Loading esculin can improve the morphology and antibacterial properties of chitosan/whey protein isolate composite film

In this study, chitosan (CTS), whey protein isolate (WPI) and glycerol were used as biodegradable film-forming matrices to prepare composite films by solution blending. Esculin (ES) as antibacterial active compound, was added during the film modification process. CTS, CTS/WPI (C/W) and CTS/WPI/ES (C/W/ES) films were compared in terms of structure, physical properties and functions. Due to the effect of ES, C/W/ES film has good mechanical properties, barrier properties, and biodegradability. Compared with C/W film, the tensile strength, elongation at break, antioxidant activity, and biodegradability of C/W/ES film increased by 36.4%, 9.6%, 37.0%, and 33.65%, respectively. Its antibacterial activity against <i>Escherichia coli</i> and <i>Staphylococcus aureus</i> was significantly enhanced. The cherry tomato preservation test showed that C/W/ES film had a good effect on weight loss rate and decay rate of the fruits. In summary, loading ES can improve the morphology and antibacterial properties of the biodegradable composite film.