JPH0451862A - Soybean curd containing lactic bacterium metabolite - Google Patents

Abstract

PURPOSE:To improve taste of soybean curd and reduce denaturation by passage of time by adding metabolite of lactic bacterium to soymilk together with a protein-solidifying agent. CONSTITUTION:Lactobacteria of various kinds of bacterial strains are simultaneously cultured and metabolite and cultured mixture produced from bacterial cells during culture are heat-treated to give extract from bacterial cell and the resultant extract is filtered and the resultant product is added to soymilk together with a protein-solidifying agent and solidified at about 70 deg.C and then allowed to stand at ambient temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for producing tofu, and particularly to a method for producing tofu with excellent flavor and less deterioration over time.

(Conventional technology and problem to be solved by the invention B) Tofu is a nutritious food that contains soybean protein as its main ingredient, but it is easy for bacteria to grow on the surface within a relatively short period of time after production, and it is also sealed. Even in some cases, dehydration occurs and the texture and flavor are likely to deteriorate.

(Means for Solving the Problems) In the process of conducting various studies on tofu that undergoes little deterioration over time, the present inventors discovered that tofu with excellent flavor and little deterioration over time could be obtained by adding metabolic products of certain lactic acid bacteria. This discovery led to the completion of the present invention.

In other words, the problem with the prior art described above is that lactic acid bacteria of different strains are simultaneously cultured, and the metabolic products produced from the bacterial cells during the culture and the extract from the bacterial cells obtained by heating the culture are filtered. The problem is solved by a method for producing tofu containing metabolic products of lactic acid bacteria, which is obtained by adding the product obtained by adding a protein coagulant to soy milk and coagulating it at a temperature of about 70°C.

(Function) The tofu in the present invention is basically produced by heating an aqueous slurry obtained by grinding soybeans in water.
It is produced by coagulating the protein by adding a coagulant such as, and is obtained by adding a metabolic product of lactic acid bacteria at the same time or before or after the addition of the coagulant.

As will be explained later, the tofu obtained in this way has a significantly reduced syneresis rate (reduction in gel water retention rate), which is commonly known as a measure of deterioration over time, compared to regular tofu, and is free from the growth of E. coli and other bacteria. In addition, the flavor of tofu is significantly improved and remains constant for a long period of time.

The metabolic products of lactic acid bacteria used in the present invention are produced by culturing different types of lactic acid bacteria simultaneously and heat-treating the metabolic waste from the lactic acid bacteria produced during the culture and the resulting culture. Obtained by filtering the extraction product from the cytoplasm itself.

The filtrate obtained from the lactic acid bacteria contains, in addition to metabolic products excreted from the bacterial cells, various amino acids, proteins, nucleic acids derived from the constituent substances of the bacterial cells themselves that have been subjected to heat treatment, etc.
It contains lipids, glycoproteins, polysaccharides, etc., and these are collectively referred to as metabolic products.

The characteristics of the metabolic products of lactic acid bacteria are that they are metabolic products from bacterial species that can be selectively obtained during mutually competitive growth by culturing multiple different types of lactic acid bacteria at the same time; In particular, instead of using live bacteria as is, as seen in conventional lactic acid bacteria drinks, etc., the cell constituents of the bacteria are produced by using metabolic products excreted from the bacteria during cultivation and heat treatment, etc. The purpose is to use products extracted from

Although it is not necessarily clear why such metabolic products produce the above-mentioned excellent effects, the multi-I! A variety of components such as these act comprehensively to suppress the decline in gel water retention rate (increase in water separation rate) over time and give tofu a pleasant flavor. This is thought to be due to the suppression of the growth of other undesirable bacteria and the reduction of changes over time due to decomposition of soybean protein.

There are various types of lactic acid bacteria used in the present invention, and there are also a wide variety of methods for culturing them.
philus 1. M-1actisacidi),
II (B, bulgaricus B, B.

acidophilus, M. 1actisacidi
), III (Kornchenbacillus
A, B, acidophilus, M, 1actis
acidi) and IV (Kornchcnbaci)
llus B+ B, actdophilus W, 1
actisacidi), each group contains at least one Lactobacillus and Lactococcus, and the bacterial strains differ between each group. Favorable results can be obtained by performing primary culture under predetermined conditions and then combining the resulting cultures of each group and further performing simultaneous secondary culture.

In this case, it is preferable to remove the metabolic products (lactic acid and others) during the primary culture by filtration or the like, and then further culture only the bacterial cells.

The lactic acid bacteria obtained by the secondary culture are subjected to heat sterilization or other treatments to separate the metabolic products excreted outside the cells during the culture and the extracts from inside the cells and from the cell constituents of the cells themselves. For example, by filtration and fractionation with a microfilter under vacuum, the filtrate is obtained as a transparent acidic liquid (pH 3~
4) is further purified and used as an additive.

In the present invention, the amount of the metabolic products added to soybean milk is already significant at about 1 pp-;
Even if more than P is added, the effect does not improve much.

The effects of the present invention were evaluated by the syneresis rate of tofu over time, the inhibiting effect on the propagation of Escherichia coli, and the flavor test by Panela, as described below.

In addition to tofu, the metabolic products of lactic acid bacteria used in the method of the present invention include
It can also be applied to other foods that are obtained by gelation of the main ingredient and deteriorate over time with syneresis, such as konjac, agar jelly, and pudding.

Example The present invention will be explained below with reference to Examples.

I (B, bulgaricus A, B, acido
philus, M. 1actisacidi>, II
(B, bulgaricus B, B, acidop
hilus, M. 1actisacidi), I
IICKornchenbacillus A, B, a
cid.

philus, M, 1actisacidi) and IV (Kornchcnbacillus B, B
, acidophilus J, 1actisacidi
), yeast was added to lactic acid bacteria groups (I) to (IV) with different strains between each group, and a medium for lactic acid bacteria with the following composition was used at an average temperature of about 37°C. Each was cultured for 120 hours.

Tributicase peptone・・・・・・10.00
0 g yeast extract ・・・・・・・・・5.
000 g monopotassium phosphate ・・・・・・・・・
6.000 g ammonium citrate...
・・2.000 g glucose ・・・・
...20.000 g sorbitan monooleate ...1.000 g hydrated sodium acetate ...
・・・－・・・25.000 g Magnesium sulfate
・・・・・・・・・0.575 g Manganese sulfate
......0.120 g ferrous sulfate
・・・・・・・・・0.034 g agar
・・・・・・・・・15.000 gpF
l 5.5 Extract only the lactic acid bacteria from the culture obtained from these lactic acid bacteria of Groups 1 to V, and co-cultivate them together in the same medium and culture conditions as above, and incubate the resulting culture at about 65°C. The metabolic products from the lactic acid bacteria obtained during the culture and the extracts derived from the cytoplasm inside the bacterial cells are separated by heat treatment and filtration with a microfilter under vacuum. A filtrate was obtained.

A slurry obtained by grinding Kg of soybean] with 10 Il of water was heated to about 100''C for 2 minutes to obtain soybean milk.

The filtrate and Mg
C1 was added and processed in the same manner as a normal tofu manufacturing method to obtain tofu.

Test Example 1 Water Separation Rate Test 350g of the beans (approximately -10 g) were left on a chalet with a wire mesh, and the amount of water released from the tofu was determined over time by being absorbed by a filter paper, and compared with that of regular tofu. did. Results first
As shown in the figure.

As is clear from Figure 1, in the case of normal tofu (curve A
) is also the case of tofu produced by the method of the claimed invention (song &'1jB)
It was also shown that syneresis started immediately after production, indicating that the water retention state of the gel had changed. However, the increase in syneresis rate over time is clearly lower in the case of the tofu of the present invention compared to conventional tofu, and a certain difference is already observed after 1 day, especially after 2 days. The difference in water separation rate between them is extremely large.

This shows that the present invention is significantly effective in suppressing the water separation rate during 1 to 2 days, when the texture and flavor of tofu are said to change significantly.

Test Example 2 Bacterial Inhibition Test Samples of tofu produced by the production method of the present invention obtained in the above example and of conventional tofu obtained without adding lactic acid bacteria metabolic products were stored in a thermostatic chamber at a temperature of 20°C, and the surface The number of viable bacteria and Escherichia coli proliferating in the sample were measured. The results are shown in Figure 2.

As is clear from Figure 2, the growth rate of general viable bacteria and Escherichia coli, which is important as a measure of the one-day shelf life of tofu, was compared to the growth rate of tofu produced using the conventional method (-ship owner bacterial count: curve A1, E. coli count double curve Bl). ), the number of these bacteria was significantly reduced in the tofu obtained by the production method of the present invention (- shipowner bacteria count: curve A2, coliform count - curve B) (
The vertical axis shows the index value of the number of bacteria).

(Effects of the Invention) As described above, according to the method of the present invention, the flavor of tofu is significantly improved and its deterioration over time is effectively prevented.

[Brief explanation of the drawing]

Figure 1 is a graph comparing the water separation rate of tofu between the present invention and the conventional product, and Figure 2 is a graph comparing the change in the number of bacteria on the tofu surface over time between the present invention and the conventional product. This is a graph showing. In the figure: A... Water separation rate of conventional tofu B... Water separation rate of tofu of the present invention A1 - Change over time in the number of viable bacteria in conventional tofu ^2
...Temporal change in the number of viable bacteria in the tofu of the present invention B1.
・Change in the number of E. coli in conventional tofu over time B2...Change in the number of E. coli in tofu of the present invention over time Patent applicant Noriyuki Yamamoto (1 person)

Claims (2)

[Claims] (1) A product obtained by co-cultivating different strains of lactic acid bacteria and filtering the metabolic products produced from the bacterial cells during the culture and the extract from the bacterial cells obtained by heating the culture. A method for producing tofu containing a metabolic product of lactic acid bacteria, which is obtained by adding a protein coagulant to soymilk, coagulating it at a temperature of about 70°C, and then allowing it to cool. (2) A plurality of groups of lactic acid bacteria in which the metabolic products of the lactic acid bacteria contain at least lactobacilli and lactococci in each group and the bacterial strains differ between each group are cultured by adding yeast to each group and primary culturing each group. The lactic acid bacteria of each group were combined and further co-cultured,
The manufacturing method according to claim 1, which is obtained by treating this secondary culture.