Chitosan/gelatin-based multifunctional films integrated with sulfur-functionalized chitin for active packaging applications

Sulfur-functionalized chitin composite (S-chitin) was prepared through sulfur-amine complex formation using ethylenediamine. The S-chitin exhibited excellent antioxidant, antimicrobial, and UV-barrier properties. Chitosan/gelatin (CS/Gel)-based active packaging films containing S-chitin (CS/Gel@S-chitin) were prepared and characterized. The addition of S-chitin enhanced the tensile strength and elongation at the break of the CS/Gel film by 18.4% and 42.2%, respectively, and slightly lowered the transparency of the film but enhanced the UV-blocking with 98.7% UV-A and 100% UV-B light screening. The composite films showed strong antioxidant efficacy with 100% DPPH and 95.9% ABTS radical scavenging potential. The films exhibited effective antimicrobial activity and completely stopped the growth of L. monocytogenes and E. coli after 3 h and 12 h of incubation, respectively. Packaging chicken and storing at 4 °C for 20 days showed that the chicken packaged with the CS/Gel@S-chitin films preserved the quality of the chicken of appearance, pH, TBARS (thiobarbituric acid reactive substance), and TVC (total viable colony count). The multifunctional S-chitin incorporated CS/Gel films have a high potential for active packaging applications.