Green and Energy-Efficient Post-Harvest Enhancement: Low-Dose 60Co-γ Irradiation Enhances the Bioactive Profile of Lily Bulbs (Lilium lancifolium Thunb.) as Functional Food Ingredients

Edible lily bulbs (Lilium lancifolium Thunb.) are highly valued for their rich nutritional profile and significant medicinal properties. To further enhance these beneficial attributes, this study investigates a novel, green post-harvest enhancement strategy using low-dose 60Co-γ irradiation (2–5 Gy) followed by immediate freeze-drying. Experimentally, fresh bulbs were exposed to varying irradiation doses, after which physiological parameters (enzyme activities, phytochemical contents) and metabolic profiles (via LC-MS/MS) were systematically evaluated. The results demonstrated that 4 Gy represented the optimal dose; compared to the non-irradiated control group (0 Gy), the 4 Gy treatment significantly enhanced the antioxidant defense system by eliciting oxidative stress responses, increasing superoxide dismutase (SOD) and catalase (CAT) activities by 1.55- to 1.86-fold, and elevating total phenolics and flavonoids by 1.31- and 2.69-fold, respectively. Untargeted metabolomic analysis identified 42 differential metabolites, revealing that 4 Gy irradiation primarily upregulated the phenylpropanoid and flavonoid biosynthetic pathways. Key antioxidants, specifically rosmarinic acid and the newly detected alkaloid jurubine, exhibited significant accumulation. Integrated correlation analysis and molecular docking simulations elucidated the underlying mechanisms, providing theoretical insights into their transient interactions with DPPH radicals. In conclusion, low-dose 60Co-γ irradiation serves as a sustainable, green post-harvest processing strategy to improve the nutritional quality of edible lily bulbs by activating intrinsic metabolic defense mechanisms.