High pressure-treated sorghum flour as a functional ingredient in the production of sorghum bread

In this study, the application of high-pressure processing of sorghum batters was investigated in order to evaluate the potential of pressure-treated sorghum as a gluten replacement in the production of sorghum breads. For this purpose, sorghum batters were treated at pressures from 200 to 600 MPa at 20 °C, and the microstructure was investigated using scanning electron microscopy. Furthermore, the rheological properties of the control and pressure-treated batters were determined. The results revealed weakening of the batter structure at pressures ≤300 MPa. Addition of a blocker of free thiol groups indicated that protein depolymerization played a role in this strength decrease. At pressures >300 MPa, the batter consistency increased, mainly due to pressure-induced gelatinization of starch. Furthermore, freeze-dried sorghum batters treated at 200 MPa (weakest batter) and at 600 MPa (strongest batter) were added to a sorghum bread recipe, replacing 2 and 10% of untreated sorghum flour. The results showed a delayed staling for breads containing 2% of sorghum treated at 600 MPa. However, adding 10% resulted in a low specific volume and poor bread quality. The quality of breads containing different amounts of sorghum treated at 200 MPa was not significantly different from the control bread.