Permanent or Stable Emulsions; Emulsifiers

Mayonnaise, which we all know for having seen it in jars bought in the supermarket, is a stable or permanent emulsion, in which the large amount of oil it contains is emulsified in a small amount of liquid which is either vinegar or lemon juice, thanks to the egg yolks which act as an emulsifier. The role of the egg yolks is to keep the oil-and-acid solution in a colloidal dispersion that will not break.

• One of them is water soluble, consequently attracted to water and said to be hydrophilic (meaning loving water).
• The other is soluble in oil; it is repulsed by water, and attracted to oil/fat. It is said to be hydrophobic (meaning disliking water).