Application of Supercritical Carbon Dioxide Extraction in Food Industry
Supercritical CO2 extraction technology, as a high-tech processing and separation technology, has broad application prospects in the field of food processing. Many studies have shown that supercritical CO2 has high diffusion and low mass transfer resistance, so it is particularly advantageous to extract compounds from porous solid materials and grease materials. Supercritical CO2 is particularly sensitive to changes in operating conditions (such as pressure, temperature, etc.), which provides flexibility and adjustability in operation. Supercritical CO2 has the solubility of solvents, and can meet the harsh requirements of low temperature, non-toxic, solvent-free residues, especially suitable for food industry.
Soybean phospholipids are widely used in food additives, health products, cosmetics and pharmaceuticals because of their cheap price and various physiological functions. At present, the production of soybean phospholipids mainly adopts organic solvent method, in which acetone solvent is the main solvent. Acetone is slightly toxic, and its toxicity mainly plays an anesthetic role in the central nervous system. National standards stipulate that the residual organic solvents in edible vegetable oils should not be higher than 50 mg/kg. Therefore, reducing acetone residues in edible soybean phospholipids is of great significance for maintaining human health experience.
Supercritical CO2 was used to extract powder phospholipids, soybean concentrated phospholipids were used as raw materials, carbon dioxide fluid was used as solvent, and high purity soybean powder phospholipids were produced without any chemical reagents.
Soybean concentrate phospholipid enters the extraction kettle through the phospholipid pump. Supercritical carbon dioxide liquid is used as solvent. Pressure pump is used to raise the pressure to the required pressure in the process. At the same time, temperature is adjusted to the appropriate temperature to make it become supercritical carbon dioxide fluid. Carbon dioxide fluid enters from the bottom of the extraction kettle as solvent. Concentrated phospholipids are fully contacted to selectively dissolve the required chemical components. The high-pressure carbon dioxide fluid containing dissolved extract (i.e. medium oil in concentrated phospholipids) is depressurized by throttle pressure reducing valve and enters the separation kettle (analytical kettle). In the extractor, carbon dioxide contacts with the raw material particles and takes away the oil contained in the particles. The degummed mixture after deoiling will form a powder substance, namely soybean powder phospholipid.
In the separation kettle (analytical kettle), the solute is precipitated due to the sharp decrease of the solubility of carbon dioxide, which is automatically separated into two parts: solute (oil) and carbon dioxide gas. The former is a process product, which is regularly released from the bottom of the separator. The latter is a circulating carbon dioxide gas, which is condensed into carbon dioxide liquid by heat exchanger for recycling. The whole separation process utilizes the special increase of solubility of carbon dioxide fluid to organic matter in supercritical state, and the basic insolubility of organic matter in lower critical state. The carbon dioxide fluid is continuously circulated between extraction kettles, thus effectively separating the components that need to be separated from raw materials.
Hippophae rhamnoides, also known as vinegar willow and acid thorn, is a plant resource integrating economic, ecological and medical functions. Seeds mainly contain fat oil, among which linoleic acid, oleic acid, linolenic acid, palm oil, stearic acid, phospholipid, vitamin F, E, carotenoids and so on. Modern pharmacological studies show that the main pharmacological effects of seabuckthorn seed oil are not only good biological activity to heart and liver, but also anti-ulcer, lipid-lowering and anti-tumor effects. It has a wide range of medicinal prospects. The traditional extraction process of seabuckthorn seed oil mostly uses solvent extraction method, and there are solvent residues, and the solvent belongs to the pole. Explosive materials, with high production control requirements, can not be put into use in densely populated or factory areas.
The crushed Seabuckthorn material was extracted at high temperature and then separated by means of decompression. The main process equipment is seed crusher, storage tank, extraction tank, vacuum pump, condenser, compressor, solvent storage tank, evaporation irrigation, oil tank.
Supercritical fluid extraction (SFE) is used in the preparation of oils and fats. It has the characteristics of purity of triglycerides, low content of phospholipids and pigments, easy separation and no denaturation of meal protein. The prospects of the international market are promising, and the domestic market sells less because of the production cost.