Abstract: Purified calcium based bentonite from Ningming, Guangxi autonomous region was used as coating material to keep mango fresh in light of its good water absorption capacity, bondability, adsorption capacity, stability, small mineral particles and high surface area. After diluted with water at liquid-to-solid ratio of 15:1, the bentonite was coated on the surface of mango fruits. Coated mango fruits were stored at ambient temperature and measured for their skin yellowing index, decay index, weight loss rate, firmness, respiration rate and total sugar, vitamin C and total acid contents. The results showed calcium based bentonite coating significantly decreased the skin yellowing, decay incidence and weight loss rate of mango fruits and alleviated the decrease of firmness and vitamin C content. Meanwhile, the occurrence of the respiration peak was inhibited, the accumulation of sugars and degradation of acids were retarded, thereby delaying the post-harvest ripening of mango fruits. After 2 weeks of storage, the weight loss rate, decay index, yellowing index of the treatment group were decreased by 43.7%, 51.7% and 42.1% and the firmness, total acid content, VC content were increased by 53.7%, 166.7% and 66.7% respectively, compared with the control group. In addition, neither respiration nor total sugar peaks were observed for the treated group.

Key words: calcium based bentonite, coating, mango, fresh-keeping