Development of novel Co-MOF loaded sodium alginate based packaging films with antimicrobial and ammonia-sensitive functions for shrimp freshness monitoring

It is highly desirable to develop intelligent active packaging films with ammonia-sensitive performance to maintain and monitor the freshness of meat food as the ever-increasing requirement for food safe. Herein, novel cobalt-based metal-organic framework (Co-MOF) nanoparticles with ammonia-sensitive and antibacterial func-tions were successfully synthesized and then introduced into sodium alginate (SA) matrix to fabricate SA-based intelligent active packaging films by solution casting method. The effects of Co-MOF introduction on the structure, physical and functional features of the SA film were systemically studied. The results revealed that the Co-MOF nanofillers were uniformly distributed in the SA matrix, leading to obvious enhancements on tensile strength, toughness, thermal stability, UV-shielding and water vapor barrier capability of SA film. Moreover, the resultant SA/Co-MOF composite films showed outstanding antibacterial activity and ammonia-sensitive discol-oration performance. When applied to monitor shrimp spoilage, the color of SA/Co-MOF composite films turned from pale pink to brownish black. These results suggested that the developed SA/Co-MOF films could be utilized as active and intelligent food packaging materials.

Automated summary

This study successfully developed intelligent active packaging films containing novel cobalt-based metal-organic framework (Co-MOF) nanoparticles with ammonia-sensitive and antibacterial functions to maintain and monitor the freshness of meat food. The results showed that the films exhibited excellent physical and functional properties and could sense and change color in response to ammonia, allowing for monitoring of food spoilage.