A study was conducted to investigate the effect of dough formulation and hydration level on the
rheological properties of pasta dough during pasta extrusion. Semolina 100%, whole wheat 100%, and the
following mixtures semolina-whole wheat (49:51), semolina-flax seed flour (90:10), whole wheatflaxseed
flour (90:10), and semolina-whole wheat-flax seed flour (39:51:10) were the formulations
used for the experiments. Dough was hydrated at 30, 32, and 34% moisture content. Pasta was extruded
with a capillary and a semi-commercial pasta extruder to determine the apparent viscosity of the dough
during extrusion conditions and its relationship to the behavior of the dough during pasta processing.
Results showed that non-traditional pasta dough behaved like a shear thinning fluid that can be
described by the Power Law model. Increased hydration levels and/or presence of flaxseed flour on the
dough formulation decreased the apparent viscosity of the dough, which correlated with extrusion
pressure, mechanical energy, and specific mechanical energy that were required to extrude the dough in
the pasta extruder. The strong correlations found between the apparent viscosity of the dough and the
pasta extrusion parameters indicates the possibility of using a capillary rheometer to determine the
appropriate hydration level of ingredient formulations before extruding with a pasta press.