Butylated hydroxyanisole (BHA)

The self propagation of free radical reactions can be prevented by antioxidants. Some such as α-tocopherols and their congeners and ascorbic acid occur naturally.

The most widely used and highly effective synthetic antioxidants are butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), gallates, and tertiary butyl hydroquinone (TBHQ).

BHA is used as an antioxidant for oils and fats either alone or with a gallate and a synergist, such as citric or phosphoric acid.

Butylated hydroxyanisole

It is a mixture of two isomers: 2-tert-butyl-4-hydroxyanisole (2-BHA) and 3-tert-butyl-4-hydroxyanisole (3-BHA); the commercial compound contains over 90% of the3-isomer.

Butylated hydroxyanisole is prepared by alkylating p-methoxyphenol with isobutylene or tert-butyl alcohol in the presence of phosphoric acid as a catalyst.

It occurs as a white or slightly yellow, waxy solid having a faint characteristic odor. It is insoluble in water but is freely soluble in alcohol and in propylene glycol. It melts between 49° and 63°.

BHA is used in a wide variety of products, including beverages ice cream, candy, baked foods, gelatin, soup bases, potatoes, glazed fruits, potato flakes, dry breakfast cereals, dry yeasts, dry mixes for desserts and beverages, shortening, smoked dry sausages and emulsions as stabilizers for shortenings.
Butylated hydroxyanisole (BHA)

The Effectiveness of Antioxidants

The Effectiveness of Antioxidants
Some antioxidants lose their effectiveness when they combine with oxygen; therefore, there is no advantages to using this type of antioxidant unless the food is enclosed in a system from oxygen or air can be excluded. In the use of antioxidants, it should be kept in mind that other precautions are necessary to minimize oxidation since heat, light, and metals are prooxidants, that is, their presence favors oxidative reactions.

Many of the antioxidants used in commerce occur naturally in foods (e.g., vitamin C, citric acid, amines, and certain phenolics compounds). However, the amines and the phenolics compounds can be toxic to human in low concentrations; therefore, they and the synthetic antioxidants require strict regulations of their use in foods.

It should be pointed that the potency of the naturally occurring antioxidants is not as great as that of the commonly used synthetic antioxidants. The antioxidants that are considered to be the most effective and therefore are most widely used are butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and propylgallate.

These are usually used in formulations that contain combinations of two or all three of them, and often in combination with even fourth component, very often citric acid. The main purpose in adding citric acid is for its action as a chelator.

Fats and shortening, especially those used in bakery goods and fried foods, are subject to oxidation and the development of rancidity after cooking. To prevent this, chemical antioxidants in concentrations up to 0.02% of the fat components may be added.
The Effectiveness of Antioxidants