Construction of a cinnamaldehyde-loaded porous lotus petiole composite within a negative-shaped biomimetic lotus leaf film for Orah mandarin preservation.

This study proposes a novel active packaging film based on a "negative-shape biomimicry" strategy, engineered with a lotus-leaf-inspired microstructure for preserving Orah mandarin. The main spoilage fungi, isolated from deteriorating Orah mandarins, were identified as Aspergillus aculeatus, Penicillium citrinum, and P. oxalicum, which guided the active packaging design. Porous lotus petiole powder, a rich source of coumarins and flavonoids, served as a cinnamaldehyde (Cin) carrier, incorporated into a 2,5-dihydroxybenzoic acid-modified chitosan/pullulan film, with a 'negative-shape' microstructure engineered via lotus leaf templating to enhance hydrophilicity and active component adsorption. Although mechanical strength decreased, thermal stability was significantly improved. Gaussian calculations proposed a mechanism based on physical adsorption, van der Waals forces, and hydrogen bonding between the plant powder and Cin, facilitating sustained release. The resulting film exhibited effective antifungal activity against target pathogens, with molecular docking suggesting inhibition of lanosterol 14α-demethylase as a potential mechanism, and also showed excellent 1,1-diphenyl-2-picrylhydrazyl radical scavenging capacity. Upon application, the packaging significantly reduced decay incidence and weight loss of Orah mandarins during storage (P < 0.05), effectively delayed fruit senescence, maintained overall quality, and suppressed the generation of off-flavor volatile compounds, thereby demonstrating a green, multifunctional, and sustainable approach to postharvest preservation through innovative biomimetic design and the synergistic integration of natural materials.