View All Molecular Gastronomy Glossary

Surfactant

What is Surfactant?

Surfactants are often used in the creation of food emulsions. These act as binding agents, allowing unlike molecules to adhere to each other. Mayonnaise is a common kitchen emulsion which uses a surfactant. Aside from this, surfactants are also used as wetting agents which aid in the reconstitution of powders such as dried foods.

In the simplest terms, a surfactant is a compound which reduces surface tension within a liquid and lowers interfacial tension between two liquids or between a liquid and solid. This is a surface active substance which may work in several different ways, particularly as an emulsifier, dispersant, wetting agent, foaming agent and detergent.

Most common surfactants are organic compounds that contain a hydrophilic head and hydrophobic tail, making them ampiphilic. Surfactant molecules contain both an insoluble as well as a soluble component. Its hydrophilic head attaches itself to water while the tails simultaneously attaches to oil. The result of this is an alignment which keeps the molecule heads in the water and the tails extended, modifying the surface properties.