Experimental evidence for a two-step process in the aggregation of beta-lactoglobulin at pH 7

A two-step mechanism for beta-lactoglobulin aggregation at pH7 has been reported in the literature. The first aggregation step is difficult to characterise, as small particles are formed with a strong tendency to further associate in bigger aggregates. Experimental evidence for a two-step aggregation process, using scattering techniques and size exclusion chromatography, is shown here. The effect of the ionic strength, the protein concentration and the heating temperature is discussed. The results show that the first step consists in the formation of small globular aggregates, whose size are only weakly, if at all, influenced by the parameters mentioned above.