Phenolic compounds in skins and seeds of ten grape Vitis vinifera varieties grown in a warm climate

This study employed high performance liquid chromatography (HPLC) to analyse non-anthocyanin phenols present in the skins and seeds of 70 grape samples belonging to 10 cultivars. Grape skins contained tartaric esters of hydroxycinnamic acids (6–45 mg/kg of grape), monomeric and dimeric flavan-3-ols (9–96 mg/kg) and flavonols (25–197 mg/kg). The seed constituents comprised almost exclusively flavan-3-ols with concentration ranges of 330–1390 mg/kg. Certain varietal differences were observed, although other important factors have to be taken into account such as the degree of ripeness or berry size. The differences with respect to the results reported by other authors in relation to relative concentrations of procyanidins were attributable to climatic differences in the areas where the different studies were performed, in our case with very hot summers.