NADES-extracted tea stem polyphenols as multifunctional additives in chitosan films for shrimp preservation

Developing appropriate packaging technologies is crucial for maintaining shrimp quality and reducing potential food safety risks. Meanwhile, concerns over the environmental impact of petroleum-based plastics have accelerated the development of biodegradable packaging from renewable resources. In this study, bioactive chitosan (CS) composite films were developed by incorporating tea stem extract obtained using a choline chloride–glycerol-based natural deep eutectic solvent (NADES). The DES tea stem extract (DTSE) served a dual function as a plasticizer and a bioactive agent. Results showed that DTSE incorporation improved film flexibility (maximum EAB of 173%), enhanced antioxidant capacity (maximum DPPH scavenging rate of 94.8%), and provided moderate UV barrier properties without compromising hydrophobicity. Application of the CS/DTSE composite films in shrimp meat preservation demonstrated significant efficacy: the films effectively maintained shrimp meat appearance, slowed pH increase, reduced weight loss, suppressed lipid oxidation and protein degradation, inhibited microbial growth, and minimized off-odor development, thereby significantly extending shrimp shelf life by 2–3 days. These findings indicate that NADES-extracted tea polyphenols can serve as a sustainable and multifunctional additive, providing an effective strategy for the development of active packaging materials that extend the shelf life of perishable seafood products while valorizing tea stem waste.