Aeration During Bread Dough Mixing: III. Effect of Scale-up

This paper presents the results of an investigation into the scale-up of bread dough mixers. Previous research reports into dough mixer scale-up only consider the dough development aspect of mixing and neglect aeration, despite over-aeration being a known problem that occurs with scale-up. A series of experiments was performed on three scales of the Tweedy-type high-intensity mixer. A pressure step-change was introduced during mixing, and dimensionless aeration parameters for each mixer were found through measurement of the dough voidage response, using a previously reported aeration model. The degree of steady state aeration, the turnover rate and the volumetric entrainment rate were all found to increase with mixer scale, or alternatively with Reynolds number. The number density of bubbles in the dough and the mean bubble size could not be seen to vary significantly with scale, but both increased with mixer headspace pressure.

[1]  A. Williams,et al.  Breadmaking : the modern revolution , 1975 .

[2]  P. Fryer,et al.  Measurement and Interpretation of Dough Densities. , 1993 .

[3]  M. Hanna,et al.  Flow behavior of wheat flour-water dough using a capillary rheometer. II: Effects of water, protein, mix, and rest time , 1993 .

[4]  S. Zounis,et al.  Predicting Test Bakery Requirements from Laboratory Mixing Tests , 1997 .

[5]  M. Morgenstern,et al.  Comparison of Work Input Requirement on Laboratory-Scale and Industrial-Scale Mechanical Dough Development Mixers , 1997 .

[6]  R. Anderssen,et al.  The Rate-Independence of the Mixing of Wheat Flour Dough to Peak Dough Development , 1998 .

[7]  P. Fryer,et al.  Aeration of bread dough during mixing: Effect of mixing dough at reduced pressure , 1998 .

[8]  P. Fryer,et al.  Reconstruction of bubble size distributions from slices , 1999 .

[9]  M. Morgenstern,et al.  Mixing Response of a Variable Speed 125 g Laboratory Scale Mechanical Dough Development Mixer , 2001 .

[10]  J. M. Alava,et al.  The Determination of Wheat Breadmaking Performance and Bread Dough Mixing Time by NIR Spectroscopy for High Speed Mixers , 2001 .

[11]  Grant M. Campbell,et al.  Measurement of Dynamic Dough Density and Effect of Surfactants and Flour Type on Aeration During Mixing and Gas Retention During Proofing , 2001 .

[12]  Robert J. Wilkens,et al.  How to scale-up mixing processes in non-Newtonian fluids , 2003 .

[13]  Peter J. Martin,et al.  Aeration During Bread Dough Mixing: II. A Population Balance Model of Aeration , 2004 .

[14]  Peter J. Martin,et al.  Aeration during bread dough mixing: I. Effect of direction and size of a pressure step-change during mixing on the turnover of gas , 2004 .