The determination of sorption isotherm and the isosteric heats of sorption for potatoes

McLaughlin, Chris; Magee, T.R.A.

doi:10.1016/s0260-8774(98)00025-9

Cited by 221 publications

(176 citation statements)

References 18 publications

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“…Moreover, when the temperature of the product was increased, water molecules were gaining greater kinetic energy, which enables them to get away from their binding positions (Quirijns et al 2005). Similar observations were obtained by McLaughlin and Magee (1998), AlMuhtaseb et al (2004) and Erbas et al (2005). The constants C g and K give indications on energies of interaction between food and water molecules.…”

Section: Modeling Sorption Isothermsupporting

confidence: 67%

“…Furthermore, the extent of the hysteresis was obviously diminished when the temperature was increased and almost eliminated at 50°C. Similarly, Benado and Rizvi (1985), McLaughlin and Magee (1998), Yan et al (2008) found a decline of the hysteresis magnitude with increasing temperature for rice, potato and banana, respectively. While there is no concrete explanation for this phenomenon, it is commonly believed that there should be some irreversible thermodynamic reactions responsible for the changes in sorption characteristic of food.…”

Section: Resultsmentioning

confidence: 80%

“…Isosteric heat of sorption also provides valued information on the nature of the water present in the material. When the isosteric heat of soprtion exceeds the heat of vaporization of pure water, it is normally considered as an indication on bound water in food (McLaughlin and Magee 1998). Knowledge of isosteric heat of sorption is pre-requested for the overall description of the state of water in the food matrixes as well as for designing of drying operations (Al-Muhtaseb et al 2002).…”

Section: Introductionmentioning

confidence: 99%

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Sorption isotherms and isosteric heats of sorption of Malaysian paddy

et al. 2012

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Understanding the water sorption characteristics of cereal is extremely essential for optimizing the drying process and ensuring storage stability. Water relation of rough rice was studied at 20, 30, 40 and 50°C over relative humidity (RH.) between 0.113 and 0.976 using the gravimetric technique. The isotherms displayed the general sigmoid, Type II pattern and exhibited the phenomenon of hysteresis where it was more pronounced at lower temperatures. The sorption characteristics were temperature dependence where the sorption capacity of the paddy increased as the temperature was decreased at fixed (RH). Among the models assessed for their ability to fit the sorption data, Oswin equation was the best followed by the third order polynomial, GAB, Smith, Chung-Pfost, and Henderson models. The monolayer moisture content was higher for desorption than adsorption and tend to decrease with the increase in temperature. Given the temperature dependence of the sorption isotherms the isosteric heats of sorption were calculated using Claussius-Clapeyron equation. The net isosteric heats decreased as the moisture content was increased and heats of desorption were greater than that of adsorption.

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Section: Modeling Sorption Isothermsupporting

confidence: 67%

Section: Resultsmentioning

confidence: 80%

Section: Introductionmentioning

confidence: 99%

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Sorption isotherms and isosteric heats of sorption of Malaysian paddy

et al. 2012

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“…This confirms the fact that at higher moisture levels, the strength of water binding decreases. Different polar groups on the water binding polymers in foods and changes in the dimensions and geometry of the polymers during sorption are thought to give rise to this range of activity in sorption sites (McLaughlin and Magee, 1998).…”

Section: Resultsmentioning

confidence: 99%

Moisture sorption characteristics of microalgae Spirulina platensis

Oliveira

Rosa

Moraes

et al. 2009

Braz. J. Chem. Eng.

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-In recent times, the microalgae Spirulina platensis has been used as a functional ingredient in several food applications; its process involving drying and storage steps. Moisture equilibrium data for adsorption isotherms of microalgae Spirulina were investigated at 10, 20 and 30°C and for desorption, at 40, 50 and 60°C, using the gravimetric static method. The experimental data were analyzed by GAB and BET models. The GAB equation showed the best fitting to the experimental data with R² ≈ 99% and MRE < 10%. The water surface area values calculated by GAB and BET models were very similar. The isosteric heats were determined by application of Clausius-Clapeyron equation to sorption isotherms obtained from the best-fitting equation. The isosteric heat and the entropy of desorption isotherm presented similar behavior, with a sharp change in an equilibrium moisture content of 10%. The enthalpy-entropy compensation theory was applied to the isotherms, indicating that they are enthalpy-controlled.

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“…Esta ecuación está basada en la teoría de adsorción de BET (Brunauer-Emmet-Teller), la cual da una explicación física a los parámetros involucrados en ella [15]. Otro factor importante, a la hora de elegir la ecuación a utilizar, es la simplicidad y el tiempo que pueda necesitar el cálculo de la humedad de equilibrio [21].…”

Section: -Introducciónunclassified

Isotermas de adsorción en harina de maíz (Zea mays L.)

Gálvez¹,

Aravena²,

Mondaca³

2006

Ciênc. Tecnol. Aliment.

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RESuMENEl objetivo de este trabajo fue determinar las isotermas de adsorción de humedad de harina de maíz a tres temperaturas (7, 22 y 45 °C) para el rango de a w entre 0,10 y 0,95. Las isotermas se modelaron utilizando siete ecuaciones comúnmente aplicadas en alimentos. La calidad de ajuste se evaluó con el coeficiente de regresión (r 2 ) y el porcentaje de error medio relativo (% E), en función de los cuales se observó que los modelos propuestos por GAB, Oswin y Halsey ajustaron de mejor manera los datos experimentales. La humedad de la monocapa (X m ) y la humedad de seguridad (X S ) presentaron dependencia con la temperatura con valores de E a de 13,6 y 3,3 kJ/mol, respectivamente. Se cálculo el calor isostérico de adsorción (Q S ) usando la ecuación de Clausius-Clapeyron, obteniéndose un máximo de 21 kJ/mol, para una humedad de 0,075 g agua/g m.s., este parámetro se modeló utilizando la ecuación propuesta por Tsami. Palabras-clave: harina de maíz, isotermas de adsorción, Arrhenius, calor isostérico. RESuMOISOTERMAS DE ADSORÇÃO EM FARINHA DE MILHO (Zea mays L.). O objectivo deste trabalho foi determinar as isotermas de adsorção de umidade da farinha de milho a três temperaturas (7, 22 e 45 °C) para um rango de a w entre 0,10 e 0,95. As isotermas foram modelizadas por meio de sete equações normalmente utilizadas em alimentos. A qualidade do ajuste foi avaliada mediante o coeficiente de regressão (r 2 ) e a porcentagem de erro médio relativo (% E), em função dos quais se observou que os modelos propostos por GAB, Oswin e Halsey apresentaram um melhor ajuste dos dados experimentais. A umidade da monocapa (X m ) e a umidade de segurança (X S ) mostraram dependência da temperatura com valores de E a de 13,6 e 3,3 kJ/mol, respectivamente. Calculou-se o calor isostérico de adsorção (Q S ) utilizando-se a equação de Clausius-Clapeyron, obtendo-se um máximo de 21 kJ/mol. Para uma umidade de 0,075 g água/g m.s., este parâmetro modelizou-se utilizando a equação proposta por Tsami. Palavras-chave: milho, modelos, Arrhenius, calor isostérico. -INTRODuCCIÓNEl maíz (Zea mays L.) es un cereal ampliamente utilizado en el mundo entero tanto para consumo humano como para alimentación animal. Constituye junto con la patata y la tapioca, las materias primas más importantes para la obtención de almidón, de jarabes de glucosa y de bebidas alcohólicas. Para consumo humano se pueden obtener harinas de maíz, aceite de germen, productos para desayuno y conservas de maíz dulce, entre otros alimentos. Por su alto contenido de almidón, las harinas y sémolas de maíz son una fuente importante de calorías en la dieta de países de América Central y del Sur, donde este cereal es alimento básico [22].La harina de maíz, al no contener gluten, sirve de base de harinas panificadoras para los enfermos celíacos, al igual que las harinas de arroz, quínoa, soya y mandioca [18]. La celíaquia se caracteriza por la intolerancia al gluten, en concreto son las prolaminas presentes en el trigo (gliadinas), avena (avidina), cebada (hordeína), centeno (secal...

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The determination of sorption isotherm and the isosteric heats of sorption for potatoes

Cited by 221 publications

References 18 publications

Sorption isotherms and isosteric heats of sorption of Malaysian paddy

Sorption isotherms and isosteric heats of sorption of Malaysian paddy

Moisture sorption characteristics of microalgae Spirulina platensis

Isotermas de adsorción en harina de maíz (Zea mays L.)

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