Physicochemical characterization of must and wine Moscato Giallo from grapevines grown under plastic overhead cover

Abstract

The objective of this work was to evaluate the plastic overhead cover (POC) effect on must and wine composition of the cultivar Moscato Giallo. In 2006 vintage, it was performed a completely randomly designed experiment, in a vineyard covered with an impermeable plastic cloth, and without covering as control. From each vineyard, three microvinification (20 L) were elaborated. Physico-chemical analysis were performed for: musts – ^oBrix, reducer sugar contents, density, total acidity, tartaric acid, malic acid and pH; and wines – density, alcohol degree, acidity, volatile acidity, pH, dry extract, reducer sugar contents, ashes, I 420, volatile compounds and minerals. The must of the covered vineyard presented higher yield, but lower sugar content, due to delay on ripening. As consequence, the POC wines showed lower alcohol degree, but with the benefit of a lower ethyl-acetate and volatile acidity levels. The POC microclimate also caused a decrease of some minerals (mainly P and K) in the wines. POC improved the enological quality, however, this demands delay in the harvest date to achieve the adequate physiological and technological maturation of grapes.