Electron beam irradiation maintains postharvest quality of Actinidia arguta by regulating the cell wall, starch degradation, and antioxidant capacity

Abstract

Rapid postharvest softening, a major issue with Actinidia arguta, leads to a decline in quality and in commercial value. To maximally preserve fruit quality, the effects of different doses of electron beam irradiation (0.4 kGy and 1 kGy) on fruit softening and the antioxidant capacity of A. arguta after 30 days of storage were investigated. The results indicated that, compared to unirradiated fruits, A. arguta fruit subjected to electron beam irradiation maintained high levels of firmness, total phenols, flavonoids, protopectin, starch, and sucrose, and exhibited low levels of malondialdehyde and reducing sugars. Fruit receiving 1 kGy irradiation exhibited the highest firmness; however, a significant reduction in firmness was observed immediately after irradiation (day 0). An irradiation dose of 0.4 kGy did not decrease fruit firmness, and there were no significant differences in the contents of protopectin, starch, sucrose, total phenols, and flavonoids compared to fruits treated with 1 kGy irradiation. A transcriptomic analysis revealed that electron beam irradiation significantly downregulated the most genes associated with the cell wall and starch degradation, and significantly upregulated some genes related to antioxidant activity. Furthermore, there was a positive correlation between the upregulated and downregulated gene expression levels and the radiation dose. The unigenes obtained from the transcriptomic analysis were validated through integrated RT-qPCR, proteomic, and transcriptomic correlation analyses. Overall, these findings indicated that electron beam irradiation is an effective method for delaying the softening of A. arguta.