tert-Butylhydroquinone (TBHQ, tertiary butylhydroquinone) is an aromatic organic compound which is a type of phenol. It is a derivative of hydroquinone, substituted with a tert-butyl group.

chemical formula : C₁₀H₁₄O₂

TBHQ is a highly effective antioxidant. In foods, it is used as a preservative for unsaturated vegetable oils and many edible animal fats. It does not cause discoloration even in the presence of iron, and does not change flavor or odor of the material to which it is added. It can be combined with other preservatives such as butylated hydroxyanisole (BHA).

As a food additive, its E number is E319. It is added to a wide range of foods, with the highest limit (1 gram/kg) permitted for frozen fish and fish products. Its primary advantage is extending storage life.

The FDA sets an upper limit of 0.02% of the oil or fat content in foods. At very high doses, it has some negative health effects.

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