Intensidades de desfolha na cabernet sauvignon e composição físico-química do vinho no município de Bagé, campanha gaúcha.

Abstract

The Campanha Gaucha region has established itself as a wine-growing hub and today is responsible for the production of 25% of Brazilian fine wines. This is due to the edaphoclimatic conditions of the region where there is good phenolic maturation of the grapes. The Cabernet Sauvignon variety, originally from France, is known worldwide and has great commercial appeal in Brazil. Cabernet Sauvignon from the Campanha Gaucha region has shown high levels of potassium present in must and wine, but the increased photosynthetically active leaf surface of the vine tends to produce wines with a lower potassium content, probably because there is a reduction in the amount of leaves for photosynthesis reducing the production of assimilates for the grape bunches. The management of the leaf area can improve the quality of the fruits and, consequently, of the wines made from them. The defoliation consists in the elimination of the leaves of the vine, aiming to increase the temperature, solar radiation and aeration in the region of the grape bunches, to improve the color and maturity of berries. Thus, the objective of this work was to evaluate the effects of defoliation on the composition of must and wine. The grapes used for the study, were from the vineyard located in Bag? RS, 2018 harvest. Defoliation was performed in randomized blocks, on both sides of the plant with intensities of 0 to testemun now defoliation, 25, 50 and 75%, in the pea grain phenological stage, in three replications. The grapes were vinified at the Federal University of Pampa. Qualitative parameters were performed by physicochemical analysis of must: pH, total acidity, ?Babo, ?Brix, volatile acidity, Total polyphenols index and potassium; of wine: pH, total acidity, volatile acidity, Total polyphenols index, alcohol, Free SO2, tartaric acid, dry extract, anthocyanins, tannins, color in absorbances 420, 520, 620nm, and minerals such as calcium, potassium, iron and magnesium. The evaluated data were statistically analyzed. In the must, defoliation increased the pH, which can be partly explained by the defoliation that accelerates the degradation of acids, leading to an increase in the pH of the must and wine, although it did not influence the total acidity. In wine, The result of this work showed that the most intense defoliation increased the pH values. Tartaric acid decreased as defoliation intensity increased, which may be due to the fact that it is more degraded in fruits exposed to light and higher temperature and that it may be related to calcium, because the higher the amount of calcium, the higher amount of tartaric acid. The treatment with the highest defoliation intensity presented the lowest value of anthocyanins, and a higher color intensity in the wines made from grapes of the defoliation plants. Potassium concentration was higher in wine with higher defoliation intensity.