Butylated Hydroxyanisole (BHA)

Butylated Hydroxyanisole (BHA), CAS 25013-16-5, is a raw material used as antioxidant in food, cosmetics applications. Supplied by ISF CHEM.

Antioxidant with the structure 2-tert-butyl-4-methoxyphenol. Evaluated by the SCCS within the scope of cosmetics.

BHA is described as an antioxidant with a white, waxy solid structure and a melting point of approximately 48-63 °C. It is soluble in both animal and vegetable fats but insoluble in water. This antioxidant was first approved for use in food in the USA in 1948, and today it is used in solid and liquid edible fats in many countries. In some cases, it is claimed that the tertiary butyl group provides protection to the phenolic hydroxyl (-OH) group. This protects the molecule from external reactions and converts it into a less volatile and more fat-soluble form. Because of the tertiary butyl group located in the ortho or meta position relative to the hydroxyl group, BHA is called a "hindered phenol". It has been suggested that this steric hindrance, in which the tertiary butyl group interferes with the antioxidant activity of the phenolic structure, is why BHA has limited effectiveness in vegetable oils.

Butylated hydroxyanisole (BHA) has the formula C11H16O2 and is commercially available as a mixture of the 3-tert-butyl-4-hydroxyanisole isomer (85%) and the 2-tert-butyl-4-hydroxyanisole isomer (15%).

Although BHA is not an effective antioxidant in vegetable oils, when it is used together with other antioxidants (gallates), it benefits both from the synergistic effect of combining phenolic antioxidants and from its protective effect on the product in which the oil is used. When BHA is used in oils subjected to high-temperature processes such as baking or frying, it produces a sharp phenolic odor that is easily detectable.