Exploring Bread Quality through the Use of Commercial Bacterial and Fungal Xylanases: Effects on Dough Rheology, Loaf Volume, and Arabinoxylan Structure

This study evaluated the effects of eight commercial xylanases from fungal and bacterial sources on dough rheology, bread quality, and arabinoxylan (AX) hydrolysis in white pan bread. Dough properties (development time, stability, water absorption, stickiness, and extensibility) and bread quality (volume, crumb structure, and firmness) were measured at manufacturer-recommended doses. The two enzymes with the greatest positive impact on loaf volume and crumb softness, Enzyme 5 (fungal, Trichoderma reesei) and Enzyme 8 (bacterial, Bacillus subtilis), were further tested at two under-doses, the recommended dose, and two over-doses. Fungal xylanase was tested at 0.1, 0.2., 5.1, 10, and 20 ppm (enzyme activity for xylanase = 20744.5 units/g). Bacterial xylanase was tested at 5, 10, 20, 30, and 60 ppm (enzyme activity for xylanase = 1909.4 units/g). Optimal dosing for fungal and bacterial xylanases significantly increased loaf volume (up to 27% higher than control), improved crumb cell number, and reduced firmness by up to 47%. Both enzymes were robust against over-dosing, however there was an indication of deterioration in quality at the highest levels, indicating the importance of dosage control. Molecular weight analysis of water-extractable arabinoxylans (WE-AX) showed distinct hydrolysis profiles. However, this did not lead to measurable differences in dough structure or bread performance, despite varied AX degradation patterns. Findings demonstrate that targeted selection and dosing of xylanases can optimize bread quality, enhance process efficiency, and offer functional differentiation in bakery applications. PRACTICAL APPLICATIONS: Use of commercial xylanases can improve loaf volume, crumb softness, and shelf life in white pan bread; however, there is variability in the action of enzymes currently available in the market. Understanding enzyme origin and dosage effects enables bakers to tailor formulations for specific quality targets, supporting consistent product performance and potential cost savings in industrial baking.