Active Carboxymethylcellulose Edible Coating Incorporating Chitosan Nanoparticles and Microencapsulated Azadirachta indica Extract to Delay Postharvest Deterioration of Strawberries

Strawberries (Fragaria × ananassa Duch.) are highly perishable fruits whose short postharvest life is mainly associated with moisture loss, oxidative stress, and enzymatic degradation of cell wall components. This study aimed to develop and evaluate an active edible coating based on carboxymethylcellulose (CMC), chitosan nanoparticles (CNPs), and microencapsulated aqueous Azadirachta indica leaf extract (MAE) for extending the postharvest quality of strawberries. Whole strawberries were coated with CMC-based formulations containing CNPs and MAE and stored at 15 °C and 75% relative humidity for 15 days. Weight loss, titratable acidity, soluble solids, color change, antioxidant activity, malondialdehyde (MDA), hydrogen peroxide (H2O2), cellulase, and pectin methylesterase (PME) activities were evaluated throughout storage. The application of edible coatings significantly reduced weight loss and color deterioration while improving the retention of titratable acidity and soluble solids compared with the uncoated control. The CMC/CNPs/MAE-EC formulation showed the lowest MDA (0.067 µmol kg−1) and H2O2 (14.23 µmol kg−1) contents at the end of storage, together with the highest antioxidant activity (81.35%). Furthermore, this formulation exhibited lower cellulase and PME activities, indicating a reduction in cell wall degradation and delayed fruit softening. Overall, the incorporation of chitosan nanoparticles and microencapsulated A. indica extract enhanced the protective functionality of the CMC coating, demonstrating its potential as an active approach for maintaining postharvest quality.