A synergy exists between pentosanase and glucose oxidase.

Glucose oxidase (GOX) is a highly specific enzyme from the fungi Aspergillus niger and Penicillium. It catalyzes the oxidation of b-glucose to glucono-1,5-lactone, which spontaneously hydrolyzes nonenzymatically to gluconic acid, using molecular oxygen and releasing hydrogen peroxide. GOX finds use in removing either glucose or oxygen from foodstuffs to improve their storage.

GOX is often used in a synergistic combination with pentosanase. European scientists studied the involvement of pentosans, both in breadmaking and in gluten-starch separations, in order to explain this synergy.

The investigators examined the effect of adding water-soluble pentosans (WSP) and water-insoluble pentosans (WUS) together with GOX. In both cases the extensibility of the doughs further decreased. Then they added modified WSP. Sodium hydroxide-modified WSP that was low in ferulic acid (FA) significantly counteracted the effect of GOX.

Pentosanase-modified WSP further diminished the effect of GOX, improving dough elasticity. Adding FA by itself completely counteracted the effects of GOX. However, FA also decreased the quantity of the glutenin macropolymer. This was not the case when using modified WSP, which tells us that the quality of the network was affected and not the amount.

Model studies focusing on gluten formation and on the formation of pentosan polymers revealed that oxidation leads to the formation of high-molecular-weight (HMW) pentosans. This hampers the formation of a gluten network. GOX induces the formation of peroxide that, together with flour peroxidases, catalyzes the formation of such HMW pentosans.

Adding small pentosan fragments limits the formation of HMW pentosans and thus removes this negative effect of GOX. Adding pentosanase leads to the generation of pentosan fragments and, consequently, the breakdown of HMW pentosans. The scientists believe that this action of pentosanase counteracts the effect of GOX and explains the synergy between the two enzymes.

Further information. William Lichtendonk, TNO Nutrition and Food Research, Utrechtseweg 48, 3704 HE Zeist, P.O. Box 360, 3700 AJ Zeist, The Netherlands; phone: [phone]; fax: [phone]; URL: www.tno.nl.