JPS5889155A - Production of dried "tofu" (soybean curd) - Google Patents

Abstract

PURPOSE:Soy milk is combined with starch, soybean protein and casein, made into TOFU and freeze-dried to produce dried TOFU, which is readily resotrable with cold or hot water, with white color and fine and smooth texture. CONSTITUTION:1pt.wt. of soy milk and/or a powder of soybean protein (calculated as pure protein) is homogenized uniformly together with 0.1-1.5pts.wt. of a starch such as wheat starch, corn starch, processed starch or starch hydrolyzate, 0-0.5pt.wt. of soybean protein such as separated soybean protein or extracted soybean protein and 0.05-0.5pt.wt. of casein or its salt. Then, a coagulant is added to the mixture to form TOFU and the product is subjected to freeze drying at -80--10 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing dried tofu that can be rehydrated with water or hot water to produce tofu with excellent texture, and has a long shelf life.
This provides a protein food that is easy to handle.

Tofu is a protein food that has been widely used as a traditional Japanese food since ancient times, but its shelf life is extremely poor due to its high moisture content. Various studies have been conducted to improve the shelf life of tofu, including improvements to packaging methods, but no fundamental solution has been found. Generally, methods such as freezing or drying are used to improve the shelf life of foods, but it is a well-known fact that when this method is applied to tofu, it transforms into another food such as frozen tofu. . That is, when tofu is frozen, soybean protein, which is the main component of σ-fu, undergoes freezing denaturation and becomes organized into layers, so even if it is thawed, it does not have the smooth texture of tofu if frozen.

This fact is used in reverse in the production of frozen tofu.
It is well known that even if tofu is rehydrated after being frozen and dried, it will not return to its pre-frozen state.

As a method that does not cause this freezing denaturation, there is a known method of adding starches and sugars to soymilk (Japanese Patent Application Laid-Open No. 54-122
No. 755, JP-A-55-153574). The dried tofu obtained by these methods is not freeze-denatured and has a tofu-like texture when reconstituted with water or hot water, but it does not have the smooth texture of silken gufu, and is more like fragrant firm tofu. It has a similar texture and a pale yellow appearance. There is a need for dried tofu that, when rehydrated in water or hot water, is white in color and exhibits a fine-grained, smooth texture similar to silken tofu.

The present inventors conducted various studies to solve the above problem 1, and found that 0.1 to 1.5 parts by weight of starch, soybean protein, and 1 part by weight of protein in soymilk and/or soymilk powder. 0 parts by weight to 0.5 parts by weight, 0 casein or its salts
．． After mixing 05 parts by weight to 0.1 parts by weight, a conventional method t
It was discovered that dried tofu with a white color similar to silken tofu and a finely textured and smooth texture, which is easily rehydrated with water or hot water, can be obtained by adjusting and freeze-drying the tofu.The present invention was based on this discovery. I've reached the point where it's completed.

Starches used in carrying out the method of the present invention include:
Raw starches such as potato starch, wheat starch, corn starch,
Alternatively, these various processed starches, such as α-starch, oxidized starch, fat-processed starch produced by the method taught in Japanese Patent Publication No. 45-32898, dextrin, starch decomposition products such as sugar, starch ester, starch ether, Starch derivatives such as cross-linked starch are used. Although all types of these starches provide the same effect as that of starch, α-starch is particularly preferred as it provides high-quality dried tofu. The amount of these starches does not need to be used in large quantities, and depends on the type, but
0.1 for 1 part by weight of protein (in terms of pure protein) in soy milk or/and soy milk powder (hereinafter, all parts refer to parts by weight)
The effect is expressed at ~1.5 parts, preferably 0.1-1.0 parts. The improvement effect is particularly great when oil- or fat-processed starch is used.

Suitable soybean proteins include soybean proteins that have solubility, gelling properties, and emulsifying properties, such as isolated soybean protein, extracted soybean protein, and concentrated soybean protein.
- or more, preferably 60% or more. A neutralized product of acid-precipitated soybean protein powder may also be used. Solubility is NS
The gelling property was 50% or more in I, and the gel that was prototyped by adding 3.5 times more water was 5oot/f or more in the Kaida type gel strength measuring machine.
It is sufficient that the emulsifying property is 70 or more.

Furthermore, casein or its salt is blended. Specifically, it refers to casein, sodium caseinate, casein/calcium, potassium caseinate, etc. In the case of soybean protein, the blending ratio is 0 part (・0.5 part, preferably 0.1 part).
part to 0.3 parts, 0.0 in the case of casein or its salts
5 parts (・0.5 part, preferably 0.05 part to 0
．． There are 3 parts.

When carrying out the method of the present invention using soy milk as a starting material,
After adding the above-mentioned additives to soy milk and homogenizing it, according to Tokota,
Add known tofu coagulants such as calcium salts, magnesium salts, and glucono delta lactone, coagulate, and prepare tofu for freeze-drying (・ Raw soy milk includes whole soybeans, defatted soybeans, and soybean milk. Use the powder prepared by adding water and using the conventional method.

The freeze-dried tofu thus obtained is stored in the freezer as follows (-).
Freezing is carried out by air blasting or liquid nitrogen, and the freezing temperature is preferably 1-80C to 10C1, preferably 160tZ' to -40C, in order to suppress freeze denaturation and to obtain high-quality dried tofu. I prefer bullets.

Furthermore, by drying the frozen tofu under vacuum and reconstituted with hot water, tofu with an excellent texture that is not the same as so-called frozen tofu can be obtained.

The present inventors further researched the present invention and found that in addition to the additives used in the present invention 1, gums such as xanthan gum, karachinan, guar gum, locust bean gum, and gum arabic, glycerin , tulpitol, propylene glycol, etc., ascorbic acid, erythorbic acid, sulfite, cysteine, homocysteine,
It has been found that the texture of tofu after thawing can be further improved by using alginic acid and its salts/carboxymethyl cellulose, especially high-strength type, in combination with the above-mentioned additives3. Although it has some effect depending on its type, it is effective at 0.001 part to 0.5 part, preferably 0.01 part to 0.1 part, per 1 part of raw protein (in terms of pure protein). manifest.

As is clear from the above description, the present invention provides a method for producing dried tofu with improved quality, and greatly contributes to food products and industry.

The present invention will be explained below with reference to Examples.

Example 1 Based on the formulation table in Table 1, a mixed soybean milk solution was prepared and heated with gentle stirring until it boiled for 15 minutes.
5 Ci was cooled. Next, 10 oIle of glucono delta lactone aqueous solution (concentration 't/di) was added, and after mixing well, a vinylidene chloride tube (Oriyama 35.) was added.
This was filled and coagulated by heating in a hot bath at 90 C1 for 30 minutes. This coagulated material was shredded into pieces and then frozen at -40C to obtain frozen tofu. This frozen tofu was freeze-dried using a Kyowa vacuum freeze dryer to obtain dried tofu.

Table 1 The obtained dried tofu was rehydrated with warm water (approximately 80 c) and subjected to sensory evaluation. The results are shown in Table-2.

Table 2-Example 2 Based on the recipe in Table 3, a soybean milk mixture solution was prepared and heated until it boiled for 15 minutes with gentle stirring.
It was cooled to c. Next, 1 oat of glucono delta lactone aqueous solution (concentration 6 y/dl) was added, and after mixing well, a vinylidene chloride tube (Oriyama 35+m+) was added.
This was filled and solidified by heating in a hot bath at 90C for 30 minutes.

This coagulated product was shredded into 1-40 Ur pieces and frozen to obtain frozen tofu. This frozen tofu was freeze-dried using a Kyowa vacuum freeze dryer to obtain dried tofu.

Table 3 The obtained dried tofu was rehydrated with warm water (approximately 800 ml) and subjected to sensory evaluation. The results are shown in Table 4.

Table 4 Example 3 Based on the recipe in Table 5, a soybean milk mixed solution was prepared and heated to boiling point for 15 minutes with gentle stirring, resulting in approximately 2.5
Cooled to U. Next, an aqueous glucono-delta-lactone solution (concentration 6 t/dl) was added, mixed well, and then placed in a vinylidene chloride tube (Oriyama 35 mn).
) The mixture was filled with a 90 Ct trowel and coagulated by heating in a hot bath for 30 minutes. After shredding this coagulum into 1 crtl -4
Frozen tofu was obtained by freezing at 0.r. This frozen tofu was freeze-dried using a Kyowa vacuum freeze dryer to obtain dried tofu.

Table-5 * Obtained by the method described in Example 1 of Japanese Patent Publication No. 55-19581.

The obtained dried tofu was rehydrated with warm water (approximately 80 C) and subjected to sensory evaluation. The results are shown in Table 6f.

Table-6

Claims (1)

[Claims] For 1 part by weight of protein in soy milk and/or soy milk powder,
Starches 0.1 to 1.5 parts by weight, soybean protein 0 to 0.5 parts by weight, casein or its salt 0.05
A method for producing dried tofu, which comprises mixing parts by weight to 0.5 parts by weight, preparing tofu by a conventional method, and then freeze-drying.