JPH0380058A - Production of soybean milk - Google Patents

Abstract

PURPOSE:To obtain soybean milk suitable for producing soybean milk beverages and retortable bean curds by removing soluble saccharides in soybean milk with a specific ultrafiltration membrane and regulating the content of the soluble saccharides based on proteins to a specific value or below. CONSTITUTION:Soluble sacchardes in soybean milk are removed with an ultrafiltration membrane having >=30000, preferable 30000-150000 fractionation molecular weight and the content of the soluble saccharides based on proteins is regulated to <=0.17 to afford the objective soybean milk.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for producing soymilk, and its object is to provide soymilk suitable for producing retort tofu.

<Prior Art and Problems> Recent developments in retort food have been wide-ranging, and many products are actually distributed on the market. Under these circumstances, retorting tofu has been considered for some time, and various manufacturing methods have been proposed.

Since retort processing involves heating under high temperature and pressure, all foods have unavoidable problems, such as heated odor, browning, or changes in flavor, especially tofu, which is white and Since the taste and aroma are bland, the influence of these problems is large, and it is not easy to produce retort tofu.

The heating odor and browning in retort tofu are caused by the reaction between soluble sugars and free amino acids in soymilk during heating to produce browning substances, so removing these substances from soymilk will eliminate the heating odor and browning. After thinking that heat browning could be prevented, the company established a method for producing retort tofu by removing soluble sugar from raw soybeans and using the soymilk obtained from the soybeans, and has already applied for a patent. (Special Application No. 59-3530)
Although this method removes soluble cosmetics by soaking raw soybeans in hot water, we believe that similar results can be obtained by removing soluble sugars using other methods.
I came up with the idea of using an ultrafiltration membrane.

For example, a method of treating soy milk with an ultrafiltration membrane is disclosed in a patent application filed in 1973.
-6897, Patent Application No. 1982-81564, Patent Application No. 1983
Although attempts have already been made in No. 64806, etc., these methods are aimed at removing off-flavor components or concentrating. This is different from the purpose of the invention.

In addition, the ultrafiltration membranes used in these known methods have a molecular weight cut-off of about 5,000 or 13,000, and although these membranes can remove soluble sugars, filtration It cannot be adopted industrially from the point of view of efficiency.

The present inventors conducted tests and studies using ultrafiltration membranes with various molecular weight cutoffs, taking into consideration filtration efficiency, protein loss, etc., and found that the molecular weight cutoff was 30. Even when soy milk is filtered using an ultrafiltration membrane of 000 or higher, protein loss is almost negligible, and the filtration efficiency is also satisfactory. When retort tofu is produced using soy milk treated in this way as a raw material, We have obtained the knowledge that it is possible to obtain a product without heating browning or heating odor.

That is, the present invention reduces the soluble sugar content in soymilk with a molecular weight cut-off of 30,
This is a method for producing soymilk, which is characterized in that the amount of soluble sugar relative to protein is reduced to 0.17 or less by using an ultrafiltration membrane of 0.000 or less.

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

The raw soymilk used in the present invention is no different from the production of soymilk used in conventional tofu production.

For example, whole soybeans are soaked in water for 6 to 20 hours, the sufficiently swollen soybeans are ground, and the resulting soybeans are heated to about 90 to 120°C and then filtered, or the soybeans are heated after filtration. However, the former is preferable. It is also possible to directly subject raw soymilk to membrane treatment at low temperatures.

When removing soluble sugar by soaking, dehulled soybeans have been preferably used to increase removal efficiency, but whole soybeans may be used in the present invention. Of course, dehulled soybeans can also be used.

The protein concentration of soy milk is 15-65%, especially 2.0-65%.
45% is preferred.

In addition, if soy milk is homogenized in advance, the efficiency of membrane treatment can be increased, and for the purpose of sterilization,
By performing heat treatment at 40° C. for 1 to 120 seconds, microbial contamination during membrane treatment can be prevented.

Such raw soymilk is treated using an ultrafiltration membrane with a molecular weight cutoff of 30,000 or more to remove soluble sugars.

If a membrane with a molecular weight cutoff of 30,000 or less is used, the filtration efficiency will be poor, as will be clear from the experimental examples below, and an ultrafiltration membrane with a molecular weight cutoff that is too large will also pass through the protein in soymilk, allowing it to be used as a raw material. molecular weight cut-off of 30.00.
A film of about 0 to 150,000 is preferred.

The ultrafiltration membranes used are polysulfone, polyolefin,
It is made of a synthetic polymer material such as polyacrylonitrile, or a zirconia ceramic membrane, and any ordinary shape such as a flat membrane or hollow fiber can be used.

It is necessary to remove the amount of soluble sugar so that the amount of soluble sugar relative to protein is 0.17 or less, and this value corresponds to 45% or more of the soluble sugar in the raw soybean. Insufficient removal of soluble sugars will cause heating odor and browning when made into retort tofu.

Soluble sugar refers to water-soluble sugar that is eluted by immersion in water, grinding, etc., and its total amount can be 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.

Soymilk in which the amount of soluble sugar is 0.17 or less relative to the amount of protein can be suitably used as soymilk for retort tofu. Of course, it goes without saying that it can be used as a raw material for soy milk drinks.

An experimental example is shown below.

Experimental Example 1 Whole soybeans were immersed in tap water for 16 hours to swell the soybeans, which were then ground, and the resulting raw soybeans were heated at 105°C for 30 seconds and then filtered.
Soy milk with a protein concentration of 5% was obtained. This was sterilized by heating at 125° C. for 110 seconds using a plate heater, and membrane treatment was performed while adding water to this raw soymilk 52 until the soluble sugar content/protein content became 0.16.

The filter used was Amicon's TS5E type (Guiaflow membrane 150 mmφ x 5 stages), and the ultrafiltration membranes were Amicon's YM (Polyzaccarai F system) and X.
M (vinyl/acrylic copolymer) series, operating conditions are pressure 15 kg/cm2 - G1 flow rate 50 JL/h
r, soy milk temperature is 5°C. The results are shown in Table 1.

Table *1 Average permeation flow rate m1 10.1 resistance/hr Experimental example 2 The same raw material soymilk used in Experimental example 1 was used at a pressure of 2.0 kg using Carbosep membrane (zirconia ceramic membrane) manufactured by Sumitomo Heavy Industries Empirotic Co., Ltd. /cm
2.G, flow rate 4202/hr, and soy milk temperature 45° C., while adding water, the treatment was carried out until the ratio of soluble sugar M/protein amount reached 0.16.

The results are shown in Table 2.

Table 2 Molecular weight cutoff from the above experimental example: 30,000 to 150,00
It can be seen that the ultrafiltration membrane of No. 0 can be efficiently deeared.

Examples of the present invention and examples of producing retort tofu using the soy milk obtained in the examples will be described below.

Example: Whole soybeans were soaked in tap water for 16 hours, swollen soybeans were milled 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 12%. When this soymilk was processed using Carbosep 2SV7C test machine manufactured by Sumitomo Heavy Industries Empirotic Co., Ltd. at an operating pressure of 4 kg/cm2・G, an operating temperature of 50°C, and a flow rate of 500 B/hr, the soluble sugar content was 0.76.
%, and soy milk with a protein concentration of 6.5% was obtained. The soluble sugar content/protein content of this soymilk is 0.117.

Production of retort tofu The above soymilk was homogenized using a high-pressure homogenizer, then degassed, heated at 120°C for 3 seconds, cooled, and 3% glucono delta-lactone was added as a coagulant. The tofu was placed in a gusseted bag made of polypropylene laminated with aluminum and sealed, and then subjected to pressure heat treatment at 120° C. for 50 minutes to obtain retort tofu.

0 On the other hand, according to the method described in Japanese Patent Application No. 59-3530, dehulled soybeans were soaked in warm water at 50°C for 2 hours to reduce the soluble sugar content by 60%.
Protein concentration 6.55%, made from soybeans with % removed.
Soluble sugar content 0.811% (Soluble sugar content/Protein content =
0.12) soy milk was prepared.

This was homogenized using a high-pressure homogenizer and then degassed, and retort tofu was produced in the same manner as above.

Both retort tofu had no difference in color, aroma, and taste.

Claims (1)

[Claims] A method for producing soymilk, which comprises removing soluble sugar in soymilk using an ultrafiltration membrane with a molecular weight cutoff of 30,000 or more, and reducing the amount of soluble sugar to protein to 0.17 or less.