Critical Analysis of the Use of Semiempirical Models on the Dehydration of Thin-Layer Foods Based on Two Study Cases

Abstract

Moisture transport during food drying can be phenomenologically described by Fick’s second law and by the so-called anomalous diffusion model. However, in the literature, many studies have shown the extensive use of empirical/semiempirical models (EMs/SEMs) to adjust experimental data for the drying of thin-layer foods. This research aims to perform a critical analysis of the most commonly used EMs/SEMs and compare them with Fick’s second law and an anomalous diffusion model using two different sets of hot-air drying data. Two waste byproducts from the food industry, spent coffee grounds and passion fruit peels, were selected for analysis. The selected EMs/SEMs were found to be mathematically interrelated (i.e., some are a subset of others), and their appropriateness was incorrectly justified mainly by their statistical goodness-of-fit. As shown, it is highly recommended that researchers start analyzing drying data with phenomenological models. The extensive use of EMs and SEMs can be replaced by the anomalous diffusion model, which has a high capacity to adjust empirical data and a sound phenomenological description of the process.

Development of an Apple Snack Enriched with Probiotic Lacticaseibacillus rhamnosus: Evaluation of the Refractance Window Drying Process on Cell Viability

“…Several studies have concluded that the fit with the anomalous model is better than that with Fick’s model [ 31 , 54 , 62 , 93 ]. Vega-Castro et al [ 95 ] concluded that the reason is that the anomalous model has a sound phenomenological description of the process and a high capacity to adjust empirical data.…”

Drying kinetics and mathematical modeling of seeds of two mango varieties at different temperatures and with different pretreatments

“…Several mathematical models were used to determine the kinetics of drying mango seeds (local and hybrid) and to calculate the ideal drying parameters to evaluate the performance of the drying process. These mathematical models can be divided into three major categories: theoretical, semitheoretical, and empirical 47 . The first category of models considers the internal resistance to moisture transfer only, whereas the other two consider the external resistance to moisture transfer between the seeds and air 48 .…”

“…The first category of models considers the internal resistance to moisture transfer only, whereas the other two consider the external resistance to moisture transfer between the seeds and air 48 . The models most commonly used for oilseeds and agricultural products are empirical and semitheoretical models, based on Fick's second law 47 . Different empirical and semiempirical mathematical models have different performance and fitness to experimental data, so it is essential to select a good mathematical drying model that best fits the drying curves under different conditions.…”

“…These mathematical models can be divided into three major categories: theoretical, semitheoretical, and empirical. 47 The first category of models considers the internal resistance to moisture transfer only, whereas the other two consider the external resistance to moisture transfer between the seeds and air. 48 The models most commonly used for oilseeds and agricultural products are empirical and semitheoretical models, based on Fick's second law.…”

“…48 The models most commonly used for oilseeds and agricultural products are empirical and semitheoretical models, based on Fick's second law. 47 Different empirical and semiempirical mathematical models have different performance and fitness to experimental data, so it is essential to select a good mathematical drying model that best fits the drying curves under different conditions. Despite many models being used for drying oil seeds, only the three most commonly used (the Lewis model, the Henderson and Pabis model, and the Page model) and one recently developed model (Avhad and Marchetti) were considered for this study.…”