CHANGES IN ANTIOXIDANT ACTIVITY AND THE PROANTHOCYANIDIN FRACTION OF RED WINE AGED IN CONTACT WITH PORTUGUESE (QUERCUS PYRENAICA WILLD.) AND AMERICAN (QUERCUS ALBA L.) OAK WOOD CHIPS

摘要

A red wine made from the Syrah grape variety was matured in contact with 5 and 10 g/L of oak wood chips from Portuguese (Quercus pyrenaica Willd.) or American (Quercus alba L.) oak species for 90 days, in order to evaluate the effects of the presence and concentration of these oak wood chip species on the antioxidant activity and the evolution of the proanthocyanidin fraction (monomeric, oligomeric and polymeric). The results showed an increase in the antioxidant activity in red wines aged in contact with the oak wood chip species during the first 52 days of storage followed by a slight decrease. The antioxidant activity values in the wine aged without oak wood chips remained nearly constant during the storage time. After 90 days, the presence of oak wood chips (especially a high concentration of the Portuguese oak species) had a positive effect on the antioxidant activity values and there was a high concentration of the monomeric proanthocyanidin fraction. For all the wines studied, the correlations between antioxidant activity and the monomeric fraction of proanthocyanidins were always high.