ROLE OF MELATONIN IN MAINTAINING THE FRUIT QUALITY OF EARLY GRAND PEACH DURING STORAGE

Abstract

Postharvest deterioration significantly limits the storage life and market quality of peach fruit, leading to considerable economic losses. This study investigated the effectiveness of exogenous melatonin application in maintaining the postharvest quality and nutritional attributes of ‘Early Grand’ peach fruit during cold storage. Freshly harvested peaches were treated with different concentrations of melatonin (Control, 50, 100, and 150 µM) and stored at low temperature for up to 28 days. The results demonstrated that storage duration was a primary factor driving quality changes, leading to a significant decline in titratable acidity and anthocyanin content, alongside increases in total soluble solids (TSS), pH, sugar-acid ratio, and reducing sugars. Exogenous melatonin treatment effectively modulated these postharvest physiological processes. Treatment with 150 µM melatonin was particularly effective, significantly retaining higher titratable acidity, maintaining lower juice pH, and slowing the rate of TSS and reducing sugar accumulation compared to control fruits, indicating a suppression of respiration and a delay in ripening. Melatonin application also enhanced the retention of anthocyanins. Furthermore, melatonin treatment influenced flavor development, leading to a significantly higher sugar-acid ratio in treated fruits after extended storage, especially at 200 µM. In conclusion, postharvest melatonin treatment, particularly at 150 µM, extends the storage life of peach fruit by slowing senescence, preserving nutritional quality, and maintaining a favorable biochemical balance for longer shelf life.