Preparation and characterization of whey protein isolate/chitosan/microcrystalline cellulose composite films

Abstract A bio‐based composite film was prepared using whey protein isolate (WPI), chitosan (CS) and microcrystalline cellulose (MCC). The effects of film‐forming material concentration ratio, pH value and glycerin addition on the mechanical properties, water vapour permeability and transmittance of the composite film were investigated using response surface methodology. Optimum film‐forming process conditions were obtained, including a CS/MCC concentration ratio of 1.5:1, pH 3.6 and 30% glycerin addition. Scanning electron microscopy and atomic force microscopy images showed that the surface of the WPI/CS/MCC composite films was flat, uniform and smooth. Fourier‐transform infrared spectroscopy analysis indicated that hydrogen bonds occurred between the film‐forming materials. The film‐forming materials were concluded to have good compatibility, while the WPI/CS/MCC composite film showed better mechanical properties and moisture barrier properties, which will provide a good application prospect and foundation for the food packaging industry.