Effect of SDS on Casein Micelles: SDS-Induced Milk Gel Formation

The addition of sodium dodecyl sulfate (SDS) during skim‐milk reconstitution contributed to a modification of hydrophobic interactions and, consequently, to change in the micellar structure. SDS‐induced modifications in casein micelles were investigated by biochemical measurements (soluble mineral and protein analyses, granulometric and electrokinetic potential measurements, and casein micelle solvation). SDS induced micellar κ‐casein dissociation and caused a decrease in steric, hydration, and electrostatic repulsive forces between casein micelles and as a result altered micellar stability. Consequently, SDS‐modified micelle aggregation occurred. Mineral analysis indicated that Ca, PO43‐ and Mg partitioning between aqueous phase and curd is similar, suggesting a possible bridging mechanism via minerals and SDS molecules.