Smart Dimethylacrylamide/Gelatin–Rosa Hydrogels for Application in Food Packaging Materials

A multifunctional bio-based hydrogel, p(Gelatin-co- N,N-dimethylacrylamide) Cirtic acid-Rosa Extract (p(Gelatin-co-DMAAm)/CA-RE), was developed as a smart food packaging material. Synthesized via redox polymerization of N,N-dimethylacrylamide, gelatin, citric acid, and Rosa extract (RE), the hydrogel formed robust films with enhanced mechanical strength and water resistance through crosslinking with citric acid and MBA. Entrapped RE imparted antioxidant, antimicrobial, and pH-responsive colorimetric properties, enabling real-time monitoring of food freshness. Characterization by Thermo-gravimetric, Fourier transform infrared spectroscopy, Dynamic mechanical analysis and Scanning Electron Microscopy (DMA, TGA, FT-IR, and SEM) confirmed network formation, thermal stability up to 527°C, and molecular interactions between polymer components and RE. The hydrogel exhibited effective antimicrobial activity against Escherichia coli, Bacillus subtilis, and Staphylococcus aureus, while rapid and visible color changes under varying pH highlighted its sensing capability. Application to pasteurized milk and cheese demonstrated simultaneous microbial inhibition and spoilage detection. The combination of mechanical robustness, bioactivity, and intelligent colorimetric response positions p(Gelatin-co-DMAAm)/CA-RE as a sustainable, multifunctional smart packaging platform with potential extensions to biomedical and other functional material applications.