The effect of commercial β-glucosidase and its immobilization on quality of red wine production

Abstract

To find a feasible strategy for commercial β-glucosidase to enhance red wine quality, immobilized enzyme technology were considered. The preferred epoxy resin using the covalent binding method was ES-103B, and its optimal immobilization conditions were pH 4.9, 25 h immobilization time and 3 mg/g enzyme concentration. Meanwhile, this immobilized β-glucosidase still contained weak esterase activity just like commercial β-glucosidase. Free commercial β-glucosidase had different effects on the fermentation of 11 clones from three grape varieties (Syrah, Merlot and Cabernet Sauvignon) to produce wine. For example, the free enzyme increased the concentrations of β-damascenone, 1-hexanol, phenylethyl alcohol, and three ethyl esters (ethyl hexanoate, ethyl octanoate and ethyl decanoate) in a Cabernet Sauvignon (CS169) wine, but total anthocyanins level was reduced, affecting the color depth (a* value). Notably, during the alcoholic fermentation stage of CS169, immobilized β-glucosidase did not significantly decrease polyphenolic levels and color depth (a* value). What's more, using immobilized β-glucosidase under this treatment condition resulted in the highest levels of higher alcohols, ethyl esters, and acetate. Moreover, β-damascenone content increased by more than 25.35%, as well as phenethyl alcohol and benzaldehyde of benzenic compounds significantly increased by over 72.23% and two-fold, respectively. As a result, CS169 wine possessed more complex aroma and highest sensory score. Therefore, enologists can use immobilized β-glucosidase to develop various strategies that enhance wine quality and produce different wine styles.