Potato starch films by incorporating tea polyphenol and MgO nanoparticles with enhanced physical, functional and preserved properties

Due to the massive environmental pollution caused by synthetic plastic packaging accumulation and contemporary necessities of food packaging materials, the biodegradable and multifunctional bionanocomposite films based on potato starch (PS) incorporating tea polyphenol (TP) and MgO nanoparticles (MgO-NPs) were successfully fabricated by the solution casting method, and their physical and functional properties and application in fruits preservation were systematically investigated. Incorporation of TP and MgO-NPs improved the films' tensile strength, UV light-blocking, hydrophobicity and thermal stability, and decreased their moisture content (from 14.02 % to 11.21 %), water solubility (from 19.57 % to 16.56 %), and water vapor permeability (from 17.32 to 9.07 × 10-11 g∙m-1∙s-1∙Pa-1). Moreover, the PS/TP/MgO-NPs films exhibited strong antioxidant activity, and remarkable antibacterial activity against Escherichia coli and Staphylococcus aureus with the diameter of inhibition zone of 25.60 mm and 27.50 mm, respectively. SEM, ATR-FTIR and XRD analyses indicated the TP and MgO-NPs were dispersed homogeneously in the PS matrix, and identified the molecular interactions of hydrogen bond, hydrophobic interaction and electrostatic attraction. Biodegradability assessment showed that all the films were rapidly decomposed within ~20 days under simulated environmental conditions. Compared to control, the PS/TP/MgO-NPs film-forming solution coatings were capable of maintaining fruit quality by reducing the change in weight loss, firmness and total soluble solids. Overall, these results suggested that the multifunctional bionanocomposite films could be a potential approach for developing sustainable active food packaging.