Effect of SDS on whey protein polymers. Molecular investigation via dilute solution viscometry and dynamic light scattering

Whey proteins are of special importance in formulated foods due to their rich nutritional and functional benefits. Whey proteins form large polymers when heated to a temperature greater than the denaturation temperature. Hydrophobic interactions play an important role in building whey protein polymers. In this study, the effect of Sodium Dodecyl Sulfate (SDS) on whey protein polymers was assessed. Although SDS was expected to dissociate protein polymers into smaller chains, interestingly, polymer molecules got larger upon SDS addition as revealed by both viscometry and dynamic light scattering. Addition of SDS shifted the molecular size distribution of whey protein polymers to higher size and fragmented the bimodal size distribution into trimodal distribution. The study opens a venue for manipulating and enhancing whey protein functional properties by manipulating the hydrophobic interactions via surfactants.