Water vapour permeability of whey protein emulsion films

A water vapour adsorption experiment was carried out using whey protein films containing a small fraction of fatty acid. This experiment was performed in 3 different configurations. Some film samples were held in a vertical plane, and the other samples were laid on a horizontal plane. Half of these were placed with the external face upward and the other half with the external face downwards. The mass of water adsorbed was weighed for different periods of time until stationary state was reached. Finally, a linear diffusion equation model was used to fit the experimental data and determine the diffusion coefficient for each vertical and horizontal configuration.