Fouling and cleaning of stainless steel surface: Adsorption and desorption behavior of bovine serum albumin and gelatin

Adsorption and desorption behavior of bovine serum albumin (BSA) and gelatin on the surface of stainless steel particles are studied. The amount of BSA adsorbed increases significantly with temperature above 60 degrees C whereas that of gelatin decreases slightly with increasing temperature, Results of adsorption experiments with S-carboxymethylated BSA show that the thermal aggregation of BSA molecules at the surface through intermolecular thiol-disulfide interchange reactions plays an important role in the adsorption of BSA at elevated temperatures. Furthermore, the initial desorption rate constants and residual amounts of the two proteins during caustic and enzymatic cleanings of the fouled particles are compared under various conditions. As a result, a large difference is found in the temperature dependence of the initial desorption rate constant in caustic cleaning, suggesting different modes of adsorption of the proteins.