The ethylene permeability of a wheat gluten film was studied as a function of relative humidity (RH) (from 0 to 100%) and temperature (from 3 to 45 degrees C), using response-surface methodology. Ethylene permeability values ranged in a wide scale from 1 to 3098 arnol m(-1) s(-1) Pa-1. The exponential effect of relative humidity on ethylene permeability was related to the boosting effect of increasing film water content on ethylene solubility and diffusivity in the hydrated film. The temperature dependency of the ethylene permeability data showed a strong disruption near the glass transition temperature value (25 degrees C at 75% RH). The glass transition phenomenon and its effect on chain mobility could explain the interesting synergic effect of both temperature and relative humidity on ethylene permeability of wheat gluten film. (c) 2005 Elsevier B.V. All rights reserved.