Surface Evaluation of Resin Zein Films Containing Sugar Plasticizers by Permeability and Atomic Force Microscopy Analysis

Zein is one of the best biopolymer for edible film making and sugars are naturalplasticizers for biopolyrners. in this research, sugars (fructose, galactose andglucose) at three levels (0.5, 0.7, 1 gig of zein) were used as plasticizers for zeinprotein films and their water vapor permeability (wvp), oxygen permeability (op)and atomic force microscopy (afm) topography were studied. the pure zein filmshad the highe st wvp and adding sugars to 0.7 gig of zein decreased wvp of thefilms. in comparison among different zein films, those plasticized by galactose andfructose had the highest and lowest barrier properties, respectively. the zein filmswithout plasticizer had low op and increasing plasticizers to 0.5 gig of zeindecreased op values in all samples . the films containing galactose and fructose hadthe lowest and highest op, respectively. afm images were used to evaluate surfacetopography (a qualitative parameter) and roughness (a quantitative parameter) ofthe zein films. the films plasticized by fructose had smoother surface and lowerroughness than the other films . interrelation between wvp, op and the roughnessof zein films were not observed.