JPS63269961A - Production of plastic dried bean curd - Google Patents

Abstract

PURPOSE:To produce dried bean curds having excellent shelf stability and handleability, by immersing a coagulated thin film of soybean milk in a solution of salt. CONSTITUTION:Soybean milk is heat-treated to form a coagulated thin film. The coagulated thin film is immersed in 2-3% solution of salt for 2-3min. Thereupon salt is attached to the coagulated thin film to improve water retention. When the coagulated thin film is dried to 13-14% water content in this state, water content in the coagulated thin film is slightly reduced to <= a fixed value by water retention of salt and yet dried bean curds have sufficient plasticity at this water content. Consequently, handleability of dried bean curds can be improved while maintaining shelf stability well.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing dried bean curd, and particularly to a method for producing dried bean curd that has plasticity.

[Prior art] Yuba, which is obtained by heating soy milk and collecting the coagulated thin film that forms on the liquid surface, is widely known as a traditional food in Japan. It is also attracting attention as a health food rich in vegetable lipids.

Conventionally, to produce yuba, soybeans are soaked in water, then ground and filtered to obtain soymilk, which is poured into a heating tank and heated at a temperature of about 90°C for 10 to 15 minutes. Then, the solidified thin film formed on the liquid surface was scooped up one by one with a stick.

However, the coagulated thin film (raw bean curd) in this state has an extremely high moisture content (around 60%) and is easily perishable, so it lacks storage stability and is extremely difficult to obtain.

Therefore, dried yuba has been produced in the past by drying the water content of raw yuba to around 5%, and has good suitability in terms of storage stability.

[Problems to be Solved by the Invention - Problems of the Prior Art However, since the dried Yuba has extremely low moisture content, it is brittle and easily breaks during transportation.

In addition, dried bean curd must be soaked in water or hot water for a long time to soften it before cooking, making it complicated to use.

OBJECTS OF THE INVENTION The present invention has been made in view of the shortcomings of the prior art, and it is an object of the present invention to provide a method for producing plastic dried bean curd that has high retention, bendability, and is easy to handle.

[Means for Solving the Problems] In order to achieve the above object, the method for producing plastic dried bean curd according to the present invention includes a coagulation thin film forming step, a dipping step, and a drying step.

In the coagulated thin film forming step, the soybean milk is heat-treated to form a coagulated thin film.

In the immersion step, the coagulated thin film formed in the coagulated thin film forming step is immersed in saline solution.

In the drying step, the coagulated thin film immersed in the saline solution is dried.

[Function] Since the method for producing plastic dried bean curd according to the present invention has the above-described means, the coagulated thin film formed in the coagulated thin film forming step is of the same quality as normal bean curd.

Then, by immersing the solidified thin film in saline solution,
Salt is attached to the coagulated thin film, improving water retention. By drying in this state in the drying step, the water content of the coagulated thin film is reduced, but due to the water retention properties of the salt, it is difficult to reduce below a certain value, and at this water content, the dried bean sprouts have sufficient plasticity.

Although it has a higher moisture content than regular dried yuba,
Due to the preservative properties of common salt, problems such as spoilage do not occur, and the preservation is good.

As described above, according to the method for producing plastic dried bean curd according to the present invention, it is possible to maintain good storage stability of bean curd and improve its handling properties.

[Example] Background of the Invention As mentioned above, fresh tofu skin has good handling properties such as bendability, but has extremely poor storage stability.On the other hand, dried tofu skin has good storage stability but lacks handling properties, and the In order to develop a wide range of markets, it was considered essential to produce bean curd bean curd that had both good shelf life and ease of handling.

Therefore, the present inventor first attempted to retort the raw bean curd after packaging it.

However, due to the retort treatment at 120° C. for 18 minutes, the raw bean curd is dissolved and becomes liquid.

Therefore, the present inventor next dried raw Yuba and determined the minimum moisture content within the range of plasticity.

As a result, it was found that the plasticity of Yuba disappeared at a moisture content of about 7.5%. However, simply drying ordinary raw Yuba to a moisture content of around 8% causes it to lose its plasticity due to the extremely long time before packaging or after opening, or depending on the packaging material used, it dries during the packaging period and loses its plasticity. This results in a significant loss of handling properties.

Therefore, the present inventor considered making Yuba itself maintain water retention properties.

Salt was selected as the water retaining material, taking into account the cooking style of the tofu skin and other factors.

However, if salt is simply added to soymilk, the soymilk itself will gel, and the yield of bean curd will be extremely poor. This is thought to be due to the damming effect or protein denaturation effect of common salt.

Therefore, we decided to heat soybean milk to form a coagulated thin film and then immerse it in saline solution to make the salt adhere to the bean curd skin.

Incidentally, it is also possible to use sorbitol or calcium lactate as a water-retaining material, but these are expensive and are inferior in usability compared to common salt.

Note that unrefined salt such as bittern or rock salt is more suitable as the common salt because it has better water retention properties.

Note that some sheets made from soybean protein as the main raw material are plastic, but in these cases, other gel-like materials (gelatin, agar, starch, etc.) are mixed in. .

Specific Examples First, the appropriate moisture content of dried plastic Fi leaves produced by the method according to the present invention will be examined.

The following table shows the relationship between water content and plasticity.

Table 1 The moisture content was determined by a normal pressure heating drying method in which the sample was dried for 2 hours in a 105° C. dryer, then left in a desiccator for 30 minutes to cool.

In addition, the plasticity state indicates the bendability of the dried bean curd in 10 pieces (the more +, the better the plasticity).

As is clear from Table 1, the lower limit of water content is 7.80%. On the other hand, if the moisture content exceeds 15%, a problem of rot will occur, so the appropriate moisture content 1 is set at 7°80 to 15.0%.

Next, the concentration of the saline solution in which the coagulated thin film is immersed will be considered.

The following table shows the relationship between the salt concentration of the saline solution, the salt adhesion amount, the salty taste water content, and the plastic state.

Table 2 In this experiment, raw Yuba was immersed in saline solution of each concentration for 1 to 2 minutes, and then indoors (temperature 24℃, humidity 54℃).
%) for about 2 hours.

In addition, in the above table, the amount of salt attached is 100% of dried Yuba.
The amount of salt deposited per unit c was determined by silver nitrate titration.

Saltiness is indicated by the results of a tasting test, and the more 10s there are, the stronger the saltiness is.

As is clear from the above table, as the salt concentration of the saline solution increases, the amount of salt adhering to the bean curd and the saltiness of the tofu skin increase. Here, yuba is preferred for its relatively bland taste, and it is preferable for the salt solution concentration to be as low as possible.

On the other hand, the water content Km and the plastic state are almost constant in the 2% to 10% range, and considering the salty taste etc., it is understood that a saline solution concentration of about 2% is suitable. .

In reality, a thin film of coagulated soymilk obtained by a conventional method is immersed in a 2-3% saline solution for 1-2 minutes, taken out and air-dried, and when the moisture content reaches 13-14%, it is molded. Pack it.

As a result, even after one month had passed since packaging, the tofu skin maintained a moisture content of ff111.12% and was bendable.

On the other hand, if raw yuba is dried as it is, the moisture content will be 13 to 14.
When it was molded and packaged at the point where the moisture content reached 4.47% in about one week, it became brittle and could not be bent.

In this example, an example was explained in which raw tofu skin is immersed in saline water as it is, but the same effect can be obtained by, for example, immersing raw tofu skin in saline water after being dried.

Here, when immersing the tofu in saline after drying, the saline permeates into the inside of the bean curd, so the salt concentration tends to increase slightly.

On the other hand, if the raw bean curd is immersed in saline as it is, the amount of salt adhering to the surface of the bean curd will increase, and the salt can be removed relatively easily, for example, by blanching.

As described above, according to the production method according to this example, dried bean curd with excellent preservability and plasticity can be produced, and at the same time, other foods can be wrapped and cooked as a substitute for "nori" in the cooking stage. This makes it possible to greatly expand the field of application of yuba.

[Effects of the Invention] As explained above, according to the method for producing plastic dried bean curd according to the present invention, the coagulated thin film of soybean milk is immersed in saline solution, so dried bean curd has excellent preservability and handling properties. It becomes possible to manufacture

Claims (4)

[Claims] (1) A coagulated thin film forming step of heating soybean milk to form a coagulated thin film, an immersing step of immersing the coagulated thin film in saline solution, and a drying step of drying the thin film after the immersion. A method for producing plastic dried bean curd. (2) In the method described in claim (1), in the dipping step, the solidified thin film is soaked in saline solution having a concentration of 2 to 3%.
A method for producing plastic dried bean curd, characterized by soaking for a minute. (3) In the method according to claim (1) or (2), the drying step includes drying the thin film after immersion to a moisture content of 13 to 14%. How to make Yuba. (4) A method for producing a plastic dried bean paste according to any one of claims (1) to (3), characterized in that in the coagulated thin film forming step, the coagulated thin film is once dried.