JPS6364186B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing dried tofu that becomes tofu with excellent texture by reconstitution with water or hot water,
The present invention provides a protein food that has a long shelf life and 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, the main component of tofu, undergoes freezing denaturation and forms a layered structure, so even when thawed, it does not retain the smooth texture of tofu before freezing. This fact is used in the production of frozen tofu, and it is well known that even if tofu that has been frozen and dried is rehydrated, 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 Nos. 122755-1982 and 153574-1982). 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 tofu, but rather has the texture of 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 has a fine-grained, smooth texture similar to silken tofu. As a result of various studies to solve the above problems, the present inventors found that protein 1 in soy milk and/or soy milk powder
After mixing 0.1 to 1.5 parts by weight of starch, 0 to 0.5 parts by weight of soybean protein, and 0.05 to 0.5 parts by weight of casein or its salt, and preparing tofu by a conventional method, The present inventors have discovered that dry tofu can be obtained by freeze-drying, and has a white color similar to silken tofu, a fine texture, and a smooth texture, which is easily rehydrated with water or hot water, and has led to the completion of the present invention. The starches used in carrying out the method of the present invention include raw starches such as potato starch, wheat starch, and corn starch, and various processed starches thereof, such as alpha starch, oxidized starch, and Japanese Patent Publication No. 45-32898. Oil-processed starch produced by the method shown, starch decomposition products such as dextrins and sugars, and starch derivatives such as starch esters, starch ethers, and crosslinked starches are used. These starches have almost the same effect regardless of their type, but α-starch is particularly preferred because it provides high-quality dried tofu. The amount of these starches does not need to be used in large quantities and varies slightly depending on the type, but the amount of protein (in terms of pure protein) in soy milk or/and soy powder is 1 part by weight (hereinafter, all parts are (indicates parts by weight), 0.1 to 1.5 parts, preferably 0. to 1.5 parts
Effects appear at 1.0 parts. The improvement effect is particularly great when oil- or fat-processed starch is used. In addition, soybean protein has solubility, gelling properties,
and emulsifying properties, such as isolated soybean protein, extracted soybean protein, concentrated soybean protein, etc., as long as the protein content is 50% or more, preferably 60% or more. It may also be a neutralized product of acid-precipitated soybean protein powder. It is sufficient if the solubility is 50% or more by NSI, the gelling property is 500g/cm ² or more by the Okada type gel strength measuring device of a prototype gel made by adding 3.5 times water, and the emulsifying property is 70% or more. be. Furthermore, casein or its salt is blended. Specifically, it refers to casein, sodium caseinate, calcium caseinate, potassium caseinate, etc. These proportions range from 0 parts to 0 parts for soybean protein.
0.5 part, preferably 0.1 part to 0.3 part, and in the case of casein or a salt thereof, 0.05 part to 0.5 part, preferably 0.05 part to 0.3 part. When carrying out the method of the present invention using soymilk as a starting material, the above-mentioned additives are added to the soymilk and homogenized, and then calcium salt, magnesium salt,
A known tofu solidifying agent such as glucono-delta-lactone may be added to solidify the tofu to obtain freeze-dried tofu. The raw soybean milk used is one produced by adding water to whole soybeans, defatted soybeans, or soybean milk powder in a conventional manner. The tofu for freeze-drying thus obtained is then frozen in a freezer, airplast, liquid nitrogen, etc., and the freezing temperature is -80°C to -10°C, preferably -60°C to -40°C. often,
Rapid flash freezing is preferred in order to suppress freeze denaturation and ultimately obtain high quality dried tofu. Furthermore, by drying frozen tofu under vacuum and reconstituted with water or hot water, so-called frozen tofu is not obtained, but tofu with excellent texture can be obtained. The present inventors further researched the present invention and found that in addition to the additives used in the present invention, gums such as xanthan gum, carrageenan, guar gum, locust bean gum, and gum arabic: glycerin, sorbitol, propylene, etc. Wetting agents such as glycol ascorbic acid, erythorbic acid, sulfite,
It has been found that the texture of tofu after thawing can be further improved by using cysteine, homocysteine, alginic acid and their salts/carboxymethyl cellulose, especially gum, in combination with the above additives.
For example, in the case of gum, the effect varies slightly depending on the type, but it is 0.001 part to 0.5 part, preferably 0.01 part to 0.5 part, per part of raw protein (in terms of pure protein).
Effects appear at 0.1 part. As is clear from the above description, the present invention provides a method for producing dried tofu with improved quality, and greatly contributes to the food industry. The present invention will be explained below with reference to Examples. Example 1 A soybean milk mixture solution was prepared based on the recipe in Table 1, heated to boiling for 15 minutes with gentle stirring, and cooled to about 25°C. Next, 100 ml of glucono delta lactone aqueous solution (concentration 6 g/dl) was added,
After mixing well, add vinyl chloride tube (folded cloth).
35 mm) and heated and solidified at 90°C for 30 minutes. This coagulated product was cut into pieces of 1 cm ³ and then frozen at -40°C to obtain frozen tofu. This frozen tofu was freeze-dried using a Kyowa vacuum freeze dryer to obtain dried tofu.

【table】

[Table] The dried tofu obtained was rehydrated in warm water (approximately 80°C) and subjected to sensory evaluation. The results are shown in Table-2.

[Table] Example 2 A soybean milk mixed solution was prepared based on the recipe shown in Table 3, heated to boiling point for 15 minutes with gentle stirring, and cooled to about 25°C. Next, 100 ml of glucono delta lactone aqueous solution (concentration 6 g/dl) was added,
After mixing well, add vinyl chloride tube (folded cloth).
35 mm), and was heated and solidified in hot melt at 90°C for 30 minutes. This coagulated product was cut into pieces of 1 cm ³ and then frozen at -40°C to obtain frozen tofu. This frozen tofu was freeze-dried using a Kyowa vacuum freeze dryer to obtain dried tofu.

[Table] The dried tofu obtained was rehydrated in warm water (approximately 80°C) and subjected to sensory evaluation. The results are shown in Table-4.

【table】

[Table] Example 3 A soybean milk mixture solution was prepared based on the recipe shown in Table 5, heated to boiling point for 15 minutes with gentle stirring, and cooled to about 25°C. Next, 100 ml of glucono delta lactone aqueous solution (concentration 6 g/dl) was added,
After mixing well, add vinyl chloride tube (folded cloth).
35 mm), and was heated and solidified in hot melt at 90°C for 30 minutes. This coagulated product was cut into pieces of 1 cm ³ and then frozen at -40°C to obtain frozen tofu. This frozen tofu was freeze-dried using a Kyowa vacuum freeze dryer to obtain dried tofu.

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

【table】

【table】

Claims (1)

[Claims] 1. 0.1 to 1.5 parts by weight of starch, 0 to 0.5 parts by weight of soybean protein, and 0.05 to 0.5 parts by weight of casein or its salt are mixed with 1 part by weight of protein in soy milk and/or soy milk powder. After that,
A method for producing dried tofu, which is characterized by preparing tofu using a conventional method and then freeze-drying it.