Development and characterization of PH-sensitive, bio-nanocomposite film based on sodium alginate/carrageenan blend incorporated with silver nanoparticle and vitis vinifera peel extract.

This study presents the development and characterisation of a biodegradable, pH-sensitive active-intelligent food packaging film using anthocyanin extract derived from Vitis vinifera (grape) peels incorporating silver nanoparticles. The natural anthocyanins were extracted using methanol and filtered. Silver nanoparticles were obtained by reducing AgNO3 (Ag+) with tannic acid to Ag0. These were incorporated at varying concentrations (10%ext, 20%ext, 10%AgNP, 20%AgNP) into a K-carrageenan/sodium alginate (KC/SA) biopolymer matrix to form films via solution casting. Comprehensive physicochemical characterization revealed decreased moisture content, water solubility, and water vapor transmission rate (WVTR), thereby improving the films' barrier properties. Antioxidant assays (DPPH and ABTS) confirmed the strong radical scavenging activity of the films, particularly at higher AgNP’s concentrations. FTIR analysis indicated interactions between anthocyanins/AgNP’s and the polymer (KC/SA) matrix, while UV-Vis spectroscopy and pH buffer tests demonstrated vivid color transitions in response to pH changes, confirming their suitability for active-intelligent packaging applications. Application testing on poultry meat showed distinct color changes to yellow as spoilage progressed, effectively signalling freshness loss due to rising pH levels. These results underscore the potential of Vitis vinifera anthocyanin-incorporated with silver nanoparticle films as sustainable, functional packaging materials for real-time freshness monitoring.