Terroir and variety: Two key factors for obtaining stilbene-enriched grapes

Grapes and wine are among the main sources of bioactive stilbenes in the diet. The stilbene composition of grapes depends on both variety and terroir. The effect of terroir on grape stilbenes has not been widely studied. In this research the study of the stilbene content (resveratrol, piceatannol and viniferins) in four different red grape varieties (Syrah, Merlot, Cabernet sauvignon and Pinot noir) and from four different Andalusian terroirs (Jerez, Cabra, Cadiar and Ronda) was carried out during the 2009 vintage. In addition, stilbene induction capacity was studied in each terroir and variety after ultraviolet-C (UVC) postharvest treatment. Data were analysed by multivariate statistical methods. Principal component analysis applied to the oenological parameters and stilbene data classified varieties into two terroir groups satisfactorily: Jerez and Cabra on the one hand, and Ronda and Cadiar on the other hand. Terroir effect is stronger than variety on stilbene induction capacity after UVC treatment. Syrah from Cabra stood out due to both the high basal (13.07 mg/kg fw) and induced (33.14 mg/kg fw) stilbene concentration attained. Therefore, it can be affirmed that Cabra and Syrah are the most suitable terroir and variety, respectively, for obtaining a stilbene-enriched wine.