Fully bio-based, heterogeneous composite hydrogel films for enhancing fruit preservation

The food industry's escalating demand for elevated fruit preservation standards is fostering a gradual transition from traditional petroleum-based packaging materials to fully bio-based alternatives. In this work, a fully bio-based heterogeneous hydrogel film is fabricated for fruit preservation. Uniformly sized chitosan-cinnamaldehyde microspheres (CSNMP) synthesized via microfluidic technology are incorporated into the methacrylated gelatin (GelMA) hydrogel precursor solution. The solution was then coated onto fruit surfaces and then cured to generate composite films (GelMA-CSNMP, viz. GM-CSNMP). The composite film achieves effective antibacterial rate against E. coli (antibacterial rate ≥ 80%), which is approximately 2-fold that of films containing chitosan microspheres alone. Compared with the GelMA film, GM-CSNMP exhibits superior properties. The water contact angle increases by 30°, the antioxidant capacity is enhanced by 3-fold, and the ultraviolet-C transmittance is reduced to 0.5%. The fully bio-based composite film extends the shelf life of treated fruits by approximately 50%, which demonstrates its potential in the field of modern green sustainable packaging.