Soy protein isolate/corn-zein laminated films: Transport and mechanical properties

Soy protein films were thermally laminated with either single or double coats of corn-zein. Microstructural characterization of the surfaces and cross-sections reveals a ductile protein matrix of the soy component, but a brittle layered structure for the corn-zein component. The hydrophobic nature of the corn-zein improved the water vapor barrier properties of the laminates, while the superior oxygen barrier characteristics remained unaffected, as compared with the base soy film. The haze values of the laminates increased without much change in total light transmission. Tensile properties supported observations from microscopy, in that tensile properties indicated ductile behavior of the soy films, but a brittle behavior for the double-coat laminates.