Multiscale Modeling for Food Drying: State of the Art

Abstract

Plant-based food materials are mostly porous in nature and heterogeneous in structure with huge diversity in cellular orientation. Different cellular environments of plant-based food materials, such as intercellular, intracellular, and cell wall environments, hold different proportions of water with different characteristics. Due to this structural heterogeneity, it is very difficult to understand the drying process and associated morphological changes during drying. Transport processes and morphological changes that take place during drying are mainly governed by the characteristics of and the changes in the cells. Therefore, to predict the actual heat and mass transfer process that occurs in the drying process and associated morphological changes, development of multiscale modeling is crucial. Multiscale modeling is a powerful approach with the ability to incorporate this cellular structural heterogeneity with microscale heat and mass transfer during drying. However, due to the huge complexity involved in developing such a model for plant-based food materials, the studies regarding this issue are very limited. Therefore, we aim in this article to develop a critical conceptual understanding of multiscale modeling frameworks for heterogeneous food materials through an extensive literature review. We present a critical review on the multiscale model formulation and solution techniques with their spatial and temporal coupling options. Food structure, scale definition, and the current status of multiscale modeling are also presented, along with other key factors that are critical to understanding and developing an accurate multiscale framework. We conclude by presenting the main challenges for developing an accurate multiscale modeling framework for food drying.

A multiscale approach to estimate the cellular diffusivity during food drying

“…Approach 2 resulted in an average ICW diffusivity of 1.5×10 -10 m 2 /s. Most literature on the diffusivity of food material during drying has only investigated the tissue level (macroscale) (Welsh, et al, 2018).…”

“…Recently, researchers have shown their immense interest in multiscale food drying modeling and provided some general background into the topic (Ho et al, 2013;Rahman, Joardder, Khan, et al, 2018;Welsh, Simpson, Khan, & Karim, 2018). Additionally, Welsh, et al (2021) developed a multiscale food drying model utilizing knowledge of the microstructural evolution.…”

Insights of Drying

“…Water distribution inside the food tissue significantly affects the degree of structural changes. Depending on the properties, water in food materials may be categorized into three types, namely free water, loosely bound water, and strongly bound water [45,46]. Based on the distribution of water inside the food tissue, water can also be classified as cell wall water, intercellular water, and intracellular water (See Fig.…”

A multiscale approach to estimate the cellular diffusivity during food drying

“…The migration of ICW causes dynamic modifications to the materials physical structure and nutritional characteristics effecting the products quality (Pham, Khan, & Karim, 2020), and therefore needs be considered to accurately predict the drying kinetics and optimize the drying processes. To address such a research problem, multiscale modeling has been introduced to the field of food drying (Welsh, Simpson, Khan, & Karim, 2018).…”