Natural bioactive-loaded deep eutectic solvent-chitosan films as novel antioxidant packaging for color preservation...

Active packaging systems that effectively inhibit oxidation are crucial for maintaining the color fidelity and extending the shelf life of pre-prepared meals. In this study, we developed chitosan-based films plasticized with novel ternary deep eutectic solvents (DES) synthesized from choline chloride, glycerol, and natural bioactive compounds. Comprehensive characterization confirmed the excellent compatibility of the ternary DES within the chitosan matrix, yielding films with smooth, dense morphologies, improved thermal stability, and significantly enhanced mechanical properties-notably, elongation at break increased from 53% to 528%. The films also demonstrated complete biodegradation within 30 days, underscoring their environmental sustainability. Among the formulations evaluated, the film incorporating resveratrol exhibited the most outstanding performance, achieving high antioxidant activity (> 90%) and antibacterial performance (> 97%), high optical transmittance (54.04% at 700 nm), and effective UV-blocking capacity (2.86% at 350 nm). When applied to cooked green peppers, this resveratrol-based film extended color retention by 58.71%. This work establishes ternary DES-plasticized chitosan films as a sustainable and high-performance active packaging material, demonstrating strong potential to replace conventional petroleum-based materials for quality preservation of pre-prepared foods.