Quality, phenols and oxidative enzymes of 'Itália' grape under calcium influence, during ripening

Abstract

This work was conducted with the objective of evaluating the effect of preharvest Ca treatment on quality, phenols content and activity of oxidatives enzymes of 'Itália' grape (Vitis vinifera L.), during maturation, at Empresa Timbaúba Agrícola S.A, at Petrolina, Pernambuco State, Brazil. Application of 0, 0.5, 1.0 and 1.5% Ca was used, under the form of dihydrated calcium chloride, by immersion of the labelled bunches during 10 seconds, in the phase of color change and beginning of berry softening (57 days after fruit set). Evaluations were performed at 28, 43, 57, 72 and 92 days after fruit set. Experimental design was completely randomized in a factorial 4 x 5, with four replications. The variables evaluated were: total soluble solids (TSS), total titrable acidity (TTA), TSS/TTA ratio, pH, total phenols, polyphenoloxidase (PPO) and peroxidase (PDO) activities. TSS content and TSS/TTA ratio were reduced with the increment in calcium doses. However, the medium values of TSS attended the requirements of the market. PDO activity was 13.26% reduced by Ca 1.0% and it was 27.15% increased by Ca 1.5% compared to control. The other characteristics were not affected by exogen Ca.