Preharvest treatment of growth regulators influences postharvest quality and storage life of cashew apples

Abstract

Growth regulators may influence fruit development and thus, their postharvest quality. This study aimed to evaluate the effects of preharvest treatment with aminoethoxyvinylglycine (AVG) or gibberellic acid (GA3) on postharvest quality and life of apples of two cashew cultivars, CCP 76 e BRS 189, during cold storage. Growth regulators (180mgL−1) were applied at maturation stage 1 and apples were harvested at stage 7, ripe. Ripe, treated and control, apples were stored at 3±2°C for CCP 76 and at 5±2°C, for BRS 189 and evaluated at harvest (0day) and every 5days up to 20days of storage. The influence of growth regulators preharvest treatment on cashew apples differed among cultivars. For BRS 189 apples, GA3 treatment slowed down mass loss, as treated samples lost 0.72% while control lost 0.81%; and avoided the development of undesirable characteristics during storage. GA3-treated samples were statistically firmer, 13.61N than control, 9.93N; and together with AVG-treated samples showed a significantly reduced pectin methyl esterase (PME) activity to 1492.88UAmg−1P when compared to control 2129.87UAmg−1P. For cv. CCP 76, GA3 treatment also slowed down mass loss, as treated samples lost 0.85% and control, 0.99%, however apples were inapt for consumption after 15days of storage. GA3-treated samples were statistically firmer, 15.40N than control, 11.38N. The constituents of the antioxidant metabolism of both cashew apples varieties were mainly affected by storage period, but not by growth regulators. Therefore, results of preharvest AVG treatment on cashew apple physiology and quality were inconsistent. However, GA3 treatment improved postharvest quality of CCP 76 e BRS 189 cashew apples through reduction of mass loss and firmness loss, without any negative impact on physicochemical variables. GA3 exerted a greater influence on BRS 189 apples which showed, besides lower mass and firmness loss, a better visual appearance and lower cell wall hydrolase PME activity, during storage.