Solid-liquid extraction (leaching) in the food industry

The chapter has been prepared to inform readers about modeling of solid-liquid extraction processes, which are common in food science and technology and related industries. The chapter has been built-up with system modelling in terms of fluid flow and accompanying mass and heat transfers. For solid-liquid extraction processes, it is well known that the main mechanisms, including fluid flow, and mass and heat transfers, should be considered together. Thus, as a first step, fluid flow has been examined for the batch and semicontinuous systems and, as a modelling approach, computational fluid dynamics (CFD) is investigated in its details and procedures. Once the flow dynamics are defined, the mass transfer of extracted solutes and the heat transfer through the extraction medium, if it is applicable, have been introduced, including the terms based on the velocity profile developed by CFD. All these equations are produced based on Navier-Stokes equations. Finally, industrial concepts have been evaluated for the solid-liquid extraction processes. This chapter provides essential knowledge about the analysis and design of the solid-liquid extraction processes in batch and semicontinuous systems for readers and is a good starting point to understand and plan their future work.