Paper Number
PF5 

Session
Applied Rheology for Pharmaceuticals, Food and Consumer Products

Title
Describing the shear and elongational rheology of wheat flour dough by the fractional Maxwell-KBKZ model

Presentation Date and Time
October 12, 2022 (Wednesday) 5:05

Track / Room
Track 2 / Sheraton 3

Authors (Click on name to view author profile)

1. Meeus, Yannick (KU Leuven, Department of Chemical Engineering)
2. Meerts, Mathieu (KU Leuven, Department of Chemical Engineering)
3. McKinley, Gareth H. (Massachusetts Institute of Technology, Mechanical Engineering)
4. Cardinaels, Ruth (KU Leuven, Soft Matter, Rheology and Technology)
5. Moldenaers, Paula (KU Leuven, Soft Matter, Rheology and Technology)

Author and Affiliation Lines (in printed abstract book)
Yannick Meeus¹, Mathieu Meerts¹, Gareth H. McKinley², Ruth Cardinaels¹ and Paula Moldenaers^1
1Soft Matter, Rheology and Technology, KU Leuven, Leuven, Vlaams-Brabant 3001, Belgium; ²Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02142

Speaker / Presenter 
Moldenaers, Paula

Keywords
experimental methods; theoretical methods; biomaterials; food rheology; rheometry techniques

Text of Abstract
Wheat flour dough is a viscoelastic material with a multi-scale structure. On a microscopic level it consists of a gluten matrix in which starch granules and a variety of minor components are dispersed. The complex interplay of interactions that takes place on this microscopic level results in a macroscopic rheological behavior of dough that is difficult to model accurately. A better understanding of dough rheology is highly desirable in view of the link between dough rheological properties and final bread quality. The linear rheology of dough can be accurately described using the fractional Maxwell model (FMM). By extending the FMM with the K-BKZ equation, the non-linear extensional behavior can be captured as well, at least from a qualitative point of view, although quantitatively an overestimation of the extensional stress growth is predicted. To overcome this limitation, a suitable damping function can be included into the Fractional K-BKZ framework to account for strain-softening at large strains. Conventional shear stress-relaxation measurements, which are typically used to circumvent the difficulties associated with extensional experiments, fail to provide an adequate damping function. Here we show that extensional stress-relaxation measurements performed on a highly viscous material such as bread dough allow to determine an extensional damping function. Incorporating this damping function into the Fractional K-BKZ framework allows us to account for the disruption in gluten-starch interactions when dough is exposed to extensional deformations. Thereby, the model can accurately predict the extensional viscosity and its strain hardening for a range of extension rates.