Resveratrol content of some wines obtained from dried Valpolicella grapes: Recioto and Amarone.

Resveratrol (trans-3,5,4'-trihydroxystilbene), a phenolic substance present in both grape skin and wines, is a phytoalexin involved in grey mould resistance. A new interest has surfaced in recent years related to the antioxidative actions of resveratrol, which in vivo could be related to the prevention of cardiovascular diseases linked to lipid metabolism, particularly HDL production, while the antifungal activity may be of interest in wine production technology. These aspects have led to the publication of a number of papers reporting data on the resveratrol content of several kind of wine: for Italian wines, it ranges between 0.5 and 10 ppm, depending on cultivar, area of cultivation, climate and wine-making technology. In this work, resveratrol was quantified in samples of two unusual Italian wines, Recioto (sweet) and Amarone (dry), produced with the same cultivar mixture in the same area (Valpolicella, Verona, Italy) and with the same grape conditioning technique. After resveratrol extraction, reversed-phase HPLC analysis was carried out and several elution conditions were tested. The resveratrol content of Recioto and Amarone wines was lower than the values reported in the literature for other wines, ranging between 0.05 and 0.8 ppm.