Surfactants may act as detergents, wetting agents, emulsifiers, foaming agents, and dispersants. A range of different emulsifiers or surfactants are used to emulsify waxes. DAGs can act as surfactants and are commonly used as emulsifiers in processed foods. The lipid core is stabilized by surfactants (emulsifiers). They are thus often used as thickeners, emulsifiers, conditioners, clarifying agents, and even drag reducers. Fatty phosphate esters, emulsifiers, and glycols are also used. Monoglycerides are primarily used as surfactants, usually in the form of emulsifiers. One class of emulsifiers is known as "surface active agents", or surfactants. The products include additional ingredients such as emulsifiers, preservatives, and perfumes. Commercially bottled versions may include emulsifiers such as lecithin. As food additives, tartrates are used as antioxidants, acidity regulators, and emulsifiers. Sorbitan esters are also used as emulsifiers and stabilisers in food. Soy lecithin and polysorbate are two popular emulsifiers used for ice cream production. Many different emulsifiers are used in pharmacy to prepare emulsions such as creams and lotions. The proteins and lecithin in the egg yolk serve as emulsifiers in mayonnaise.