Variabilidade do perfil aromático de uvas pálava e sauvignon kretos no sul do Brasil

Abstract

The process of alcoholic fermentation is a series of sequences of biochemical reactions that transform grape must into wine, a beverage composed mainly of water and alcohol and secondary compounds. Within the class of secondary compounds, we can mention those that are directly related to the characteristic of the grape and those that come from the metabolism of the yeasts responsible for alcoholic fermentation. Saccharomyces and non-Saccharomyces yeasts have, in their genetic code, different enzymatic devices, which makes the secondary compounds from their metabolism also different in composition and concentration. In this context, the present study aims to evaluate whether different yeasts can impact the typicality of wines in relation to physicochemical composition, volatile composition and sensory characteristics. For that, three experiments were carried out. Experiment 1 consisted of 9 treatments performed on cv. Palava, testing 5 different commercial yeasts, and two different producing regions (Serra Gaúcha and Campanha Gaúcha). Experiment 2 consisted of 5 treatments performed on cv. Kretos Sauvignon from Serra Gaúcha, testing 5 different commercial yeasts. Experiment 3 consisted of 2 treatments, a test of two different yeasts in Cabernet Sauvignon grapes from Campanha Gaúcha, one of the yeasts was commercial, and the other was previously isolated from the own vineyard from which the grapes were harvested. To evaluate the impact of the treatments on the wine profile, physicochemical analyzes were carried out for the classical parameters through Fourier Transform Infrared Spectrometry (WINE SCAN), volatile analysis by Gas Chromatography coupled to Mass Spectrometry (GC-MS) and sensory analysis by Quantitative Descriptive Analysis (QDA). As expected, yeasts impact the physicochemical composition of wines and the methodology used in the putative identification of volatile compounds allowed the identification of a varied group of compounds. The interference of treatments, in all experiments, had a greater impact on the composition of volatile compounds than on the sensory quality.