What is the primary role of antioxidants in emulsions?

• A. They prevent oxidation by scavenging free radicals
• B. They change color
• C. They act as emulsifiers
• D. They catalyze oxidation

Answer: (A)

In emulsions, oxidation happens through free-radical chain reactions, so the main job of antioxidants is to intercept those radicals and stop the chain before lipids break down. They donate hydrogen or electrons to reactive lipid radicals (like peroxyl radicals), forming more stable species and effectively quenching the damaging reactions that lead to rancidity and quality loss. The effectiveness of an antioxidant in an emulsion depends on where oxidation tends to occur and where the antioxidant partitions: lipophilic (oil-soluble) antioxidants protect the oil phase and often accumulate at the oil–water interface, while hydrophilic antioxidants protect the aqueous phase. The antioxidant’s role is not to change color, to act as an emulsifier, or to catalyze oxidation.