Influence of simulated grape crushing process on phenolic compounds extraction, astringency and color of Cabernet Sauvignon model wine

Phenolic compounds extracted from grapes play a decisive role on organoleptic properties of wine, especially wine astringency and color. In this study, the skins and seeds of Cabernet Sauvignon grape were implemented 4 physical treatments (tearing, shearing, rubbing and squeezing) to simulate mechanical damage caused by crusher or de-stemmer in the process of industrial wine production. Equivalent weight of treated grape skins (14.79%) or seeds (6.11%) separated from grapes were added into pre-prepared synthetic wine to simulate the maceration for 14 days to obtain the model wines. Polyphenolic components, astringency and color index as well as sensory evaluation of model wines were then analyzed. The results indicated that 4 physical treatments led to an increase of the mean degree of polymerization and percentage of galloylation of proanthocyanidin in model wines. A significant increase of b* value of model wine by the rubbing or squeezing treatment on both skins and seeds was detected, despite of no significant difference of total anthocyanin in skin model wines. The physical treated skins and seeds gave model wine a more effective capacity in precipitating proteins, indicating a stronger astringency potential, among which the rub treatment strengthened the most of astringency perceptions.