ANTIOXIDANT ACTIVITY OF CHOKEBERRY EXTRACTS OBTAINED IN SUPERCRITICAL CONDITIONS

Extraction of phenolic compounds from berries using the infusion method has disadvantages, alternative methods of extraction being of special interest. Supercritical extraction is one of such methods. This paper deals with the influence of Supercritical extraction conditions on antioxidant properties of extracts. Chokeberry growing on the territory of the Samara region was chosen as the object of our research. Extraction was carried out at a pressure of 40 MPa and temperatures of 120, 150 and 200°C using water and alcohol as solvents. The extracts (aqueous, alcoholic and 50% aqueous ethanol) obtained at atmospheric pressure and a temperature of 37°C were used as a control group. Various techniques were used to determine the level of antioxidant activity: the content of total amount of phenolic compounds equivalent to Gallic acid, flavonoids equivalent of catechin, anthocyanins equivalent of cyanidin-3-glycoside, antiradical capacity using a free radical DPPH method (2,2-diphenyl-1-picrylhydrazyl), restoring force using the method of FRAP (ferric reducing antioxidant power), antioxidant activity in linoleic acid system. A considerable number of methods to assess antioxidant activity of compounds is classified with the method of registration parameters used to determine antioxidant activity, including its quantitative estimation. The use of high-pressure supercritical extraction allows increasing the yield of phenols and antioxidants in the extracts. However, high temperature leads to degradation of compounds.