A novel extracellular β-glucosidase from Issatchenkia terricola: Isolation, immobilization and application for aroma enhancement of white Muscat wine

Since most Saccharomyces strains show no β-glucosidase activity, the importance of non-Saccharomyces β-glucosidases in the development of wine aroma has been highlighted. However, only a few enzymes from yeasts isolated from grape-must and enological ecosystems are active in the stringent conditions of wine and the wine-making process (low pH, high concentrations of ethanol or glucose). A purified extract of extracellular β-glucosidase from Issatchenkia terricola, proved to be very active in the presence of glucose (100 g/L), ethanol (18%) and metabisulfite (60 mg/L). It is also active and relatively stable at acidic pH over 3.0. Immobilization onto Eupergit C greatly improved its stability, allowing the aromatization of white Muscat wine over a 16-day experiment. The released aroma compounds of control and treated wine were analyzed by GC–MS. The enzymatic treatment significantly increased the amount of monoterpenes and norisoprenoids, showing the potential of the immobilized enzyme for aroma development in wines.