JPH03123464A - Production of germ-free soybean curd - Google Patents

Abstract

PURPOSE:To obtain a tough germ-free soybean curd without causing deterioration of guality even in retort treatment by adding a specific amount of egg white to a specific soy milk, further adding a coagulating agent thereto, packing and sealing the mixture into a vessel and heating the mixture under pressure. CONSTITUTION:Egg white of 5-50 % (solid content of egg white/solid content of protein in soymilk) is added to soymilk being <=0.17 in amount of soluble sugar content to protein and further coagulating agent is added thereto and the mixture is packed and sealed into a vessel and heated under pressure to provide the aimed soybean curd.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for producing aseptic tofu to which egg white is added.

<Prior art and problems> As one of the methods for producing sterile tofu, so-called retort tofu production method involves filling soybean milk with a coagulant into a container, sealing the container, and then heating under pressure at high temperature to coagulate and sterilize the container. There is.

When producing tofu by retort processing, the quality deteriorates significantly, such as browning of the tofu due to high temperature heating, production of off-flavors such as heating odor, and furthermore, the structure of the tofu is destroyed and water retention is lost.

As one of these solutions, it is known that by removing 45% or more of the soluble sugar content in soybeans in advance and producing retort tofu using this as a raw material, it is possible to obtain tofu that eliminates most of the above-mentioned drawbacks. A patent application has also been filed based on this. (Japanese Patent Application No. 149354/1982) On the other hand, techniques for using egg whites during tofu production have also been attempted; for example, Japanese Patent Publication No. 50940/1983 titled "Production method for tofu-like food with shelf life"; An example of this can be found in No. 31941 ``Method for producing frozen tofu''. In particular, the former is a method for producing tofu-like foods without degrading quality during coagulation sterilization by retort treatment, and can be said to advance the method of the present invention and its industrial application field. The tofu is coagulated with acid or salts to form a curd, then this curd is dispersed in water, egg white is added and mixed, and this is retorted. It is far from the image of tofu in terms of texture and texture, and belongs to the category of tofu-like foods. There is also a method using isolated soybean protein and egg white, but since curd formation is performed with acid in the process of producing isolated soybean protein, the same results as above are obtained.

In view of this current situation, the present inventors investigated ways to improve retort tofu, and found that by adding egg white to soy milk with a soluble sugar content of 0.17 or less relative to protein.
The present invention was completed based on the knowledge that hard tofu can be obtained with little deterioration in quality even when subjected to retort treatment.

That is, in the present invention, the amount of soluble sugar relative to protein is 0.17.
Sterile tofu characterized by adding 5 to 50% egg white (egg white solid content/protein solid content in soy milk) to the following soy milk, further adding a coagulant, filling it into a container, sealing it, and heating it under pressure. This is the manufacturing method.

Means to solve problems〉 The present invention will be specifically explained below.

The raw material soymilk used in the present invention is soymilk in which the amount of soluble sugar relative to protein is 0.17 or less.

To obtain such soymilk, for example, dehulled soybeans can be soaked in warm water at around 50°C for about 2 hours to leaching out the soluble sugars in the soybeans, or soybean milk obtained by a conventional method can be divided into It can be obtained by filtration using an ultrafiltration membrane of 30,000 or more.

The soluble sugar content in the present invention refers to water-soluble sugar content that is eluted by immersion in water, grinding, etc., and the total amount thereof is determined by the following method.

That is, raw soybeans are soaked in a certain amount of water, ground together with the soaking water, and the resulting soymilk is adjusted to pH 4 with hydrochloric acid.
5, the protein is precipitated, centrifuged, and the sugar concentration of the supernatant is determined as the amount of glucose using the phenol-sulfuric acid method.

The protein concentration of soy milk is 3 to 8%, and the higher the protein concentration, the harder the tofu can be obtained.

A coagulant, such as glucono delta lactone (GDL), is added in an amount of 0.10 to 0.35% to the soymilk thus obtained, and further egg white is added.

Incidentally, as the coagulant, magnesium chloride, calcium chloride, calcium sulfate, etc. can also be used.

The amount of egg white added is 5 to 50%, preferably 10 to 30%, as an egg white solid content, based on the protein solid content in soy milk.
If the amount is too large, a sulfur odor characteristic of eggs will occur, which is not preferable.

After adding and mixing the coagulant and egg white, deaeration treatment is performed if necessary, and the mixture is filled and sealed in a heat-resistant container, such as a gusset bag made of aluminum polypropylene laminate, and retorted.

The retort treatment may be performed so that the F value is 8 or more, and for example, heat treatment at 118° C. for 50 minutes allows coagulation at the same time as sterilization.

The tofu obtained in this way does not have the strange taste and odor characteristic of retort processing, is white in color, and is considerably harder than regular tofu, so it is a tofu that does not lose its shape even when used in, for example, tofu steaks. Therefore, it has a very wide range of uses as a cooking base material.

The effects will be explained below using experimental examples.

Experimental Example Dehulled soybeans were soaked in warm water at 50'C (10x Ik) adjusted to pH 9 with alkali for 2 hours, cooled, and then soaked in 4°C at 2°C.
Grind the resulting Go with twice the amount of cold water at 110°C for 30 minutes.
Heating was performed for 0 seconds, followed by solid-liquid separation using a screw decanter to obtain soymilk.

The soluble sugar content of this soymilk was 0.8%, the protein concentration was 6.5%, and the ratio was 0.13.

After deaerating this soymilk, it was heat sterilized at 110°C for 5 seconds, and 35% GDL O and egg white (manufactured by Kewpie ■, dried egg white type) were added to it at 6 to 48% (egg white solid content/
Protein solid content in soy milk) was added, and after deaeration, it was packed in an aluminum/polypropylene/laminate gusset bag and sealed.
The mixture was heated at ℃ for 50 minutes and cooled to obtain retort tofu.

The hardness and color of these tofus were measured and the results shown in Table 1 were obtained.

In addition, in the comparative example, 210 g of isolated soybean protein, 105 g of soybean oil,
Mix 2560 g of water, homogenize it, and add 95 g of water.
℃, heated for 10 minutes, cooled, and added GDL O, 35
This is retort tofu obtained by adding 20% egg white (egg white solid content/protein solid content in soy milk) and then processing in the same manner as above.

Table 1 Hardness was measured using a tensipresser (manufactured by Taketomo Electric Co., Ltd.), and the units are tensipresser units (T, U,).
The cohesiveness is measured by compressing tofu cut into 17 mm squares repeatedly with a tensipresser 10 times with a clearance of 9.5 mm, and the first peak (height) of the waveform of the stress curve obtained.
It is expressed as the ratio of the 10th peak to that of the 10th peak. L, a, b
was measured using a colorimeter (manufactured by Nippon Heavy Industries Co., Ltd.).

<Example> Hereinafter, the present invention will be explained in more detail using Examples.

Example 1 Dehulled soybeans were immersed in 5 times the amount of 500C warm water adjusted to pH 8.0 for 1 hour, the immersion water was removed, and the soybeans were immersed again in the same immersion water for 1 hour.

The soaked soybeans were ground while adding 4 times the amount of cold water at 1°C, heated at 110°C for 20 seconds, and subjected to solid-liquid separation to obtain soybean milk.

The soluble sugar content of this soy milk is 0.72%, and the protein concentration is 6.
0%, and the ratio was 0.12.

Dry egg whites previously dissolved in twice the amount of water were added to this soymilk so that the egg white solids content was 22% relative to the protein solids content in the soymilk, and 0.3% GDL was added and mixed. After filling and sealing the same gusset bag, it was heated at 120° C. for 50 minutes (retort treatment) and cooled to obtain retort tofu.

The hardness of this tofu is 14 according to the tensipresser measurement value.
20, indicating excellent shape retention.

Example 2 Whole soybeans were soaked in tap water for 16 hours, swollen soybeans were ground while adding 8 times the amount of water, and the raw soybeans were ground at 105°C.
After heating for 30 seconds, the mixture was filtered using a screw decanter to obtain soymilk. The protein concentration of this soymilk was 3.8%, and the soluble sugar content was 1.2%. This soymilk was tested using a Carbosep 2SV7C test machine manufactured by Sumitomo Heavy Industries Empirotic Co., Ltd.
Operating pressure 4kg/Cm2・G1 Operating temperature 50℃, Flow rate 5
When treated at 00B/hr, soluble sugar content was 0.76%
, soy milk with a protein concentration of 6.5% was obtained. The soluble sugar content/protein content of this soymilk is 0.117.

The above soymilk was homogenized using a high-pressure homogenizer, then deaerated, heated at 120°C for 3 seconds, and then cooled, containing 0.3% GDL and 0.05% calcium chloride.
% and further added 20% egg white (egg white solid content/protein solid content in soy milk), placed in the same gusset bag as in Example 1, sealed, and heat-treated under pressure at 120°C for 50 minutes. and obtained retort tofu.

The hardness of this tofu is 14 according to the tensipresser measurement value.
It was 38.

Claims (1)

[Claims] Add 5 to 50% egg white (egg white solids/protein solids in soymilk) to soymilk with a soluble sugar content of 0.17 or less relative to protein, and then add a coagulant and fill and seal the container.
A method for producing aseptic tofu characterized by pressure heating.