Volume change in the bread baking process

PURLIS EMMANUEL; SALVADORI VIVIANA O.

Orlando, FL, USA

Congreso; IFT 2006 Annual Meeting; 2006

IFT

Bread baking is a complex process in which several physical, chemical and biochemical changes in the product are involved. These changes are volume expansion, water evaporation, porous structure formation, protein denaturalization, starch gelatinization, crust formation and browning reactions. Mathematically, the process could be described as a simultaneous mass and energy transfer inside the product and with the ambient existing in the baking chamber. Most of the mathematical models presented in literature simulate the flat product processing, i.e. the volumetric expansion is neglected. This is not valid when the product has sponge dough, which is the bread case. The aim of this work was to study the volume change during bread baking and to obtain a regression equation to use in process modelling and simulation. Volume expansion in white bread was followed by two techniques: rapeseed displacement method and image processing. Different measures were taken as baking time elapsed. Comparisons between both methods were made and regression was performed over experimental data. Results showed a linear trend in volume expansion at the first stage of baking. Once an external rigid structure (crust) is developed, volume is remained constant till the end of process. Both applied techniques had similar performance. These results can be used in bread baking modelling to improve mathematical approaches by simulating more realistic systems. Moreover, image processing appears as a useful technique to this aim. The methods developed in this work can be applied in other bakery products such as cakes.