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-degrees-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.