A Novel Edible Coating of Beeswax Impregnated with Karonda Polyphenol Rich Extract Maintains the Chemical and Bioactive Potential of Fresh Ber Fruit During Storage at Low Temperature

Ber fruit is highly nutritious and rich in bioactive compounds known to have several health benefits. However, the significant loss of such compounds during long-term storage is a concern. Retaining its quality during post-harvest by natural preservatives could be a novel approach towards sustainability. In the present study, a novel composite edible coating of beeswax and polyphenols was developed. Beeswax, a lipid-based material with anti-transpiration properties, was derived from honeycomb and polyphenols with huge antioxidant and antimicrobial properties were extracted from underutilized fruit, karonda. The purpose of the present work is to evaluate the effect of this composite coating on the storage life of ber fruits. For this, beeswax (2%) alone or impregnated with the polyphenols at different concentrations 0.5% (300 mg/L), 1% (600 mg/L) and 1.5% (750 mg/L) was applied on the fruit's surface. The effect of this composite edible coating on the physicochemical properties, bioactive compounds and antioxidant enzymes activities of ber fruits was studied for 28 days during cold storage. The results revealed that the combination of beeswax coating with karonda polyphenols markedly reduced spoilage and maintained the firmness of ber fruit during storage. The coating has resulted in higher retention of ascorbic acid, flavonoids, phenolics and antioxidant activity during storage. The treated fruits showed delayed ripening by slowing down the synthesis of carotenoids as compared to the control fruit. Further, the coating resulted in the lower activities of cell wall degrading enzymes like pectin methyl esterase and cellulase enzymes in the stored ber fruits. Moreover, the concentrations of karonda polyphenols (KPP) have worked in a dose-dependent manner in the coating system, as beeswax with 1.5% KPP was found to be more effective in maintaining the quality and nutritional potential of ber fruit during storage.