Glucose Oxidases

Glucose oxidase (GOX, EC; see Chapter 30 for detailed information) catalyzes the conversion of glucose into the mild-tasting gluconic acid via glucono-<5-lactone and hydrogen peroxide. GOX complies with the FAO/WHO and GRAS requirements for food grade enzymes and is one of the few commercially available oxidases from Aspergillus niger and Penicillium strains at relatively low costs. Especially, the generation of hydrogen peroxide is believed to give the antiweakening effect in bread doughs (40). In a recent study by Hilhorst et al. (49) the effect of GOX on Dutch rusk dough was dough stiffening with a clear loss in extensibility. This made the overall effect quite undesirable. For comparison, they also tested peroxidase (see Sec. III.C above). This enzyme gave a dough-stiffening effect without loss in extensibility. The authors explain the difference by the fact that hydrogen peroxide from the GOX-catalyzed reaction oxidizes randomly and links the gluten network with the arabinoxylan network, whereas the peroxidase only increases the amount of crosslinks in the arabinoxylan fraction without affecting the gluten network or the coupling between the networks.

It has been found that synergistic effects occur when using a combination of oxidative enzymes like the combination of GOX and SOX (50). Furthermore, the dough has an increased stability.

0 0

Post a comment