JPH0484860A - Preparation of separated soybean protein - Google Patents

Abstract

PURPOSE:To reduce the change in the color of the subject protein by extracting defatted soybean with water, depositing the prepared water-soluble fraction at an isoelectric point to separate into a curd fraction and a whey fraction, washing the curd fraction with warm water and subsequently neutralizing and drying the washed curd fraction. CONSTITUTION:Defatted soybean is extracted with warm water in a volume of 10-30 times that of the soybean to separate into a water-insoluble fraction (bean curd refuse) and a water-soluble fraction (bean milk). The water-soluble fraction is subjected to an isoelectric precipitation process to fractionate into a water-insoluble fraction (curd) and a water-soluble fraction (whey). The separated curd is washed with 30-65 deg.C warm water in a volume of 1-20 times by weight that of the curd, neutralized and subsequently dried.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for producing isolated soybean protein that exhibits little color change even when used in high-temperature cooked foods such as retort foods.

(Prior art) Isolated soybean protein is generally produced by extracting defatted soybeans with water, separating it into a water-insoluble fraction (okara) and a water-soluble fraction (soy milk), and then subjecting the water-soluble fraction to isoelectric point precipitation. It is obtained by separating both components (curd) and a water-soluble fraction (whey), neutralizing the curd, and drying it.

Various inventions have been made to improve the physical properties of this isolated soybean protein, such as color tone, flavor, and gel-forming ability.

In the above step, methods such as washing the card with water or alcohol are known. Practically speaking, efforts are being made to reduce the amount of water used as much as possible from the standpoint of wastewater treatment.

(Problem to be solved) Many processed foods undergo high-temperature cooking such as retort sterilization.

By the way, some foods are preferable if their color tone does not change due to this high-temperature heat treatment (for example, foods whose selling point is the whiteness of the dough), and other foods do not like changes in color tone.

In the case of conventional isolated soybean proteins, the color tone of foods made with the isolated soybean protein often changes due to high-temperature cooking such as retort processing or due to the color of the isolated soybean protein itself.

(Means for Solving the Problem) Therefore, in the course of intensive research to solve the above problem by practical means, the inventors of the present invention found that when washing cards, if they are washed with hot water at a certain temperature, The present invention was completed based on the knowledge that isolated soybean fluorescein can be obtained which has a small amount of heat-discolored components (such as minor class Ii) and is resistant to coloring or discoloration even when used in retort foods.

That is, in the present invention, defatted soybeans are extracted with water, separated into a water-insoluble fraction (okara) and a water-soluble fraction (soy milk), and the water-soluble fraction is isoelectrically precipitated to obtain a water-insoluble fraction (curd). and a water-soluble fraction (whey), washing the curd with water, neutralizing it, and drying it to produce isolated soybean protein, which comprises washing the curd with warm water. It is the law.

The defatted soybeans used in the present invention can be obtained by pressing round soybeans and removing oil with a known organic solvent (hexane, alcohol, azeodorope, etc.).

Although the water extraction conditions of the present invention are not particularly limited, it is practical that the amount of water is usually 10 to 30 times the weight of defatted soybeans. Warm water has better extraction efficiency and is preferable.

Known means such as filtration and centrifugation can be used to separate the water-insoluble fraction (Okara) and the water-soluble fraction (soy milk).

The present invention is characterized in that the separated water-insoluble fraction (curd) is washed with warm water.

The greater the number of washings, the better the separation of soybean protein with a whiter flavor and color, but from the standpoint of wastewater, it is practically preferred to wash once or twice.

The temperature of hot water is 30°C to 65°C, preferably 30 to 5
5°C is appropriate.

Compared to the method of washing with water at room temperature (0°C to 20°C),
The isolated soybean protein obtained by washing and separating components that are soluble or highly soluble in hot water has less discoloration when heated.

A practical amount of warm water for the card is 1 to 20 parts of hot water per liter of dry weight of the card.

It is more effective to use a large amount of hot water for washing, but in practice it is expensive due to wastewater problems, so preferably 2 to 10
is more practical.

Although it is not necessary to particularly adjust the pH of the hot water, it may be adjusted.

It depends on the number of times you wash daffodils, but at least 1 thing to do is to wash the daffodils with warm water for the first time, or use warm water for the second time even if the first time is room temperature water.
It is preferable to wash twice with warm water.

The curd thus obtained can be neutralized and dried using a known drying method such as spray drying to obtain isolated soybean protein.

The isolated soybean protein of the present invention has a low Group 11 content of 0.4% by weight or less, and changes in color tone due to heating are extremely small, so it can be used in various heated foods.

For example, seafood paste products are heated foods that take advantage of the whiteness of surimi, but when conventional isolated soybean protein is used, it is difficult to avoid slight discoloration when heated at high temperatures.

However, by using the isolated soybean protein obtained by the method of the present invention, heated foods that take advantage of the whiteness of surimi become possible.

(Example) Embodiments of the present invention will be described below with reference to Examples.

Comparative Example 1 15 parts of warm water was added to 1 part by weight (the following parts) of defatted soybeans (NSI=85), stirred, and centrifuged to separate okara and soy milk. Then, acid was added to the soymilk to adjust the pH to 4.5, and the mixture was centrifuged to separate whey and curd (dry solid content: 16% by weight).

Furthermore, 12 parts of tap water was added to the obtained card, stirred, and then centrifuged to obtain a washed card.

Next, this water-washed curd was neutralized, diluted to a concentration of 8%, and spray-dried to obtain about 0.3 part of isolated soybean protein.

Example 1 Comparative Example 1 except that the card washing method was changed to the conditions shown in Table 1.
A curd was obtained in the same manner as in Comparative Example 1, and neutralized and spray-dried to obtain isolated soybean protein.

Experimental Example 1 The quality of isolated soybean protein obtained in the same manner as Comparative Example 1 and Example Process is shown in Table 2. 4.5 times as much water was added to 1 part of this isolated soybean protein and kneaded to form a paste at 80° 30 minutes at C and 1
Table 3 shows the color tone after heating at 20'C for 20 minutes.

Table-1 Card Table-2 Separated soybean protein Crude protein is determined by Kelpur method, and minor II is 80%
Ethanol-soluble free fRs were measured by liquid chromatography.

Further, the color tone was measured using a color difference meter manufactured by Nippon Denshoku Kogyo ■.

Next, add 4.5 times as much water to 1 part of isolated soy protein and make a paste for 39 minutes at 120°C or at 120°C.
The gel was heated for 0 minutes and the color tone was measured. Display the results -
Shown in 3.

Table-3 Heated paste pork fat 8 Cornstarch 8 Rolling water 12 Emulsion *1 20 Salt 8.8 Sand 1! 1. 2 Others
1. 0 Compared to Comparative Example 1, T2, T3, and T4 of Example 1 had a lower oligosaccharide content and also had a lower pigment content in terms of color tone.

Example 2 Using the isolated soybean protein obtained in the same manner as in Comparative Example 1 and T1 to T3 of Example 1 as an emulsion, a fish retort sausage was produced as a prototype.

Table 4 Formulation *1: An emulsion was obtained by homogenizing 1 part of isolated soybean protein, 4 parts of water, and 1 part of pork fat using a silent cutter.

The raw materials shown in Table 4 were kneaded with a silent cutter to form a paste, which was filled into a pear casing, and then heated (at 120°C for 20 minutes) to obtain a fish retort sausage.

This color tone is shown in Table-5.

Table 5 Color tone of retort fish sausage In the flavor sensory test using minced gelatin panel, T4 was the best, followed by T2. T3. There was TI in that order. There was almost no difference between T2 and T3.

(Effects) As explained above, the present invention makes it possible to obtain isolated soybean protein with extremely little color change even when used in high-temperature heated foods through a practical production process, which is industrially beneficial.

Claims (1)

[Claims] (1) Defatted soybeans are extracted with water, separated into a water-insoluble fraction (okara) and a water-soluble fraction (soy milk), and the water-soluble fraction is isoelectrically precipitated to form a water-insoluble fraction (curd) and a water-soluble fraction. 1. A method for producing isolated soybean protein, which comprises washing the curd with warm water in the step of separating it into a sex fraction (whey), washing the curd with water, neutralizing it, and drying it to produce isolated soybean protein.