Study of mechanical properties, oxygen permeability and AFM topography of zein film plasticized by polyols

Abstract. Zein edible films were plasticized with sorbitol, mannitol or glycerol at <=1 g/g zein and effects of plasticizer addition on mechanical properties, O2 permeability and AFM topography were determined. Zein films containing sorbitol as plasticizer had the highest ultimate tensile strength at low levels of plasticizer addition (<=0.7 g/g), highest values for strain at break at the 1 g/g addition level and lowest O2 permeability values. Films plasticized with glycerol had similar strain at break values to sorbitol films at low plasticizer addition levels as well as smoother surfaces and lower roughness as determined from AFM images. Films containing mannitol had the lowest O2 permeability. No association was found between O2 permeability and film roughness values