Proving of Bread Dough: Modelling the Growth of Individual Bubbles

Abstract

roving of bread dough was modelled using classical one-component diffusion theory, to describe the rate of growth of bubbles surrounded by liquid dough containing dissolved carbon dioxide. The resulting differential equation was integrated numerically to predict the effect of initial bubble size and system parameters (carbon dioxide concentration, surface tension at the bubble interface, temperature) on bubble growth. Two situations exist, potentially; the dough could be either supersaturated or subsaturated with carbon dioxide. When the dough is supersaturated, the model predicts a critical bubble size above which bubbles grow inde® nitely, while below the critical bubble size bubbles reach a limiting size and stop growing. The critical bubble size decreases with increasing carbon dioxide concentration and increases with increasing surface tension. Below saturation, all bubbles reach an upper size limit proportional to their initial size. The ® nal bubble size increases with carbon dioxide concentration and decreases with increasing surface tension. Higher temperatures increase the rate of bubble growth and reduce the critical bubble size for supersaturated doughs, by increasing the value of Henry' s Law constant. Higher temperatures also increase the ® nal bubble size for subsaturated systems. The model could be extended to include yeast kinetics and entire bubble size distributions, to develop a full simulation of the proving operation.

Assessment of Bread Dough Expansion during Fermentation

“…Others authors tried to evaluate the expansion by measuring the air content of the dough and the bubble size distribution (Shimiya and Nakamura 1997;Whitworth and Alava 1999;Bonny et al 2004). Modeling of the growth of bubbles in dough has been presented by Shah et al (1998) or Chiotellis and Campbell (2003). But the different biological and physical phenomena occurring during proving are very complex and difficult to model.…”

Bran in Bread: Effects of Particle Size and Level of Wheat and Oat Bran on Mixing, Proving and Baking

“…Similarly, the growth of these bubbles depends on the mass transfer dynamics of CO 2 diffusion into the nitrogen nuclei initially created. This depends on the solubility and diffusivity of CO 2 in the liquid dough phase, as well as the initial bubble size distribution (Shah et al, 1998;Chiotellis and Campbell, 2003a,b). Bran in the formulation could conceivably affect these and thereby slow bubble growth during proving, such that more of the CO 2 produced by the yeast is lost from the dough surface, giving less expansion and smaller loaf volumes.…”

Evolution of bubble size distribution in baked foods

“…The model involved growth of a single bubble but the initial bubble size was determined by averaging the experimentally obtained bubble size distribution in the dough. Similar bubble growth models have been developed by Shah et al (1998) and Fan et al (1999). Shah et al (1998) took into account the diffusion of only CO 2 and neglected dough rheology, because according to them, the surface tension effects predominate over rheological factors.…”

“…Similar bubble growth models have been developed by Shah et al (1998) and Fan et al (1999). Shah et al (1998) took into account the diffusion of only CO 2 and neglected dough rheology, because according to them, the surface tension effects predominate over rheological factors. On the other hand, Fan et al (1999) assumed a temperature dependent power law rheology, a linear variation in temperature with time and diffusion of both CO 2 and water vapor.…”

“…Though, Chiotellis and Campbell (2003) extended the work of Shah et al (1998) to model a bubble size distribution, they did not take into account the continuous nucleation of new bubbles. The objective of the present work is therefore to model the dynamic evolution of the bubble size distribution inside the dough using a general population balance approach which takes into account both nucleation and growth of bubbles.…”