Mass Spectral Characterization of Uva Longanesi Seed and Skin Extracts

Abstract

Polyphenolics in grape seed and skin extracts of Uva Longanesi were analyzed at harvest with selected chromatography techniques. Seed extract of Uva Longanesi was characterized by high content of proanthocyanidins (average 49 g/100 g extract), of which 42% was polymeric and ~28% was oligomeric. Epicatechin comprised the primary extension subunit (~75%), whereas catechin predominated as the terminal unit (~67%); epicatechin-gallate was present in both extension (~11%) and terminal subunits (~9%). As skins matured, terminal unit galloylation decreased and extension unit galloylation increased. The mean degree of polymerization of seed proanthocyanidins was relatively constant (average 2.7 subunits) across the sampling dates.