An emulsion is a macroscopic dispersion of two liquids, one of which forms the continuous part of the system (Friberg, 1976). Proteins as emulsifiers form a thick film (skin) around the surface of emulsified droplets. Such a film is usually of anisotropic character and its viscoelastic properties mainly determine the extent of emulsion stability against coalescence. The emulsion stability of food systems is, in general, a function of oil volume fraction, oil type, temperature, pH, type and amount of emulsifier(s), and the presence of counter ions and legends (e.g. salts, sugars, and carbohydrates).