JPS6087754A - Preparation of pressed tofu (bean curd) - Google Patents

Abstract

PURPOSE:To prepare pressed TOFU (bean curd) having fine tissue, elasticity, good taste and shelf stability, by subjecting curd obtained from soybean milk, etc. to cutting treatment, compressing it, heat-treating it. CONSTITUTION:A coagulating agent is added to soybean milk or to an aqueous solution of separated soybean protein to give curd, which is subjected to cutting treatment such as cutting, grinding, boring, etc., so that it becomes a state to ooze easily water contained in the curd. The curd is compressed to <=80wt%, preferably 80-55wt% water content, it is packed into a container, sealed hermetically, and heated at about 80-135 deg.C for about 5-60min.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing pressed tofu. More specifically, the present invention relates to an efficient method for producing pressed tofu with a fine texture, elasticity, and good preservability.

Pressed tofu is also called ``dried tofu'' or ``tofu roe'' in China, and because of its good shape retention, it is suitable as an ingredient for stir-fries, and because it is highly processable, it is used in a wide variety of dishes. It is possible to use. In addition, its chewy texture matches the tastes of modern people, and demand for it has been increasing in Japan in recent years.

However, due to the low demand for conventional pressed tofu, the scale of production was small, and we were careful to make it almost handmade.

Therefore, a method for advantageously producing high-quality pressed tofu in a single strip, that is, a method suitable for mass production has not yet been established.

In addition, the conventional method requires an extremely long correction process, and in order to make the texture firmer, a large amount of salt must be added, which ultimately impairs the processing suitability of pressed tofu. It was causing a decline. Furthermore, no consideration has been given to the shelf life of the final product.

In view of the current situation, the present inventors have conducted intensive research to establish an industrially advantageous manufacturing method for high-quality pressed tofu, and as a result, they have developed a method for dividing curd obtained from soy milk or an aqueous solution of separated protein. The present invention was completed based on the discovery that it is effective to produce pressed tofu with high quality and good productivity by compressing it until the moisture content becomes gθ% or less, and then heat-treating it.

Therefore, the main object of the present invention is to provide an industrially advantageous method for producing high-quality pressed tofu.

Another object of the present invention is to provide pressed tofu that has a dense structure and elasticity, has good storage stability, and has an excellent texture.

The above and other objects of the present invention are (1) subjecting a curd obtained by adding a coagulant to soymilk or an aqueous solution of isolated soybean protein to a dividing treatment so that the moisture contained therein can be easily exuded; This can be achieved by compressing the divided curd to reduce its water content to go% or less, and then filling it into a container, sealing it, and subjecting it to heat treatment.

Among the above three steps, step (1) is effective for improving the dewatering efficiency during the compression treatment in step (11), that is, for performing the same treatment effectively in a short time. In addition, the heat treatment in the process (iiD) re-bonds the alternate layer structure that was once separated during the process to form a dense weave, which gives the final pressed tofu an appropriate elasticity and improves its texture. This is an extremely important step in improving the quality of the product.

Thus, by organically combining the three steps described above, all aspects of the present invention can be achieved.

The method of the present invention will be explained in more detail below.

In the method of the present invention, soy milk or an aqueous solution of isolated soy protein is used. Here, soy milk can be produced by conventional methods. For example, it is produced using whole soybeans, dehulled soybeans, or defatted soybeans as raw materials and following the steps of (raw material) → soaking in water → adding water → grinding (kure) → heat treatment → separation → (soy milk). In some cases, the heat treatment may be omitted at the "go" stage and the soy milk may be directly subjected to a separation process to produce soy milk. However, in the present invention, it is desirable to perform heat treatment such as boiling heat treatment at about 30-100° C. for about 30 seconds to io minutes. Similarly, such heat treatment is a desirable process because it causes appropriate thermal denaturation of soybean protein, thereby increasing the repellency of the finished tofu and further improving its mouthfeel.

In addition, in the present invention, the soymilk obtained as described above is powdered or granulated by spray drying etc.)')i
It is also possible to use MW powdered soymilk.

In this case, it is preferable to use the product after dispersing and dissolving it in water or hot water.

On the other hand, the aqueous solution of isolated soy protein used in the present invention is prepared by adding a precipitant such as an acid to soy milk obtained by a conventional method to precipitate soy protein, and then dispersing and dissolving the precipitate in writing water. can be obtained.

A curd is then formed by adding a coagulant to the thus obtained aqueous solution of soy milk or isolated soy protein.

The solid content concentration in the soybean milk used in the present invention or in the curd obtained from the aqueous solution is not particularly limited, and can be adjusted as appropriate by adjusting the amount of water added during the various manufacturing steps described above. However, in the case of soy milk, by setting the solid content concentration in the range of 3 to 20% based on the total weight of soy milk,
It is possible to obtain a soymilk curd that is suitable for the next compression process (11), that is, has a hardness that makes it easy to dehydrate. Even more preferable results can be obtained by setting the solid content to 0.0 g to 1 g/g.

Furthermore, as the coagulant, any of those conventionally known as coagulants for tofu can be used. Metal salts can be mentioned. These can be used alone or in combination of two or more.

The coagulant is used in a conventional manner. That is, the powder can be directly mixed with soy milk or the like, or it can be dissolved in water in advance and added as a solution.

The amount of coagulant added can be selected as appropriate; for example, G, D
, L, it is preferable to use the curd in the range of 0.25 to θ, 65% (weight ratio of soy milk), and in this case, the curd has no sour taste and has a hardness suitable for compression processing. can be obtained. Furthermore, even better results can be expected by using it within the range of 0.3 to θ.

Furthermore, when using calcium sulfate as a coagulant, the range is preferably from 0.25 to 0.65% in order to obtain a card with a hardness suitable for compression treatment, and the more preferred range is θ,
3~θ, left side.

The curd of the present invention can be obtained by adding a coagulant to the soybean milk or aqueous isolated soybean protein solution and allowing the mixture to stand for about 5 to 60 minutes after mixing.

According to the invention, the card obtained as described above is then subjected to a cutting process. As mentioned above, this treatment is intended to create a situation in which the moisture contained in the curd can easily ooze out. That is, this dividing process is carried out for the purpose of improving the dewatering efficiency in the next compression/compression process and shortening the time required for this process. If this process is not adopted, the compression process will take a long time, resulting in a decrease in productivity.

On the other hand, if a compression process is performed under high pressure for a relatively short time without performing a dividing process, the 1g m weave will be destroyed and a dense structure will be formed. .

The dividing process in the present invention may be any process that can physically divide the tofu curd structure. Specific aspects are as follows.

b) Cutting process: Cutting the card with a cutter, etc. Note that the cut shape t may be arbitrary, such as a cyclone shape or an irregular shape.

口) Crushing treatment: Crush the card with an agitator, etc.

c) Drilling process: Using a small diameter metal rod, etc.
Make holes at appropriate intervals.

2) Engraving process: Engraving an appropriate number of line grooves on the card using a cutter or the like.

fΔ), the above-mentioned dividing process may be performed at any time, for example, while the curd is kept in its forming container, after it is transferred to a different container, or even after the curd is filled into a compression container. good.

In addition, among the above-mentioned dividing processes, the cutting process (a), the drilling process (c), or the creation process (ii) remove the moisture contained in the card while maintaining the overall shape of the card without significantly destroying the card structure. To facilitate the exudation of
In order to carry out the compression process efficiently and to obtain pressed tofu that is elastic, denser, and has a good texture, it is preferable to use the above three types of processing methods.

In addition, the amount of syneresis generated after the separation process is defined as the amount of syneresis (weight ratio of moisture contained in the card) that occurs when the card after the separation process is placed on a /20 mesh stainless steel gilt copper using a separating device. If we look at it as an indicator of the degree of occurrence, the same amount of occurrence is 4.
If the dividing process is carried out at a temperature of 6%, the moisture in the curd will easily ooze out, and the dehydration efficiency during the compression process will improve, resulting in compressed tofu that can be effectively compressed and has a better texture. It is preferable because it can be obtained. Also, the amount generated is 9~
32-chi togi is even more preferable.

In the present invention, the card after the dividing process is filled into a compression container (if the dividing process is performed in the compression container, leave it as it is), and the card is compressed to reduce the moisture content to less than gθ%. Make it. The compression container used in this Zorosenu is as follows:
Its shape or capacity may be arbitrary. However, it is preferable that an appropriate number of holes be provided on the side or bottom surface of the curd to ensure smooth dehydration of moisture contained in the curd to the outside of the container during compression. In addition, for this compression process, it is preferable to use a compression device such as a hydraulic press, and gradually increase the pressure from low pressure to high pressure, thereby suppressing the destruction of the card structure. It is possible to obtain pressed alternating layers with a dense and elastic texture.

Seven examples of the operating conditions are approximately θ, 0/I to 0. g
Kv'cr! , preferably θ, 2 to 0.11. 2/T
The compression operation is started at an initial pressure of hJ, and the pressure is gradually increased to about 0. θ~3.2 KvAm preferably 0. g −
It is desirable to complete the operation at a final pressure of 2 Kv/crl. Similarly, the pressure in the present invention is expressed as the compressive load applied per unit area on the surface of the compressed material (tofu curd after dividing treatment) (the same applies hereinafter).

In the present invention, since the card to be compressed is divided in advance, the dehydration speed of the card is high. Therefore, the compression process is approximately
- It is possible to complete the process in an extremely short time such as 120 minutes.

In addition, through this compression process, it is possible to make pressed tofu f:PJ with a dense surface texture and elasticity by reducing the water content i of the curd to below go%, and furthermore, it is possible to make pressed tofu f:PJ with a dense surface texture and elasticity. When making it vertically, press 1 with even more elasticity.
7 Preferable in terms of tofu being obtained 11 Next, in the present invention,
The card after the compression treatment is taken out from the compression container, filled into a heat-resistant container made of synthetic resin, metal, or a laminate thereof, sealed, and then subjected to heat treatment GID.

By employing this heat treatment, the curd weave that was once divided in the previous dividing treatment is bound together to form a dense structure, and it also gives the pressed tofu good elasticity and improves its texture. Furthermore, it is possible to impart desired storage stability.

In particular, if the card is divided by crushing with an agitator or the like, and the degree of fragmentation is high, such as when there are holes, that is, if the amount of syneresis generated is large, the resulting card will not hold even after the compression process. Although the curd has a rough texture and lacks elasticity and denseness, the heat treatment is particularly effective for such curd, and it can be made into high-quality pressed tofu.

Regarding the specific embodiment of the heat treatment of the present invention, any method can be adopted, but pressurized heat treatment using a retort and heat treatment in hot water (so-called hot water sterilization) are suitable. Said heat treatment is preferably about g O-/3! It is carried out for about 3 to 60 minutes at f°C (more preferably 70 to 20 minutes at W θ to IQ 5°C).The texture is significantly improved, and even for curds with a high degree of fragmentation as described above, a higher effect can be obtained. Therefore, it is preferable to perform the heat treatment under the above-mentioned moxibustion conditions. In the present invention, after the heat treatment is completed, the pressed beans 6 of the present invention are preferably cooled to about room temperature.

The present invention will be explained in more detail below using Examples and Comparative Examples.

Example: After soaking whole soybeans in water, water was added thereto and the resulting soybeans were ground, centrifuged to remove bean curd, and soy milk with a solid content of 9 g was obtained.

After boiling this soy milk for 7 to 2 minutes, 0.3 wt% as a coagulant is added.
G, D, L, (ratio to soy milk) were added and mixed, and left to stand for further 75 minutes to form a curd.

Next, the card is crushed and divided using an agitator, and then filled into a compression container with an appropriate number of holes on the side, lined with a dry cloth, and then placed in a hydraulic press. From θ, koV- to 1. Compression was performed while gradually increasing the pressure to λV- to obtain a compressed card of 4# with a water content of 7 g (compression time: 26 minutes).

Next, the card was filled into a heat-resistant container made of synthetic resin, sealed in a vacuum container, and then soaked in 100 ml of boiling water for 75 minutes.
The pressed tofu (sample A) of the present invention was obtained by heating the tofu for 1 minute and cooling it.

Example: After filling a compression container with a suitable number of holes on the side with a card obtained in the same manner as in Example 1 by laying a dry cloth, insert a thin stainless steel plate over the card. The card was cut into cylindrical shapes and divided, and then the edges were pressed with a hydraulic press to 0.2V-
The curd was compressed while gradually increasing the pressure from 1 to 2 to obtain a compressed curd with a moisture content of 7 g and 9% (compression time: 3
).

Next, the card was filled into a thermal container made of synthetic resin, sealed in a vacuum pack, and then heated in a retort tζ for 20 minutes at /°C. Tofu (sample B) was obtained.

Comparative Example 1 A card obtained in the same manner as in Example/ was filled into a compression container in the same manner as in Example/(!) without being subjected to the cutting process, and then compressed to zero using a hydraulic press. 2 Kv'
It was compressed while gradually increasing the pressure from d to /, , 2 Kt/cdl to obtain a compressed card with a moisture content of 79.7% (compression time: S time).

The card was heat-treated in the same manner as in Example, and then cooled to obtain pressed tofu (sample C) as a control product.

Comparison example compression processing was performed from 0.2 Kg/d to θkg Kv'c
Compression time: 2/min)
, except that it was a compressed card with a moisture content of g'1.7%.
Pressed tofu (sample D) as a control product was obtained in exactly the same manner as in Example.

Comparative Example 3 A pressed tofu (sample E) as a control product was obtained in exactly the same manner as in Example except that no heat treatment was performed.

For each of the samples obtained above, a taste test was conducted to compare the density, hardness, and elasticity. The results are shown in Table 1.

As is clear from the results in Table 1 and above, the control sample CFi, which lacks the cutting process of the present invention, takes a long time to compress and is unsuitable for single-strand production, as well as the control samples D and E.
Both the denseness and elasticity, which are the lifeblood of pressed tofu, are poor. On the other hand, the products of the present invention Zander A and B
It can be seen that all of these can be compressed efficiently and have extremely good density and elasticity, making them high quality pressed tofu.

Furthermore, the product of the present invention, Zannol 8, which was subjected to retort treatment as a heat treatment, could be stored for a long period of time at room temperature, and no deterioration in quality was observed even after storage for 1 year.

Claims (1)

[Claims] A coagulant is added to soy milk or an aqueous solution of isolated soy protein to form a curd, and the curd is then subjected to a fragmentation process,
A method for producing pressed tofu, which further comprises compressing the tofu so that its moisture content is below the gO coefficient, filling it into a container, sealing it, and then heat-treating it.