The skin and seed extracts of the grape varieties had high total
phenolic contents and high antioxidant activity, these contents being
significantly correlated (pb0.05). The grape seed extracts, which had
higher total phenolic contents compared with those of the skin, were
rich in flavanols like oligomeric and polymeric compounds with high
antioxidant activity. Our results also confirm that grape skin is a
potential source for the extraction of anthocyanins and suggest that
although the differences in the total polyphenol content and
antioxidant activity between the varieties analyzed were significant,
the levels of polyphenol content are such that extracting polyphenol
from them might be economically viable.