Chitosan based edible coating reinforced with citrus mandarin cv. terigas essential oil for shelf life extension and green mold prevention in Nagami Kumquats

• Transforming citrus peel waste into a high-value antimicrobial nanoemulsion coating • Combining nanotechnology and natural polymers for post-harvest citrus protection • Offering a chemical-free strategy to control green mold on fresh kumquats • Increasing fruit shelf life while maintaining quality without synthetic preservatives • Demonstrating an environmentally friendly solution for active, biodegradable fruit packaging. Nagami kumquat (Fortunella margarita) fruit is susceptible to post-harvest damage due to P. digitatum infection, which reduces quality and shortens shelf life. This study aims to develop a chitosan-based edible coating enriched with Mandarin cv. Terigas essential oil nanoemulsion to inhibit the growth of P. digitatum and maintain the physical quality of the fruit during storage. Essential oil nanoemulsions were formulated using the ultrasonic homogenisation method with various concentrations. The smallest particle size (13.6 nm) was obtained at 1% concentration, while the 5% concentration exhibited the highest antifungal activity with 45 ± 0.11% growth inhibition against P. digitatum . This formulation was incorporated into chitosan coatings at varying concentrations (0.5–3%). Higher chitosan levels increased the solution viscosity to up to 952 mPas, resulting in a thicker coating layer. Edible coating with 2% chitosan minimized fruit weight loss (29.04% on day 7) and delayed peel discoloration over 14 days of storage at room temperature. FTIR analysis confirmed the presence of intermolecular interactions between the essential oil components and the chitosan functional groups. These findings indicate that the combination of essential oil nanoemulsion and chitosan edible coating is effective in extending the shelf life and maintaining the post-harvest quality of Nagami kumquat fruit and has the potential to be applied in natural and environmentally friendly fruit packaging.