Influence of Casein Hydrolysates and Yeast on the Rheological Properties of Wheat Dough.

The influence of casein hydrolysates (CHs) and yeast on the viscoelasticity of wheat dough at 25 °C were analysed. Three wheat doughs were studied: the unyeasted dough (UYD), the unyeasted dough with CHs (UYD-C) and the yeasted dough (YD). The characteristic parameters in the linear viscoelastic range (LVER) were analysed by stress sweep at 6.3 rad/s: UYD-C dough exhibited higher values of stress ( σ max ) and strain ( γ max ) amplitudes, and softer gel network (lower complex modulus, G *) comparing with UYD dough. The oscillatory data suggest that CHs would work as (energy and time) stabilising-agents based on the greatest reticular energy ( E parameter) and the lowest frequency dependence of phase angle ( δ ) at the low frequency range. The rotatory tests show that CHs may act as shear thinning agents in the gluten-starch network, facilitating the solid-fluid transition at the yield point (UYD-C dough). The yeasted dough (YD) exhibited a more shear sensitive structure, evidenced in the highest influence of frequency on the elastic ( G ') and viscous ( G ″) parameters, and gel to sol transition at 0.23 rad/s was observed.