Polyphenolic compounds and antioxidants of skin and berry grapes of Greek Vitis vinifera cultivars in relation to climate conditions.

The Greek vineyard is home to many minor, indigenous grape cultivar whose diverse polyphenolic content has remained largely unexploited. The study aimed at assaying and assessing the polyphenolic content and antioxidant capacity of: (a) five obscure cultivars; (b) Six biotypes of cultivar 'Liatiko'; (c) Five prominent cultivars; and (d) three French varieties included for comparison reasons. Results revealed all samples exhibiting high polyphenol content and antioxidant capacity levels. 'Vertzami' recorded the highest concentrations in berry skins total anthocyanins, flavanols, flavonols, antioxidant capacity. 'Mandilaria' scored the highest value in seed total flavanols compared to all biotypes and cultivars. All 'Liatiko' biotypes scored the highest concentrations in seed total flavonoids and flavonols. 'Liatiko' and its biotypes exhibited different polyphenolic profiles between them. Owing to the climate change, those indigenous varieties' substantial polyphenol amounts, and the differences between biotypes, will allow viticulturists to select the varieties/biotypes most appropriate for obtaining higher quality products.