High-Performance Unpurified Food-Grade LBG/k-Carrageenan Antibacterial Films Functionalized with Pomegranate Peel Byproducts

To address the challenges of persistent plastic pollution and food waste reduction, sustainable active packaging systems derived from renewable biopolymers represent alternative to non-renewable petroleum-based fossil plastics. In this context, an active, soil-biodegradable bio-packaging film was engineered via solvent casting from a synergistic binary blend of food grade carob seed flour (E410) and kappa-carrageenan (E407) plasticized with glycerol and functionalized with an aqueous extract from red pomegranate peel, a byproduct of pomegranate processing. The extract, recovered from this agricultural byproduct through ultrasound-assisted water extraction, exhibited rich phenolic, flavonoid, and anthocyanin contents together with strong radical scavenging capacity and broad-spectrum antibacterial activity against foodborne pathogens. When incorporated into the biopolymeric polysaccharide network, these bioactive constituents significantly enhanced tensile strength while maintaining high film flexibility and a hydrophobic surface character. The natural polyphenols were physically integrated into the matrix without disrupting the hydrocolloid framework. The functionalized films demonstrated antibacterial activity against Gram-positive and Gram-negative bacterial strains, good water vapor and gas barrier performance, and complete biodegradation in agricultural soil. Overall, this fully bio-based material demonstrates the technological potential of valorizing agro-industrial byproducts into high-performance active packaging capable of extending the shelf life of perishable food while aligning with circular bioeconomy frameworks.