Emulsifier

A substance that stabilises an emulsion — a mixture of two immiscible liquids (typically water and oil). Emulsifiers contain both hydrophilic (water-loving) and hydrophobic (oil-loving) regions, allowing them to sit at the interface between oil and water droplets and prevent separation. Common food emulsifiers include lecithin (INS 322), mono- and diglycerides (INS 471), and certain modified starches.