Emulsification is the process of forcing two unmixable liquids to form a seemingly homogenous solution. An emulsion happens when tiny droplets of a certain solution are dispersed throughout another solution, like when mixing oil and vinegar to create a vinaigrette dressing.
For the common emulsification of liquids and other substances an emulsifier is needed. This emulsifier coats the dispersed particles of one solution to keep them from clumping together, preventing the separation of the emulsion. However, micro and nano emulsions do not need emulsifiers as they rely on extremely small droplet sizes to form a stabilized emulsion.
In the food industry, numerous chemical additives encourage the suspension of one liquid in another. For example, the egg yolk in mayonaise keeps an oil-in-water emulsion stabilized while milk proteins in homogenized milk act as an emulsifier in the emulsion of milk fat in water