In emulsions, what is used to provide stability and prevent separation?

• A. Thickeners
• B. Emulsifiers
• C. Preservatives
• D. Surfactants

Answer: (B)

Emulsifiers provide stability in emulsions by lining up at the oil–water interface, where they lower interfacial tension and form a protective film around droplets. This barrier keeps droplets from merging (coalescing) and helps prevent separation like phase separation or creaming, giving the mixture long-term stability. Thickening agents can make the mixture more viscous to slow separation, but they don’t directly stabilize the droplet interfaces. Preservatives combat microbes and don’t affect physical separation. Surfactants are surface-active and can act as emulsifiers; however, the term emulsifier specifically refers to the ingredient used to stabilize the emulsion, which is why it’s the correct choice.