Novel intelligent packaging films based on starch/PVA with Cu-ICA nanocrystal as functional compatibilizer for monitoring food freshness.

Considering public health and environmental safety, the development of reliable and efficient monitoring methods is essential to ensure food quality and safety. Herein, a new Cu-based metal organic framework (Cu-ICA) nanocrystal with ammonia-sensitive performance was built up and then introduced as a functional compatibilizer of starch/polyvinyl alcohol (STA/PVA) blend to develop high-performance intelligent packaging films for food freshness monitoring. The introduction of Cu-ICA upgraded the compatibility, mechanical strength (42.9 MPa), UV-protection (with UV transmittance of only 2.8 %), and moisture/oxygen barrier performances of STA/PVA film. Furthermore, the developed STA/PVA/Cu-ICA films presented long-term colour stability, outstanding antibacterial efficacy (over 99.5 %) toward both Escherichia coli and Staphylococcus aureus bacteria, as well as remarkable ammonia-sensitive discoloration capability. The STA/PVA/Cu-ICA films possessed visually identifiable colour change during the monitoring of shrimp spoilage. These findings indicate that the developed STA/PVA/Cu-ICA film possesses tremendous potential as an intelligent active packaging material.