Conclusion

This study successfully fabricated a CS/N-TiO₂/NT composite film and demonstrated its efficacy in extending the postharvest storage life of S. rugosoannulata. Mechanistically, nitrogen-doped TiO₂ extends photocatalytic antimicrobial activity into the visible spectrum, while natamycin provides targeted fungicidal effects, synergistically reinforced by the film-forming and barrier functions of chitosan. The concerted action of these components substantially enhances the overall preservation efficacy. Furthermore, the preservation efficacy of the coating was highly temperature-dependent. At 25 °C, protection was marginal due to accelerated senescence. At 10 °C, the primary determinant of quality retention shifted from endogenous oxidative enzyme regulation to microbial control, highlighting the dominance of antimicrobial functionality. Optimal preservation occurred at 4 °C, where the coating exerted multi-target effects, suppressing respiration, inhibiting microbial proliferation, and stabilizing SOD-mediated antioxidant defense. Cox proportional hazards model analysis revealed a 33.33–38.46% extension in storage life for coated samples at 4 °C compared to uncoated controls.These findings establish the CS/N-TiO₂/NT composite as an effective, temperature-responsive preservation strategy for perishable mushrooms, providing both a practical solution and a mechanistic framework for the rational design of postharvest interventions under varying storage temperatures.