Characterization of seed and skin polyphenolic extracts of two red grape cultivars grown in Croatia and their sensory perception in a wine model medium

A study of proanthocyanidin and anthocyanin composition and concentrations in seed and skin extracts of two Croatian native red grape cultivars (Plavac mali and Babić) by HPLC-UV-Fluo/MS analysis was conducted in this work. A sensory analysis of extracts astringency and bitterness intensity was also performed. In the seeds, Babić showed generally higher concentrations of proanthocyanidins, while in the skins, Plavac mali showed higher concentrations of proanthocyanidins and anthocyanins. Babić proanthocyanidin seed fractions, greater in polymer size and percentage of galloylation, were perceived to be significantly more astringent. Babić proanthocyanidin skin fractions, greater in polymer size and lower in percentage of galloylation and prodelphinidins, were perceived to be significantly bitterer, but only in polymeric fractions. A positive correlation was found between the degree of polymerization, the percentage of galloylation and astringency intensity in the seeds. A negative correlation was found between the percentage of prodelphinidins and bitterness intensity in the skins.