Surface evaluation of whey protein films by atomic force microscopy and water vapour permeability analysis

The atomic force microscopy (AFM) technique is a powerful tool for studying surfaces and has been used to provide qualitative and quantitative information about nanometer-scale matter properties that are often inaccessible by any other experimental technique. In this work AFM was used to evaluate the surfaces of edible films produced with whey protein concentrate (WPC). The morphology and the roughness of the films were analysed. The effects of WPC and plasticizer concentration were characterized in terms of water vapour permeability (WVP) and roughness parameters. Roughness was calculated through the images captured with AFM. AFM can be useful to identify structural changes of the film resulting from sample preparation. The results showed a relation between water vapour permeability and area roughness, through different sample preparation. The analyses of topography through roughness obtained with AFM, demonstrated the correlation between the morphology of the film, obtained with nanometer resolution and WIT. Copyright (C) 2004 John Wiley Sons, Ltd.17526727