Effect of Type of Plasticizers on Mechanical and Water Barrier Properties of Transglutaminase Cross-Linked Zein–Oleic Acid Composite Films

Abstract

Abstract The effect of using four plasticizers namely ethylene glycol, propylene glycol, glycerol and sorbitol on mechanical and water barrier properties of transglutaminase cross-linked zein–oleic acid composite films was investigated. Results revealed that both mechanical and water barrier properties of the films were significantly affected (p<0.05) by plasticizer type. Tensile strength (TS), water vapour permeability (WVP) and solubility (SB) values were all better in ethylene glycol control plasticized films compared to other plasticizers. Furthermore, irrespective of plasticizer type, transglutaminase treatment improved TS while when oleic acid was incorporated into the films in the range of 1–4% based on zein weight, the mechanical and water barrier properties of the composite film were diversely affected. Results from scanning electron microscopy for the 2% oleic acid-incorporated composite films revealed a rough and irregular surface morphology for the sorbitol plasticized films. Overall, ethylene glycol provided better mechanical and water barrier properties.