Influence of Yeast and Enzyme Formulation on Prosecco Wine Aroma During Storage on Lees

This study investigated the impact of two yeast strains (SP665 and CGC62) and glucanase enzyme treatments (A-D) on the secondary fermentation kinetics and aroma profile of sparkling Prosecco wines. The strains exhibited markedly different fermentation behaviors: SP665 induced rapid refermentation, reaching 8.5 bar in 46 days, while CGC62 showed a slower fermentation rate, reaching 6.5 bar in 64 days. Despite these kinetic differences, basic enological parameters after refermentation and following three months of lees aging were similar for both strains. A total of 66 volatile compounds across various chemical families were identified and quantified. Principal component analysis (PCA) revealed that aging time (T1 vs. T2) was the main driver of variability (50.74% of total variance), with SP665 and CGC62 wines showing distinct profiles. At T1, SP665 wines had higher levels of acetate esters and norisoprenoids, while CGC62 wines were richer in volatile sulfur compounds (VSCs) and monoterpenoids. At T2, SP665 wines showed increased levels of carbon disulfide, higher alcohols, and ethyl butanoate, whereas CGC62 wines retained higher concentrations of varietal compounds and certain esters. The effect of glucanase enzymes varied depending on yeast strain and aging stage. Enzyme treatments, especially C (beta-glucanase) and D, influenced the concentration of several aroma compounds, particularly in CGC62 wines, enhancing varietal aromas and esters. However, the impact on SP665 wines was more limited and emerged primarily after aging. Although differences in aroma composition were statistically significant, most changes were below olfactory perception thresholds. Overall, glucanase enzymes and yeast selection influenced aroma development, though their effects may have limited sensory relevance.