Single foam films made from aqueous protein solutions containing aggregates have been Studied using a thin film balance apparatus. When the solutions are free from non-aggregated proteins, the films are either fluid or gelified, depending on the aggregate size. When non-aggregated proteins are present, they adsorb at the film surfaces, acting as anchors for the aggregates, and ultimately leading to stable foam films if the amount of non-aggregated proteins is sufficient. In all cases, gel-like films are more stable than fluid films and there is a good correlation between foam and film stability. (C) 2009 Elsevier Inc. All rights reserved.