Moisture adsorption–desorption isotherms of Citrus reticulata leaves at three temperatures

Jamali, A.; Kouhila, M.; Mohamed, Latifa A.; Idlimam, Ali; Lamharrar, Abdelkader

doi:10.1016/j.jfoodeng.2005.06.045

Cited by 75 publications

(61 citation statements)

References 13 publications

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“…Marquardt-Levenberg (Jamali et al 2006) non-linear optimization method, using the computer programs Curve Expert 1.4, and Origin 8.5 were used to find the best equation for bay leaves sorption isotherms.…”

Section: Determination Of the Isosteric Heatmentioning

confidence: 99%

Moisture sorption isotherms and heat of sorption of Algerian bay leaves (Laurus nobilis)

Ouafi

Moghrani

Benaouada³

et al. 2015

Maderas, Cienc. tecnol.

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The moisture sorption isotherms of Algerian bay leaves (Laurus nobilis) were determined experimentally in this work. The equilibrium moisture contents of the leaves were measured at 40, 50, and 60 °C using static gravimetric method. Six mathematical models were tested to fit the experimental data of sorption isotherms and predict the hygroscopic behavior during storage or drying. Peleg model was found to be the best fitting model for describing the sorption curves. The net isosteric heat of sorption was computed from the equilibrium data at different temperatures by applying the integrated form of the Clausius-Clapeyron equation.The net isosteric heat of sorption is inversely proportional to the equilibrium moisture content and is found to be an exponential function of moisture content.

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Section: Determination Of the Isosteric Heatmentioning

confidence: 99%

Moisture sorption isotherms and heat of sorption of Algerian bay leaves (Laurus nobilis)

Ouafi

Moghrani

Benaouada³

et al. 2015

Maderas, Cienc. tecnol.

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“…At increased temperatures, molecules are in an increased state of excitation, thus increasing their distance decreases the attractive forces between them (Kaya and Aydin 2009). This leads to a decrease in the degree of water sorption at a given water activity with increasing temperature (Jamali et al 2006). Whereas Mazza and Lemaguer (1980) suggested that increase in temperature induces physical and chemical changes in the product that can reduce the number of active sites for water binding.…”

Section: Sorption Isothermmentioning

confidence: 99%

Thermodynamic analysis of sorption isotherms of cassava (Manihot esculenta)

et al. 2012

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Sorption isotherms of cassava were determined experimentally using a static gravimetric method at 30, 45 and 60°C and within the range of 0.10-0.90 water activity. At a constant water activity, equilibrium moisture content decreased with increasing temperature. The equilibrium moisture content increased with increasing water activity at a given temperature. The experimental results were modelled using seven sorption models using non-linear regression technique. Results demonstrated that the GAB model adequately predicted equilibrium moisture content of cassava for the range of temperatures and water activities studied. The thermodynamic functions such as net isosteric heat of sorption, differential entropy of sorption, net integral enthalpy and entropy were evaluated to provide an understanding of the properties of water and energy requirements associated with the sorption behaviour. Net isosteric heat and differential entropy decreased with increasing equilibrium moisture content. The net integral enthalpy decreased while net integral entropy increased with increasing equilibrium moisture content. Net integral entropy was negative in value. All thermodynamic functions were adequately characterised by a power law model. The point of maximum stability was found between 0.053 and 0.154 kg water/kg db for cassava.

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“…The standard error of estimate, SEE, gives an indication of the precision of the experiment estimation. The model which has the smallest RSS/SEE and the highest R 2 was considered to be the best fitted equation (Chowdhury et al, 2006;Foster et al, 2005;Jamali et al, 2006). Another parameter, the mean relative percentage deviation modulus, M e , is also an important index to select the best fitted equation with a modulus value below 10% indicative of a good fit of practical data on a model equation (Al-Muhtaseb et al, 2004).…”

Section: Methodsmentioning

confidence: 99%

Thermodynamic properties of water sorption isotherms of grape seed

Majd¹,

Karparvarfard²,

Farahnaky³

2014

International Agrophysics

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A b s t r a c t. In this study the moisture sorption isotherm of grape seed was determined by using a static gravimetric method at 35-65°C and 0.108-0.821 water activity range. The sorption isotherms were found to be typical sigmoid shape of most food materials. Five models including the Brunauer-Emmett-Teller (2-parameter), Guggenheim, Anderson and De Boer (3-parameter), Oswin (2-parameter), and Peleg (4-parameter) models were considered to fit the experimental data. The FerroFontan and Peleg equations (at three temperatures 35, 45, 65°C) having R 2 greater than 0.97 and lower values of standard error of estimate and deviation modulus gave the best fit of the experimental data throughout the entire range of water activity. The net isosteric heat of sorption, calculated by Calusius-Clapeyron equation on experimental data, was found to be a polynomial and exponential function of equilibrium moisture content within the temperature range investigated.K e y w o r d s: moisture sorption isotherm, thermodynamic properties, grape seed INTRODUCTION Grapes (Vitis vinifera) originated in Western Asia and Europe. It accounts for about 16% of the global fruit production. Among the major grape producing countries, Iran with the production of 3 mln t ranks the seventh after Turkey (FAO, 2009). Grape seed, a by-product of grape processing, is a well-known oilseed containing about 8-20% oil, 11% protein, and 10-20% polyphenolic compounds like tannins, sugars, minerals and other substances (Campos et al., 2008).Drying grape seed is a critical processing step in the preparation of the seeds for oil extraction. Moisture reduction is necessary to increase shelf-life and to prevent microbial and chemical deterioration. Drying also facilitates handling conditions and reduces storage costs (García-Pérez et al., 2008). In order to describe the process of drying and its effect on water activity (a w ), knowledge of the relationship between equilibrium moisture content (EMC) and water activity/equilibrium relative humidity (ERH) is essential. This relationship, known as moisture sorption isotherm, depends on structure, composition, as well as pressure and temperature (AmiriChayjan and Esna-Ashari, 2010, Chowdhury et al., 2006). It is useful for modelling, designing and optimization of the drying process. The water sorption isotherms can also be used to calculate the net heat of sorption which provides the energy requirements associated with the sorption behaviour. The differential heat of sorption is an indicator of the state of water adsorbed by the solid particles, and its knowledge is important in designing drying unit operation (Chowdhury et al., 2006;Goula et al., 2008).Numerous mathematical models have been used to describe the moisture sorption behaviour of foods. Van den Berg and Bruin (1981) gave more than 200 equations that had been developed theoretically, semi-theoretically and empirically to model the sorption isotherms of different biological materials. Some of those models are based on theories on the sorption mechanism, ...

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Moisture adsorption–desorption isotherms of Citrus reticulata leaves at three temperatures

Cited by 75 publications

References 13 publications

Moisture sorption isotherms and heat of sorption of Algerian bay leaves (Laurus nobilis)

Moisture sorption isotherms and heat of sorption of Algerian bay leaves (Laurus nobilis)

Thermodynamic analysis of sorption isotherms of cassava (Manihot esculenta)

Thermodynamic properties of water sorption isotherms of grape seed

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