Physical, thermal, and barrier characterization of casein-wax-based edible films

Lactic acid casein-wax-based edible films were prepared to study the effect of carnauba and candelilla waxes. Water and oxygen permeability, thermal properties, and microstructure were determined as a function of relative humidity. Scanning electron microscopy showed a partial phase separation of wax and protein. Water permeability decreased as wax content increased and as relative humidity decreased from 70 to 50%. Despite containing wax, films overall showed low decrease in water permeability. However, films with candelilla wax had lower water permeability values than those with carnauba wax. Films were able to be heat-sealed. There was no difference in oxygen permeability compared to films without wax.