The impact of a Saccharomyces cerevisiae bio-protective strain during cold static clarification on Catarratto wine.

The study aimed to evaluate the impact of the early addition of a Saccharomyces cerevisiae HD A54 strain before pressing during winemaking. This approach aimed to reduce the dissolved oxygen in the grape must, thus preserving the wine characteristics. Two different treatments were settled: Trial A, where sulphite or other substances were not added during pressing; and Trial B, where a S. cerevisiae strain was added at the pressing stage. The chemical parameters were determined through an enzymatic analyzer, which indicated a faster fructose consumption compared to the glucose in Trial A. The plate counts were measured to monitor the microbial groups during vinification. Both treatments showed regular trends with respect to the Saccharomyces population. Trial B exhibited a higher oxygen consumption compared to the control trial, especially in the early stages of winemaking. This was determined through a dissolved O₂ analysis. Furthermore, Trial B had lower absorbance values at the post-pressing and pre-clarification stages. Both the dissolved oxygen and the absorbance analyses underscored the positive impact of the S. cerevisiae HD A54 strain in protecting against oxidative processes in the grape musts at the pre-fermentative stage. The analysis of volatile organic compounds detected 30 different compounds, including alcohols and esters. Trial B had higher alcohol levels, particularly hydroxyethylbenzene (135.31 mg/L vs. 44.23 mg/L in Trial A). Trial A had almost a four times higher ethyl acetate concentration than Trial B, which is an indicator of oxidation. Interestingly, Trial B showed higher concentrations of 3-methyl-butyl acetate and 2-phenylethyl acetate, which are molecules that correspond to fruity (banana) and floreal (rose) aromas, respectively. Regarding the sensory analysis, Trial B received better scores for the fruity and floral attributes, as well as the overall wine quality.