An antibacterial γ-CD-MOF complex functionalized film for fish meat safety and freshness

Abstract

In this study, we developed a functionalized film for packaging refrigerated fish fillets. The functionalized film was produced using a γ-cyclodextrin metal–organic framework (γ-CD-MOF) loaded with gold nanoparticles (γ-CD-MOF complex), with polydimethylsiloxane serving as the substrate. The obtained functionalized film significantly enhanced antioxidant activity, demonstrating a 44% 2,2-diphenyl-1-picrylhydrazyl radical (DPPH˙⁺) scavenging rate and a 58% 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical (ABTS˙⁺) scavenging rate, much higher than those of the pure film. Furthermore, the functionalized film reduced the bacterial counts of Escherichia coli O157:H7 (E. coli O157:H7) by approximately 99.4% and Staphylococcus aureus (S. aureus) by approximately 80% within 24 hours. Moreover, the functionalized film maintained the pH within 6.70 ± 0.02 and the volatile basic nitrogen (TVB-N) value within 8.71 mg/100 g on day 4. It also exhibited a lower total viable count (TVC) value compared to both the control and pure film groups during the first four days, significantly improving the storage safety of refrigerated fish meat. Additionally, the embedded γ-CD-MOF complex affected the tensile strength, water contact angle, and water vapor transmission rate (WVTR) of the functionalized film. In conclusion, this functionalized film increased the shelf life of refrigerated fish fillet samples by inhibiting microbial growth and reducing the oxidation rate, compared to the control sample.