FOULING OF MODEL SURFACES - ADSORPTION AND REMOVAL OF KAPPA-CASEIN AND BETA-LACTOGLOBULIN

The surface adsorption behaviour of the dairy proteins kappa-casein A, beta-lactoglobulin A, and mixtures of the two proteins at the open circuit platinum electrode has been investigated by dipping the electrode into separate protein solutions in a phosphate buffer (pH 7.0, 0.33 M ionic strength) thermostatted to temperatures over the range 299-368 K. Cyclic voltammetry was used to measure the charge density due to protein adsorption at the electrode surface after the electrode was transferred to the electrochemical cell containing only the phosphate buffer. The competitive adsorption behaviour of the proteins was also investigated. Protein removal was also studied by measuring the current response during extended potential cycling in the phosphate buffer maintained at 273 K, 299 K and at the temperature of the dip solution. The results obtained suggest a possible treatment for the fouling of surfaces resulting from adsorption of kappa-casein and beta-lactoglobulin.