PRESENCE OF FLAVONOLS IN MUST AND GRAPE S KIN AND THEIR EVOLUTION DURING RIPENING

The presence of flavonol aglycones in the skin and must of grapes grow n in Madrid (Spain) during ripening was studied by TLC and HPLC. Two g rape varieties, one red (Cencibel) and one white (Airen) were consider ed from veraison to the industrial definition of berry maturity, over 2 consecutive years. Myricetin, quercetin, kaempferol and isorhamnetin were detected in the skin of the two varieties, although isorhamnetin was only recorded in Airen skin samples collected at around maturity. In contrast, only myricetin and quercetin were found in must of both Airen and Cencibel varieties. The trends in the concentration of these components were not linear but comprised of patterns of alternating m axima and minima.