The volatile composition of grapes (free and bound forms) contributes greatly to the varietal aroma and quality of wines. Several agronomical parameters affect grapes composition and wine quality: maturity level at harvest, water status, and the intensity of sun exposure. Of course vinification of non-healthy grapes can induce off-flavors in the wine. All these parameters are strongly linked with the climate (meso or micro), and its modification may induce strong modification of the grape composition. In this context, several studies were run these last years to study the origin of the dried fruit flavors (DF, prunes and dried figs) detected in must and young red wines. Indeed, these nuances are becoming more and more frequent in young wines, especially those made from Merlot grapes.
The aroma compound composition of Merlot (M) and Cabernet Sauvignon (CS) musts and wines was investigated to identify specific molecular markers responsible for DF. Organic extracts were prepared and analyzed by GC-O-MS. Furaneol (1), homofuraneol (2), γ -nonalactone (3), 3-methyl-2,4-nonanedione (4), (Z)-1,5-octadien-3-one (5), δ-decalactone (6), and massoia lactone (7) were detected at high concentrations (higher than their individual detection thresholds) in musts or wines marked by DF aromas. Certain molecular markers of DF aromas were specific to musts or wines. Reconstitution experiments revealed that a specific mixture of compounds (1-4) expressed these aromas in red wines. Additional experiments conducted with 180 wine consumers revealed how the level of these compounds might modify their willingness to pay (WP).
Author: Alexandre Pons
Unité de recherche Oenologie – EA 4577 – USC 1366 INRA – ISVV – Univ. de Bordeaux, Villenave-d’Ornon – France