Enzymes that catalyze the transfer of hydrogen from a donor molecule to oxygen in an acceptor molecule. Oxidative enzymes (e.g. glucose oxidase) can partially replace the use of chemical oxidants and achieve better bread quality. Enzymes such as oxidases can directly or indirectly improve the strength of the gluten network and so improve the quality of the finished bread.

An oxidase is any enzyme that catalyzes an oxidation/reduction reaction involving molecular oxygen (O2) as the electron acceptor. In these reactions, oxygen is reduced to water (H2O) or hydrogen peroxide (H2O2).