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Keywords:

  • Astringency;
  • polyphenols;
  • saliva protein;
  • sensory;
  • tannin

Summary

Grape seed and skin proanthocyanidins undergo significant changes during grape maturation. Those changes have been associated with a decreased astringency of grapes collected at later maturation stages. We have now compared the ability of proanthocyanidin-rich extracts from Carménère grape seeds collected at two stages of berry development (veraison vs. harvest) both to interact with salivary proteins and to produce astringency. Interaction of proanthocyanidins with the salivary protein was assessed by analysing the concentration-dependent effect of seed extracts both on inducing salivary protein precipitation and on restricting diffusion of the salivary protein on cellulose membranes. Seed extracts from grapes collected at veraison compared with those of grapes collected at harvest displayed a higher ability both to interact with the salivary protein fraction and to produce astringency. As a whole, our observations show that astringency is closely dependent on the magnitude of the interactions between proanthocyanidins and the salivary protein fraction.