Functions as an emulsifier (holding water and oils in suspension), in various foods and supplements. Polyethylene sorbitan mono-oleate is derived from the fatty acids from vegetable oil that have undergone "esterification," a chemical process that changes the oil molecule, which keeps other ingredients from separating.

Polyethylene sorbitan mono-oleate (Polysorbate 80) belongs to a general class of emulsifiers called Polyoxyetheylene Sorbitan Fatty Esters or Polysorbates. Other common polysorbates include polysorbate 20 (polyoxyethylene [20] sorbitan monolaurate E432) and polysorbate 65 (polyoxyethylene [20] sorbitan tristearate) E436.

Polysorbates are made by reacting ethylene oxide (a gas) with sorbitan esters (derivatives of sorbitol, another sugar alcohol similar in function to mannitol). Polysorbates are generally used in combination other emulsifiers such as mono- and diglycerides or sorbitan monostearates for various purposes such as to disperse flavours and colours, to make essential oils and vitamins soluble and to improve volume and texture in bakery products.