The effects of wheat flour, water, salt and mixing on the rheological properties and the gas phase of bread dough

Health Canada recommends an approximately 30% reduction of sodium levels in bread products, which brings a great challenge for bakery industry due to dough handling difficulties and product quality issues induced by sodium reduction. In order to address this challenge, the effects of wheat cultivar, water content and mixing time on the response of dough’s rheological properties and gas phase to salt (NaCl) reduction were investigated to develop processing strategies for improving the breadmaking performance of reduced salt content doughs. The rheological properties of doughs with a wide range of formulations were examined using the mixograph, dynamic oscillatory rheometry and creep-recovery tests. Outcomes from these rheological studies indicated that doughs with a better tolerance to salt reduction were prepared at higher water contents, and/or optimal mixing time. The gas phase parameters, i.e., the gas volume fraction and the volumetric bubble size distribution, of doughs were examined using synchrotron X-ray microtomography. In terms of the time evolution of the bubble size distribution in unyeasted doughs, increased water content, reduced salt content, and/or increased mixing time were seen to promote disproportionation in the dough. Dough gas phase studies also confirmed a cultivar-dependent response of dough to salt reduction and suggested that the optimal-mixing condition developed the doughs to be more tolerant to salt reduction compared to under- and over-mixing conditions. In conclusion, formulation and mixing conditions play an important role in determining dough’s response to salt reduction. The type of wheat flour (associated with the cultivar’s tolerance to salt reduction), water content and optimal mixing time need to be considered when improving the breadmaking performance of reduced-salt doughs.