Influência de leveduras autóctones em diferentes processos de elaboração de vinhos tintos finos na campanha gaúcha

Abstract

Using selected yeasts for the alcoholic fermentation of fine wines is a strategy that aims to guarantee quality sensory and physical-chemical characteristics to the final product, in addition to ensuring that the process begins and ends without problems such as fermentation stops and the production of volatile compounds of little interest. Selecting yeasts from a wine region adds to the characteristics of the wine, as they are supposed to be more adapted to local conditions, in addition to contributing to the idea of the local terroir. Therefore, the objective of this study was to characterize sensorially and chemically, Tannat and Cabernet Sauvignon wines fermented with different winemaking processes, using commercial and autochthonous yeasts Saccharomyces cerevisiae and Lachancea thermotolerans, isolated from the Campanha Gaúcha region. The experiment was conducted with three treatments in triplicate for each variety, the control, T1 (commercial S. cerevisiae), T2 with autochthonous S. cerevisiae and T3 with sequential fermentation of L. thermotolerans and autochthonous S. cerevisiae. The vinification process took place according to a standard protocol for red wines, and the autochthonous yeasts were multiplied in YEPD liquid medium. The physicochemical analyzes were carried out by Fourier Transform Infrared Spectroscopy (FT-IR) on the WineScan SO2 equipment, anthocyanins and total tannins were carried out by spectrophotometry and the antioxidant activity by DPPH, in addition to sensory analysis using quantitative descriptive profile sheets. Autochthonous yeasts impacted the fermentation kinetics, resulting in a slight delay in the completion of alcoholic fermentation (F.A.) for T3 and non-completion of F.A. for T2. L. thermotolerans was not able to impact the production of glycerol and lactic acid, not increasing the total acidity of the wine, however it generated an increase in volatile acidity and S. cerevisiae was able to increase the production of glycerol and, sensorially, treatments with autochthonous yeasts were described with greater aromatic complexity, better scored and preferred by evaluators, showing the potential and positive sensorial impact of the strains used.