Development of Proanthocyanidins inVitis viniferaL. cv. Pinot noir Grapes and Extraction into Wine

The effect of grape maturity on proanthocyanidin concentration, composition and transfer into wine was studied. Vitis vinifera L. cv. Pinot noir grapes (Pommard clone) were monitored for three consecutive vintages (2001 to 2003). Proanthocyanidin content was monitored by reversed-phase HPLC after acid-catalyzed cleavage in the presence of excess phloroglucinol (phloroglucinolysis). After three growing seasons, results indicated that an increase in heat summation between fruit set and veraison was associated with an increase in proanthocyanidin content in grapes and wine. Maturity did not have a consistent effect on the total proanthocyanidin content in wine, but the proportion of seed-derived proanthocyanidins extracted consistently increased with maturity.