Composite Active Packaging Film of Zein, Citric Acid, and FBTE: Fabrication, Property Analysis and Its Preservation Impact on Lard

Advancing bio-based intelligent packaging is crucial for improving food protection and prolonging storage duration. This research fabricated zein/citric acid (Z/CA) hybrid films embedded with Fu brick tea ethanol extract (FBTE) via a casting technique. The films were comprehensively assessed for their physicochemical attributes, mechanical strength, antioxidant and antimicrobial efficacy, and biodegradability. Findings indicated that FBTE inclusion notably improved film hydrophobicity and antioxidative power, elevating DPPH and ABTS radical quenching efficiencies by 83.75% and 89.33%, respectively. However, the incorporation of high-dose FBTE (8 wt%) increased the water vapor permeability by 57.19%, which was unfavorable for moisture barrier performance, and SEM showed surface morphology and phase segregation at 8 wt% FBTE. These hybrid films demonstrated specific antibacterial behavior against Gram-positive microorganisms. Importantly, the 6 wt% FBTE film exhibited obvious inhibitory effects on lipid oxidation, decreasing peroxide value by 68%. Observations during the 28-day soil burial degradation test revealed gradual morphological changes in the film samples. These results illustrate that Z/CA/FBTE hybrid films have possess potential application value in food active packaging.