Impact on dough aeration of pressure change during mixing

- Faster degassing kinetics were observed for a higher pressure drop during mixing.
- A higher agitation speed provided more energy per revolution.
- The agitation speed did not influence gas incorporation per revolution.
- The final gas content was only dependent on the pressure at the end of mixing.
- Aeration and degassing dynamics during mixing were fitted by exponential models.

This study aimed to provide a better understanding of the impact on dough aeration of pressure change during dough mixing with a spiral dough mixer with the possibility of controlling the temperature and the overhead pressure from −960 mbar to +500 mbar during mixing. The objectives were to understand the effect of pressure on dough during kneading in order to optimize dough kneading conditions. The well-known experimental strategy was to knead with overpressure to incorporate gas into the dough and maximize dough aeration then to subdivide the gas bubbles introduced in the previous step by applying a vacuum in the mixer's overhead. The results showed that dough aeration was proportional to the number of rotations of the spiral. The time to reach equilibrium was longer for a larger pressure drop. The kinetics of disentrainment were slower with the highest pressure drop.