Sistemas de condução : interferências na composição química e parâmetros cromáticos de vinhos tropicais cabernet sauvignon

Abstract

This research had the objective of evaluating the influence of two systems of conduction (simple curtain and monoplane vertical ascending) in experimental wines of Cabernet Sauvignon elaborated in the Valley of the São Francisco, harvests 2014, 2015 and 2017. They were evaluated, in triplicate, the classical oenological parameters, phenolic composition and antioxidant activity - spectrophotometry, color parameters - spectrophotometry and colorimetry, and organic acid profile - high efficiency liquid chromatography). Student's t-test (p <0.05) was used to verify significant variations between the conduction systems and principal components analysis was applied seeking grouping of the samples. The wines presented values, within the limits established by the Brazilian Legislation, for the classical oenological parameters, however the pH values were superior to those suggested for red wines. Wines from the ascending system presented significant superiority in the total acidity, and alcoholic content in the simple curtain system. The concentration of phenolic compounds in all wines presented values consistent with those reported in the literature for commercial wines from this region. Total polyphenol content higher than 60 units was obtained in wines from the simple curtain system, harvests 2015 and 2017, favoring the potential of guard. Wines from this conduction system had significantly higher concentrations of total polyphenols and total tannins, a fact observed only in the 2017 harvest for the total anthocyanins content. The wines presented high antioxidant capacity (81.55 to 94.71% inhibition of DPPH*). The spectrophotometric color intensity was significantly higher for wines from the simple curtain system. By colorimetry, the wines of the simple curtain system presented higher chroma values, except in the 2017 harvest, and this color variation can be perceived visually by the consumer. The profile of organic acids showed that the concentration of tartaric and lactic acids was higher in the wines of the simple curtain system. The multivariate analysis led to the separation of wines as a function of the conduction and harvest system, with the first two principal components accounting for 79.60% of the total data variance. The best expression of the characteristics evaluated, in the climatic conditions of the Submédio São Francisco Valley, was obtained in wines whose grapes were produced with a conduction system that favors the shading of the bunch, minimizing the photo and thermodeation. Wines with greater stability and guarding potential may have a positive impact on the Local Productive Arrangement of the Grape and Wine and to consolidate the Geographical Indication of Provenance of the São Francisco Valley.