2.6. Rheological characterisation
The flow curve and viscoelastic property of whole wheat flour (WWF) with the addition of 10% of unprocessed hull powder (SBH-C) or hull dietary fibre powder (SBH-T) were measured by Physica MCR 301 Rheometer (Anton Paar, Ashland, VA, USA).
The method of yield fluid with logarithmic ramp stepwise was selected from a standard template in the RheoManager software.
The flow curve was evaluated on a stress-controlled rheometer equipped with 50 mm smooth parallel plate geometry (50 mm diameter, 2 mm gap).
Dough was mixed at 30 °C until well developed.
A sample of dough with 50% moisture content was immediately removed from the bowl and placed between the plates of the rheometer.
Excess dough was carefully trimmed. Sample was rested 10 min after loading before testing. Viscosities were measured for shear rate increasing from 0.01 to 250 s−1 at 25 °C. In a dynamic test, the method of amplitude sweep under oscillation category with LVE-range and structural strength was chosen from a standard template.
The dough with 50% moisture content was placed between two parallel plates, and the gap between two plates was set to 2.0 mm.
Strain ranged from 0.01% to 100%.
Angular frequency was set at 10 rad/s.
The storage modulus (G′), loss modulus (G″), and damping factor (tan δ) were recorded.