The effect of steady shearing versus z-blade mixing on mechanical aeration and gas retaining ability of the dough during processing and subsequent proofing and bread baking stages was investigated. Reduction in moisture content led to reduction in both static and dynamic densities of z-blade mixed dough. At low moisture content, dough had higher consistency and tended to physically entrap more air bubbles upon processing, leading to a higher dough volume and, thereby a low density. The results showed that both processes led to similar mechanical aeration as measured by static dough density immediately after processing. Shearing at a low rotational speed, led to similar proofing dough volume as z-blade mixing did. Nevertheless, both dough expansion test and breadmaking trials showed a significant reduction in gas retaining ability of sheared dough, especially at higher rotational speeds. This is explained by the fact that higher shear rates could break up the gluten network and negatively influence gas retaining ability. The results revealed the influence of processing conditions; e.g. the type of deformation flow on dough aeration. Furthermore, it was shown that rotational speed in the shearing system influences the aeration and gas holding ability of the dough during proofing and baking processes.
- simple shear