Abstract: This study investigated the regulatory effect of gaseous chlorine dioxide (ClO2) on postharvest ripening of ‘Narcissus’ and ‘Tainong No.1’ mangoes and the cultivar-dependent responses of mangoes to this disinfectant. Mango fruits were treated with 20 mg/L gaseous ClO2, and changes in physicochemical quality attributes and physiological metabolism were systematically evaluated. The results showed that both gaseous ClO2 and ethephon treatments significantly accelerated the ripening process of the two cultivars. With prolonged storage, the pulp gradually turned yellow, accompanied by increases in total carotenoids, total soluble solids, and soluble sugar contents, while fruit firmness, titratable acidity, and starch content decreased in both cultivars. Notably, gaseous ClO2 treatment exerted a more pronounced promotive effect on carotenoid accumulation in ‘Tainong No.1’ mango. Moreover, fruits treated with gaseous ClO2 exhibited higher sweetness compared with those treated with ethephon. Gaseous ClO2 significantly increased the contents of sucrose, fructose, and glucose in both cultivars, with a stronger enhancement of fructose accumulation in ‘Narcissus’ mango and sucrose accumulation in ‘Tainong No.1’ mango. Meanwhile, gaseous ClO2 treatment effectively promoted the accumulation of key aromatic compounds including alcohols, ketones, and terpenes in the two cultivars. It also significantly promoted the accumulation of key ester and aldehyde compounds in ‘Tainong No.1’ mango fruits, thereby enhancing their contribution to the overall aroma. In addition, gaseous ClO2 treatment increased respiratory intensity and ethylene release rate in both cultivars and advanced their peaks by 0.5 days. Compared with ethephon treatment, gaseous ClO2 treatment resulted in lower fresh mass loss in both cultivars, and the residual chlorine dioxide levels in fruits complied with international safety standards. Overall, gaseous ClO2 shows great potential as a postharvest ripening agent for mango. This study provides a theoretical basis for the application of gaseous ClO2-induced ripening strategies considering cultivar-specific responses.

Key words: gaseous chlorine dioxide; ‘Narcissus’ mango; ‘Tainong No.1’ mango; ripening