Gelatin-Based Active Edible Film with pH-Sensing for Maintaining and Monitoring Fish Freshness

Thedevelopment of packaging films with food preservationand monitoringfunctions is of great significance and applications. Herein, gelatinwas combined with rosmarinic acid (RosA) and blueberry anthocyaninextract (BAE) to fabricate RosA-gelatin/BAE (RGA) films with pH-responsivenessand long-term antioxidant and antibacterial activities. The filmshave better surface hydrophobicity and antiswelling performance thanthat of pure gelatin film. The films show good ductility and the elongationat break of the films can be easily adjusted in the range of 1.01-292.19%by adjusting the content of BAE. The films can block ultraviolet light,scavenge the ABTS(+) radical, and kill bacteria almost 100%.Significantly, the films showed good pH/NH3 responsivenessas an obvious color change. Comparing with polyethylene film, therewas a reduction of around 60.8% in the release of volatile base nitrogencompounds from crucian in storage using RGA5. Overall, these filmsmay be useful for food preservation and real-time quality monitoring.