ADSORPTION OF BETA-LACTOGLOBULIN ONTO THE SURFACE OF STAINLESS-STEEL PARTICLES

The adsorption of beta-lactoglobulin (beta-Lg), one of the main constituents of fouling deposits in milk processing, onto the surface of stainless steel particles was studied under various conditions, The adsorption isotherm of beta-Lg at 25 degrees C was of the Langmuir type, and the plateau suggested that the surface was covered by a monolayer of beta-Lg, The amount of beta-Lg adsorbed steeply increased above 65 degrees C, At 75 degrees C, it increased almost linearly with the protein concentration in the bulk solution. Heating and chemical modification of the SH-group caused a much smaller amount of beta-Lg to be adsorbed at 75 degrees C, These findings indicate that the thermal aggregation of denatured beta-Lg at the surface is important in the adsorption, More beta-Lg was adsorbed at pH 4 than at pH 6.85, This suggests that the electrostatic interaction between beta-Lg and the surface contributes to the adsorption behavior.