Compositional and sensory characterization of grape proanthocyanidins and oak wood ellagitannin

Aimed at increasing our knowledge on the astringency of sensory-active non-volatile compounds migrating principally from grapes and from oak wood into the wine, grape extracts and an aqueous ethanolic extract from oak wood chips were used for their key taste compounds. Monomeric/oligomeric and polymeric proanthocyanidin fraction of seed and skin extracts were obtained from grapes. Ellagitannins were extracted and purified from oak wood. Compositional characterization, purity and sensory evaluation of grape extracts were performed by liquid chromatography/mass spectrometry and sensory analysis, respectively. Purification of ellagitannin extract at 93.4% was realized by successive fractionations on Toyopearl TSK HW-40 (F) and on C-18 column. At the same concentration, ellagitannin fraction was perceived rather mellow, seed and skin monomeric/oligomeric fraction was characterized slight astringent, polymeric seed fraction was identified as tannic whereas polymeric skin fraction was appreciated rather mellow.