INTERACTIONS BETWEEN MILK-PROTEINS AND LIPIDS - A MOBILITY STUDY

The interactions between the main milk proteins (whey proteins and caseins) and nitroxide homologs of fatty acids, either dispersed in a solution or included in oil droplets, were studied using Electron Spin Resonance. The affinity of the proteins for the fatty acids increased in the order: alpha-lactalbumin < alpha-S-1, beta and whole casein < beta-lactoglobulin and whey proteins. It appeared that the interactions between milk proteins and lipids occured through their polar groups. Chemical and biochemical modifications of the amino residues of the proteins confirmed the contribution of these residues to the interaction. No evidence of any significant modification of the conformation of the proteins or of the organization of the lipid monolayer at the interface between water and the oil droplets was observed.