Milk proteins in caustic solutions: Physico-chemical properties and flocculation by bentonite and polyacrylamide polymers

Milk protein concentrate was dispersed in strong alkaline solution (2% NaOH) and heated at different temperatures to simulate cleaning conditions in dairy plants. Protein partially hydrolyzed and hydrophobic residues were probably destroyed by hydroxides ions. The flocculation kinetics of milk protein dispersion, induced by bentonite and polyacrylamide polymers followed a 4 parameter logistic model. Flocculation rate and efficiency were influenced by the heating temperature of the dispersion. The type of bentonite and polyacrylamide polymers had significant effect on flocculation efficiency and flee volume. Addition of ionic calcium (CaCl2) improved the flocculation process. In controlled conditions, clarification of milk protein dispersion reached 82.0% and required less than 3 min.