Water and Glycerol as Plasticizers Affect Mechanical and Water Vapor Barrier Properties of an Edible Wheat Gluten Film

ABSTRACT Glycerol improved film extensibility but reduced film puncture strength, elasticity, and water vapor barrier properties. The plasticizing effect of water was highly temperature dependent. During hydration of gluten film, a sharp decrease in puncture strength, elasticity, and an increase of extensibility and water vapor transmission rate were observed at 5, 30 and 50°C for respective water contents of 30 (0,8 a w ,), 15 (0,7 a w ) and 5% (0,4 a w ). This was related to disruptive water‐polymer hydrogen bonding and glass‐to‐rubber transition.