ADSORPTION BEHAVIOR OF β-LACTOGLOBULIN ONTO STAINLESS STEEL SURFACES

Nonporous stainless steel particles with an average diameter of 25.5 μm and an average surface area of 215 cm²/g were used to study the adsorption of β-lactoglobulin (β-lg). Scanning electron microscopy of stainless steel particle surfaces with adsorbed β-lg showed an obvious eradication of crevices as protein was adsorbed. The adsorption process for β-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 was very slow compared to monolayer deposition of β-lg. A monolayer of β-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.