Bilayer films comprising chitosan-gelatin blend film loaded with turmeric peel-derived carbon dot and polylactic acid film as active packaging for refrigerated Asian hard clams

Bilayer (BL) active packaging films were fabricated by solvent-casting by depositing chitosan-fish gelatin (CS-FG) blend containing turmeric peel-derived carbon dots (Tu CD ) at 0.75 – 3% (w/w, based on CS-FG), onto a polylactic acid substrate (PLA). This study elucidated the application of novel Tu CD in active food packaging at the first time. The incorporation of Tu CD at 3% (w/w) significantly improved the tensile strength, elongation at break, and water vapor permeability of the films, which rose up to 28.40%, 116.40%, and 16.50%, respectively ( p < 0.05). The 3% Tu CD film exhibited exceptional UV-blocking efficacy (97.47% of UVB and 99% of UVC), and also demonstrated a dose-dependent antioxidant property with a DPPH radical scavenging activity of 58.98 mmol Trolox equivalent/g film. FTIR spectroscopy confirmed new molecular interactions within the film matrix, indicated by a broadened O–H/N–H stretching peak (3275 cm −1 ) and a shifted C=O stretching peak (1640 to 1643 cm −1 ). Those chain interactions contributed to the enhanced mechanical properties of resulting film. SEM images revealed uniform Tu CD dispersion in defect-free matrices. BL pouches were designed with CS-FG containing Tu CD as the food-contact layer and PLA as the outer layer. The 3% Tu CD incorporated pouches showed superior preservation efficacy for Asian hard clam edible portion during 15-day refrigerated storage via lowering the lipid oxidation and microbial load (<6 log CFU/g). The release kinetics followed Fickian diffusion (Korsmeyer-Peppas model), enabling sustained antimicrobial action. These findings demonstrated that Tu CD -containing BL films could effectively extend the shelf-life of seafood through synergistic antioxidant and antimicrobial mechanisms, offering a sustainable alternative to conventional packaging. • Bilayer (BL) films containing turmeric peel carbon dots (Tu CD ) were prepared • Tu CD enhanced the UV-barrier/antioxidant/antibacterial properties of the BL films • Tu CD was released from film following Fickian diffusion, sustaining its activity • Pouch made from Tu CD loaded film retarded microbial and lipid deterioration in clam