Porosity and stability of bread dough during proofing determined by video image analysis for different compositions and mixing conditions

A method was developed to study the modifications of volume and shape of wheat flour dough during fermentation process by digital camera. Various compositions and mixing conditions were implemented in order to prepare dough pieces with different rheological properties. Results were analyzed in terms of porosity and stability, defined as the shape ratio of the dough. The kinetics of the two variables, were fitted by simple mathematical models. Porosity evolution was a lot influenced by the composition of the dough and results were found in agreement with those obtained by X-Ray Microtomography, but less by the mixing conditions. Conversely, the stability was favoured by larger levels of specific mixing energy, in the range (20, 60 kJ/kg). The interpretation of these results suggested that gas production is the main variable governing expansion kinetics whereas rheological properties, mainly strain hardening, has the most significant role on stability.