Mechanical Characterisation and modelling of the rolling process of potato-based dough

Motivated by social, economic and health factors, food product manufacturers are increasingly attracted towards the incorporation of potato into snack foods. However, the lack of gluten degrades the mechanical properties of potato dough, posing a challenge in ensuring optimal manufacturing processes. An important process of industrial dough production is the sheeting or rolling process. This study developed a computational design tool to ensure smooth sheeting processes for potato doughs. A visco-hyperelastic constitutive model was calibrated using uniaxial compression data, providing the required material parameters for the rolling simulation. The model output was validated through tests on a laboratory small-scale instrumented rolling rig, where the roller speed and roll gap were varied to determine the effect on the rolling force and sheet exit thickness. A good agreement between the experimental and numerical results for the roll force and sheet exit thickness was found for smaller reduction ratios. At larger reductions, the numerical rolling force and exit thickness values were higher than the experimental values, and this was attributed to the dough being damaged while being fed through small roll gaps. A critical tensile strain-based failure criterion was proven to be accurate in predicting conditions for sheet tearing. The combination of the newly developed numerical model and tensile strain failure criterion can serve as a simple and powerful design tool for predicting the roll forces, the rolled sheet height as well as the process conditions which may lead to damage in the potato dough. As a result, interruptions in the continuous sheeting process associated with sheet damage or tearing may be avoided. Since the present study focuses on rolling parameters in a laboratory scale setup, future work will provide greater insight in scaling up the results to industrial rolling processes.