Attenuation of postharvest peel browning and chilling injury of banana fruit by Astragalus polysaccharides

Abstract The effect of Astragalus polysaccharides (APS) on peel browning and chilling injury (CI) of banana fruit was investigated. The results showed that APS induced the activities of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and reactive oxygen species (ROS) scavenging, reduced the H2O2 accumulation and the membrane lipid peroxidation and electrolyte leakage, by which delayed fruit CI, alleviated peel browning and the loss of nutrients in the flesh. It also improved the antioxidant capacity of fruit, enhanced the expression of MaSOD, MaCAT, MaAPX and led to the increase of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) activities. Moreover, APS up-regulated the expression of MaPOD, MaPAL, MaCHS and down-regulated the expression of MaPPO, resulting in the composition changes of the phenolics and flavonoids in banana fruit. Higher levels of hesperidin, ferulic acid, acacetin and myricetin were detected in APS treated fruit and were involved in alleviating fruit CI and peel browning. The present results for the first time demonstrated that APS treatment alleviated the CI of banana fruit, and provided a promising strategy for enhancing postharvest chilling tolerance.