Interactions of β-Lactoglobulin and κ-Casein after Addition of Low Levels of a Disulphide Reducing Agent

Heating milk at temperatures above 70 °C leads to the exposure of the free thiol group of β-lactoglobulin (β-lg). Free thiol group can then initiate thioldisulphide exchange reactions with other whey proteins or caseins (especially κ-casein, κ-cn) that contain disulphide bonds. The intermolecular aggregation reactions can play a significant role in determining the functional properties of milk. In this study, skim milk was treated with low levels of disulphide reducing agent (β-mercaptoethanol, β-ME) prior to heating. Then the treated milk was made to acid gels. • The functionality of the acid gels were examined using rheology. • The proteins interactions and distributions between the serum and colloidal phase were investigated using electrophoresis