β-Lactoglobulin aggregates in foam films: Effect of the concentration and size of the protein aggregates

Single foam films made from mixtures of nonaggregated proteins and protein aggregates have been studied using a thin film balance apparatus. Their features (heterogeneity, stability and resistance to pressure change) are dependent on the aggregate size and on the ratio between nonaggregated proteins and protein aggregates. A phase diagram of these foam films has been drawn and a correlation of the structural properties of foam film and stability of real foams has been found. In particular, the formation of a gel-like network within the foam film coincides with the stability of the corresponding 3-D foams.

Graphical abstractTop view of foam films (bulk concentration 1 g/L) containing 50% protein aggregates for: (a) Rh = 35 nm (b) Rh = 71 nm; (c) Rh = 117 nm and (d) Rh = 197 nm. A pressure ramp is applied (10 Pa per 10 min) and, for all images, the final pressure is 100 Pa.Figure optionsDownload full-size imageDownload high-quality image (82 K)Download as PowerPoint slide