Riboflavin alleviates senescence and maintains quality in fresh-cut pomegranate arils by improving antioxidant systems and energy homeostasis during cold storage

Fresh-cut pomegranate arils are highly susceptible to microbial decay, oxidative injury and rapid quality deterioration during cold storage, creating a need for safe and sustainable preservation strategies. Riboflavin, a natural vitamin involved in redox regulation and flavin-dependent energy metabolism, was evaluated as a postharvest treatment for maintaining fresh-cut aril quality. Fresh-cut pomegranate arils were immersed in riboflavin solutions at 0, 40, 80, and 120 μM and stored at 5°C and 90% relative humidity for 20 d. Among the tested concentrations, 80 μM riboflavin showed the most consistent preservation effect and was selected for further analysis. Riboflavin treatment reduced decay incidence, bacterial counts, respiration rate, weight loss, and firmness decline. It also alleviated membrane deterioration, as indicated by lower electrolyte leakage and reduced accumulation of hydrogen peroxide, superoxide radicals and malondialdehyde. These protective effects were associated with enhanced enzymatic and non-enzymatic antioxidant defenses, including higher activities of superoxide dismutase, catalase, ascorbate peroxidase, and glutathione reductase, together with increased levels of phenolics, anthocyanins, ascorbate, and glutathione. Additionally, riboflavin maintained higher ATP and ADP levels, suppressed AMP accumulation, and preserved energy charge by sustaining energy metabolism-related enzyme activities. Consistently, genes involved in antioxidant defense, energy metabolism and phenolic metabolism were differentially regulated, with PgPAL upregulated and PgPPO suppressed. Overall, riboflavin delayed senescence of fresh-cut pomegranate arils by coordinating redox balance, energy homeostasis and phenolic metabolism, suggesting its potential as a safe and sustainable postharvest treatment for maintaining the quality of fresh-cut fruit during cold storage.