Tannin content and antioxidant capacity of five Greek red grape varieties

Tannins are located in skins and seeds and are responsible for important sensory and quality attributes of red grapes and wines, such as astringency, bitterness and colour stability. However, little is known regarding Greek Vitis vinifera varieties. The aim of this study is to evaluate the grape phenolic content and to present data that may contribute to the development of suitable winemaking techniques for these varieties. In this study berry attributes, skin and seed content of tannins and antioxidant capacity from five Greek Vitis vinifera varieties, namely 'Mavrotragano', 'Mandilaria', 'Kotsifali', 'Agiorgitiko' and 'Xinomavro' were analyzed. Significant differences were observed in berry weight and the distribution of berry component mass in mature berries, among the different varieties. 'Mandilaria' and 'Kotsifali' had the heavier berries while the higher contribution of skins and seeds in berry was observed in 'Agiorgitiko' and 'Mavrotragano' grapes respectively. According to the results, the higher content of seed tannins in berries was determined in 'Mandilaria' and the lower in 'Kotsifali'. Finally, varieties with high concentrations of tannins, 'Mandilaria' and 'Mavrotragano', also demonstrated significant high values of antioxidant capacity.