Effects of noble rot on must composition and aroma profile of Amarone wine produced by the traditional grape withering protocol

The effects of noble rot on the overall quality of Amarone wine, a Passito dry red wine, produced by a traditional withering grape process are poorly understood. Wines obtained from healthy and selected grapes infected by noble rot were compared. Validation of the experimental plan was carried out by determining glycerol and gluconic acid content, laccase activity and microbial analysis of the musts. Botrytis cinerea infection produced significant variation in esterase and beta-glucosidase activity of grape must. Aroma analysis in healthy and botrytised wines was carried out by SPE extraction followed by GC-MS quantification. A decrease of several fermentative esters was observed in botrytised wine, while wine produced from healthy grapes showed a higher fatty acid content. Molecules such as 1-octen-3-ol, phenylacetaldehyde and furaneol were positively linked to the noble-rotten grapes. Interestingly, gamma-nonalactone and 4-carbethoxy-gamma-butyrolactone increased, while sherry lactones decreased in botrytised wine. The strong increase of N-(3-methylbutyl)acetamide was related to B. cinerea grape infection. (C) 2011 Elsevier Ltd. All rights reserved.