Development and Characterization of Smart, Biodegradable Gelatin‐Based Films With Graphene Oxide and Anthocyanins for Real‐Time Fish Freshness Monitoring

ABSTRACT This study focused on the development of a multifunctional, biodegradable and intelligent food packaging film based on fish scale–derived gelatin reinforced with bio‐synthesized graphene oxide (GO) and pH‐responsive anthocyanins for real‐time fish freshness monitoring. Gelatin extracted from underutilized fish scales served as the primary biopolymer, while GO synthesized from wood apple shells was incorporated to overcome gelatin's inherent mechanical, thermal and barrier limitations. Anthocyanins isolated from jamun fruit were integrated as natural colourimetric indicators. Structural and physicochemical characterization using FT‐IR, SEM–EDS, UV–Vis, TGA‐DTG and mechanical analyses confirmed effective incorporation and homogeneous dispersion of GO and anthocyanins within the gelatin matrix. The incorporation of GO/anthocyanin increased tensile strength by 75.8% relative to the control film, improved thermal stability, reduced water vapour permeability and enhanced UV‐blocking performance. Soil burial tests demonstrated rapid biodegradation of the nanocomposite films, with GO‐containing formulations exhibiting ~97% weight loss within 7 days. The anthocyanin‐containing film exhibited distinct pH‐dependent colour transitions during fish storage at 25°C, correlating strongly with fish pH (6.9–8.4; R 2 = 0.94) and TVB‐N content (7.2–36.5 mg/100 g; R 2 = 0.97). These findings demonstrate that the developed gelatin/GO/anthocyanin composite films function as mechanically reinforced, rapidly biodegradable packaging materials with reliable real‐time freshness‐sensing capability.