From Wikipedia, the free encyclopedia
Azodicarbonamide, or azobisformamide, is a chemical compound with the molecular formula C2H4O2N4. It is a yellow to orange red, odorless, crystalline powder. As a food additive, it is known by the E number E927.
Use as a food additive
Azodicarbonamide is used as a food additive, a flour bleaching agent and improving agent. It reacts with moist flour as an oxidizing agent. The main reaction product is biurea, a derivative of urea, which is stable during baking. Secondary reaction products include semicarbazide and ethyl carbamate. The United States permits the use of azodicarbonamide at levels up to 45 ppm. In Australia the use of azodicarbonamide as a food additive is banned. In Singapore, use is punishable by up to 15 years in prison and a fine of $450,000.
The principal use of azodicarbonamide is in the production of foamed plastics as an additive. The thermal decomposition of azodicarbonamide results in the evolution of nitrogen, carbon monoxide, carbon dioxide, and ammonia gases, which are trapped in the polymer as bubbles to form a foamed article.
Azodicarbonamide as used in plastics, synthetic leather and other uses can be pure or modified. This is important because modification affects the reaction temperatures. Pure azodicarbonamide generally reacts around 200 °C, but there are some products that the reaction temperature must be lower, depending on the application. In the plastic, leather and other industries, modified azodicarbonamide (average decomposition temperature 170 °C) contains additives that accelerate the reaction or react at lower temperatures.
Azodicarbonamide as a blowing agent in plastics has been banned in Europe since August 2005 for the manufacture of plastic articles that are intended to come into direct contact with food.
In the United States, azodicarbonamide has generally recognized as safe (GRAS) status and is allowed to be added to flour at levels up to 45 ppm.
In the UK, the Health and Safety Executive has identified azodicarbonamide as a respiratory sensitizer (a possible cause of asthma) and determined that products should be labeled with “May cause sensitisation by inhalation.” TheWorld Health Organization has linked azodicarbonamide to “respiratory issues, allergies and asthma.” Britain, Europe, and Australia now ban its use in food.
Toxicological studies of the reactions of azodicarbonamide show that it is rapidly converted in dough to biurea, which is a stable compound not decomposed upon cooking.