Soybean Protein Isolate(SPI) Technology

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Soybean Protein Isolate (SPI) Production Line

CHEMSTA make use of Alkali-Solution and Acid-Isolation Extraction process to separate fiber and protein from low-temperature soybean flakes. Then, separated protein solids go through high pressure homogenization, high temperature sterilization and spray drying to produce protein isolates.            1. Raw Materials: low-temperature soybean flakes(white Flake).                                                                                     2. Products: soybean protein isolate (protein content>90%)       By-Products: soybean dregs (used for production of soybean dietary fiber)

SPI Application

1 . Severing as a kind of food additive, soybean protein isolate is able to efficiently improve the protein content of the food, thus improving food functional performance.
2. SPI is also suitable for production of health care products.
3. It can be used for production of environment friendly binding agents as well.

SPI Process

1. Process Workflow:

2.Raw material receiving & storage section:

Raw materials(soybean white flake) transported to the workshop unloading platform, then poured into the hopper, elevated into the day warehouse through bucket elevator. The soybean meal should be uniform distributed to Z-type scraper by frequency feeding auger after deironing by magnetic separator, and then elevated into the 1st extraction tank by the scraper. Feeding system auger is equipped with automatic control, operated by the personnel in central control room, and also set up with a process chain and security chain.

3.SPI Extraction Section:

The soybean meal out of raw material warehouse enter into CHEMSTA 1st extraction tank after removing iron and impurity. At the same time, water from hot water tank added into the extraction tank, and a certain concentration of diluted alkali solution is added on the pipeline which connecting to the extraction tank, thus adjusting the PH value of material in extraction tank. The temperature of the material liquid in the reaction tank is controlled by controlling the temperature of added process water. After reaction for a certain time, the material enter into the 1st extraction centrifuge for separating, liquid phase enter into soybean milk tank, solid phase enter into 2nd extraction tank. Hot water and diluted alkali solution should be added into the 2nd extraction tank for two-step extraction. The two-step extraction time should be controlled reasonably. The material which after two-step extraction should be pumped into the 2nd extraction centrifuge, the liquid phase flow into soybean milk tank, solid phase (i.e.soybean dregs) should be conveyed into the soybean dregs discharging plant. The wet soybean dregs can be sold directly or after drying.

4.Acid Precipitation Section:

The mixed soybean milk in soybean milk tank is conveyed into CHEMSTA acid precipitation tank, adding diluted hydrochloric acid solution, adjusting the PH value of solution to about 4.5, so that make the protein precipitate in condition of isoelectric point. The precipitation time is controlled by precipitation tank volume. Centrifugal dehydration with horizontal centrifuge, liquid phase is whey water and pumped into the waste water treatment plant, mixture of solid phase and a certain amount of process water enter into the smashing tank, the granular material in smashing tank cut into paste protein slurry, and then the paste protein slurry is pumped into plate heat exchanger for cooling ,and finally enter into the neutralization tank.

5.Neutralization, Homogeneous,Sterilization, Flash Evaporation,Dry Section:

In order to improve the functionality of the final product, it is necessary to add a certain amount of NaOH solution to curd protein which separated from acid precipitation section, and then stir the mixture to adjust the PH value of the curd.
The well-stirred protein slurry should be homogenized under a certain pressure condition, making it become small uniform particles, and then the homogenized soybean protein isolate slurry is conveyed into the sterilizer for high temperature instantaneous sterilization. The sterilized protein slurry should be conveyed into the flash evaporation tank for CHEMSTA flash evaporation dehydrating and removing beany flavor, then pumped into the drying section by high pressure homogenizing pump.
The material which pumped into the drying tower by high pressure pump should be atomized by spraying nozzle, and also conducting parallel flow heat exchange with hot air to complete dehydrating and drying.

7. Major Equipment:

Rising conveyor, magnetic separator, scale,CHEMSTA extractor, high pressure pump, separator, quantifying pump for PH value, neutralization tank, flash tank, sterilizer, homogenizer, spray drying tower, classifying screen, heat exchanger, air heater, vacuum system, protein collector, protein packing system, elctrical control equipment and other auxiliary devices

Automatic Control System

In CHEMSTA production lines, we make use of Siemens PLC control system, which is one of mainstream automatic control systems in today`s industry. The efficient, stable and advanced DCS control system consists of operation station, control station and communication network. We utilize high-speed and large-capacity S7-400 series PLC at the control system, large-screen LCD at the operation station, WINCC 7.0 industrial control software as monitoring software and PROFIBUS filed bus network for communication.


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