Abstract: To investigate the relationship between the peel wax and storability of citrus fruits, freshly harvested fruits of ‘Gonggan’ mandarin (Citrus reticulata ‘Gonggan’) and ‘Shatangju’ mandarin (Citrus reticulata ‘Shatangju’), both endemic to the Xijiang River Basin in southwest China’s Guangdong, were packaged in plastic bags and stored at (14.2 ± 2.8) ℃ (control) and (6.5 ± 0.5) ℃ (cold storage) for 90 days, separately. Changes in mass loss rate, decay incidence, peel structure and peel wax content and its chemical composition were analyzed periodically during storage. The results showed that mass loss rate and decay incidence in the citrus fruits significantly increased with increasing storage time for both storage temperatures (P < 0.05), accompanied by alternations in peel structure and a significant decrease in peel wax content and the contents of the main components (long-chain fatty aldehydes, long-chain fatty acids and long-chain aliphatic hydrocarbons, and long-chain aliphatic primary alcohols) in peel wax. Cold storage inhibited these changes and consequently maintained fruit quality better as compared to room temperature storage. Both fruit mass loss and decay incidence were significantly correlated with peel wax content and the contents of the four main wax components (P < 0.01). During storage, these wax components decreased to different extents. Among them, the contents of long-chain fatty acids and long-chain aliphatic primary alcohols showed the biggest and smallest decrease in ‘Gonggan’ mandarin with strong storability, respectively, while the opposite result was observed in ‘Shatangju’ mandarin with poor storability. Small-molecular-mass branched alkanes, alkenes and alkenals were all sensitive to storage temperature, implicating that the storability of the two citrus fruits was closely related to peel wax content and its components.

Key words: ‘Gonggan’ mandarin; ‘Shatangju’ mandarin; storability; storage temperature; peel wax