Development of chitosan coating product containing bitter gourd extract to delay anthracnose disease in mango

Mangifera indica cv. ‘Nam Dok Mai’ is the most popular fruit in Asia and worldwide, but it often faces anthracnose disease both in the vegetative stage (on leaves) and the reproductive stage (on fruit). The symptoms of this disease affect low yield and limit export; therefore, the effect of coating to reduce the incidence of anthracnose disease in mango fruits is necessary. This research aimed to develop an edible chitosan coating containing bitter gourd extract. Mango fruits were coated with 0.5, 1.0 and 2.0% chitosan solution (70-75% deacetylation; 310-375 kDa) and appropriate 500 ppm bitter gourd extract. The results showed that the chitosan coating with bitter gourd extract extended the shelf life of mango fruits and decreased the incidence of disease more effectively than coatings with chitosan or bitter gourd extract alone. Further, it could also delay ripening. Disease incidence and lesion diameter on mangoes coated with 2% chitosan with bitter gourd extract were the most effective (P < 0.05) within 5, 7 and 10 days after storage. Weight loss in mangoes increases during ripening; however, chitosan coating can help reduce weight loss. Fruits coated with 1% chitosan were the best formula for reducing weight loss. Chitosan coating adding bitter gourd extract is the best choice to replace chemical treatment to obtain better quality before export or transportation.