~Soybean pretreatment mainly includes cleaning, crushing, softening, flaking, expanding, drying and so on. The performance of oil pretreatment not only affect the permeability in the process of extracting, residual oil content in soybean meal and other indicators directly, but also affect various components in the oil, the quality and refining efficiency of the crude soybean oil, the quality of the final product and the energy consumption in the of production of soybean oil plant, etc.
Soybean Oil Extraction
There are two main types of soybean oil extracting production process: extrusion extraction of soybean flakes and direct extraction of soybean flakes. Extrusion extraction of soybean flakes is a new manufacturing process, starting in the 80 s in the United States, Brazil and other countries. In recent years, it has been popularized rapidly. Extrusion extraction of soybean flakes refers to the process of soybean cleaning, crushing, softening, drying and extrusion to produce expanded particles for oil extraction.
Soybean Oil Refining
Soybean oil refining is the second processing step in soybean oil plant. Since crude soybean oil contains many impurities that need to be removed to obtain edible soybean oil. The oil-insoluble impurities can be removed with filtration, while soluble impurities should be removed through different processes including degumming (removing of phosphatides), alkali refining (with alkaline solution to remove free fatty acids, colorants, insoluble matter and gums) and bleaching (with activated earth or activated carbon to remove color and other impurities).