Analysis of carotenoids in grapes to predict norisoprenoid varietal aroma of wines from Apulia.

To determine a correlation between carotenoid precursors in grapes and norisoprenoid varietal aroma of wine, carotenoids were identified and quantified by HPLC-DAD-MS (ESI+) from four representative wine grape varieties of the Apulian region (Chardonnay, Merlot, Negroamaro, Primitivo) in two years of study (2006-2007), and C13-norisoprenoid aroma potential, DeltaC (microg/kg), was calculated from the difference of total carotenoid concentration between veraison and maturity. C13-norisoprenoids were analyzed by GC-MS in the obtained wines from 2006 and 2007 vintages. Higher DeltaC values, found in Chardonnay and Merlot grapes, corresponded to higher norisoprenoid contents in the respective wines, particularly characterized by highly flavorant compounds such as beta-damascenone and 3-oxo-alpha-ionol. A linear regression was determined that was significant at the 0.01% level (F=36.12, p=0.00096) with R=0.9261, between grape DeltaC values and total norisoprenoid contents in wine. These findings support the hypothesis that DeltaC could be a useful technological tool to predict norisoprenoid aroma of wine and, consequently, to identify grapes with higher aroma potential.