A smart bilayer film containing zein/gelatin/carvacrol and polyvinyl alcohol/chitosan/anthocyanin for Lateolabrax japonicus preservation and freshness monitoring

Smart packaging systems with multiple functions have recently received great attentions. In this study, a bilayer film with antibacterial activity and indicating ability was developed by electrospinning method for simultaneously preserving and monitoring Lateolabrax japonicus freshness. The lower layer, serving as the antibacterial layer, was composed of zein (ZN), gelatin (GA) and carvacrol (CA). The upper layer, working as the indicating layer, was composed of chitosan (CS), polyvinyl alcohol (PVA) and blueberry anthocyanins (BBA). It was found that the film had strong antibacterial activity against common foodborne bacteria, suggesting it could prolong the shelf life of fish by 24 h during storage at 4 degree celsius. Meanwhile, the bilayer film was sensitive to NH3, with a LOD value of 0.03357 mu M. It exhibited a red-to-blue color change when was used to monitor the freshness of fish, due to the increasing content of volatile amines of fish.