title: Finding robust descriptive features for the characterization of the coarsening dynamics of three dimensional whey protein foams.
abstract: OBJECTIVE
  Understanding the coarsening behavior of foams is of great interest for their deliberate design. In order to systematically quantify the influence of surfactants and other chemical parameters, identifying robust descriptive features of observed foam aging dynamics is essential. Existing coarsening theories for both wet and dry foams provide concise models with respective descriptive parameters.
  
  
  METHODS
  Multiple micro computed tomography scans of moderately wet polydisperse β-Lactoglobulin foam are recorded over a period of 15min. The growth behavior of a large fraction of about 5×10(4) pores that constitute the imaged volume is individually observed and statistically analyzed as a function of pore radius as well as number of neighboring pores.
  
  
  RESULTS
  The three-dimensional analog of von Neumann's law for dry foams by Glazier is confirmed as a suiting empirical model, whereby a critical number of 13±7 neighbors and a diffusion coefficient of (1.8±0.8)×10(-11)m(2)/s are found for an exemplary sample. The pores growth can as well be related to their radius by means of Lemlich's coarsening model for wet foams though, whereby a critical radius marking the transition between shrinkage and growths is found to be Rc=(300±85)μm. Although different, both models fit similarly well given the broad variance of the observed growth rates.
authors.affiliation: Lehrstuhl für Röntgenmikroskopie, Universität Würzburg, Josef Martin Weg 63, 97072 Würzburg, Germany. Electronic address: jonas.dittmann@physik.uni-wuerzburg.de.
authors.forename: J
authors.initials: J
authors.lastname: Dittmann
authors.affiliation: Fraunhofer EZRT, Flugplatzstr. 75, 90768 Fürth, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Eggert
authors.affiliation: Lehrstuhl für Röntgenmikroskopie, Universität Würzburg, Josef Martin Weg 63, 97072 Würzburg, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Lambertus
authors.affiliation: Wissenschaftszentrum Weihenstephan, Technische Universität München, Alte Akademie 8, 85354 Freising, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Dombrowski
authors.affiliation: European Synchrotron Radiation Facility (ESRF), CS 40220, Grenoble, France.
authors.forename: A
authors.initials: A
authors.lastname: Rack
authors.affiliation: Lehrstuhl für Röntgenmikroskopie, Universität Würzburg, Josef Martin Weg 63, 97072 Würzburg, Germany; Fraunhofer EZRT, Flugplatzstr. 75, 90768 Fürth, Germany. Electronic address: simon.zabler@physik.uni-wuerzburg.de.
authors.forename: S
authors.initials: S
authors.lastname: Zabler
mesh_terms: D007782:Lactoglobulins / Q000737:chemistry* / Q000302:isolation & purification; D010316:Particle Size; D013499:Surface Properties
chemical_list: D007782:Lactoglobulins
keywords: Coarsening; Foam aging dynamics; Foam characterization; Micro computed tomography; Ostwald ripening; Pore tracking; Synchrotron radiation; Wet protein foam