Soybeans, as the most important oil seed crop all over the world, ranked among the world in both production and international trade volume among vegetable oils. Soybean oil extraction by pressing is a traditional and widely used oil production process. The following is an introduction to the soybean oil pressing process:
Pretreatment of raw materials before pressing has a significant impact on the final oil yield and oil quality. This stage mainly consists of three steps: cleaning, crushing, and roasting. First, the raw soybeans need to undergo multiple processes such as screening and destoning to effectively remove impurities such as stones and stems, ensuring the safety of subsequent production equipment and the purity of the oil. Then, the cleaned soybeans are crushed. This stage mainly uses mechanical action to break down their intact cell structure, creating physical conditions for oil release. Finally, the crushed soybeans are sent to a roaster. Under suitable temperature and humidity conditions, the proteins in the soybeans are denatured and the cell membranes are further damaged, thereby significantly improving the fluidity of the oil. At the same time, the roasting process also inhibits enzyme activity, reduces the acid value of the oil, and imparts the unique roasted aroma of soybean oil, laying a good foundation for subsequent pressing and extraction.
Finally, and most importantly, is the pressing process. Pretreated soybeans are poured into the oil press. During this process, oil continuously seeps out from the solid material, while the defatted oil cake is discharged from the end of the pressing chamber. The screw press features continuous processing,simple operation,reasonable structure,large production capacity and low residual; by adjusting pressure and temperature parameters, it can ensure oil extraction efficiency while also preserving the flavor and nutrients of the oil. Besides pressing soybeans, screw oil presses can also press peanuts, rapeseeds, sunflower seeds and other oil seeds.
