| Abstract: | β-Lactoglobulin A and β-lactoglobulin B were heated at 75°C in the absence and presence of α-lactalbumin, and the aggregation products were characterized by size exclusion chromatography in combination with multi-angle laser light scattering and electrophoretic techniques. α-Lactalbumin did not form aggregates when heated alone, but in admixture with β-lactoglobulin it was incorporated into both the disulphide-bonded and the hydrophobically associated aggregates as well as forming α-lactalbumin dimers and other oligomers. The presence of α-lactalbumin diminished the proportion of smaller aggregates and increased the number of very large aggregates within both variant protein mixtures. In the presence of α-lactalbumin, β-lactoglobulin A was converted into a series of disulphide-bonded and the hydrophobically associated aggregates more slowly, but with a greater proportion of hydrophobically associated aggregates, than β-lactoglobulin B. These patterns are similar to that when β-lactoglobulin A or B are heated on their own. These and other results indicate that the mechanism of aggregation of α-lactalbumin/β-lactoglobulin mixtures is governed by β-lactoglobulin. |
