Effect of tannic acid as crosslinking agent on fish skin gelatin-silver nanocomposite film

Abstract Gelatin was obtained from the Nile tilapia skin and used to prepare and stabilize silver nanoparticles (AgNPs) at a pH of 11.0. The properties gelatin-AgNP and gelatin-AgNP films with tannic acid (TA) were evaluated. TA is a non-toxic cross-linker agent and was add to enhance the mechanical properties of the gelatin-AgNPs nanocomposite. The films were studied by UV–vis and infrared (FT-IR) spectroscopy, thermal gravimetric analysis (TGA), mechanical analysis (tensile strength and elongation at break), water vapor permeability, solubility, scanning electron microscopy and antimicrobial activities (tested against two pathogens: S. aureus (gram-positive) and E. coli (gram-negative)). The gelatin films containing 5.0 wt% of TA, 0.2 wt% of AgNPs and 20 wt% of glycerol exhibited high mechanical strength, low water barrier, and antimicrobial activity against both pathogens. The presence of TA in gelatin-AgNPs nanocomposite was essential to promote these properties. Therefore, films with TA presented greater possibility to be used as food packaging.