Dual system to develop fish gelatin films with improved water resistance properties: enzymatic cross-linking and multilayer lamination.

Fish gelatin is a promising polymer for creating plastics derived from agro-industrial waste, offering a sustainable alternative to single-use plastics. This research aimed to develop fish gelatin films that can be used to replace conventional single-use plastics employed in food packaging. Specifically, our focus was on reducing the high hydrophilic behavior of fish gelatin films which limits their possible applications. To address this, mono-, bi-, and tri- layer films were fabricated from fish gelatin and amylopectin. The fish gelatin was cross-linked with the enzyme transglutaminase to reduce its hydrophilicity achieving two levels of cross-linking: 40 ± 2%, and 65 ± 4%. Micrographs confirmed crack-free films and bilayer/trilayer formation. The cross-linked films exhibited reduced solubility: about 30% in monolayer and 40–67% in bilayer and trilayer films compared to pure protein films. Regarding the water vapor transmission rate, the highly cross-linked trilayer film displayed a value of 0.95 g/m² h which is significantly lower than pure protein films (2.89 g/m² h) and amylopectin films (9.37 g/m² h). Additionally, Young's modulus and the thermal stability were improved with the lamination. These results suggest an effective method for manufacturing films from fish waste, which could contribute to a circular economy for the fishing industry. Enhanced water resistance also makes the films potentially suitable for sustainable biopolymer-based active food packaging. [ABSTRACT FROM AUTHOR]