Heat and mass transfer analysis of intra-kernel wheat drying and rewetting

Water absorption and starch gelatinization in whole rice grain during soaking

“…The starch swells when it becomes wet, so that, in the hydration process the grain size increases; however, this effect is not considered here. Experimental work for water hydration of grains (Fortes, Okos, & Barret, 1981;Kustermann, Scherer, & Kutzbach, 1981) demonstrated that the heating process proceeds far more rapidly than hydration process; hence the two processes can be considered decoupled in any model. Although rice has not defined geometry, the grain was assumed a sphere to have an analytical solution for hydration process (Bandyopadhyay & Roy, 1978;Suzuki et al, 1976).…”

Convective Drying Analysis of a Single Wheat Kernel Based on an Irreversible Thermodynamics Model

“…The main thin-layer theoretical models are included mechanistic models, such as liquid diffusion models and=or vapor diffusion, [6][7][8][9][10][11][12][13][14][15] statistical models and models derived from the thermodynamics of irreversible processes and=or mixed models. [1,[16][17][18][19][20] Durst, [21] based on literature data, pointed out that the kinetic theory of gases provided excellent qualitative descriptions of drying processes, but led to inaccurate prediction of the quantitative aspects such as temperature jumps. The statistical rate theory utilized the transition probability concept and did not adequately predict the energy flux.…”

“…Fortes [29] and Fortes et al [1] proposed a drying theory of hygroscopic capillary-porous products based on irreversible thermodynamics and mechanistic approaches. The model utilized Onsager's reciprocity theorem and did not require the specification of drying mechanisms.…”

“…Additionally, their physical, chemical, and biochemical behaviors change during drying, depending on the variety, physiological maturity at harvesting, and history of drying and rewetting while in the field. [1][2][3] Generally, deep-bed grain drying simulations and subsequent analyses have made use of thin-layer and singlekernel drying equations. [2] In this work, following classical definitions, [1][2][3] we have defined a thin layer as a layer of material fully exposed to the airstream during drying, such that each one of its particles dries as a single kernel.…”

“…[1][2][3] Generally, deep-bed grain drying simulations and subsequent analyses have made use of thin-layer and singlekernel drying equations. [2] In this work, following classical definitions, [1][2][3] we have defined a thin layer as a layer of material fully exposed to the airstream during drying, such that each one of its particles dries as a single kernel. The thin-layer=single-kernel concept is useful to evaluate hydro and thermal stresses which can lead to cracks and possibly can compromise the grain quality during the drying process.…”