Sustainable Postharvest Preservation: A Novel Edible Coating from Hydroxypropyl
Methylcellulose, Chitosan, and Beeswax for Mango Fruits

The increased need for sustainable food preservation has fuelled interest in environmentally friendly, "zero-waste" methods for reducing post-harvest losses. This study created and tested three nanoemulsion-based edible coatings, HCB-OPE (orange peel extract), HCB-APE (apple peel extract), and HCB-SPE (spinach extract), which are made of hydroxypropyl methylcellulose, chitosan, and beeswax and enriched with essential oils and polyphenols derived from agro-industrial byproducts. Mangoes were coated and kept at 4 ± 1°C for 13 days. The bioactivity of the coatings was established using physicochemical characterisation (zeta potential, FTIR, XRD, and AFM), and antioxidant and antibacterial testing (against Staphylococcus aureus and Escherichia coli). By day 13, HCB-OPE outperformed other coatings with lower weight loss (6.8% ± 0.06), higher stiffness (3.70 ± 0.04 kg/cm²), decreased decay (20.0% ± 0.9), lower ethylene production (5.10 ± 0.05 µg/g/h), and higher phenolic retention (1.12 ± 0.05 mg GAE/g FW). The barrier qualities of beeswax, HPMC, and chitosan, along with citrus-derived polyphenols (e.g., ferulic acid and hesperidin), with significant antioxidant and antibacterial activity, contribute to HCB-OPE's increased efficacy. Overall, our findings provide a sustainable and scalable technique for prolonging mango shelf life while adhering to circular bioeconomy and zero-waste principles.