Effect of Preharvest Spray of Diethyl Aminoethyl Hexanoate on Postharvest Fruit Quality and Reactive Oxygen Species Metabolism in ‘Kyoho’ Grape

The vigorous metabolism of reactive oxygen species (ROS) in postharvest ‘Kyoho’ grapes shortens the storage period, and reduce the commercial value. In this study, different concentrations (0, 10, 30, 50 and 70 mg/L) of diethyl aminoethyl hexanoate (DA-6) were sprayed on table grapes at veraison to investigate the effects of DA-6 treatment on postharvest fruit quality and ROS metabolism in ‘Kyoho’ grapes. By measuring the physiological indexes related to fruit quality, it was found that DA-6 treatment significantly reduced fruit mass loss, and delayed the decrease in fruit firmness and total soluble solid content, and this effect was most significant at a concentration of 50 mg/L. More importantly, 50 mg/L DA-6 treatment significantly increased the activity of superoxide dismutase, ascorbate peroxidase, catalase, glutathione reductase, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity and total reducing capacity, and suppressed the decrease in reduced ascorbic acid and glutathione contents and the accumulation of superoxide anion radical and malondialdehyde. In conclusion, pre-harvest spray of DA-6 maintained the stability of the ROS scavenging system in postharvest table grapes, kept ROS metabolism in a relatively balanced state, reduced oxidative damage, delayed fruit senescence, and prolonged the shelf life of ‘Kyoho’ grapes.