Abstract
Grape condensed tannins (proanthocyanidins) are phenolic substances of utmost importance in the sensory characteristics of wine. Not only does their final concentration affect the fermentation process, but their structure also greatly influences the negative attribute of astringency. Determining the exact amount of proanthocyanidins in the grape pericarp is a real challenge, and a prerequisite in any breeding research program aimed at the improvement of the quality of grape berry tannins. We analyzed pericarp condensed tannins in four species of Asian and American wild grape vines in comparison with four accessions of the domestic grape vine, Vitis vinifera. The mass of tannins per berry ranged from 0.1 to 1.2% FW; however, the relative mole percentage of epigallocatechin in Asian species was 10 times lower than in American species and the domestic grape vine, while the tannin galloylation degree of American vines was 4 and 10 times higher than in domestic and Asian vines, respectively.