Novel cross-linking of toxic-free biopolymers for cellulose-gelatin films from avocado seed waste

Renewable, low-cost, and environmentally friendly processes have been continuously developed to produce biopolymers for various functional materials. This study aims to develop cellulose-gelatin film as a toxic-free biopolymer. Combining the excellent properties of cellulose and gelatin offers a promising alternative for improving the desirable properties. Herein, avocado seed waste was chemically treated and used as a cellulose-rich filler for gelatin-based film synthesis. Furthermore, different influences were examined with- and without- citric acid addition as a cross-linker agent. The citric acid cross-linked film has cellulose trapped in gelatin matrix structure with a smooth surface, good elasticity, sufficient flexibility, and free-toxic substance. Moreover, this study demonstrated that citric acid cross-linking design successfully improved the percent elongation film from 2.47 to 68.04 %, enhanced the water absorption capacity to 99.71 % at 24 h, and revealed high antibacterial activity, implying potential future application, especially for wound dressing.