Effect of laccase and manganese peroxidase on wheat gluten and pentosans during mixing

Wheat gluten and water extractable pentosans (WEP) were mixed in a batch-mixer in the presence of laccase or manganese peroxidase (MnP). The enzymes provoked different changes in mixing behaviour. Doughs were analysed at time to peak (t) and over two t (2t or overmixed). The effects of the oxidative enzymes were studied on ferulic acid (FA), arabinoxylans (AX), proteins and possible intermolecular associations in these dough systems. Changes in macromolecular structures were followed using reverse phase-high performance liquid chromatography of phenolic compounds, AX extractability and the viscosity measurements, size exclusion-high performance liquid chromatography and sodium dodecyl sulfate-polyacrylamide gel electrophoresis of proteins. The oxidative enzymes increased dough consistency, accelerated the loss in total FA, decreased AX water extractability and water extractable AX apparent intrinsic viscosity in the dough water extracts. The effects of laccase and MnP were similar on feruloylated AX when compared on a reaction time basis. No covalent complex between AX and protein was detected in mixed and oxidised gluten/WEP.