pH-responsive PLA/ZIF-8@cinnamaldehyde nanofiber membrane for active food packaging

Foodborne illnesses caused by pathogenic bacteria pose a significant threat to food safety and human health. In this study, a pH-responsive PLA/ZIF-8@CA packaging membrane developed by polylactic acid (PLA) nanofiber as a matrix, where ZIF-8 was loaded via in-situ growth. The membranes were then immersed in CA to produce PLA/ZIF-8@CA nanofiber membrane, effective encapsulation of CA to address issues of volatility of the CA. The deterioration of ZIF-8 in an acidic environment leads to the pH-responsive release of CA from the PLA/ZIF-8@CA nanofiber membrane. The XRD and FT-IR characterization confirmed the successful encapsulation of CA within ZIF-8 and its uniform loading onto the PLA nanofiber matrix. The PLA/ZIF-8@CA nanofiber membrane demonstrated exceptional flexibility, a noteworthy antioxidant activity (radical scavenging rate of 92.05 %), outstanding sustained release performance, and exceptional antibacterial efficacy against Escherichia coli and Staphylococcus aureus (inhibition rates all exceeded 99 %). Furthermore, the PLA/ZIF-8@CA nanofiber membrane exhibited high biological safety, as evidenced by the 100 % survival rate of zebrafish after 15 days. The membrane also exhibited significant soil biodegradability, with complete degradation achieved after 150 days, resulting in a weight loss rate of 100 %. The pH-responsive PLA/ZIF-8@CA nanofiber membrane, which has been demonstrated to exhibit excellent performance, has been utilized as an active packaging in the preservation of broccoli, thereby effectively prolonging its shelf life from 5 to 9 days. The findings underline the potential of this pH-responsive membrane for utilization in active packaging systems for food preservation.