Paper Number
VP59 

Session
Pre-recorded Flash Presentations (virtual)

Title
Extensional stress-relaxation measurements on wheat flour dough – The key to finalizing the Fractional K-BKZ framework?

Presentation Date and Time
All Week (Asynchronous) Any Time

Track / Room
Pre-recorded Presentation / Virtual

Authors (Click on name to view author profile)

1. Meeus, Yannick (KU Leuven, Chemical Engineering)
2. Meerts, Mathieu (KU Leuven, Chemical Engineering)
3. Szilvási, Dóra (KU Leuven, Chemical Engineering)
4. McKinley, Gareth H. (Massachusetts Institute of Technology, Mechanical Engineering)
5. Cardinaels, Ruth (KU Leuven, Chemical Engineering)
6. Moldenaers, Paula (KU Leuven, Chemical Engineering)

Author and Affiliation Lines (in printed abstract book)
Yannick Meeus¹, Mathieu Meerts¹, Dóra Szilvási¹, Gareth H. McKinley², Ruth Cardinaels¹ and Paula Moldenaers^1
1Chemical Engineering, KU Leuven, Leuven, Belgium; ²Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA

Speaker / Presenter 
Meeus, Yannick

Keywords
experimental methods; theoretical methods; biological materials

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 determination of 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.