Foliar nitrogen application from veraison to preharvest improved flavonoids, fatty acids and aliphatic volatiles composition in grapes and wines.

This study investigated the effects of foliar nitrogen application from veraison to preharvest (FNVH) on flavonoids, fatty acids and aliphatic volatiles in Cabernet Sauvignon grapes and wines. Solutions with 69 and 138 mg N/plant phenylalanine (P1 and P2, respectively), 69 and 138 mg N/plant urea (U1 and U2, respectively), as well as an aqueous solution without nitrogen (CK), were sprayed three times from veraison to preharvest. U1, P1 had the highest anthocyanins and acylated anthocyanins contents in grapes, respectively. U1 and P2 showed great potential to promote the accumulation of flavonols and flavanols in grapes and wines. U2 increased the contents of almost all free aliphatic volatiles in grapes, while it didn't affect the undesirable smell, and increased the concentrations of fruity esters in wines instead. The study showed FNVH was a useful fertilization way for improving contents of flavonoids and fruity aroma in grapes and wines in deficit-nitrogen vineyards.