Adsorptive properties of milk proteins onto novel porous zirconia

Abstract

In this study, porous zirconia (PZ) was synthesised by sol–gel process and evaluated for the adsorption of milk proteins such as β-casein and β-lactoglobulin. The particles manifested an extremely good adsorption affinity for β-casein, with very short adsorption times. In addition, increasing of the adsorption times afforded aggregation of the β-casein-adsorbed particles. Adsorption–desorption experiments, carried out by immersing the PZ in HEPES buffer solution containing 2 M sodium chloride, revealed that only a small amount of adsorbed β-casein was leached from the particles, which suggests that the protein was tightly adsorbed. Taken together, the results obtained suggest that the strong adsorption affinity and specific adsorption behaviour of PZ for the phosphate group render it a promising candidate for the development of phosphoprotein adsorbents.