The leaching process is one of the most widely used oil processing technologies in the industry, and according to the characteristics of different raw materials, the commonly used leaching processes include direct leaching and pre-pressing-leaching. The pre-pressed leaching process is commonly used with high oil content for oil processing, the direct leaching process is suitable for oil with less oil content, such as soybean, rice bran and other oil seeds are leached at one time by direct leaching process, which can fully extract oil and obtain better quality soybean meal.
The production of soybean oil using the leaching process requires pretreatment of soybeans. There are two types of pretreatment processes for leaching soybean oil, soybean embryo extrusion and extrusion leaching and soybean embryo direct leaching. Before leaching, soybean should be cleaned, crushed, softened, rolled, steamed and fried to obtain soybean embryo, which can be directly used to leach oil, or can be extruded and puffed, and then leached to make oil after being made into puffed particles.
The extrusion leaching process can improve the leaching efficiency, reduce steam consumption, improve the refining rate, and produce better quality of finished meal. After the puffed oil cells are completely destroyed, the oil is on the surface of the puffed material, which reduces the leaching time and increases the production capacity of the leaching equipment, which is conducive to the leaching of the oil.
In the puffing process, the soybean is moistened and heated by high-temperature friction and high-temperature water vapor, which effectively destroys the phospholipids and oxidase enzymes in the soybean, and accelerates the transformation of non-hydrated phospholipids to hydrated phospholipids, so that the content of non-hydrated phospholipids in the crude oil produced is greatly reduced, and the refining rate of oils and fats can be improved during refining. In addition, soybean is subjected to high temperature and short-term heat treatment during the puffing process, and these enzymes are passivated to varying degrees. The passivation of urea destroys the activity of toxic components and antinutrients in soybean meal, improving the quality of soybean meal.
The above are the advantages of soybean extrusion leaching process, the development of puffing leaching technology in China appeared in the mid-80s, and now the technology is very mature, and it can often be seen in the production of rice bran oil and soybean leaching. The soybean extruded leaching production line has a series of advantages such as high efficiency, large output, high oil yield and good oil quality, but the leaching process has high requirements for the quality of the production environment and equipment, so when choosing an equipment manufacturer, it is recommended to choose an experienced and powerful manufacturer.