Influence of Composite Edible Coating of Pectin, Glycerol, and Oregano Essential Oil on Postharvest Deterioration of Mango Fruit

To control mango postharvest deterioration, an edible coating based on pectin, glycerol, and oregano essential oil (OEO) was developed using a three-step process involving optimization, validation, and comparison with a commercial fungicide. An extreme vertices mixture design approach was initially used to optimize the pectin, glycerol, and OEO concentrations in the coating formulation. We evaluated the impact of the coating components on the respiration rate, quality parameters, and anthracnose disease of mangoes. The optimal coating composition was 3.91% (w/v) pectin, 0.57% (w/v) glycerol, and 0.52% (w/v) OEO, with a desirability value of 0.8998. Model validation demonstrated that the measured values for all parameters fit the prediction interval of 95%, and the relative error varied between 0.88% and 12.28%. Validation experiments of the optimal coating compared to untreated mango and mango treated with a commercial fungicide showed that the optimal coating delayed ripening and effectively controlled the incidence of anthracnose for 18 days at 14°C and 85% relative humidity.