Antioxidants of blushed and unblushed sides in relation to superficial scald of ‘NY2’ (RubyFrost®) apples treated preharvest with 1-methylcyclopropene and aminoethoxyvinylglycine

Abstract

The effects of plant growth regulators (PGRs) and harvest date on antioxidant contents at harvest and superficial scald development in ‘NY2’ apple during storage have been studied. Aminoethoxyvinylglycine (AVG, ReTain®) and 1-methylcyclopropane (1-MCP, Harvista™) were sprayed two and one weeks, respectively, before the first of three weekly harvests. The apples were stored at 0.5 °C for 20 weeks + 7 d at 20 °C. At harvest, color and index of absorbance difference (IAD) values, and contents of total phenolics, anthocyanins, chlorophylls, carotenoids, ascorbic acid (TAA), dehydroascorbic acid (DHA) glutathione (GSH), reduced glutathione (GSSG) and total antioxidant activity of blushed and unblushed sides of the apple were measured. The antioxidant contents increased with later harvest dates. Chlorophyll and GSSG were higher in unblushed than blushed skin tissues, while all antioxidant contents were highest in blushed skin tissues. Superficial scald incidence was highly correlated with less mature fruit, lower fruit anthocyanin, higher chlorophyll content at harvest. α-Farnesene, conjugated trienols (CTols), and IAD value index were measured at 0, 1, 2, 4, 6, 10, 15, and 20 weeks at 0.5 ⁰C for fruit from harvest 1. Scald incidence and severity was higher in AVG-treated fruit than untreated or 1-MCP treated fruit and did not decrease at later harvest dates. Using harvest management and preharvest application of plant growth regulators is a promising strategy to improve the nutritional value of 'NY2′ apples, reduce physiological disorders, and maintain fruit quality.