Chitosan-based melatonin coating effects on apricot postharvest life

Apricot (Prunus armeniaca L.) is a climacteric and perishable fruit prone to rapid postharvest deterioration due to microbial decay, moisture loss, and chilling injury. This study investigated the combined effects of chitosan (CT) and melatonin (MLT) coatings on the postharvest quality of apricot fruits (cv. Roxana) stored at 0- 1 °C for 28 days. Treatments included control, melatonin (1000 µmol l⁻¹), 1% chitosan, and a combined CT+MLT coating. Weight loss, soluble solids content (TSS), titratable acidity (TA), fruit firmness, respiration rate, total phenolic content, antioxidant content, decay rate and internal browning index were measured at 7-day intervals. CT+MLT-treated fruits showed superior retention of firmness, slower increase in TSS, reduced TA loss, and delayed respiration peaks. Furthermore, CT+MLT coating significantly preserved total phenolic content and antioxidants, which declined in control fruits over time. Importantly, CT+MLT and MLT alone effectively inhibited internal browning and decay throughout the storage period, with no incidence observed until the end of storage. These findings suggest that chitosan coating enriched with melatonin provides a synergistic effect in preserving apricot fruit quality during cold storage, by delaying senescence, maintaining bioactive compounds, and minimizing postharvest losses.