Giovanni Luzzini, Davide Slaghenaufi, Maurizio Ugliano
University of Verona, Department of Biotechnology
Email contact: giovanni.luzzini[@]univr.it
AIM: Valpolicella is a wine region located in Italy north-east, famous for the production of dry and sweet red wines from withered grapes, including Amarone and Recioto. The aim of this study is to understand the influence of the withering process on Corvina and Corvinone wines aroma profiles.
METHODS: Wines were produced with a standard red wine winemaking protocol with Corvina and Corvinone grapes from different Valpolicella vineyards and vintages. In consideration of the local traditional practice of post-harvest withering of the grapes, wines from each vineyard were obtained from either fresh and withered grapes. Wines were analysed by Solid Phase Extraction and Solid Phase Micro Extraction gas chromatography coupled to mass spectrometry.
RESULTS: Within each variety, multivariate analysis showed a greater effect of the withering process compared to grape geographical origin. Withered grapes wines exhibited higher content of norisoprenoids, in particular TPB, vitispirane e β-damascenone, with increases up to 2,8-folds compared to wines produced with fresh grapes. Withering also induced an increase in benzenoids such as vanillin, methyl vanillate, ethyl vanillate and benzyl alcohol. Terpene content of withered wines was lower compared to fresh grape wines except for β-citronellol which generally increased. Wine esters content, except ethyl butanoate, generally decreased with grape withering.
CONCLUSIONS: The withering process deeply changes wines aroma profile. Modifications induced by withering cannot be simply ascribed to the concentration effect of evaporation, but involve more complex phenomena affecting grape and yeast metabolism.
ACKNOWLEDGMENTS: Azienda Agricola f.lli Tedeschi is acknowledged for financial support