Studies on the effect of glucose oxidase in bread making

Abstract

AbstractTo obtain insight into the dough improver effect of glucose oxidase (β‐D‐glucose:oxygen 1‐oxidoreductase, EC 1.1.3.4) different possible reaction sites of hydrogen peroxide, which is a product of reactions catalysed by glucose oxidase, were analysed and compared to the effects of other additives. A technical enzyme preparation as well as the pure enzyme were studied. Neither oxidation of tyrosine residues to dityrosine nor oxidation of thiols was promoted by glucose oxidase. The effects caused by the enzyme were intensified when it was applied in combination with its substrate, glucose. After the addition of the enzyme and glucose the effects were comparable to the addition of hydrogen peroxide alone. For the technical enzyme the decrease of monomeric ferulate was much stronger as compared to hydrogen peroxide. Therefore, in a model experiment, the activity of the technical enzyme was determined, which was as high as 0.01 U mg−1 (1 U corresponds to a ferulic acid consumption of 1 µmol min−1). This activity was not present in the pure enzyme. From these results it was assumed that side activities present in technical glucose oxidase preparations have a substantial impact on their improver effect in breadmaking. Copyright © 2006 Society of Chemical Industry