A Diffusion Model with a Concentration‐Dependent Diffusion Coefficient for Describing Water Movement in Legumes During Soaking

Abstract

A mathematical model based on Fick's diffusion equation with a concentration-dependent diffusion coefficient was proposed to describe the absorption of water by legumes. The equation was solved by using a numerical scheme. Parameter study was performed. The model is capable of predicting sigmoidal-shaped water uptake curves common to many legumes. Differences are discussed between the surface resistance boundary condition used in this study and the radiation boundary condition widely used for dehydration calculations. The validity of using the proposed model to described the water uptake of legumes was verified by the good fit between the experimental and theoretical curves.

Kinetic, thermodynamic properties, and optimization of barley hydration

“…Higher temperatures are known to expand and soften grains (KASHANINEJAD et al, 2007). Several studies have shown that increasing the temperature of the soaking medium is an excellent way to accelerate the water absorption of various seeds, reducing the soaking time (QUAST; DA SILVA, 1977;KON, 1979;OBEKPA, 1990;ABU-GHANNAM;MCKENNA, 1997;TANG;SOKHANSANJ;SOSULSKI, 1994;HUNG et al, 1993;SEYHAN-GÜRTAS;AK;EVRANUZ, 2001;HSU, 1983a;MASKAN, 2002). The moisture content of the grains during hydration can be directly related to two variables: time and temperature.…”

“…It can be observed that at all temperatures, water uptake was faster in the initial stages, especially in the first four hours, and gradually slowed down as the moisture content approached saturation. According to Hsu (1983a), it had been demonstrated that diffusion in the solid endosperm is the main mechanism that controls the rate of absorption in seeds regardless of the process conditions. There was a significant effect of temperature on the grain moisture (p ≤ 0.05), mainly on the dynamic of hydration isotherms and also on the equilibrium moisture of the five cultivars.…”

Drying kinetics of barley grains and effects on the germination index

“…Phenomenological models consider the elementary steps of mass transfer by diffusion (Fan et al, 1962;Hsu, 1983).…”

A Polymer Science Approach to Physico-Chemical Characterization and Processing of Pulse Seeds

“…Water uptake behavior cannot solely be linked to seed coat thickness. Seed size has also been linked to water uptake behavior (Arechavaleta-Medina and Synder, 1981;Hsu et al, 1983a;Seyhan-Gurtas et al, 2001). As water uptake is determined via mass uptake such that a smaller seed would exhibit a proportionally greater increase in water mass uptake than a larger seed if both were taking up water at the same rate.…”

“…no lag) can be considered well hydrating seeds. For example, seeds like peas (yellow, green and Marrowfat), navy beans, kidney beans, chickpeas, lentils, and most soybeans have been noted to possess rapid water uptake and do not possess a lag period prior to imbibition Abu-Ghannam & McKenna, 1997;Hsu, 1983a;Hsu, 1983b;Liu et al, 2005;Meyer et al, 2007;Ross et al, 2008;Seyhan-Gurtas et al, 2001). However some pulses like pinto beans, black beans, dried green beans, red beans possess a significant lag period prior to the initiation of water uptake (Liu et al, 2005;Ross et al, 2008).…”