Stabilizers, thickeners and gelling agents, like agar or pectin (used in jam for example) give foods a firmer texture. While they are not true emulsifiers, they help to stabilize emulsions.
Stabilizer is a chemical which tends to inhibit the reaction between two or more other chemicals. It can be thought of as the antonym to a catalyst. The term can also refer to a chemical that inhibits separation of suspensions, emulsions, and foams.
Stabilizers are usually added to polymers during production. The trend is towards fluid systems, pellets, and increased use of masterbatches. There are monofunctional, bifunctional, and polyfunctional stabilizers.
Some kinds of stabilizers are:
antioxidants, preventing unwanted oxidation of materials.
sequestrants, forming chelate complexes and inactivating traces of metal ions that would otherwise act as catalysts
emulsifiers and surfactants, for stabilization of emulsion
sultraviolet stabilizers, protecting materials, especially plastics, from harmful effects of ultraviolet radiation