Nanocomposites of soluble soybean polysaccharides with grape skin anthocyanins and graphene oxide as an efficient halochromic smart packaging

Abstract

In this study, an environmentally-friendly pH-responsive (halochromic) film was introduced based on the composite of soluble soybean polysaccharide (SP), grape skin anthocyanin extract (GE) and graphene oxide (GO) to monitor food freshness/spoilage in terms of smart packaging. GO was firstly synthesized and characterized; then, SP-based film containing 5 wt% GE and the optimum amount of GO (0.5 wt%) was fabricated through the solvent casting method and characterized in terms of physico-mechanical, thermal, microstructural, spectroscopic, release, pH sensitivity and colorimetric properties. Our results revealed that addition of GE into the SP matrix induced pH sensitivity to the film; however, it decreased the mechanical and thermal properties, and increased moisture content (MC) and water vapor permeability (WVP) of the film. The incorporation of GO into the film eliminated the GE-caused weaknesses and improved the mechanical and thermal properties, and also decreased the MC and WVP of the film. Moreover, the SP-GE-GO nanocomposite film represented a distinguishable color variation in response to TVB-N release and pH changes when used as the salmon fish packaging. Generally, the obtained results indicated that the SP-GE-GO film can be considered a promising candidate for halochromic smart food packaging.