Three ingredient blends were prepared containing 20%, 30% and 40% DDGS and the net protein adjusted to 28% were formulated and extruded in a single screw extruder. Modeling of the viscosity of dough in the barrel by restricting the reference viscosity has shown shear thinning behavior, and the R2 value obtained between the apparent viscosity calculated by the concentric cylinder method, and viscosity calculated by the model equation, was found to be over 0.99. Increasing the DDGS content had resulted in higher mass flow rate and decreased absolute pressure inside the die. The torque requirement at 40% DDGS was also found to be high leading to increased SME and apparent viscosity of the dough. The ingredient mixes had shown shear thinning behavior indicated by the flow behavior index ‘n’ value of <1 and the torque requirement, SME and apparent viscosity decreased as screw speed was increased. Viscosity modeling had resulted in positive coefficient for moisture content, but the measured apparent viscosity did not show any particular trend with respect to moisture content. At higher barrel and die temperature, viscosity of the dough found to decrease leading to lesser torque, and specific mechanical energy. The coefficient for DDGS in the viscosity model was found to be positive and the measured apparent viscosity had increased as the DDGS content was increased.