JPH02167044A - Production of soybean curd - Google Patents

Abstract

PURPOSE:To obtain the subject soybean curd free from unevenness of quality by seeding lactic acid bacillus on soybean milk prepared from a soybean from which most part of soluble sugar is removed, charging the soybean milk into a vessel, closing the vessel, carrying out lactic fermentation, then coagulating the fermentated material by heating and utilizing lactic acid bacillus in place of a coagulant. CONSTITUTION:Lactic acid bacillus is seeded on a soybean milk prepared from a soybean from which 60-80wt.% soluble sugar is removed and the soybean milk is charged into a vessel. The vessel containing the soybean milk is closed and lactic fermentation is carried out. The fermentated material is then coagulated by heating, thus obtaining the objective soybean curd. In addition, the removal of the soluble sugar is recommendably carried out, e.g. by immersion at 50-55 deg.C for 6-10hrs. in case of a non-peeled soybean and at 30-55 deg.C for 2-10hrs. in case of a peeled soybean.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Field of Application> The present invention relates to a method for manufacturing tofu using lactic acid bacteria instead of a coagulant.

<Prior art> Generally, tofu is obtained by adding coagulants such as divalent metal salts or glucono delta-lactone to soymilk and coagulating it by heating, but instead of these coagulants, lactic acid bacteria are added to soymilk. A method has also been proposed in which the gel is inoculated, fermented with lactic acid to form a gel, and the gel is solidified by heating.
Examples thereof can be found in JP-A-26167, JP-A-57-141264, and JP-A-62-48349.

<Problem to be solved by the invention> Nowadays, there is a desire for food without additives, and tofu production using lactic acid bacteria is suitable for this purpose, but it is still not practical due to difficulties in controlling fermentation. The current situation is that it has not reached the level of becoming a reality. In other words, when obtaining tofu of the same quality as tofu obtained by adding a coagulant by inoculating lactic acid bacteria, it is necessary to carry out lactic acid fermentation to bring the pH of soymilk to 5.0 to 6.0. If lower than this,
If tofu becomes sour and lactic acid fermentation is stopped at a point higher than this, the tofu will not have sufficient firmness.

Controlling the pH of soymilk within the above-mentioned range through lactic acid fermentation requires extreme care, and if you want to produce it in small quantities, it will be a problem, but if you want to produce it continuously in large quantities, there will be variations in pH. , which in turn leads to variations in quality.

<Means for solving the problem> Did the inventors use lactic acid fermentation? As a result of various studies aimed at the practical application of Koyo tofu production, we found that soy milk obtained by removing a certain amount of soluble sugar from soybeans, which are the raw material for soy milk, has a pH lowering due to lactic acid fermentation. Therefore, it is easy to control lactic acid fermentation, and it has been found that tofu of stable quality can be obtained.

The present invention was completed based on this knowledge, and
The present invention will be explained in detail below.

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.

The raw soybeans are soaked in a certain amount of water and then ground together with the soaking water.The soy milk obtained by filtering this is adjusted to pH 4.5 with hydrochloric acid to precipitate the protein, and then centrifuged to remove the sugar in the supernatant. The concentration is determined as the amount of glucose using the phenol-sulfuric acid method.

Soluble sugar can be removed by soaking raw soybeans in water. For example, in the case of whole soybeans, soaking them at 50-55°C for 6-1
In the case of dehulled soybeans, it may be soaked at 30 to 55°C for 2 to 10 hours.

Furthermore, when eluting soluble sugars from whole soybeans or dehulled soybeans, it is desirable to use the soybean in its intact form as much as possible without damaging parts such as the endosperm of the soybean. This is because when soybeans or dehulled soybeans are crushed or cracked, the cells are broken and enzymes such as poxidase come into contact with their substrates, producing an unpleasant odor and taste, and also promoting the elution of proteins at the same time as the elution of sugars. This is because it leads to increased protein loss.

The soybeans from which 60 to 80% of the soluble sugar content has been removed are washed and drained if necessary, and then put into a grinder with 2 to 4 times the amount of water and ground.

Although the grinding may be carried out at room temperature, it is preferable to grind at a low temperature of 10° C. or lower in order to prevent quality deterioration due to the action of oxidase, peroxidase, etc. during grinding.

The raw soybean paste obtained by grinding is heated at 95-110''C for 0.5-5 minutes and then filtered to separate it into okara and soy milk.

Next, the soy milk is homogenized using a high-pressure homogenizer if necessary, and then degassed. If necessary, this is preheated at a high temperature for a short time, for example, at 120 to 140°C for 11 to 4 minutes, and then cooled. Inoculate with lactic acid bacteria.

The lactic acid bacteria used are Streptococcus thermophilus,
Streptococcus faecium, Streptococcus lacteis, Streptococcus thalemoris, Leuconostoc thalemoris, Lactobacillus bulgaricus, Lactobacillus a/dophilus, etc., and the contact MfA of lactic acid bacteria is 103 to 107 for soy milk.
ke/txl.

Fill and seal the soymilk inoculated with lactic acid bacteria in an appropriate container.
Hold at 19-45°C for 2-20 hours or more to carry out lactic acid fermentation.

The soymilk used in the present invention has a soluble sugar content of 60 to 80%.
As the raw material is soybeans from which % has been removed, the pH does not drop below a certain level, as is clear from the experimental examples described below, making it easy to control lactic acid fermentation.

The soymilk subjected to lactic acid fermentation is then heated and coagulated. Heat coagulation can be done by soaking for 20 to 60 minutes in warm water at 80 to 95°C, or in the case of aseptic tofu, 105 to 1
A method of retorting at 40°C for 20 to 120 minutes can be used.

After heating and solidifying, the product is cooled with water, for example.

The product thus obtained has a good taste and texture, and the retort-treated product is also free from heating odor and heating browning.

The present invention will be explained in detail below using experimental examples.

Experimental example: Dehulled soybeans were soaked in hot water to remove 30-80% of soluble sugar, and after grinding with 2°C cold water of 5 times the amount of raw soybeans, heated at 100"C for 30 seconds. Thereafter, the soymilk obtained by filtration and deaeration was heated at 135°C for 10 seconds, and then cooled to 25°C.

This was then treated with the lactic acid bacterium Streptococcus thermophilus lT (Christian Hansen, Denmark).
After inoculating 105 g/me of a mixture of Lactobacillus bulgaricus (commercial product, Christian Hansen, Denmark) (50:50), the containers were filled and sealed, and kept at 42°C for 16 hours. Lactic acid fermentation. During this time, the pH of the soymilk and the amount of lactic acid produced were measured over time. The results are shown in Table 1.

Then lactic acid fermentation was carried out for 4 hours at 95°C.
The mixture was heated for 40 minutes to solidify, and then cooled to obtain tofu.

When a panel of 10 people tasted these tofu, they ranked second.
The results shown in the table were obtained.

Table 2 Hardness: 17 using tensipresser (manufactured by Taketomo Electric)
12 pieces of tofu cut into mm cubes in a 40 mm diameter glass/jar
ILw was crushed, and the amount of work at that time was expressed in tennbresser units (T, U, ).

<Examples> Example 1 Whole soybeans were heated to bring the surface temperature of the soybeans to 80°C, and then passed through a rubber roller to be cut in half, which was then dehulled using a peeler. This dehulled soybean is 50 times the amount of soybeans.
After being immersed in warm water at °C for 1 hour, the water was drained and immersed again in fresh warm water for another 1 hour. This method removed 70% of the soluble sugars in soybeans.

After washing the soaked soybeans with water, add 4 times the amount of cold water (2°C) to the dry dehulled soybeans, grind them, immediately heat at 105"C for 30 seconds, cool to about 80°C, and then place in a screw decanter. The soymilk was separated into solid and liquid.The obtained soymilk was introduced into a degassing tank to remove air mixed in the soymilk and cooled to 45"C.

This soymilk was homogenized under a pressure of 300 kg/ca, heated to 135°C for 10 seconds using a plate heater, cooled to 10°C, and then dried using the same lactic acid bacterium Streptococcus thermos as used in the experimental example. Filstructobacillus bulgaricus a synergistic bacteria 105 cases/me
The contents were added in such a manner that the mixture was added and filled into a plastic container (150 x 80 x 40) that had been sterilized using H202. After holding this at 42°C for 6 hours, it was heated to 90°C.
After heating for 40 minutes, the mixture was cooled in cold water to obtain product tofu.

Example 2 The soymilk with 8 lactic acid bacteria from Example 1 was filled into an aluminum gusset bag, put into a mold, fermented at 42°C for 6 hours, put into a retort pot, and heated at 120°C for 140 minutes to produce retort tofu. .

Patent applicant: Kikkoman Corporation

Claims (1)

[Claims] This method of producing tofu is characterized by inoculating lactic acid bacteria into soybean milk obtained from soybeans from which 60 to 80% of soluble sugar content has been removed, filling and sealing the container, subjecting it to lactic acid fermentation, and then heating and coagulating it.