While the TF content declined during storage the quantification of individual flavonols indicated that concentrations of myricetin and quercetin aglycones increased slightly. Fig. 3 presents the percentage of glycosylated flavonols versus aglycones during storage. A constant decrease of glycosylated forms and increase of aglycones was observed that should be attributed to hydrolysis of flavonol glycosides catalyzed by enzymes, like b-glucosidase. Some S. cerevisiae yeasts possess a gene coding for b-glucosidase. Mateo and Di Stefano (1997) demonstrated the hydrolysis of grape glycosides by crude extracts of Saccharomyces strains. This activity was suggested to be related to the major exo-b-glucanase of S. cerevisiae
(Gil, Manzanares, Genovés, Vallés, & González-Candelas, 2005).