Diferentes aplicações de frio em macerações na vinificação de Petit Verdot

Abstract

Faced with the search for red wines with intense color, body and aroma, winemakers investigate the use of different winemaking techniques for the extraction of phenolic compounds. In this work, the effect of different maceration techniques on the extraction of polyphenols in red wines from cv. ‘Petit Verdot’ from the Gaucha Campaign. The hypothesis is that the use of cold in maceration favors the extraction of color and aromatic precursors, to test this hypothesis, the experimental design was as follows: (T1) traditional maceration (occurred together with alcoholic fermentation, for 7 days), (T2) cryomaceration with the addition of 500 g L-1 of dry ice in each fermentation unit and subsequent maceration for 7 days, and (T3) pre-fermentation cold maceration, where the must remained in a cold chamber at 5 °C for 72 hours and, subsequently, carried out alcoholic fermentation in the presence of grape skins, totaling maceration for 10 days. At the end of the period of alcoholic fermentation, analyzes of alcohol, density, reducing sugars, volatile acidity, total acidity, pH, Free SO2 and Total SO2, color tone and intensity, polyphenols and total tannins were carried out, using the methodology Fourier Transform Infrared Spectroscopy (FTIR), and sensory analysis with two tests, a discriminative one with ordering test and qualitative descriptive analysis with trained tasters. For the results, analysis of variance (ANOVA) was used and the means were compared using Tukey's Test, at 5%, for physical-chemical analyzes and Friedman's Test at 5% of significance for sensory analysis of the test of ordination. The results showed a significant difference in pH parameters, especially for traditional maceration and lactic acid for pre-fermentative cold maceration treatments. Refuting the initial hypothesis that cold treatments would provide greater color extraction, the sensory analysis showed that the intensity and color tonality was more intense in traditional maceration, in relation to the olfactory character, wines to which dry ice was added showed a fruity and floral character, pre-fermentation maceration wines cold showed fruity aromas and aromatic complexity, however, the 'overall quality' parameter was higher in the traditional method.