Antioxidant activity of wine pomace

Extractable polyphenols and antioxidant activity of white and red grape pomaces were determined. Total extractable polyphenols assayed by the Folin-Ciocalteu method in white grape pomace (6.5%), skins (5.3%), and seeds (9.2%) were higher than those in red grapes: 2.2%, 2.1%, and 2.1%, respectively. Red grape skin antioxidant activity determined by the ferric thiocyanate method was the strongest; however, it was 1.5 to 2 times lower than that of red wine. Red grape pomace and seeds, and white grape pomace did not exhibit any antioxidant capacity at concentration of 0.25% (w/v). Polyphenolic content of the samples did not seem to be the only factor determining the antioxidant activity.