Measurement of Water Diffusivities in Barley Components Using Diffusion Weighted Imaging and Validation with a Drying Model

Ghosh, P. K.; Jayas, Digvir S.; Gruwel, Marco L.H.

doi:10.1080/07373930802682973

Cited by 7 publications

(3 citation statements)

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“…Barley is commonly used in industry for malting and as animal feed. However, its high fiber content has motivated interest in increasing human consumption of it, for example in bakery products (Ghosh, Jayas, & Gruwel, 2009;Sharma, Singh, & Rosell, 2011). Different cultivars may influence the barley's chemical composition and hydration thermodynamic properties (Montanuci, Jorge, & Jorge, 2013).…”

Section: Introductionmentioning

confidence: 99%

<b>Statistical evaluation of models for sorption and desorption isotherms for barleys

et al. 2018

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This study presents a novel approach to evaluate water sorption and desorption isotherm modeling consisting in statistical evaluation of the fit followed by the ranking of the models. Water sorption and desorption isotherms for BRS Elis and BRS Cauê barley cultivars were evaluated at 40, 50, and 60°C. Data were analyzed by the GAB, Freundlich, Halsey, Henderson, Langmuir, Oswin, and Smith models. The BET model was also fitted to determine the moisture content. All models were submitted to five tests to determine whether the model was statistically significant. Then, the models were ranked using corrected Akaike information criterion. At all temperatures, the equilibrium moisture content increases as water activity increases and temperature decreases. Data showed no hysteresis in both cultivars. The statistical parameters evaluated indicate the goodness of the fit for all models except for the GAB model for BRS Elis cultivar at 60°C. The analysis with the corrected Akaike information criterion revealed that the Oswin and Henderson models showed best results at 40 and 50°C for both cultivars studied. At 60°C, the Freundlich model was the best for both cultivars. For both cultivars, the value of isosteric heat decreases with an increase in moisture content.Avaliação estatística de modelos de isotermas de sorção e dessorção em cultivares de cevada RESUMO. Este trabalho apresenta uma nova abordagem para avaliar modelos de sorção e dessorção de umidade, que consiste em avaliar estatisticamente a classificação dos modelos ajustados. Isotermas de sorção e dessorção para as cultivares de cevada BRS Elis e BRS Cauê foram determinadas a 40, 50 e 60°C. Os dados foram analisados pelos modelos GAB, Freundlich, Halsey, Henderson, Langmuir, Oswin e Smith. O modelo BET também foi ajustado para determinar o teor de umidade. Os modelos foram submetidos a cinco testes estatísticos para determinação da significância estatística; para fins de classificação, foi utilizado o Critério de Informação de Akaike corrigido (AICc). Em todas as temperaturas, a umidade de equilíbrio aumenta com o aumento da atividade da água e com a diminuição da temperatura. Os parâmetros estatísticos avaliados indicaram um bom ajuste dos modelos, com exceção do modelo GAB para a BRS Elis a 60°C. A análise com a utilização do AICc mostrou que os modelos Oswin e Henderson possuem melhores resultados a 40 e a 50°C para as duas cultivares. A 60°C, o modelo de Freundlich foi o melhor para as duas cultivares. Para ambas as cultivares, o calor isostérico diminuiu com o aumento do conteúdo de umidade.

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Section: Introductionmentioning

confidence: 99%

<b>Statistical evaluation of models for sorption and desorption isotherms for barleys

et al. 2018

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“…Here, we have used the porous media model (8,9), which provides a simple, physically based method for parameterizing the diffusion time dependence of ADC (D(D)), based on the Mitra equations (10)(11)(12)(13). This model was initially proposed for use in biological tissues (14) and has been applied to various biological systems in vivo (15) and ex vivo (8,16,17) and to microstructure phantoms (18,19), but, as we are aware, it has never previously been used for in vivo human tissues. For restricted diffusion in porous media, Latour et al (14) simplified the model using a Pade approximant to Equation [1]:…”

Section: Introductionmentioning

confidence: 99%

“…Here, we have used the porous media model , which provides a simple, physically based method for parameterizing the diffusion time dependence of ADC ( D (Δ)), based on the Mitra equations . This model was initially proposed for use in biological tissues and has been applied to various biological systems in vivo and ex vivo and to microstructure phantoms , but, as we are aware, it has never previously been used for in vivo human tissues. For restricted diffusion in porous media, Latour et al simplified the model using a Pade approximant to Equation :

D (Δ) = D o {1 - (1 - \frac{1}{α}) (\frac{c \sqrt{Δ} + \frac{(1 - \frac{1}{α}) Δ}{θ}}{(1 - \frac{1}{α}) + c \sqrt{Δ} + \frac{(1 - \frac{1}{α}) Δ}{θ}})}

where D o is the unrestricted self‐diffusion coefficient, Δ is the diffusion time,

c = \frac{4}{9 \sqrt{π}} (\frac{S}{V}) \sqrt{D_{o}}

, θ is a time scaling factor, which depends on the characteristic size of restricting and hindering microstructure, α is the (dimensionless) tortuosity index of the medium, relevant in the long Δ regime in which spins diffuse greater distances than the characteristic restriction lengths and hence sample the connectivity of spaces within the tissue, and S / V (mm −1 ) is the surface‐to‐volume ratio of the medium reflected in the short Δ regime where surfaces are probed by a fraction of molecules.…”