Group: E400–E499 (thickeners, stabilisers, emulsifiers)
Polysorbate 80 is a nonionic surfactant and emulsifier often used in foods and cosmetics. This synthetic compound is a viscous, water-soluble yellow liquid. Polysorbate 80 is used to enable medications to pass through the blood brain barrier.
There some that question it's use as a food additive as when it is consumed in food it may allow toxic chemicals in the body to pass through the blood brain barrier.

Food use
Polysorbate 80 is used as an emulsifier in foods. For example, in ice cream, polysorbate is added up to 0.5 % (v/v) concentration to make the ice cream smoother and easier to handle, as well as increasing its resistance to melting. Adding this substance prevents milk proteins from completely coating the fat droplets. This allows them to join together in chains and nets, which hold air in the mixture, and provide a firmer texture that holds its shape as the ice cream melts.