Exogenous Glucose Enhances Cold Resistance in Postharvest Apricot Fruit by Regulating Sugar Metabolism

This study was conducted in order to explore the effect of exogenous glucose treatment on postharvest cold resistance and sugar metabolism in apricot fruit. Xinjiang-grown ‘Saimati’ apricots were subjected to vacuum osmosis treatment with different concentrations of glucose followed by cold storage at (0 ± 1) ℃ for 49 days. The incidence of chilling injury, chilling injury index, quality and sugar metabolism-related indicators of apricot fruit were measured at regular intervals during the storage period. The results showed that 200 mmol/L exogenous glucose treatment could effectively inhibit the increase in the incidence of chilling injury, chilling injury index, cell membrane permeability and the accumulation of malondialdehyde (MDA), and well maintain the hardness, color, soluble solids content (SSC), titratable acid (TA) and ascorbic acid (ASA) contents of apricot fruit. Meanwhile, compared with the control group, the exogenous glucose treatment increased the activities of acid invertase (AI), neutral invertase (NI), sucrose phosphate synthase (SPS) and sucrose synthase (SS) in apricot fruit, and significantly increased the accumulation of glucose and fructose during storage. However, the content of sucrose decreased during the mid-to-late stage of storage (21–49 days). In summary, exogenous glucose treatment could enhance the contents of glucose and fructose by regulating the activity of enzymes related to sugar metabolism, thereby enhancing cold resistance and maintaining the storage quality of the fruit. The results of this study can provide a reference for controlling chilling injury in postharvest apricot fruit.