scholarly journals Mathematical Modeling of Moisture Sorption Isotherms and Determination of Isosteric Heats of Sorption ofZiziphusLeaves

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Amel Saad ◽  
Boumediene Touati ◽  
Belkacem Draoui ◽  
Boufeldja Tabti ◽  
Asma Abdenebi ◽  
...  
Keyword(s):  
Mathematical Modeling ◽  
Experimental Data ◽  
Adsorption Equilibrium ◽  
Sorption Isotherms ◽  
Moisture Sorption ◽  
Static Method ◽  
Clapeyron Equation ◽  
Moisture Sorption Isotherms ◽  
Increasing Temperature

Desorption and adsorption equilibrium moisture isotherms ofZiziphus spina-christileaves were determined using the gravimetric-static method at 30, 40, and 50°C for water activity(aw)ranging from 0.057 to 0.898. At a givenaw, the results show that the moisture content decreases with increasing temperature. A hysteresis effect was observed. The experimental data of sorption were fitted by eight models (GAB, BET, Henderson-Thompson, modified-Chung Pfost, Halsey, Oswin, Peleg, and Adam and Shove). After evaluating the models according to several criteria, the Peleg and Oswin models were found to be the most suitable for describing the sorption curves. The net isosteric heats of desorption and adsorption ofZiziphus spina-christileaves were calculated by applying the Clausius-Clapeyron equation to the sorption isotherms and an expression for predicting these thermodynamic properties was given.

scholarly journals Moisture sorption isotherms of millet seeds

2000 ◽  
Vol 18 (No. 3) ◽  
pp. 86-90 ◽  
Author(s):  
N.D. Menkov ◽  
D.I. Gelyazkov
Keyword(s):  
Experimental Data ◽  
Relative Humidity ◽  
Moisture Content ◽  
Equilibrium Moisture Content ◽  
Sorption Isotherms ◽  
Moisture Sorption ◽  
Static Method ◽  
Moisture Contents ◽  
Moisture Sorption Isotherms ◽  
The Relationship

The equilibrium moisture contents were determined for millet seeds of two cultivars using the gravimetric static method at 10, 25 and 40°C over a range of relative humidities from 0.112 to 0.868. The sorption capacity of the seeds decreased with an increase in temperature at constant relative humidity. The hysteresis effect is not distinctly expressed but statistically significant. The differences between equilibrium moisture contents of the cultivars are small. Four models were applied for analyzing the experimental data using the following equations: modified Chung-Pfost, modified Halsey, modified Oswin, and modified Henderson. The modified Chung-Pfost model was found to be the most suitable for describing the relationship between equilibrium moisture content, relative humidity and temperature.

Determination of the Moisture-Sorption Isotherms and Isosteric Heat of Henna Leaves

2015 ◽  
Vol 88 (1) ◽  
pp. 52-62 ◽  
Author(s):  
S. Bennaceur ◽  
B. Draoui ◽  
B. Touati ◽  
A. Benseddik ◽  
A. Saad ◽  
...  
Keyword(s):  
Sorption Isotherms ◽  
Moisture Sorption ◽  
Isosteric Heat ◽  
Moisture Sorption Isotherms

Moisture Sorption Isotherms of Lentil Extrudates

2012 ◽  
Vol 8 (3) ◽  
Author(s):  
Nikolay Penov ◽  
Todorka Petrova ◽  
Milena Ruskova ◽  
Nesho Toshkov ◽  
Nikolay Menkov
Keyword(s):  
Experimental Data ◽  
Relative Humidity ◽  
Sorption Isotherms ◽  
Moisture Sorption ◽  
Processing Conditions ◽  
Moisture Contents ◽  
Moisture Sorption Isotherms ◽  
The Relationship

Abstract The equilibrium moisture contents (EMC) were determined for lentil extrudates produced under different processing conditions at 25°C and eight relative humidity (RH) in the range of 0.113 – 0.902. It was established that for the ten extruded samples the EMC values at the same RH were not statistically equal. Four models – Chung-Pfost, Halsey, Oswin, and Henderson equations were applied for analyzing the experimental data. The Oswin model was most suitable for describing the relationship between the EMC and RH.

scholarly journals New approach to the calculation of pistachio powder hysteresis

2016 ◽  
Vol 30 (2) ◽  
pp. 245-251 ◽  
Author(s):  
Hamid Tavakolipour ◽  
Mohsen Mokhtarian
Keyword(s):  
Goodness Of Fit ◽  
Capillary Condensation ◽  
Gravimetric Method ◽  
Sorption Isotherms ◽  
Moisture Sorption ◽  
Suitable Model ◽  
Moisture Sorption Isotherms ◽  
Different Temperatures ◽  
Definite Integration ◽  
Increasing Temperature

Abstract Moisture sorption isotherms for pistachio powder were determined by gravimetric method at temperatures of 15, 25, 35 and 40°C. A selected mathematical models were tested to determine the best suitable model to predict isotherm curve. The results show that Caurie model had the most satisfactory goodness of fit. Also, another purpose of this research was to introduce a new methodology to determine the amount of hysteresis at different temperatures by using best predictive model of isotherm curve based on definite integration method. The results demonstrated that maximum hysteresis is related to the multi-layer water (in the range of water activity 0.2-0.6) which corresponds to the capillary condensation region and this phenomenon decreases with increasing temperature.

scholarly journals Beta-glucan rich composite flour biscuits: modelling of moisture sorption isotherms and determination of sorption heat

2014 ◽  
Vol 52 (9) ◽  
pp. 5497-5509 ◽  
Author(s):  
Narender Raju Panjagari ◽  
Ashish Kumar Singh ◽  
Sangita Ganguly ◽  
Kangampalayam Palaniswamy Indumati
Keyword(s):  
Sorption Isotherms ◽  
Moisture Sorption ◽  
Composite Flour ◽  
Beta Glucan ◽  
Moisture Sorption Isotherms ◽  
Sorption Heat

Thermodynamic properties of water sorption isotherms of grape seed

2014 ◽  
Vol 28 (1) ◽  
pp. 63-71 ◽  
Author(s):  
Kamran Maleki Majd ◽  
Seyed H. Karparvarfard ◽  
Asgar Farahnaky ◽  
Sara Ansari
Keyword(s):  
Experimental Data ◽  
Water Activity ◽  
Gravimetric Method ◽  
Sorption Isotherms ◽  
Moisture Sorption ◽  
Isosteric Heat ◽  
Grape Seed ◽  
Clapeyron Equation ◽  
Moisture Sorption Isotherm ◽  
Best Fit

Abstract 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), Ferro-Fontan (3-parameter) and Peleg (4-parameter) models were considered to fit the experimental data. The Ferro- Fontan and Peleg equations (at three temperatures 35, 45, 65°C) having R2 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.

scholarly journals Moisture Sorption Isotherms And Thermodynamic Properties Of Urtica Dioica Leaves

2016 ◽  
Vol 12 (24) ◽  
pp. 376 ◽  
Author(s):  
Abdelkader Lamharrar ◽  
Ali Idlimam ◽  
Mohammed Kouhila ◽  
Lamya Lahnine ◽  
Hind Mouhanni
Keyword(s):  
Water Activity ◽  
Gravimetric Method ◽  
Sorption Isotherms ◽  
Moisture Sorption ◽  
Storage Conditions ◽  
Urtica Dioica ◽  
Endemic Plant ◽  
Clapeyron Equation ◽  
Moisture Sorption Isotherms ◽  
Different Temperatures

Urtica dioica is a Moroccon endemic plant of used for its virtues in traditional medicine. Thus, it is necessary to study the effect of preservation processes on the storage conditions of the plant. The static gravimetric method was used to determine sorption isotherms of Urtica dioica leaves at three temperatures (40, 50 and 60 °C) and in the range of water activity ( w a ) ranging from 0.0572 to 0.898. Six mathematical models were used to fit the experimental data. The Enderby and Peleg models were found to be the most suitable for describing the sorption curves. The optimal water activity for conservation of Urtica dioica leaves was determined. Isosteric heats of desorption and adsorption were calculated by applying the Clausius- Clapeyron equation to the sorption isotherms at different temperatures; it decreased with increasing moisture content. A linear relation exists between the enthalpy and entropy of the sorption reaction.

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