Supercritical fluid extraction is the most advanced physical extraction technology in the world, referred to as SFE (supercritical fluid extraction). At lower temperatures, when the pressure of a gas continues to increase, the gas will transform into a liquid. When the pressure increases, the volume of the liquid increases. There is always a critical temperature and critical pressure for a specific substance. The point above the critical temperature and critical pressure that a substance does not become a liquid or gas is the critical point . In the range above the critical point, the state of matter is between gas and liquid, and the fluid within this range becomes a supercritical fluid (SF). Supercritical fluids have strong penetrating power similar to gases and large density and solubility similar to liquids. They have good solvent properties and can be used as solvents to extract and separate monomers.

When a fluid is heated or compressed to a state above the critical temperature and critical pressure, and the gas in this state is pressurized, the gas will not liquefy, but will increase in density and have liquid-like properties while retaining gas properties. In this state, The fluid is called a supercritical fluid .

Most of the vegetable oil extraction methods on the market are pressing and leaching. The residual oil in the cake of the pressing method is high, the oil yield is low, and the energy consumption is large, while the crude oil extracted by the solvent method contains There are more non-oily substances and the color is darker. The vegetable oil obtained by supercritical CO2 extraction is relatively pure and has a high oil yield .

Supercritical extraction is the cleanest extraction method . Since there is no solvent residue in the extract . It also prevents poisoning of the human body and pollution of the environment during the extraction process.

By adjusting the extraction parameters, free fatty acids are removed, and refining processes such as oil degumming, deacidification, and decolorization are omitted to avoid interference with the nutrition and function of fatty acids and fat concomitants , and the vegetable oil obtained has higher quality and value .

Supercritical extraction has higher contents of squalene, VE, flavonoids and polyphenols.