The antigenic response of β-lactoglobulin is modulated by thermally induced aggregation

The antigenic response of thermally denatured and aggregated beta-lactoglobulin was determined by an indirect competitive enzyme-linked immunosorbent assay using polyclonal antibodies from the egg yolk of chicken immunized with heat-denatured beta-lactoglobulin as a measure for the potential antigenicity/allergenicity. The heat denaturation and the aggregation of heated whey protein isolate solutions were followed by reversed-phase high-performance liquid chromatography and photon correlation spectroscopy. Thermally modified whey proteins showed a remarkable increase of antigenicity when heated to 90degreesC, possibly as a consequence of the exposure or formerly hidden epitopes. Above 90degreesC, the antigenic response decreased owing to the loss of conformational epitopes and masking of sequential epitopes in the course of aggregation to particles. When large and compact particles were formed, the antigenicity was reduced remarkably. Depending the heating conditions applied, the structure and the size of whey protein particles and thus the potential allergenicity may be modulated in a wide range.