Rheological properties of vital wheat gluten suspensions

Flour and doughs represent theologically complex materials whose properties are dependent on many factors including processing conditions. To avoid so me of the problems associated with the rheological characterization of doug h, we have initiated a study focused on the rheological properties of one o f the major components of dough, vital wheat gluten. Suspensions of vital w heat gluten were prepared with concentrations of 225-325 mg/mL. The moduli of the gluten suspensions was 0.2 Pa at 225 mg/mL to 37 Pa at 325 mg/mL. At <250 mg/mL, the gluten suspensions exhibited fluidlike behavior. The cross over frequency, (G'[<omega>] = G"[omega]) shifted slightly from 0.5 rad/sec at 225 mg/mL to 0.9 rad/sec at 250 mg/mL. At >300 mg/mL, the gluten suspen sions exhibited solidlike behavior. The crossover frequencies were independ ent of concentration and equal to 100 rad/sec. At <250 mg/mL, the high-freq uency behavior of moduli were proportional to <omega>(3/4), as expected for a semiflexible coil. At >300 mg/mL, the high-frequency behavior of moduli were proportional to omega (1/2), indicating a flexible coil. These results suggest vital wheat gluten suspensions undergo a structural change between 250 and 300 mg/mL.