Poly(vinyl alcohol)-based multifunctional smart packaging films with carbon dots-loaded metal-organic frameworks for freshness indicator and shelf-life extension of shrimp

This study aims to fabricate poly(vinyl alcohol)-based films (PVA-based films) incorporated with carbon dots- loaded metal-organic frameworks (CD@MOF) for freshness indicator and shelf life extension of shrimp. Incorporation of CD@MOF to PVA-based composite films (PVA/CD@MOF) showed excellent antimicrobial and antioxidant activities with 77.44 % ABTS radical scavenging efficiency. Additionally, the composite films showed a superior UV-barrier of 99.48 % compared to 23.28 % for neat PVA film. The color of PVA/CD@MOF composite films changed from green to blue when exposed to ammonia. In shrimp freshness monitoring tests, the color of PVA/CD@MOF composite films turned brown simultaneously with changes in the chemical parameters of shrimp, providing a visual indication of changes in the quality of stored shrimp. Additionally, PVA/CD@MOF films effectively inhibited weight loss, pH increase, microbial growth, and oxidation of stored shrimp. These results imply that CD@MOF can serve effectively as a dual-purpose active and indicator additive in practical packaging materials.