Evaluation of Candida easanensis JK8 β-glucosidase with potentially hydrolyse non-volatile glycosides of wine aroma precursors.

Important 'floral' aromas naturally occur in grapes predominantly as flavourless glycoconjugate precursors. Since these aroma compounds can be released by hydrolysis, different glycosidase enzymes can potentially contribute different aromas to wines. In this paper, the effects of crude and purified Candida easanensis JK8 β-glucosidases on wine aroma precursors of Muscat of Alexandria grape powder were investigated by GC/MS combined with stir bar sorptive extraction (SBSE). A total of 19 bound volatile compounds were identified, including phenols, terpenes, aldehyde, ester and alcohols. The concentrations of terpenes especially nerol and geraniol, and β-Damascenone, a C13-norisoprenoid, contributes flowery and slightly fruity aromas were significantly increased in enzyme treated. These results suggest the potential application of this yeast β-glucosidase as an aroma-enhancing enzyme in winemaking.