the diamide of azodicarboxylic acid

Azodicarbonamide, the diamide of azodicarboxylic acid, is an orange-red crystalline solid. Industrially, it is produced by the condensation reaction of hydrazine sulfate and urea under high temperature and high pressure, and then oxidized with NaOCl.

Azodicarbonamide has several commercial uses: it is a foaming agent for foaming rubber and plastics, a bleaching (oxidizing) agent in cereal flours, and a dough improver for baked bread.

In the United States, azodicarbonamide has GRAS (Generally Recognized As Safe) food use. The World Health Organization also says it is safe. But European countries and Australia have banned its use in food, and some European countries have used it to make plastics that come into contact with food. Some research suggests that consuming it or its byproducts may cause respiratory problems.

Earlier this year, the fast-food chain Subway, which it calls a "shoe rubber chemical," decided to remove azodicarbonamide from its bread-making process.

In 1959, the use of azodicarbonamide H2N–CO–N=N–CO–NH2 (ADA) for cooking flour was patented. The optimal amount of flour added is 10 to 20 mg per kg of flour. ADA is one of the fastest oxidizing agents used as a dough improver in bread making, reacting within minutes of mixing flour and water (Tsen, 1964). ADA works similarly to iodate, but faster. It reduces the SH content of the dough, thereby converting to biurea (eq. 18.7). The reaction scheme shows that one molar equivalent of ADA is required to oxidize two equivalents of thiol.

Its role in dough is to form a dry dough with a stickiness that can withstand high water absorption. Mixing times are even shorter compared to an equivalent weight of iodate, energy input in dough mixing is reduced, and dough properties are improved by increasing resistance to extensibility. The resulting bread has better loaves in terms of texture and volume, especially when combined with bromate. Overprocessing with the ADA is characterized by a loss of volume and the formation of gray, streaky crumbs as the dough is firm and extensible. This must be counteracted by mixing with other oxidizing agents and enzymes in a commercial amendment mixer.
Posted in Other on August 09 at 02:13 AM

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