Some clues about the changes in wine aroma composition associated to the maturation of neutral grapes

This paper presents a study of the influence of the harvesting date on concentrations of odorants in Moristel wines of two vintages. The wine made from grapes harvested early facilitated the accumulation of acetaldehyde (associated with low polyphenols concentrations) and higher concentrations of branched acids. A reason for these greater levels could be the lack of reduction factors (NADH or NADPH). Other changes with potential sensory consequences are the decrease of the branched acid/branched alcohol, branched ester/branched acid and branched ester/branched alcohol ratios that occurs as the grapes ripen. Besides, the variations of varietal or typical maturation markers did not have sensory importance. These results suggest that the characteristics of wines associated to the degree of maturity of grapes are mostly related to the changes in the profiles of fermentative compounds (especially acetaldehyde) induced by changes in the polyphenolic content and in the medium in which the yeast develops.