Effect of pre-bloom leaf removal on grape aroma composition and wine sensory profile of Semillon cultivar.

Background: Early leaf removal at pre-bloom is an innovative viticultural practice for regulating yield components and improving grape quality. The effects of this technique on vine performance, grape composition and wine sensory profile of Semillon variety were assessed.
Results: Pre-bloom leaf removal enhanced canopy porosity, total soluble solids in musts and reduced cluster compactness. This practice had a strong effect on glycoside aroma precursors, in particular by increasing glycoside terpenols and norisoprenoids. Metabolites of linalool were the most responsive to leaf removal. Wine produced from defoliated vines was preferred in tasting trials for its more intense fruity notes and mouthfeel attributes.
Conclusion: Pre-bloom leaf removal is a powerful technique for modifying canopy microclimate, vine yield, grape composition and wine quality. The increase of glycoside aroma compounds in treated grapes has potential positive effect in improving the sensory profile of the resulting wines. © 2017 Society of Chemical Industry.
(© 2017 Society of Chemical Industry.)