MULTIPHYSICS DURING BREAD MAKING: NUMERICAL MODELLING AND TECHNOLOGICAL TEACHINGS FROM SIMULATIONS

A model of baking has been developed for one-dimension geometry. This model consists into coupled heat transport (conductivity, evapo-condensation-diffusion, con¬vection), mass transport (diffusion, convection) and mechanical behaviour inside dough. It was validated with a set of experimental data gathering profiles in tempera¬ture, in water content, total water loss, total CO₂ release, global and local expansion as measured continuously by MRI. Simulation makes it possible to study the relative influence of the parameters that favour expansion (kinetics of vaporisation and expansion of gases) and the restricting parameters: rupture of dough films according to a pressure differential and stiffening of the same films following heat modification of the macromolecules (starch and proteins). The latter are expressed in the model by the introduction of temperature ranges for rupturing of dough films (TKg) and for their stiffening (T). The effect of these temperatures of mechanical changes in dough films on the local and global expansion was studied. Additionally to these parameters related to the constitution of the dough, the effect of the external pressure was studied as an example of process parameters affecting expansion with a first experimental validation.