Method of extracting and separating soybean protein

Abstract

The method of extracting and separating soybean protein includes the following steps: 1. adding water in 12-18 times at 45-55 deg.c into crushed soybean dregs, adding sodium hydroxide solution to regulating pH value to 8-9 and stirring to form protein emulsion; 2. filtering the protein emulsion in plate-frame filter to eliminate insoluble dreg and fiber; 3. membrane system separation and concentration to obtain liquid protein with water content of 85 %; 4. adding small amount of hydrochloric acid solution into the liquid protein to regulate pH value to 7; and 5. spray drying the neutralized liquid protein to produce soybean protein. The present invention has the advantages of no protein denaturation, low production cost, high protein yield, and high production efficiency.

Description

Technical field [0001] The invention relates to a method for extracting soybean protein isolate, in particular to a new method for extracting soybean protein isolate using inorganic ceramic membrane technology. Background technique [0002] Protein is the main component of biological cells. Soy protein has good nutritional functions, can supplement the human body's essential energy, strengthen the human body's immunity, and has a certain effect on the prevention and treatment of heart disease, diabetes, cancer and other diseases. The protein content of soy protein isolate is not less than 90%, which is the highest purity soy protein product. [0003] Soy protein isolate is obtained from low-temperature soybean meal after extracting soybean oil. The protein content of low-temperature soybean meal is about 45%, the relative molecular weight of the protein is between 8,000 and 600,000, and the isoelectric point is pH 4.5. The current common process is to pulve...

AI Technical Summary

Problems solved by technology

[0005] 1. After the acid precipitation process, it will cause protein denaturation;

[0006] 2. A large amount of hydrochloric acid is needed in the acid precipitation process, which increases the production cost, and also increases the inorganic salt in the system, which affects the protein precipitation, resulting in a low protein yield. Usually, the protein yield after alkali dissolution is only about 85%, the highest Not more than 90%;

[0007] 3. Due to the addition of a large amount of hydrochloric acid, the COD of whey water after protein extraction is as high as 20,000 mg / L, which increases the difficulty of comprehensively utilizing whey water to extract oligosaccharides and other products, and also increases the cost of sewage treatment

[0009] 1. The membrane working area per unit area of ​​plate filter equipment is small and the efficiency is low;

[0010] 2. The pores of the plate filter membrane are easy to be blocked, and it is very difficult to clean and restore the system;

[0011] 3. The membrane material is organic material, which has poor acid and alkali resistance and short service life