Effect of a Xylanase from the ThermophilicThermomyces lanuginosus on Wheat FlourBreadmaking Quality

摘要

A xylanase from the thermophilic fungus Thermomyces lanuginosus CBS288.54 waspurified and evaluated for its suitability in wheat flour breadmaking. Xylanase was purified33.6-fold to homogeneity with a recovery yield of 21.5% It appeared as a single protein band onSDS-PAGE gel with a molecular mass of approx. 26.2 kDa. The purified xylanase was most activein the neutral pH, namely pH 7.0-7.5, and exhibited its optimal activity at 70-75°C The study wasfurther carried out to investigate the effect of the purified xylanase on the properties of wheatbread and its staling during storage. The presence of xylanase in the dough improved thebread-making quality (i.e. specific volume and crumb structure) and provided an anti-staling effecton breads. Addition of purified xylanase at 1.5 ppm (mg/kg flour basis) was found to be the mostsuitable, and caused approx 43.2% increase in bread specific volume in comparison with thecontrol. The crumb-firming kinetics was fitted the Avrami equation. It was shown that thethermostable xylanase retarded the bread staling process by reducing the initial crumb firmnessand slowing down the firming process during storage. Hence, the xylanase seems to be useful toimprove the quality of bread.