The determination of the parameters of sub- and supercritical extraction of plant raw materials

The extraction of biologically active substances by carbon dioxide from various plant raw materials (amaranth seeds, Sophora japonica flower buds, Stephania rotunda stems, and Stevia rebaudiana leaves) was studied at sub- and supercritical parameters. A laboratory unit for the extraction of plant raw materials by liquefied gases and supercritical fluids at 5–35 MPa pressures and 285–350 K temperatures was developed. The maximum yield of the extracted substances from plants specified was obtained at temperature and pressure exceeding the critical parameters of CO₂ (320–330 K, 28–30 MPa).