Soybean isolated protein is extracted from meal through successive processes. The product is a kind of milk white powder which contains protein content of more than 90%. Soybean isolated protein can be recombined with various food to improve and enrich food nutrition.

Process Description:

The process principle is on the basis of alkali dissolution and acid precipitation as follows:

1. Material

Low-temperature degreased soybean meal is firstly measured, then conveyed to extraction section.

2. Extracting

Initially white flakes mix with extracting solution in 1st stage extracting tank for a specific reaction time. Then mixture is pumped into horizontal screw decanter centrifuge for separating bean dregs which will be conveyed into 2nd stage extracting tank for further extraction. Mixture is pumped into horizontal screw decanter centrifuge for separating bean dregs which will be conveyed to drying section.

3 Acid Precipitation and Neutralization

Flowing acid precipitation, i.e. soybean milk is pumped into static mixer to react with a certain proportion of hydrochloric acid. Mixture is then pumped into acid precipitation tank, horizontal screw decanter centrifuge for separating curd which will be then pumped into water washing tank. Washed curd is pumped to neutralization section by rotor pump. Neutralizing tanks can be used interchangeably to achieve continuous production.PH value can be adjusted to neutral by neutralization of curd and dilute lye in neutralizing tanks.

Material Conveying Extracting Section Acid Precipitation and Neutralization

4. Flashing

Curd is pumped into filter for removing impurities by pressure pump, then into sterilizer for instant sterilization and flash tank for concentration. Finally curd is pumped to homogenizer, then to drying section by high-pressure pump.

5. Drying

Curd is pumped into spray drying tower by high-pressure pump in which curd is turned into soybean isolated protein particle, then into cyclone separator by pneumatic transmission. Finally soybean isolated protein particle treated by screener is conveyed to finished product packing machine by pneumatic transmission. 

6. Bean Dregs Drying

Bean dregs separated by horizontal screw decanter centrifuge is firstly treated by squeezing machine to remove a portion of water, then into bundle dryer for drying. Dried bean dregs is measured and packed, finally conveyed to warehouse.

Soybean protein isolated (SPI)

is a full price protein food additives, raw materials is low temperature desolventizing soybean meal. The production of soybean protein isolated is the use of the solubility of soybean protein significantly change the characteristics according to the different PH.

Soybean protein isolated contains about 20 amino acids, and contains the human body essential amino acids, protein content over 90%, and no cholesterol, is extremely rare in plant protein to replace one of the varieties of animal protein.

Capacity: 30-500T/D

Oilseeds: soybean cake

Application: isolation of protein from extracted soybean cake

Description: Soybean protein isolated (SPI) is a full price protein food additives, raw materials is low temperature desolventizing soybean meal. The production of soybean protein isolated is the use of the solubility of soybean protein significantly

Brief introduction of main soybean protein isolate process flow.

2.1 Extraction

Delivery the defatted soybean to the extraction workshop, weighing 600kg per batch hoisted into the first extraction groove by the electric hoist (101), hot water has been added in the tank advance, high speed stirring when feeding, stirring speed of 120 rev/min. Adding NaOH to adjust the pH value to 7.1, after reaction 5-10 minutes change to low speed stirring 60 rpm / min. Open the discharge valve for discharge, pump into the first extraction separator(104) by the first extraction conveying pump(103). The liquid phase flows into the mixed soy milk tank(108), and use hot water flush the solid phase to the second extraction groove(105).After second extraction, delivery the material into the second extraction separator(107) by the second extraction pump(106). The solid phase by the screw conveyer(110) send to the dregs storage stack, for sell, liquid phase flows into mixed soy milk tank(108), and mixed with the soy milk from the first extraction separator(104), then pumped them by the soy milk pump( 109) into acid precipitation tank(111) for acid precipitation. 

2.2.Acid precipitation

Adding sodium metabisulfite (0.6kg per batch) to the acid precipitation tank for bleaching and reducing viscosity the mixed soybean milk, then adding HCL(35%), as well as higher the stirring speed to 120 rev/min, adjust the pH value to 4.5. Then reduce the stirring speed to 60 rev/min after acid precipitation. The discharge pump into acid precipitation separator(113) by the acid precipitation pump(112). Liquid flow out of the workshop from pipe, and the solid(curd) flush into the crshuing machine(114) by cold water, crushing and diluting, pumped into neutralization tank(116) by the curd pump(115).

2.3. Neutralization and sterilization

Adding NaOH(10%) into to neutralization tank(116) to neutralized the diluted curd, adjust the PH value to about 7.1.

Adding cooling water in order to reduce the temperature of the neutralizing liquid to 15-20℃. 

Neutralizing liquid(A liquid) transfer by the A liquid delivery pump(117), through the filter(118) then pressed by the high pressure pump,sterilized by the direct steam in the sterilizing device(120), sterilization temperature 140℃, last 15 seconds. After sterilization, the liquid(B liquid) enter into flash tank(121), vacuum degree is 600mmHg.Vacuum is obtained by the hydraulic ejector (143).

2.4. Drying and product packaging

B liquid spray into drying tower(201) under the high pressure, droplet of the B liquid contact with 145℃ hot air from the hot-blast stove(220), hot air amount:33000Nm3/hr.the dried product with hot air(75℃) are separated in the cyclone separator (202), and the hot air is discharged into the atmosphere through draught fan (207).

The product from cyclone separator (202) enter into receiving hopper(204), then delivered to the bag filter（209） by the air flow, gas is discharged into the atmosphere by the conveying draught fan(210), The finished product to storage(212) from bag filter, mixed evenly in the storage(212) then packaging.