Sorbitan Monooleate, also known as S- 80 or SMO, is a compound synthesized from sorbitan esterified with oleic acid. Sorbitan Monooleate appears as an amber to brown viscous oily liquid. Sorbitan Monooleate is assigned the E number E494. S- 80's HLB value is 4.3 which indicates its role as a water-in-oil (W/O) emulsifier. S- 80 emulsifier is commonly used in combination with Polysorbate 80.

Sorbitan monooleate S- 80 is a common food additive that is often used as an emulsifier. This means that it helps to bind together ingredients that would normally not mix well, such as oil and water. In addition to its use in food, S- 80 emulsifiers can also be found in a variety of other products, including cosmetics, industrial lubricants, and pharmaceuticals. It is generally considered safe for consumption and has been approved for use by the US Food and Drug Administration.