Design and characterization of biodegradable curcumin-loaded active agar-based composite film packaging from Gelidium elegans seaweed for extending the shelf life of fish fillets

An agar-based biodegradable film was developed from Gelidium elegans seaweed by integrating curcumin and chitosan into an agar matrix, and its potential as a replacement for petroleum-based food packaging was analyzed. The agar–chitosan–curcumin (AG–CS–CUR) films exhibited significantly higher ( p < 0.05) opacity and notable antioxidant activity, with 2,2-diphenyl-1-picrylhydrazyl and hydroxyl radical scavenging activity score of 68.83% and 60.33%, respectively. The AG–CS–CUR films exhibited good mechanical strength and enhanced barrier properties, with reduced water-vapor and oxygen permeabilities of 2.99 × 10 −10 g/m·s·Pa and 6.62 × 10 −7 g/m·s compared to AG films (3.88 × 10 −10 g/m·s·Pa and 8.48 × 10 −7 g/m·s), respectively. Although the moisture content was not significantly different, the swelling degree decreased markedly to 161.90% from 686.31% of AG, attributed to changes in hydrogen bonding indicated by Fourier-transform infrared peak shifts (3200–3400 cm −1 ) toward lower wavenumbers. Overall migration from AG–CS–CUR occurred at a low rate (