ABSTRACT
This chapter presents a general discussion on emulsion stability and the molecular properties of proteins affecting their emulsifying properties. It examines the mechanism of adsorption and formation of protein films at interfaces followed by analyses of the molecular factors affecting the stability of protein-stabilized foams and emulsions. Foods are multiphasic and multicomponent systems composed of proteins, polysaccharides, fats, water, and other minor nutrients and additives. Depending on their relative concentrations and solubility limits and limited thermodynamic compatibility in this complex milieu, the lipids and macromolecules generally exist as colloidally dispersed particles and aggregates. The physical principles governing the formation and stability of food colloids, e.g., foams and emulsions, are complex, especially if protein macromolecules are involved as surfactants. The most critical requirement for the formation of foams and emulsions during whipping or homogenization is rapid reduction of the free energy of the newly created interface.
