JPS643465B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing fried tofu. In the present invention, fried tofu refers to products made from tofu and fried in oil, such as fried tofu, namaage, ganmodoki, and similar foods. The traditional manufacturing method for fried tofu using whole soybeans is complicated and relies on experience and intuition, and production on an industrial scale has not been carried out much. The commercial value of fried tofu products lies in the fact that they give a unique texture by expanding to 2.7 to 3.1 times the surface area of the dough. It is necessary to carry out the heating and cooling processes strictly and quickly. It is explained that the addition of cold water during the process is a process to provide an appropriate amount of denaturation and to avoid providing an appropriate amount of heat history. Various methods have been proposed to simplify such complicated steps. For example, a method has been proposed in which a special heat-treated soybean protein is added to soybean juice or soymilk after heating in the conventional method (Japanese Patent Application Laid-Open No.
53-115842). This method is also simple and currently the best method, but it uses a lot of water and waste water, is too soft for deep-fried tofu, and is not strong enough especially when used for Inari sushi, bagged side dishes, etc. However, it often breaks. Therefore, there is a demand for durable products that are resistant to tearing as fried tofu. As a result of extensive research into the above problem, the present inventors discovered that by adding calcium-containing soy protein to soy milk, mixing it, shaping it and frying it, the resulting fried tofu can be removed as so-called "yu". The present invention was completed based on the discovery that the amount of waste water used is small, and the product is durable enough to be particularly suitable for fried tofu for Inari sushi, bagged side dishes, etc. The present invention is a method for producing fried tofu, which is characterized by adding and mixing calcium-containing soybean protein to soymilk obtained by a conventional method, and then shaping the mixture and frying it in oil. Calcium-containing soybean protein as used in the present invention is
For example, create it as follows. That is, ordinary undenatured defatted soybeans are soaked in water and extracted, and if necessary, the insoluble segment (so-called "Okara") is removed to obtain an extract. An acid is added to this extract to cause isoelectric point precipitation, and the soluble segment is extracted. (so-called "whey") is removed to obtain acid-precipitated soybean protein. An apparently neutral isolated soybean protein powder obtained by mixing this dried acid-precipitated soybean protein with a sufficient amount of calcium hydroxide to adjust the pH of the acid-precipitated soybean protein to 6.0 to 8.0. When this product is dispersed in water, it shows neutrality)
A similar mixture is used. In this method, acid-precipitated soybean protein is not dried after neutralization as in the conventional method, but is dried at the stage of acid-precipitated soybean protein. In addition, as another method, the following calcium-containing soybean protein can also be used. That is,
An aqueous solution or aqueous suspension of undenatured defatted soybeans with an NSI of 85 or higher is adjusted to pH 6.5 to 7.5, and if necessary, water-insoluble fractions are removed to obtain a protein extract. Next, the pH of this extract was adjusted to 4.1 to 4.7 to collect acid-precipitated proteins, and if necessary, water was added to the acid-precipitated proteins to make a dispersion with a solid concentration of 5% to 30%. Calcium oxide is added to contain calcium ions in an amount of 0.2% to 1.4% based on solid matter,
The pH is adjusted to 5.7 to 7.0 to obtain a protein aqueous suspension containing 65% or more of soybean protein based on the solid matter. This aqueous suspension is dried directly or preferably in direct contact with water vapor in a pipeline for 50 minutes.
The mixture is heated for 2 seconds or more at 120°C to 120°C, and dried if necessary to obtain calcium-containing soybean protein. Alternatively, an aqueous solution or aqueous suspension of undenatured defatted soybeans with an NSI of 85 or higher may be adjusted to pH 6.2 to 7.5, and water-insoluble fractions may be removed if necessary to obtain a protein extract. Calcium salts are added to aggregate the proteins, which are then separated from the solution section.
Furthermore, if necessary, this agglomerated section is treated with calcium salt.
Adjust the pH to 5.7 to 6.5 to obtain a protein water suspension. This aqueous suspension is dried directly or preferably brought into direct contact with water vapor in a pipeline.
A similar calcium-containing soybean protein can be obtained by heating at 50°C to 120°C for 2 seconds or more and drying if necessary. Although the above calcium-containing soybean protein is an example in which only calcium hydroxide is added as an alkaline agent, the present invention is not limited to this, and other edible soybean proteins may be used as long as calcium ions are effective. Alkali agents (sodium hydroxide, magnesium hydroxide, etc.), edible salts (carbonates, sulfates, chlorides, etc.) can be used. What is the range in which calcium ions are effective?
Refers to the range containing calcium ions at 0.2% or more, preferably 0.6% or more based on the protein weight,
If the amount is less than this, the effect of calcium ions will not be recognized. Further, if the calcium ion concentration is higher than 1.4%, it is not preferable because the puffiness of the fried tofu is suppressed. Such calcium-containing soybean protein does not have gel-forming properties because the protein is aggregated by calcium ions even when water is added. When calcium-containing soybean protein is dispersed in water, it has a lower viscosity than ordinary isolated soybean protein, so it is easy to operate and a highly concentrated protein dispersion can be obtained. Furthermore, calcium-containing soybean protein is a combination of calcium and protein, and when fried in oil, it is possible to produce fried tofu with the same strength as the conventional method. This kind of calcium-containing soy protein is added to soy milk, but it can be added in powdered form,
The powder can be added in a suspended state in a liquid such as water, soy milk, or "yu", or in an emulsified state with water, edible oil, or the like. When adding powder, it is also possible to add a predetermined amount of powder to soymilk, or to strain soymilk and add a predetermined amount of powder and (warm) water. When adding the powder in a suspended state in a liquid such as water, Yu, or soy milk, dissolve 1 part of calcium-containing soy protein powder in 4 to 50 parts of water.
For example, it is also possible to dissolve the powder in water, prepare a suspension with the same concentration as soy milk (usually 3 to 5%), and add the suspension. When adding in an emulsified state, water and fat are added and kneaded.The blending ratio varies slightly depending on the desired fried tofu, but from the viewpoint of operability, a fluid state is preferable.Calcium-containing soybean protein 1
parts, 5 parts to 50 parts of water, 5 parts to 50 parts of oil and fat
The proportion of parts is preferred. The oils and fats used are not particularly limited, and animal oils such as beef tallow and pork fat, or vegetable oils and fats such as soybean oil, palm oil, rapeseed oil, sesame oil, and rice oil are used. Kneading these raw materials is
This can be carried out satisfactorily using an emulsifying machine such as a mixer or a silent cutter. At this time, it is not particularly necessary to use an emulsifier, but if it is desired to increase the fat and oil content, a known edible emulsifier such as lecithin may be used. Such calcium-containing soybean protein is added to soybean milk, mixed well, and molded to prepare dough for deep-frying. One feature of the present invention is that calcium-containing soybean protein is added to soymilk. Such calcium-containing soybean protein has the same effect on soymilk as a conventional coagulant, and the soymilk coagulates to form tofu curd. Rather, it contains the same level of calcium ions as conventional tofu, so the resulting fried tofu is comparable in appearance (surface structure) and inner layer to conventional fried tofu, and the texture is moderately elastic, depending on the amount added. have. Calcium-containing soybean protein is added to soymilk, mixed well to make it homogeneous, and molded to prepare dough for deep-frying. The mixing ratio of soybean milk and calcium-containing soybean protein should be in a weight ratio of 95:5 to 5:95, preferably 80:20 to 20:80. If it is outside this range, the effects of the present invention cannot be fully exhibited.
That is, if the amount of calcium-containing soybean protein is less than 5 parts, the skin will not be good, and if it is more than 80 parts, the flavor will be unfavorable. In addition, for example, in the case of Ganmodoki and Ganmodoki-like foods, carrots, kelp, sesame, ginkgo, etc., and various seasonings can also be added as necessary. It is then fried in oil in the conventional manner. Although the temperature of the oil varies depending on the object, it is preferable to slowly fry the first stage at 100 to 110°C, and then fry the second stage at 150 to 180°C. In addition, for Ganmodoki, the first stage is heated to 100 to 110℃, and the second stage is heated to 120 to 160℃.
It is best to fry at ℃. The fried tofu produced by the method of the present invention has a higher degree of puffiness than conventional fried tofu, and the variety of raw soybeans,
The product was of stable quality regardless of storage time. Furthermore, the surface structure was the same as that of conventional fried tofu, and it was strong and elastic, making it particularly suitable for fried tofu that requires a relatively strong skin, such as Inari sushi and packaged side dishes. In addition, the calcium-containing soybean protein used in the present invention has low viscosity, so it is easy to operate, and a highly concentrated dispersion can be obtained.As a result, the amount of water used in the fried tofu manufacturing process is small, so the amount of waste water is small, and drainage problems are avoided. It has been vastly improved. The present invention will be explained below with reference to Examples. Example 1 1 kg of whole soybeans (protein content 40%) was added with 5 ml of water and soaked overnight, and the soybeans that had absorbed the water were ground. Next, water from Step 5 was further added and heated, and the mixture was held at 98°C for 3 minutes, and then water from Step 5 was added and rapidly cooled to separate okara to obtain soymilk at about 70°C. After adding 20 g of calcium chloride to this soy milk and coagulating it, it was poured into a mold box and pressed to make tofu, which was cut into thin pieces, placed on a bamboo rack, and further pressed to obtain dough for deep-fried tofu. This dough was fried in oil for 5 minutes at 110°C in the first stage and at 170°C for 5 minutes in the second stage to obtain normal fried tofu. (Conventional method) On the other hand, normal undenatured defatted soybeans were placed in warm water at 50°C.
Extraction was carried out with stirring for 30 minutes, and the insoluble fraction (Okara) was separated to obtain an extract. Sulfuric acid was added to this extract for isoelectric precipitation at pH 4.5, and the dissolved fraction (whey) was removed. The obtained acid-precipitated protein was crushed and dispersed using a crusher and spray-dried to obtain acidic isolated soybean protein. 100 g of this acidic isolated soybean protein and 1 g of calcium hydroxide were thoroughly mixed to obtain calcium-containing soybean protein. (PH = 7.0) Add this calcium-containing soy protein to 3 kg each of soy milk (solid content concentration 4%) obtained in the process of obtaining normal fried tofu in the proportion shown in Table 1 (powder addition method), After stirring, add 6g of calcium chloride
was added to solidify. This is poured into a mold box and pressed to make tofu, which is then cut into thin pieces, placed on a bamboo rack, and further pressed to obtain dough for deep-frying.
℃ for 5 minutes, and in the second stage, fried in oil at 180℃ for 5 minutes to obtain fried tofu. After measuring the swelling degree of each of these fried tofu, and seasoning these fried tofu in the usual way, peel them into two pieces, cut them out with a No. 3 dumbbell (minimum width 1 cm), and pull them using a rheometer. Tests were conducted and sensory evaluations were also performed.
The results are shown in Table 1.

[Table] As shown in Table 1, compared to conventional fried tofu, the mixture of calcium-containing soybean protein had a higher swelling degree and tensile strength increased by 20 to 50%. Also, from a sensory point of view, the mixture of calcium-containing soybean protein had a chewy texture, depending on the amount added, and the flavor was comparable to that of regular fried tofu. However, in the blending ratio of tofu and calcium-containing soy protein, if the calcium-containing soy protein is less than 5%, the effect will not be noticeable, and if it is more than 95%, the swelling degree and tensile strength will increase, but the flavor will be lower. This poses a practical problem as it gives off a slight soybean odor. Example 2 The acid-precipitated protein obtained in Example 1 was crushed and dispersed using a crusher, and after adjusting the calcium ion concentration to 0.6% and pH 6.0 with calcium hydroxide, it was brought into direct contact with steam in a pipeline. solids concentration 16%,
After heating at 90°C for 1 minute, the mixture was spray-dried to obtain calcium-containing soybean protein. A 20% calcium-containing soy protein dispersion was prepared using this calcium-containing soy protein. This calcium-containing protein dispersion was added to each 3 kg of soymilk obtained in the process of obtaining normal fried tofu in Example 1 in the proportions shown in Table 2 (medium addition method), and after stirring, 6 kg of calcium chloride was added.
g was added to solidify. Thereafter, the same process as in Example 1 was carried out to obtain fried tofu. As a comparative example, a commercially available isolated soybean protein (Ajipron-S ₂ manufactured by Ajinomoto Co., Inc.) was used instead of the calcium-containing protein, and the same process was carried out to obtain fried tofu. The results were shown in Table 2.

【table】

[Table] As shown in Table 2, compared to the conventional fried tofu method, the fried tofu containing calcium-containing soybean protein had a higher degree of swelling and increased tensile strength. The flavor was also comparable to regular fried tofu. In particular, the protein of the present application had good compatibility with water and good dispersibility, and even a 20% dispersion had a low viscosity and very good operability. In the case of commercially available isolated soybean protein, both appearance and texture were similar to starch. Example 3 The acid-precipitated protein obtained in Example 1 was crushed and dispersed using a crusher, and a calcium ion concentration of 0.45%, pH 6.1, solid After adjusting the mold concentration to 16%, it was brought into direct contact with water vapor in the pipeline and heated to 80℃.
After heating for 2 minutes, the mixture was spray-dried to obtain calcium-containing soybean protein. 1 part of this calcium-containing soy protein, 5 parts of water,
Five parts of white soybean oil were mixed in a mixer to obtain an emulsion. The above emulsion was added to each 3 kg of soy milk obtained in the process of obtaining normal fried tofu in Example 1 in Table 3.
In addition to the proportions shown in (emulsion addition method), after stirring, 6 g of calcium chloride was further added to solidify. Thereafter, the same process as in Example 1 was carried out to obtain fried tofu. These fried tofu were evaluated using the same measuring method as in Example 1. The results are shown in Table 3.

[Table] As shown in Table 3, compared to the conventional method of deep-frying, those mixed with emulsions have a higher degree of swelling, and those mixed with emulsions have a supple texture and a flavor similar to that of conventional deep-fried tofu. It was comparable.

Claims (1)

[Scope of Claims] 1. A method for producing fried tofu, which comprises adding and mixing calcium-containing soybean protein to soymilk, shaping the mixture, and frying the mixture in oil. 2 Calcium-containing soy protein improves the pH of dried acid-precipitated soy protein and cough acid-precipitated soy protein.
The production method according to claim 1, wherein the calcium-containing soybean protein is obtained by mixing a sufficient amount of solid calcium hydroxide to adjust the concentration to 6.0 to 8.0. 3 Calcium-containing soybean protein contains 65% or more of soybean protein based on the solid content, and calcium ion content of 0.2% to 1.4% based on the solid content, and
Claim 1: Calcium-containing soybean protein obtained by drying a protein aqueous suspension having a pH of 5.7 to 7.0 and a solids concentration of 5% to 30%.
Manufacturing method described in section.