Concentration of whey proteins by ultrafiltration: Comparative evaluation of process effectiveness based on physicochemical properties of membranes

Abstract

Permeate flux, solute rejection, membrane fouling and permeate flux recovery in ultrafiltration (UF) acid bovine cheese whey was investigated for RC70PP (regenerated cellulose acetate), ETNA10PP (composite fluoro polymer) and GR73PP (polyethersulphone) commercial UF membranes (all 10 kDa nominal pore size). Pore morphology dominantly affected water permeability; active layer porosity affected intrinsic membrane resistance. Membrane roughness was the main factor in irreversible fouling resistance; the high roughness of ETNA10PP increased the rejection of the common whey proteins and lactose. A positive surface free energy of interaction of RC70PP resulted in comparable low fouling propensity regardless of the zeta-potential. The surface charge of two hydrophobic membranes (ETNA10PP and GR73PP) significantly affected fouling resistance. The recovery ratio of initial permeate flux after cleaning was directly related to the membrane hydrophilicity. The RC70PP membrane offered much better efficiency for the concentration of whey proteins due to its high antifouling performance despite its poor selectivity.