Application of supercritical extraction technology in soybean
Supercritical CO2 extraction equipment will be widely used in soybean and other food industries. The application of this technology can reduce energy consumption and improve product quality, especially in the production of health food. With the development of high-tech and the deepening of research, the application of supercritical extraction technology will promote the development and progress of the whole food industry.
Soybean phospholipid is a kind of crude phospholipid which contains 30%-40% oil and 60%-70% phospholipid when extracting soybean oil. The high oil content of crude phosphatide limits its application in industry because of its weak hydrophilicity. The purification and separation methods of soybean phospholipids mainly include chromatographic method, CO2 supercritical extraction method, acetylation method, semi-permeable membrane method, solvent method and high performance liquid chromatography. Phospholipids are heat-sensitive substances. High temperature will affect their physical, chemical and physiological functions. Supercritical CO2 extraction technology was used to purify and concentrate phospholipids. The physical and chemical properties and physiological functions of the obtained phospholipids remained unchanged, and the purity could reach more than 96%. Therefore, the best purification method of soybean phospholipids should be supercritical fluid extraction technology.
Practice has proved that supercritical CO2 can leach oil, but not dissolve phospholipids. According to this phenomenon, the extraction technology of high purity soybean phospholipids was studied by supercritical CO2 fluid extraction technology. The content of phospholipids could be increased from 25.64% to more than 95%. Supercritical CO2 fluid extraction technology was used to purify soybean lecithin. The purity of soybean lecithin could reach 98% by changing extraction pressure, temperature and time. Supercritical CO2 extraction of soybean phospholipids has many advantages, such as stable and safe nature of CO2, simple process, single equipment, no solvent residue, low energy consumption, economic convenience and so on.
Nearly 80% of the fatty acid composition of soybean germ oil is human essential fatty acid and contains high concentration of natural vitamin E. It is far superior to health oil such as wheat germ oil and corn germ oil. It has a certain role in the prevention and treatment of cardiovascular diseases. In addition, soybean germ is also rich in soybean saponin and soybean isoflavone with physiological activity, but saponin and isoflavone are easily lost and destroyed, so it is particularly important to preserve saponin and isoflavone better when extracting soybean germ oil. Therefore, supercritical fluid extraction technology is the best method. Supercritical technology can not only obtain high-quality germ oil, but also provide high-quality raw materials for the development of other products, such as high-quality protein products and products rich in soybean saponins and isoflavones. The results showed that the extraction rate was 91.38%, and the content of unsaturated fatty acids in soybean germ oil obtained by supercritical CO2 method was 84.2%, of which linolenic acid and linoleic acid accounted for 74%.