Potassium bromate

Potassium bromate (KBrO₃) is a typical potassium salt in that it is water-soluble and has a high melting point. The bromate anion is a potent oxidizer.

KBrO₃‘s only significant commercial use is as a “flour improver” in bakeries. According to the Professional Baker’s Reference in the King Arthur Flour Web site, it “strengthens dough and allows for greater oven spring and higher rising in the oven.” The reference states that KBrO₃ is a “slow-acting” oxidizer, which means that it is effective during the mixing, fermentation, and proofing stages of the baking process.

Used properly, KBrO₃ is completely consumed by the end of baking. But because good baking practices may not always be used, its carcinogenicity (see hazard information box), prompted its ban in the early 2000s in the European Union, Canada, China, South Korea, and some South American countries. Its use is still legal in the United States, but California’s Proposition 65 law dictates that bromated flour must be labeled as a carcinogen.