physicochemical and mechanical properties of edible film containing kefiran-whey protein

this study prepared new edible composite film by blending kefiran with whey protein. the film-forming solutions used different ratios of kefiran to whey protein (70/30, 50/50, 30/70, 10/90) and were cast at room temperature. the effects of the addition of whey protein on the physical, mechanical and water-vapor permeability (wvp) properties of the film were investigated. it was found that an increase in whey protein content from 0% to 50% (v/v) decreased wvp; however, further addition of whey protein increased wvp. this increase in whey protein content increased the tensile strength and extensibility of the composite film; however, these mechanical properties decreased at higher whey protein contents. electron scanning micrography of the composite film showed it was homogeneous with no sign of phase separation between components. it was observed that these two film-forming components were compatible and that an interaction existed between them.