Starch-based intelligent indicator membranes with triple antioxidant activity for fruit preservation via self-assembled berberine-oligomeric proanthocyanidins nanoparticles encapsulating tea tree oil

A multifunctional starch-based composite membrane was developed by incorporating self-assembled berberine-oligomeric procyanidins nanoparticles (SBO) loaded with tea tree oil (TTO) into a thermoplastic starch (TPS) matrix. Characterization indicated successful SBO formation and TTO loading (up to 62.36 mg/g), which followed a monolayer adsorption mechanism with pseudo-first-order kinetics. The incorporation of SBO@TTO significantly improved tensile strength and gas barrier properties of the membranes. The composite membranes exhibited excellent pH-responsive color changes and enhanced antioxidant and antibacterial activities. TTO release was sustained and diffusion-controlled, and the membranes exhibited satisfactory in vitro cytocompatibility. TPS/4%SBO@TTO membrane effectively reduced weight loss and softening of cherry tomatoes, showing better performance than air storage and comparable performance to a commercial polyethylene membrane. These results demonstrate the strong application potential of TPS/SBO@TTO membranes as active and intelligent food packaging. The direct migration and preservation performances should be further validated under various storage conditions and for different food products.