Influence of sodium chloride on shear flow induced starch–gluten separation from Soissons wheat dough

Wheat dough can be separated into a starch-rich and a gluten-rich fraction by subjecting the dough to curvilinear shear flow. This paper presents the effect of salt (NaCl) addition on the shear-induced separation process. The separation (defined as the changes in protein concentration in the various layers, compared to the starting material) was promoted by NaCl addition up to a concentration of 4 w%. Dough without NaCl showed limited separation, but this effect could be partly compensated by a decreased processing time. Rheology measurements did not show clear differences in G′ and tan δ value, for dough with different NaCl concentration. But, shear stress and normal force did vary for various NaCl concentrations when applying a constant shear rate. Nevertheless, the large differences in separation behaviour are probably more related to the influence of salt on gluten aggregation and properties resulting thereof, than the differences in dough rheological properties.