Exogenous methyl jasmonate delays quality loss and maintains bioactive compounds in quince during long-term storage

Quince (Cydonia oblonga Mill.) is a climacteric fruit species that, despite its high nutritional value and rich phenolic composition, is prone to quality changes during postharvest handling. However, under appropriate storage conditions it can be maintained at acceptable quality for several months. This study aimed to assess the effects of exogenous methyl jasmonate (MeJA) treatments on quality attributes, and phenolic metabolism of quince fruit during cold storage. Fruits were treated with 0 (control), 0.5, and 1.0 mM MeJA and stored at 0 ± 1 °C with 90 ± 5% relative humidity for 120 days. Analyses were conducted at 30-day intervals, including physiological, phytochemical, and antioxidant activity, as well as individual phenolic compounds. During cold storage, fruits treated with 1.0 mM methyl jasmonate (MeJA) exhibited lower weight loss and respiration rate. Higher fruit firmness was also observed in MeJA-treated fruits. At the end of storage, MeJA-treated fruits showed higher vitamin C content and titratable acidity, but lower soluble solids content than the control fruits. Similarly, at 60 and 90 days of storage, fruits treated with 1.0 mM MeJA were found to contain higher levels of total phenolics, total flavonoids, and antioxidant activity. Among the phenolic acids identified in quince fruit, chlorogenic acid and 4-aminobenzoic acid were present at higher concentrations compared to the other phenolic compounds. At the end of the storage, MeJA-treated fruits generally exhibited a slower decline in phenolic acids compared to the control, indicating a protective effect of the treatment on phenolic stability. As a result, methyl jasmonate applications were identified as an effective strategy for reducing post-harvest quality losses and preserving bioactive compounds in quince fruit. Specifically, the 1.0 mM MeJA application showed the strongest protective effect on quality parameters. These findings indicate that MeJA is a commercially viable method for extending shelf life and preserving quality in quince fruit.