Adsorption behavior of beta-lactoglobulin onto stainless steel surfaces

Nonporous stainless steel particles with an average diameter of 25.5 mu m and an average surface area of 215 cm(2)/g were used to study the adsorption of beta-lactoglobulin (beta-lg), Scanning electron microscopy of stainless steel particle surfaces with adsorbed beta-lg showed an obvious eradication of crevices as protein was adsorbed. The adsorption process for beta-lg was very rapid in the first 5 min and essentially reached equilibrium within 10 min. Precipitation of calcium phosphate onto the stainless steel surface war very slow compared to monolayer deposition of beta-lg. A monolayer of beta-lg adsorbed very tightly to the stainless steel surface and a significant fraction of the protein was irreversibly adsorbed. The amount of adsorbed protein decreased with increasing ratio of surface area to reaction volume. pH in the range 6.0-6.8 did not significantly affect the amount of adsorbed protein.