The bubble size distribution and its evolution in non-yeasted wheat flour doughs investigated by synchrotron X-ray microtomography

Abstract Determination of the bubble size distribution at the end of mixing and controlling its changes are the basis for improving bread quality before it is fully manufactured. X-rays from a synchrotron source (Biomedical Imaging and Therapy beamline, Canadian Light Source) were used to rapidly characterize the bubble size distribution and its evolution in non-yeasted dough subsamples as a function of time for 3 h following mixing. A complete X-ray microtomography scan was completed within 120 s. The higher number density of bubbles in dough compared to results previously reported in the literature was attributed to the better contrast and higher resolution (smaller pixel size, 8.75 μm) of the reconstructed X-ray images generated from synchrotron X-rays. The bubble size distribution was very well characterized with a lognormal distribution function. This distribution had a median bubble radius of 22.1 ± 0.7 μm at 36 min after the end of mixing which increased to 27.3 ± 0.7 μm over 162 min, a trend indicative of transport of gas in the dough due to disproportionation. This is the first time disproportionation in non-yeasted wheat flour doughs has been monitored directly under bulk conditions relevant to dough in bakery conditions. These results show that the diffusion-driven dynamics of bubbles in non-yeasted bread doughs can be followed by X-rays from a synchrotron source via feature extraction using image analysis software.

[1]  Grant M. Campbell,et al.  Proving of Bread Dough I: Modelling The Evolution of the Bubble Size Distribution , 2003 .

[2]  Martin G. Scanlon,et al.  Bread properties and crumb structure , 2001 .

[3]  Ostwald ripening in emulsions , 1998 .

[4]  Hubert Chiron,et al.  Fast X-ray tomography analysis of bubble growth and foam setting during breadmaking , 2006 .

[5]  T. van Vliet,et al.  Strain Hardening Properties and Extensibility of Flour and Gluten Doughs in Relation to Breadmaking Performance , 1996 .

[6]  B. Murray,et al.  Foam stability: proteins and nanoparticles , 2004 .

[7]  C. J. Taylor,et al.  Segmentation and Analysis of RGB-D data , 2010 .

[8]  Hubert Chiron,et al.  In situ Fast X-ray Tomography Study of the Evolution of Cellular Structure in Bread Dough During Proving and Baking , 2008 .

[9]  L. Salvo,et al.  X-ray tomography study of the cellular structure of extruded starches and its relations with expansion phenomenon and foam mechanical properties , 2007 .

[10]  W. Stahel,et al.  Log-normal Distributions across the Sciences: Keys and Clues , 2001 .

[11]  L. Salvo,et al.  Growth and setting of gas bubbles in a viscoelastic matrix imaged by X-ray microtomography: the evolution of cellular structures in fermenting wheat flour dough. , 2015, Soft matter.

[12]  V. Leroy,et al.  Using Ultrasound to Probe Nucleation and Growth of Bubbles in Bread Dough and to Examine the Resulting Cellular Structure of Bread Crumb , 2008 .

[13]  Martin G. Scanlon,et al.  The bubble size distribution in wheat flour dough , 2006 .

[14]  W. Bushuk,et al.  Instrumental measurement of bread crumb grain by digital image analysis , 1994 .

[15]  Syed S. H. Rizvi,et al.  Use of non-invasive X-ray microtomography for characterizing microstructure of extruded biopolymer foams , 2005 .

[16]  F. Natterer.  X-ray Tomography , 2008 .

[17]  V. Leroy,et al.  Use of an ultrasonic reflectance technique to examine bubble size changes in dough , 2012 .

[18]  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 .

[19]  Peter J. Martin,et al.  Bread dough aeration dynamics during pressure step-change mixing: Studies by X-ray tomography, dough density and population balance modelling , 2013 .

[20]  Grant M. Campbell,et al.  Dough aeration and rheology: Part 2. Effects of flour type, mixing speed and total work input on aeration and rheology of bread dough , 2005 .

[21]  Rangaraj M. Rangayyan,et al.  Segmentation and analysis of neuroblastoma , 2007, J. Frankl. Inst..

[22]  G. Campbell,et al.  Dough aeration and rheology: Part 1. Effects of mixing speed and headspace pressure on mechanical development of bread dough , 2005 .

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

[24]  M. Scanlon,et al.  Ultrasonic Characterization of Unyeasted Bread Dough of Different Sodium Chloride Concentrations , 2014 .

[25]  P. Falcone,et al.  Imaging techniques for the study of food microstructure: a review. , 2006, Advances in food and nutrition research.

[26]  M. Scanlon,et al.  Effects of composition on dough development and air entrainment in doughs made from gluten-starch blends , 2012 .

[27]  Pieter Walstra,et al.  STRAIN-HARDENING OF DOUGH AS A REQUIREMENT FOR GAS RETENTION , 1992 .

[28]  M. Meinders,et al.  The role of interfacial rheological properties on Ostwald ripening in emulsions. , 2004, Advances in colloid and interface science.

[29]  Peter J. Martin,et al.  Dough aeration and rheology: Part 3. Effect of the presence of gas bubbles in bread dough on measured bulk rheology and work input rate , 2005 .

[30]  T. Yano,et al.  Rates of shrinkage and growth of air bubbles entrained in wheat flour dough , 1988 .

[31]  V. Leroy,et al.  Chapter 5 – Investigating the Bubble Size Distribution in Dough Using Ultrasound , 2008 .

[32]  Hubert Chiron,et al.  Kinetics of bubble growth in wheat flour dough during proofing studied by computed X-ray micro-tomography , 2012 .

[33]  Daniel Cohen-Or,et al.  Volume graphics , 1993, Computer.