non-patent literature]

[0007] [Non-Patent Document 1] Japan Dried Okara Association website, [online], searched on April 8, 2021,<URL:https: / / okara.or.jp> Summary of the Invention [Problem to be solved by the invention]

[0008] An object of the present invention is to provide a method for producing fried tofu that produces a small amount of "okara" and is rich in soybean dietary fiber. [Means for solving the problem]

[0009] In order to solve the above problems, the present inventors conducted intensive research and discovered that it is possible to produce fried tofu that is puffed and has an excellent texture even when using heated soy milk powder that is rich in soy dietary fiber, thereby completing the present invention. Specific means for solving the problems of the present invention are as follows. 1. A dispersion process in which fine air is introduced into soy milk powder obtained by dispersing soybean powder containing dietary fiber in water and heating the soybean milk powder; a coagulation step in which a protein cross-linking enzyme is added to coagulate the mixture without allowing it to separate; A process of frying the obtained coagulum without a dehydration process; and containing soybean dietary fiber. 2. The method for producing fried tofu according to claim 1, wherein the soybean powder is whole soybean flour. 3. The method for producing fried tofu according to 1 or 2, characterized in that the solid content of the soy milk powder is 11% by weight or more and 20% by weight or less. 4. The method for producing fried tofu according to any one of 1. to 3., wherein starch is added to the tofu in the coagulation step to coagulate the tofu. Effect of the Invention

[0010] The method for producing fried tofu of the present invention can significantly reduce the amount of "okara" generated during the production process, and can even reduce the amount generated to zero. The fried tofu obtained by the production method of the present invention is sufficiently puffed while containing dietary fiber, has a rich taste and flavor, a smooth texture, and is very delicious. The fried tofu obtained by the production method of the present invention is rich in dietary fiber, protein, etc., and is highly nutritious, because the active ingredients contained in soybeans are not removed as "okara." DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] "Dispersion process" The soybean powder used in the present invention is not particularly limited, and defatted soybean flour, oil-added soybean flour, whole soybean flour obtained by finely grinding soybeans with or without removing the skin, etc. can be used. Among these, whole soybean flour is preferred. This soybean powder is dispersed in water, and heated in the same manner as in normal soybean milk production until the grassy smell disappears to obtain soybean powder milk. The soybean powder milk preferably has a solid content concentration of 11% by weight or more and 20% by weight or less. If the solid content concentration is less than 11% by weight, the resulting tofu may not be strong enough to be difficult to handle, and if the solid content concentration is 20% by weight or more, the viscosity increases, making it difficult to mix the coagulant uniformly, resulting in non-uniform tofu. The solid content concentration of soybean powder milk is calculated by drying soybean powder milk to a constant weight in a constant temperature dryer at 105°C, dividing the weight of the residue (dry solid content) by the weight of soybean powder milk, and multiplying the result by 100.

[0012] In the method for producing fried tofu of the present invention, the soy milk powder obtained above may be used without removing the "okara", or it may be used as is without removing the "okara". If the "okara" is not removed, there is no need to invest in equipment to separate the "okara", and no disposal costs are incurred.

[0013] Soy milk powder needs to have fine air particles before the coagulation process, otherwise the dough will not rise and fried tofu cannot be obtained. A common method for making soy milk powder contain air is to inject air from a pipe upstream of the pump that transports the soy milk powder to a form for solidification, and disperse the air in the soy milk powder while transporting it. In addition, it is also possible to make the air exist by using a device that disperses the injected air through high-speed stirring or by using the principle of generating microbubbles. The diameter of the air bubbles contained in the soy milk powder is preferably 500 μm or less. The soy milk powder used in the manufacturing method of the present invention has a high solids concentration and high viscosity, so even if the air bubbles have a large diameter, their floating speed is slow, and the soy milk powder can be solidified while keeping the air bubbles contained within it.

[0014] "Coagulation process" A protein cross-linking enzyme is added to soy milk powder. The protein cross-linking enzyme cross-links the proteins in the soy milk powder, and commercially available food additives can be used without any particular restrictions. By adding the protein cross-linking enzyme, a tightly bound coagulated material (dough) can be obtained, and even if the obtained coagulated material is fried with a high water content, the skin can be prevented from bursting. The amount of the protein cross-linking enzyme added is not particularly limited as long as it is within a range that can achieve the purpose, but for example, when an enzyme preparation manufactured by Ajinomoto Co., Inc. (product name: Activa Super Card) is used, the amount added is about 0.1% by weight or more. If the amount of the protein cross-linking enzyme added is small, the skin may break during frying. When the amount of the protein cross-linking enzyme added is large, the enzyme is activated and the time during which it acts is shortened, and the same results as when the amount of the enzyme added is small can be obtained, but the cost is high. In addition, if the protein cross-linking enzyme acts too much, the stretching during stretching (frying at low temperature) becomes small. Therefore, for example, when an enzyme preparation manufactured by Ajinomoto Co., Inc. (product name: Activa Super Card) is used, the amount added is preferably about 0.4% by weight or less.

[0015] The addition of the protein cross-linking enzyme results in a fried tofu with a high moisture content, resulting in a smooth texture, and the addition of starch in the coagulation process can further impart a softer, smoother, and more easily meltable texture. Starch imparts water retention, and together with soybean dietary fiber, can prevent water from syneresis after frying, and also alleviates the action of the protein cross-linking enzyme, resulting in a smooth and easily meltable texture of the fried tofu. There are no particular limitations on the type of starch, but it is preferable that the gelatinization temperature is 70°C or higher in order to prevent the viscosity from increasing during coagulation. There are no particular limitations on the amount of starch added as long as it is within a range that can achieve the purpose, and for example, it is preferably 0.5% by weight or more and 3% by weight or less, and more preferably 1% by weight or more and 2% by weight or less. The temperature of the soy milk powder in the coagulation step must be a temperature at which the protein cross-linking enzyme is active, and is usually within the range of 40°C to 70°C, preferably 45°C to 65°C.

[0016] The coagulant may contain one or more of the emulsion-type coagulants including crude seawater magnesium chloride, magnesium chloride, calcium chloride, calcium sulfate, magnesium sulfate, glucono-delta-lactone, citric acid, gluconic acid, lactic acid, acetic acid, tartaric acid, malic acid, succinic acid, fats and oils, and / or glycerin fatty acid esters. From the viewpoint of taste, crude seawater magnesium chloride and those containing magnesium chloride as the main component are preferred. The coagulant may be used in the amount used in the production of conventional dough for deep-frying. The manufacturing method of the present invention uses soy milk powder with a high solid content concentration, which allows the production of a tofu-like coagulated product with water retention, and the "yu" does not separate during coagulation. Since the manufacturing method of the present invention does not separate the "yu," the taste and flavor of the soybeans remain in the coagulated product, and by using this coagulated product as dough, it is possible to produce flavorful fried tofu. The coagulated product is aged, if necessary, until it becomes hard enough to be handled. The aging time varies depending on the coagulation conditions, but is generally about 20 to 60 minutes.

[0017] "Oil conditioning process" The coagulation process produces a tofu-like coagulated product with water retention, and the moisture content of the coagulated product is about 80 to 92% by weight. Since the obtained coagulated product is firmly bound by the protein cross-linking enzyme, even if it is fried without going through the dehydration process while still having a high moisture content, the skin on the surface does not break and stretches, and it is possible to produce fried tofu that is rich in soybean dietary fiber. The resulting coagulated material is then heated in two stages, at a low temperature of 110°C to 120°C (stretching) and at a high temperature of 150°C to 200°C (mustard), to produce fried tofu that is rich in soybean dietary fiber. EXAMPLES

[0018] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. [Example 1] 3.6 kg of soybean powder (manufactured by OFCO Ltd., product name: soybean micron powder, whole soybean powder with the epidermis removed) was added to 16.4 kg of water and dispersed with a homogenizer until no lumps remained, after which an antifoaming agent (manufactured by Kao Corporation, product name: Creton Power) was added and the mixture was heated to approximately 100°C with steam to obtain powdered soy milk. The solids concentration of this powdered soy milk was 14.5% by weight. After dispersing the powdered soy milk adjusted to 65°C with air using a disperser capable of high-speed stirring, 0.4% by weight of a protein cross-linking enzyme preparation (manufactured by Ajinomoto Co., Inc., product name: Activa Super Card) was dissolved in water and added, and a coagulant was further added to obtain a coagulated product. The "yu" did not separate during coagulation. As the coagulant, a 30% by weight aqueous solution of magnesium chloride (manufactured by Ako Kasei Co., Ltd., product name: Soft Wafer) was used, and the magnesium chloride was added to the soy milk at 0.33% by weight. Air was supplied at a flow rate of 300 ml / min for a soy milk flow rate of 30 kg / min. The coagulated product was aged for 30 minutes to make dough (tofu) for deep-frying. The moisture content of the obtained dough (tofu) was about 85% by weight. The dough for deep-frying (tofu) was fried in oil at 120°C to expand (stretch) it, and then deep-fried in oil at 155°C for 10 minutes (with mustard) to obtain deep-frying.

[0019] [Example 2] The soy milk powder used in Example 1 was dispersed in a disperser capable of stirring the soy milk powder and air at high speed, and then 0.4% by weight of a protein cross-linking enzyme preparation (manufactured by Ajinomoto Co., Inc., product name: Activa Super Card) and 2% by weight of starch (manufactured by Matsutani Chemical Industry Co., Ltd., product name: Matsutani Yugao) were dissolved in water and added, and then a coagulant was added to obtain a coagulated product. The "yu" did not separate during coagulation. As the coagulant, a 30% by weight aqueous solution of magnesium chloride (manufactured by Ako Kasei Co., Ltd., product name: Soft Wafer) was used, and the magnesium chloride was added to the soy milk at 0.33% by weight. Air was supplied at a flow rate of 300 ml / min with respect to a soy milk flow rate of 30 kg / min. The coagulated product was aged for 30 minutes to make dough (tofu) for deep-frying. The moisture content of the obtained dough (tofu) was about 83% by weight. The fried tofu was obtained in the same manner as in Example 1.

[0020] [Comparative Example 1] 1.8 kg of soy powder (manufactured by OFCO, product name: soy micron powder) was added to 18.2 kg of water and dispersed with a homogenizer until no lumps remained, after which an antifoaming agent (manufactured by Kao, product name: Creton Power) was added and the mixture was heated to approximately 100°C with steam to obtain soy milk powder. The solids concentration of this soy milk powder was 7.2% by weight. Soy milk powder adjusted to 70°C was dispersed with air using a disperser capable of high-speed stirring, and then a coagulant was added to obtain a coagulant. A 30% by weight aqueous solution of magnesium chloride (manufactured by Ako Kasei Co., Ltd., product name: Soft Wafer) was used as the coagulant, and was added so that the magnesium chloride content was 0.33% by weight relative to the soy milk. Air was supplied at a flow rate of 300 ml / min for a soy milk flow rate of 30 kg / min. The coagulant obtained by aging for 5 minutes after coagulation was a small aggregate that was not tofu-like. It was placed in a mold box and pressed and dehydrated using a press to obtain a hard, brittle, flat-shaped dough for deep-frying. The moisture content of the obtained dough was about 70% by weight. When fried in the same manner as in Example 1, the product did not burst, but was fried without stretching at all, retaining the size of the dough, and could not be called fried food.

[0021] [Comparative Example 2] The dough (tofu) was prepared in the same manner as in Example 1, except that a protein cross-linking enzyme preparation (manufactured by Ajinomoto Co., Inc., product name: Activa Super Card) was not added. The "yu" did not separate during solidification. The moisture content of the obtained dough (tofu) was about 85% by weight. The fried tofu was obtained in the same manner as in Example 1. [Comparative Example 3] The dough (tofu) was prepared in the same manner as in Example 2, except that air was not added to the soy milk powder. No "yu" separated during solidification. The moisture content of the obtained dough (tofu) was about 83% by weight. The fried tofu was obtained in the same manner as in Example 1.

[0022] ·result The obtained fried tofu was dried in a constant temperature dryer at 105°C until it reached a constant weight, and the moisture content of the fried tofu was calculated based on the following formula. Note that for Comparative Examples 2 and 3, the moisture content was not calculated because the fried tofu exploded during frying as described below. (Formula) Moisture content (weight%) = (weight before drying - weight after drying) / weight before drying x 100

[0023] The fried tofu obtained in Example 1 could be fried without breaking, had a fragrant flavor and sweetness like roasted soybeans, and had a high moisture content of 60% and a smooth texture. The fried tofu obtained in Example 2 could be fried without breaking, and had a savory flavor and sweetness like roasted soybeans, similar to that of Example 1. In addition, the moisture content of the fried tofu was high at 66%, and it had a better melt-in-the-mouth texture and a smoother texture than the fried tofu obtained in Example 1.

[0024] The fried tofu obtained in Comparative Example 1 could be fried without breaking, but because the moisture content of the dough was low and it did not contain a protein cross-linking enzyme, it did not stretch at all when fried and retained the size of the dough, and therefore could not be called fried tofu. The fried tofu obtained in Comparative Example 2 did not contain a protein cross-linking enzyme, so although it stretched slightly at low temperatures, it tore due to its lack of strength, and burst in high-temperature oil. Therefore, no satisfactory fried tofu was obtained. The fried tofu obtained in Comparative Example 3 did not stretch at all and had large holes, and burst in the high-temperature oil as in Comparative Example 2, and no fried tofu was obtained. According to the production method of the present invention, fried tofu rich in soybean dietary fiber, which has a rich taste and flavor and a smooth texture, can be obtained.

Claims

1. A dispersion step of dispersing soybean powder containing dietary fiber in water and heating the soybean powder milk to make fine air present in the soybean powder milk; a coagulation step in which a protein cross-linking enzyme is added to coagulate the mixture without allowing it to separate; A process of frying the obtained coagulum without a dehydration process; and containing soybean dietary fiber (however, this does not include a method using a frying dough that is homogenized by adding a leavening agent and a protein-binding enzyme to a tofu paste containing denatured soybean protein that has been heat-treated in a soy milk production process, adjusting the moisture while adding soybean powder containing dietary fiber to the tofu paste, and kneading the mixture).

2. 2. The method for producing fried tofu according to claim 1, wherein the soybean powder is whole soybean flour.

3. 3. The method for producing fried tofu according to claim 1, wherein the solid content of the soybean milk powder is 11% by weight or more and 20% by weight or less.

4. 4. The method for producing fried tofu according to claim 1, wherein starch is added to the tofu in the coagulation step.