Fast X-ray tomography analysis of bubble growth and foam setting during breadmaking

The use of fast X-ray computed microtomography (CMT) shows that the development of gas cell structures during fermentation first depends on a critical time, t(1), determined by overall expansion and before which bubbles grow freely according to a simple exponential law. Afterwards, coalescence rapidly prevails and then leads to a heterogeneous structure, for t >= t(2), characterized by a continuous void phase likely to be stabilized by liquid film walls. This result confirms the involvement of minor components in addition to gluten protein for obtaining a desirable bread texture and suggests that their interfacial properties need to be investigated. The use of fast in situ CMT with careful 3D image analysis also provides data for the validation of numerical models of bubble growth. These small scale experiments could be extended to follow the theological properties of expanding doughs and the temperature-state changes of wheat flour biopolymers which govern bread baking. (c) 2006 Elsevier Ltd. All rights reserved.