Simulation of Plant Cell Shrinkage during Drying -a Sph-dem Approach

8 9 Plant based dried food products are popular commodities in global market where much research is focused to improve 10 the products and processing techniques. In this regard, numerical modelling is highly applicable and in this work, a 11 coupled meshfree particle-based two-dimensional (2-D) model was developed to simulate micro-scale deformations of 12 plant cells during drying. Smoothed Particle Hydrodynamics (SPH) was used to model the viscous cell protoplasm (cell 13 fluid) by approximating it to an incompressible Newtonian fluid. The visco-elastic characteristic of the cell wall was 14 approximated to a Neo-Hookean solid material augmented with a viscous term and modelled with a Discrete Element 15 Method (DEM). Compared to a previous work [H. C. P. Karunasena, W. Senadeera, Y. T. Gu and R. J. Brown, Appl. 16 Math. Model., 2014], this study proposes three model improvements: linearly decreasing positive cell turgor pressure 17 during drying, cell wall contraction forces and cell wall drying. The improvements made the model more comparable 18 with experimental findings on dried cell morphology and geometric properties such as cell area, diameter, perimeter, 19 roundness, elongation and compactness. This single cell model could be used as a building block for advanced tissue 20 models which are highly applicable for product and process optimizations in Food Engineering. 21 22 23