Enhanced liberation of grape terpenoids
The varietal favour of grapes is mainly determined by the accumulation and pro®le of volatile secondary
metabolites in V. vinifera [61]. However, a high percentage of these metabolites occur as their
respective, non-volatile O-glycosides. Several studies have shown that increased enzymatic hydrolysis
of aroma precursors present in grape juice can liberate the aglycone to intensify the varietal character of wines [15].