Active edible zein-based films loaded with tea tree essential oil: Physicomechanical, structural, barrier, antimicrobial attributes and food packaging potential

In the context of sustainable development, biodegradable edible films have emerged as potential alternatives to conventional petroleum-based packaging materials. From this perspective, zein which is a class of prolamin protein found exclusively in corn, is generally recognized as safe and displays considerable potential due to its hydrophobicity, biocompatibility, and excellent film-forming properties. The current study investigates the fabrication, characterization, and potential application of zein-based edible films with 0%-2% tea tree essential oil (TEO) to preserve Agaricus bisporus (Button Mushrooms). These films were synthesized using the solvent casting method and evaluated systematically for their physicomechanical, barrier, structural and antimicrobial properties. The added TEO significantly influenced the film properties. The ZF/TEO (2.0%) film showed a significant (p < 0.05) reduction in water vapor permeability (∼35%) and oxygen permeability (∼39%), compared with the ZF/TEO (1.0%) film. Similarly, tensile strength decreased from (11.31 to 9.72 MPa), while elongation at break increased from (12.34% to 13.87%), indicating improved flexibility. Furthermore, antibacterial studies showed no inhibition for films containing up to 1.5% TEO, whereas the 2% TEO film exhibited strong antibacterial activity with inhibition zones of (24.21 ± 0.18 mm) against Escherichia coli and (24.93 ± 1.02 mm) against Bacillus subtilis . When implemented on button mushrooms, delayed spoilage, lower weight loss, and better appearance were observed in packaged samples compared to unpackaged ones during storage. Overall, the results indicate that the fabricated films exhibited concentration-dependent functional improvements, with 2% TEO identified as the better concentration for enhanced antibacterial attributes and shelf-life extension performance.