Integrated enzymatic–yeast biostrategy to obtain reduced-alcohol wine

Abstract

Overripening of grapes, due to global warming, can result in unbalanced wines with higher alcohol content, lower acidity and an altered sensory profile. Pre-fermentative treatment of the must with a glucose oxidase- catalase enzyme system immobilized in silica‑calcium-alginate hydrogel capsules degraded up to 17.3% of the glucose in the must in 48 h to obtain wines with 1.0–1.3% vol (v/v) lower alcoholic strength. Most of the gluconic acid produced by glucose oxidation was retained in the capsules, resulting in a mild reduction in the pH, thereby avoiding a strong acidification of the must. The remainder of the gluconic acid present in the must was largely degraded during the fermentation process using a selected strain of the yeast Schizosaccharomyces pombe (S. pombe). Both the enzymatic treatment of the must with the capsules and the use of S. pombe, either in unique inoculation or in sequential inoculation with a Saccharomyces cerevisiae (S. cerevisiae), led to balanced wines with a unique chemical profile. The combination of these two strategies, pre-fermentative and fermentative, presents an innovative and promising approach, not investigated so far, to counteracting the adverse effects of rising temperatures due to global warming.