Development of Multifunctional and Sustainable Starch/Polyvinyl Alcohol-Polyethylene Glycol Copolymer Films Reinforced with Green Tea Extract for Food Packaging

Abstract

This study explores a sustainable alternative to conventional plastic packaging by developing biodegradable films from starch and polyvinyl alcohol-polyethylene glycol (PVA-PEG) copolymer and green tea extract (TE) as functional additive. The incorporation of TE at 0.5 % w/v demonstrated to significantly enhance tensile strength (4.7 ± 0.3 MPa) and water contact angle (70.7 ± 0.3°) in comparison to blank STKB film. The developed films also demonstrated significant improvement in barrier attributes of the film including, UV-shielding (100%), water vapour and oxygen transmission. Further, the films were analysed via several techniques, including Scanning Electron Microscopy (SEM), 3D optical profilometry, Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD) and Thermogravimetric Analysis (TGA). The results demonstrated that incorporating TE improved the structure, intermolecular interactions and thermal stability of the film. The DPPH assay and cytocompatibility (95 %) in L929 fibroblast confirmed the strong antioxidant and biocompatibility of the developed film. The incorporation of TE enhanced the antibacterial potential of the films, with significant inhibition of Escherichia coli and Staphylococcus aureus bacteria. The preservation application of developed films on fresh cut apple cubes demonstrated reduced browning index, weight loss and pH indicated better preservation compared to the blank film. Finally, the biodegradability of the film was assessed by soil burial tests demonstrated biodegradation (99.35 ± 0.64) within 10 days. These results highlight the potential of ST/PVA-PEG/TE films as eco-friendly, functional packaging materials to improve food shelf life while ensuring safety and sustainability.