CHARACTERIZATION OF PROCYANIDINS OF VITIS-VINIFERA VARIETY TINTA-DEL-PAIS GRAPE SEEDS

HPLC has been applied for the analysis of procyanidins in seeds from grapes of Vitris vinifera variety Tinta del Pais. Use of a diode array detector permitted the location on the chromatogram of peaks corresponding to procyanidins and procyanidin gallates and also a possible procyanidin esterified with p-coumaric acid. A seed extract was fractionated by gel chromatography on Sephadex LH-20 and then by preparative HPLC to isolate compounds and permit their identification. Structures were characterized by TLC, complete and partial acid hydrolysis, enzymatic hydrolysis, and thiolysis in the presence of phenylmethanethiol with later desulfuration of the benzyl thioethers obtained. The heptamers could be the compounds with the highest degree of polymerization present in the extract, although only dimer, trimer, and tetramer procyanidins were isolated.