Development and Characterization of Chitosan–PVA–Tannic Acid Film for Extended Shelf Life and Safety of Food Products

The growing demand for sustainable food packaging has led to the development of biobased and biodegradable materials that minimize the environmental impact of conventional plastics. This study introduces an eco-friendly thin film incorporating tannic acid (TA) into a chitosan-poly-(vinyl alcohol) (CPT) matrix to preserve fresh garlic. The film, produced through solvent casting, was thoroughly characterized using several analytical techniques. Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) confirmed strong molecular interactions and increased crystallinity, which enhanced the material's compatibility and structural integrity. Atomic force microscopy (AFM) revealed a surface roughness of 0.167 nm, and thermogravimetric analysis (TGA) demonstrated thermal stability up to 463°C. The CPT film exhibited notable antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa, and Aspergillus niger. Packaging trials showed that the film effectively extended garlic freshness for 24 days. These findings suggest that the CPT film offers a promising solution for sustainable packaging by combining active food preservation with real-time quality monitoring.