The characteristics of heat-induced aggregates formed by mixtures of β-lactoglobulin and β-casein

The role of β-casein as a molecular chaperone in modifying the aggregation of β-lactoglobulin was investigated. Using size-exclusion chromatography coupled with a multi-angle laser light scattering detector and dynamic light scattering, it was found that the size of the aggregates formed when β-casein was present was reduced. Transmission electron microscopy images showed that β-casein & β-lactoglobulin mixtures produced smaller globular aggregates, with more uniform size distribution, than β-lactoglobulin alone. The viscosity of the solutions after heat treatment was minimally altered by the presence of β-casein. The surface hydrophobicity of the aggregates formed when β-casein was present did not differ from those formed in β-lactoglobulin. β-Casein was present in all the aggregate fractions in significant quantities, suggesting the formation of mixed β-casein-β-lactoglobulin aggregates with a lower propensity for growth or forming secondary aggregates.