Which of the following is NOT listed as an example of antioxidants used for oil systems?

• A. Ascorbic palmitate
• B. Butylated hydroxytoluene
• C. Tocopherol
• D. Sodium thiosulfate

Answer: (D)

Antioxidants in oil systems work by interrupting lipid peroxidation, either by scavenging free radicals or by decomposing peroxides, and they need to be soluble in oil to be effective in fats. Ascorbyl palmitate is a fat-soluble form of vitamin C that distributes in oils and helps neutralize lipid radicals. Butylated hydroxytoluene is a common synthetic lipophilic antioxidant used to protect oils and fats from oxidative spoilage. Tocopherol, a vitamin E compound, is naturally lipid-soluble and widely used to shield oil-based products from oxidation. Sodium thiosulfate does not function as an antioxidant in oil systems; it is a water-soluble reducing agent with different applications and poor compatibility with lipid media, so it isn’t used to protect lipids from oxidation.