Background
The scale-up of extrusion processes like high-moisture extrusion from small bench-top extruders to large industrial-scale extruders remains challenging. This is especially true for high-moisture extrusion since the structuring mechanisms of plant proteins have not been fully understood to date. Predicting suitable processing parameters for industrial-scale extruders from pilot-scale experiments during product development is currently mainly driven by intuition. Thus, high-moisture extrusion requires extensive large-scale trials to achieve a similar degree of fibrousness while the transfer of insights from small-scale experiments to large-scale is more based on the operator’s experience and empirical testing than a profound scientific understanding. Recently, parameters of velocity gradients, mechanical shear, and the temperature gradient within the cooling die have been identified to play a major role for fibrous structure formation. Testing modifications of the temperature distribution within the cooling die, the implications of the cooling die design and geometry, and determining the temperature gradient within the product in combination with innovative technologies characterization of the product will help to understand important product structure-process interactions for successful scale-up.
Objectives of the master’s thesis
We are looking for a candidate who is highly motivated to work in a collaborative project with industry that aims at a better understanding of the high-moisture extrusion scale-up for plant-based meat analogs. Your main task will be the definition of structural parameters to quantify the quality of meat analogues for both pilot- and industrial-scale extruder using off-line techniques like texture analysis, rheology, spectroscopy, and imaging techniques to characterize the high-moisture extrudates. Ultimately, you will develop correlations between structural characteristics of the extrudates and processing parameters as well as the geometry of the cooling die to facilitate successful scale-up. Our rheology and scalable extrusion platforms at ETH Zürich will serve as the fundamental toolbox for the project.
The project will rely on a close collaboration with the whole ETH team, the KIT team and the industry partners Bühler and Thermo Fisher Scientific.
Your profile
- Student in Food Science, Food Engineering, Process Engineering, Material Science, Biotechnology or a closely related field
- Interested in high moisture extrusion and food structure
- Excellent academic qualifications
- Good communication skills and strong self-motivation
- Flexibility and curiosity
- Your initiative is required (accommodation and stipend* covering living expenses must be independently acquired by student. We will support you!)
* Mobility fellowship of DAAD, BAföG or similar.
Further information can be found here:
https://www.daad.de/de/im-ausland-studieren-forschen-lehren/stipendien-finanzierung/auslands-bafoeg/ (application 6 months before)
https://www.daad.de/de/infos-services-fuer-hochschulen/weiterfuehrende-infos-zu-daad-foerderprogrammen/promos/ (contact international office at KIT)
Further information
Contact us: corina.saegesser∂hest.ethz.ch; joseph.dumpler∂hest.ethz.ch; nico.leister∂kit.edu
How long: 6 months starting somewhen in 2025
Where: The practical work will mainly be performed at ETH Zürich with potential material characterisation at KIT and potential test trials at Thermo Fisher Scientific in Karlsruhe or Bühler in Uzwil.