Multifunctional bioinspired starch-agar/Co-MOFs films regulated by tannic acid with enhanced ammonia sensitivity and antimicrobial activity for intelligent food packaging.

چکیده اصلی

The development of intelligent and sustainable packaging materials capable of simultaneously monitoring food freshness and inhibiting microbial growth remains a persistent challenge in food science. In this study, a chemically regulated multifunctional colorimetric film was constructed by integrating cobalt-based metal-organic frameworks (Co-MOFs) into a starch/agar matrix, with tannic acid (TA) serving as a dual-functional agent. TA not only reinforced the polymer network through hydrogen bonding and coordination interactions, but also modulated the local coordination environment of Co2+ centers within the Co-MOFs. The optimized film (SA-C3T3) exhibited rapid colorimetric sensitivity toward trace ammonia with a low detection limit of 0.183 ppm, while maintaining good color stability under thermal and light exposure. Density functional theory (DFT) calculations revealed that TA-derived gallic acid moieties enhanced the Lewis acidity and electrostatic polarization of the Co-MOFs, thereby promoting ammonia adsorption. In practical application tests, the film effectively monitored the freshness of shrimp and grass carp, with its color variation closely correlated with total volatile basic nitrogen (TVB-N) values. Furthermore, the film showed significant antibacterial activity against E. coli and S. aureus, along with good cytocompatibility. Notably, the film's hydrothermal reshaping capability endows it with recyclability while maintaining high sensing performance.

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