An intelligent polybutylene terephthalate adipate (PBAT)-based packaging film incorporating functionalized chitin microcapsules as a freshness indicator for shrimp monitoring

In this study, chitin microcapsules were synthesized via the sol-gel method and subsequently functionalized through the encapsulation of curcumin and alizarin. These microcapsules were then incorporated into a polybutylene terephthalate adipate (PBAT) matrix at varying ratios to fabricate active smart packaging membranes. Microscopic morphology (SEM) analysis revealed that the microcapsules exhibited an ovoid morphology. X-ray diffraction spectroscopy (XRD) and Fourier Transform Infrared Spectrometer (FTIR) analyses showed that curcumin/alizarin does not alter the crystal structure of the microcapsules and that there are hydrogen bonding interactions with the microcapsules. To enhance antimicrobial performance, zinc oxide nanoparticles (5 wt%) were introduced into the composite film. Notably, the composite film with a microencapsulation content of 3 wt% exhibited an inhibition rate of 95.7 % and 98.3 % against E. coli and S. aureus , respectively. Finally, the composite films were assessed for their ability to monitor shrimp freshness. The results indicated that the films not only extended the shelf life of shrimp but also functioned as an effective freshness indicator by signaling spoilage.