Extensional flow studies on wheat flour doughs with different protein content

Uniaxial compression technique was used to relate the rheological behavior of dough to wheat quality for bread. Dough of nine flours of the cultivar Rayon, grown in three different regions of Sonora, Mexico, and with a protein content from 10% to 12.8%, were studied using the lubricated squeezing-flow test connected to a texturometer. Wheat flour quality determinations were protein, moisture and ash content, dry gluten, falling number, and sedimentation volume. Traditional dough rheological evaluations were made with the farinograph and alveograph. The baking test was also done. The extensional viscosity was measured at three crosshead speeds (0.2, 0.5, and 1.0 mm/min). Extensional viscosity, measured at the lowest speed, significantly (P < 0.05) and negatively correlated with protein content (r = -0.63) and bread volume (r = -0. 72). The rheological behavior of wheat doughs during lubricated uniaxial compression showed dependence on the strain rate as demonstrated by the patterns of the extensional viscosity curves.