Numerical investigation of case hardening of plant tissue during drying and its influence on the cellular-level shrinkage

Karunasena, H. C. P. and Gu, Y.T. and Brown, R. J. and Senadeera, W. (2015) Numerical investigation of case hardening of plant tissue during drying and its influence on the cellular-level shrinkage. Drying Technology, 33 (6). pp. 713-734. ISSN 0737-3937


Dried plant food materials are one of the major contributors to the global food industry. Widening the fundamental understanding of different mechanisms of food material alterations during drying assists the development of novel dried food products and processing techniques. In this regard, case hardening is an important phenomenon, commonly observed during the drying processes of plant food materials, which significantly influences the product quality and process performance. In this work, a mesh-free-based 2D numerical model developed by the authors is further improved and used to simulate the influence of case hardening on shrinkage characteristics of plant tissues during drying. In order to model the fluid mechanisms of plant cells, smoothed particle hydrodynamics (SPH), which is a popular mesh-free technique used to solve hydrodynamics problems, is used. The cell wall mechanisms are modeled using the discrete element method (DEM). The model is fundamentally more capable of simulating large deformations of multiphase materials compared to conventional grid-based modeling techniques such as finite element methods (FEM) or finite difference methods (FDM). Case hardening is implemented by maintaining distinct moisture levels in the different cell layers of a given tissue. In order to compare and investigate different factors influencing tissue deformation under case hardening, four different plant tissue varieties (apple, potato, carrot, and grape) are studied. The simulation results indicate that the inner cells of any given tissue undergo limited shrinkage and cell wall wrinkling, compared to the case-hardened outer cell layers of the tissues. For a given dried tissue condition, the case-hardened cellular deformations are highly influenced by the unique characteristics of the different tissues, such as cell size, cell fluid turgor pressure, and cell wall properties.

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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Files associated with this item cannot be displayed due to copyright restrictions.
Faculty/School / Institute/Centre: Current - Faculty of Health, Engineering and Sciences - School of Mechanical and Electrical Engineering
Date Deposited: 07 Feb 2017 04:37
Last Modified: 22 Feb 2017 06:37
Uncontrolled Keywords: case hardening; DEM; food drying; mesh-free methods; microscale models; numerical modeling; plant tissue; shrinkage; SPH
Fields of Research : 09 Engineering > 0908 Food Sciences > 090802 Food Engineering
Socio-Economic Objective: E Expanding Knowledge > 97 Expanding Knowledge > 970109 Expanding Knowledge in Engineering
Identification Number or DOI: 10.1080/07373937.2014.982759

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