Hydrolisis of grape glycosides by enological yeast beta-glucosidase.

Three enological yeast strains, belonging to the speciesDebaryomyces hansenii, Debaryomyces polymorphus, andSaccharomyces cerevisiae, characterized by an exocellular β-glucosidase activity, were examined for their ability to hydrolize a glycosidic extract from grape juice. The enzymatic preparations (culture supernant fluid) of the different yeasts released different amounts of terpenols such as linalol, α-terpineol, geraniol, nerol, citronellol and benzyl and 2-phenylethyl alcohol. The extent of release of the flavour compounds was related to yeast species. When an enzymatic preparation (concentrate culture supernatant) ofDebaryomyces hansenii was incubated with a wine containing glycosidic precursors, significant production of monoterpenols and benzyl and 2-phenylethyl alcohol was observed.