Gamma irradiation delays softening and extends postharvest shelf life of ‘Golden’ papaya by modulating cell wall enzymes

Papaya (Carica papaya L.) is a widely consumed tropical fruit but is highly perishable, which limits its storage and export potential. This study evaluated the effects of gamma irradiation (0.8 kGy) applied on the first day postharvest on the postharvest quality of ‘Golden’ papaya, focusing on pulp firmness, mass loss, enzymatic activity of ?-galactosidase, cellulase, and pectin methylesterase, titratable acidity, and soluble sugar content. Irradiated fruit maintained firmness up to four days longer than non-irradiated controls, showing a significant delay in softening. This effect can be attributed to a transient reduction of approximately 30% in the activity of cell wall-degrading enzymes between days 2 and 4 postharvest, with enzyme levels approaching those of the control group only from day 6 onward. Irradiation preserved key physicochemical attributes atthe edible stage without compromising flavor or visual qualities. These data demonstrate that low-dose gamma irradiation is an effective, non-chemical strategy to delay ripening and extend papaya shelf life while maintaining its nutritional and sensoryquality. This approach holds great potential for reducing postharvest losses and improving the fruit’s marketability and export competitiveness.