An agent that helps insure even dispersion of ingredients in a liquid mixture (an emulsion). In prepared drinks, for example, oils tend to separate out, so starchy emulsifiers are added to bind with the oils and improve miscibility.

A substance which can be used to produce an emulsion out of two liquids that normally cannot be mixed together (such as oil and water). Emulsifiers are common in foods to maintain consistency within puddings, powders, etc.

From the BioTech Dictionary at http://biotech.icmb.utexas.edu/. For further information see the BioTech homenode.