Characterization of novel anthocyanins film @ carbon quantum dot nanofiber intelligent active double-layer film, physicochemical properties and fresh-keeping monitoring in Ictalurus punctatus fish

Anthocyanins and carbon quantum dots (CQDs) were produced from highland barley bran to lower the waste of the cereal. This study successfully prepared a polyvinyl alcohol/soy protein isolate/anthocyanin@ polyvinyl alcohol/chitosan quaternary ammonium salt/CQDs nanofiber smart double-layer film (PSA@PHC). We explored the functions of anthocyanin film (PSA) and CQDs nanofiber film (PHC) as the inner and outer layers through structural characterization and property determination. The results showed that as the CQDs in nanofiber film rose, the diameter of the nanofibers expanded by 42.82 ± 9.37 nm, the free radical scavenging ability of DPPH and ABTS was 77.95 ± 2.53 % and 93.15 ± 0.70 %, respectively. When exposed to a xenon lamp, the bilayer film's CQDs generated reactive oxygen species, enhancing the inhibition of S. aureus and E. coli by 67.70 ± 0.54 % and 29.90 ± 1.87 %, respectively. The potential applications for PSA@PHC smart active double-layer film in food packaging were highly promising due to its outstanding properties. In terms of its application to the preservation and freshness monitoring of Ictalurus punctatus fish, the double layer film could extend the shelf life for 2 d and enable effective monitoring.