Aquatic polymer-based edible films of fish gelatin crosslinked with alginate dialdehyde having enhanced physicochemical properties

Fish-derived gelatin (FG), a raw material for edible films, has recently been spotlighted as an alternative source of mammalian gelatin. However, its low stability under moisture conditions and weak mechanical properties limit its application. In this study, a water-stable and mechanically robust FG film was prepared using alginate dialdehyde (ADA) as an eco-friendly crosslinking agent. The crosslinking process of FG with ADA was easily recognized by the change in the color of the FG/ADA composite film, and the browning index of the FG/ADA film could be correlated well with the actual crosslinking degree. The mechanical strength and Young's modulus of the FG/ADA composite film increased significantly withxx an increase in the content of the ADA crosslinker. In the case of FG/ADA10, the tensile strength and Young's modulus increased by 400 and 600 %, respectively, compared to those of FG. Remarkably, the FG-ADA crosslinking process greatly decreased the vulnerability of FG in moisture environments. Consequently, the FG/ADA10 film remained stable for 30 days under wet environment. In addition, the FG-ADA crosslinking process could enhance the antioxidative capacity of the FG/ADA edible film. According to this study, FG/ADA composite films fabricated in an effective manner using polymers derived from aquatic species like gelatin from fish and ADA from algae could have practical applications in the edible film-based packaging industry.

Automated summary

In this study, a water-stable and mechanically robust fish-derived gelatin (FG) film was successfully prepared using alginate dialdehyde (ADA) as a crosslinking agent. The mechanical strength and Young's modulus of the FG/ADA composite film significantly increased with an increase in the content of ADA, with FG/ADA10 film showing stability under wet conditions. The crosslinking process with ADA not only improved the mechanical properties but also enhanced the antioxidative capacity of the FG/ADA edible film, suggesting potential practical applications in the edible film-based packaging industry.