Effect of sodium dehydroacetate on the development of sour rot on Satsuma mandarin

• SD dose-dependently inhibits the mycelial growth of Geotrichum citri-aurantii.
• SD treatment significantly reduces sour rot decay in Miyagawa Wase fruits.
• SD treatment increases the activities of SOD, POD, and PAL but not CAT.
• SD treatment does not impair fruit quality of Miyagawa Wase fruits.

Sour rot, caused by Geotrichum citri-aurantii, is one of the most devastating diseases in citrus fruits. This disease is difficult to control due to the lack of registered fungicides. In this study, sodium dehydroacetate (SD), a common food preservative, was evaluated to control postharvest sour rot of citrus fruits through in vivo and in vitro experiments. Results demonstrated that SD dose-dependently inhibited the mycelial growth of G. citri-aurantii, with a minimum inhibitory concentration (MIC) and a minimum fungicidal concentration (MFC) of both 0.80 g/L. The application of various SD concentrations (1 × , 2 × , and 4 × MFC) to citrus fruits inoculated with G. citri-aurantii significantly (P < 0.05) decreased the incidence of sour rot during the entire storage period. After 8 d of storage, the decay incidences in SD (4 × , 2 × or 1 × MFC)-treated fruits were only 10%, 30%, 60%, respectively, in contrast to 100% of the control fruits. In addition, SD treatment induced an increase in the activities of SOD, POD, and PAL but not CAT. Meanwhile, SD treatment retained the fruit quality of citrus because it has no negative effect on pH, coloration index, total soluble solids, vitamin C content, firmness, and the weight loss rate. Our results suggest that SD can be considered as a good alternative to conventional fungicides in controlling the decay of citrus fruits.