Bran-induced effects on the evolution of bubbles and rheological properties in bread dough.

Evolution of bubbles is the key to volume development in bread dough. The influence of wheat bran on bubble growth in bread dough through the mixing, fermentation, and proofing stages is described as a function of its level of addition. Confocal laser scanning microscopy in combination with image processing tools was used to obtain the bubble size and shape parameters. The relationship between bubble behavior and dough rheology was mapped using biaxial extension and dynamic oscillatory rheometry studies. With increase in level of bran addition, mean bubble size decreased corresponding to each stage and showed an inverse relationship with dough overpressure and elastic modulus. Addition of wheat bran was observed to suppress the bubble coarsening phenomenon in dough. Experimental observations indicated the plausibility of coalescence-mediated bubble growth in bread dough during the latter stages of fermentation and proofing, which was hindered in the presence of bran particles. PRACTICAL APPLICATION: The results of this work provide an insight to the underlying mechanism by which wheat bran addition impacts the volume development in bread dough. The inferences presented in this research work can be used as a basis to study bubble dynamics in an opaque food system such as bread dough. This information would be of interest to industrial researchers working on the new product development of aerated bakery products with functional fibrous ingredients.