The phenolic compounds content and antioxidant activity of seed and skin of pomace from the vinification of grape varieties widely produced in Brazil were investigated with a view to their exploitation as a potential source of natural antioxidants.
There was a greater concentration of phenolic compounds in the seeds (2128 to 16,518 mg of catechin equivalents (CE)/100 g) than in the skins (660 to 1839 mg CE/100 g).
The highest antioxidant activity values determined as DPPH radical scavenging ability and ferric reducing-antioxidant power (FRAP) were found for the seeds of the Pinot Noir variety (16,925 μmol Trolox equivalents (TE)/100 g and 21,492 μmol Fe2+/100 g, respectively) and in the skin extracts of the Isabel variety (3640 μmol TE/100 g and 4362 μmol Fe2+/100 g, respectively).
The skin of Cabernet Sauvignon and Primitivo varieties had the highest contents of anthocyanins (935 and 832 mg/100 g, respectively).
The grape seed extracts were rich in oligomeric and polymeric flavanols.
The data suggested that grape seed and skin extracts may be exploited as antioxidant agents.