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The current work aimed to evaluate the efficacy of four coating formulations—chitosan coating (CH), 0.5% cinnamaldehyde + chitosan (0.5% CI–CH), 1.0% cinnamaldehyde + chitosan (1.0% CI–CH), and 1.5% cinnamaldehyde + chitosan (1.5% CI–CH)—on fresh mandarin fruit cv. Ponkan quality maintenance (weight loss, decay rate, total soluble solids, titratable acidity, vitamin C, color index, malondialdehyde, and antioxidant activity) over 100 days of storage at 20 °C. Compared to the control, chitosan treatment effectively reduced the decay and weight loss rates of mandarin fruit cv. Ponkan during storage at room temperature, delayed the decline of nutritional quality in fruits, increased the antioxidant capacity, and inhibited the accumulation of malondialdehyde (MDA). In comparison to chitosan coating, 1.5% CI–CH did not improve the fruit storage effect, but inhibited the normal color change of fruits and increased the accumulation of MDA. Both 0.5% CI–CH and 1.0% CI–CH effectively reduced the rate of fruit decay, improved the quality of fruits after harvest, and delayed fruit aging. Our study suggests that 0.5% CI–CH and 1.0% CI–CH might be good formulations for maintaining the quality of mandarin fruit cv. Ponkan during room-temperature storage.

In citrus fruit, citric acid is the predominant organic acid which influence fruit taste, flavor and quality. The effect of hot air treatment (HAT 40°C, 48 h) and 1.0% chitosan coating on the change of organic acids and the related gene expression of citric acid synthesis and degradation in ponkan (Citrus reticulata Blanco) fruit during cold storage have been studied. The results showed that citric acid was the main organic acid in fruit, the trend change of citric acid content was consistent with total organic acids and titratable acidity (TA) content, which decreased with the prolongation of storage time, hot air treatment significantly promoted but chitosan coating treatment significantly delayed citric acid degradation in Ponkan fruit. Hot air treatment could induced CitAco2/3, CitIDH2/3, CitGAD4, CitACLs, CitPEPCKs and CitFBPases expression during fruit storage period, but had no significant effect on CitGSs expression, The enhanced expression of degradation-related genes was closely related to the degradation of citric acid. The expressions of CitAco3, CitGAD4 CitACLα2/β, CitPEPCKs and CitFBPases were inhibited, which leading to the degradation rate of citric acid was slowed by chitosan coating during storage. These results showed that the degradation of citric acid in fruit was regulated by ATP citrate lyase (ACL) pathway and γ-aminobutyric acid (GABA) pathway.

This study investigates the effects of different cold storage times (30 days—CS‐30d, 40 days—CS‐40d, and 50 days—CS‐50d) on quality of “Cuiguan” pear fruits during shelf life. The data showed that, compared with 0 days of cold storage, the weight loss and rot rate of the fruit on the shelf increased, the hardness and nutritional quality of the fruit decreased rapidly, and the deterioration rate of the fruit was aggravated. By comparing the quality changes of three storage periods fruits during the shelf life at room temperature, it was found that the longer the refrigeration time was, the faster the quality of “Cuiguan” pear fruit declined in the later shelf life, and the easier the fruit deteriorated. Principal component analysis showed that the quality of Cuiguan pear fruits of CS‐50d deteriorated fastest during shelf life at room temperature, followed by fruits stored for CS‐40d and CS‐30d. This provides a theoretical basis for selecting the cold storage time of “Cuiguan” pear. Practical applications At present, the effect of the refrigeration time of Cuiguan pear on the shelf at room temperature has not been reported. By comparing the changes of fruit quality during shelf life after different cold storage time (30, 40, and 50 days), the optimum cold storage time for Cuiguan pear was 30 days. It prolong the fruit duration and ensured that the fruit quality maintained a high level during shelf life at room temperature.