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.

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.

Modeling of the Equilibrium Moisture Content (EMC) of Tarragon (Artemisia Dracunculus L.)

2005 ◽  
Vol 1 (5) ◽  
Author(s):  
Akbar Arabhosseini ◽  
Willem Huisman ◽  
Anton van Boxtel ◽  
Joachim Müller
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Equilibrium Moisture Content ◽  
Sorption Isotherms ◽  
Moisture Sorption ◽  
Relative Deviation ◽  
Artemisia Dracunculus ◽  
Significant Difference ◽  
Moisture Sorption Isotherms ◽  
The Relationship

The equilibrium moisture content of tarragon, Artemisia dracunculus L. (stem and leaf separately) was determined by using the saturated salt solutions method at three temperatures (25, 50 and 70°C) within a range of 5 to 90% relative humidity. Both adsorption and desorption methods were used for stem and leaf of two varieties: Russian and French tarragon. Experimental curves of moisture sorption isotherms were fitted by modified Henderson, modified Halsey, modified Oswin, modified Chung-Pfost and GAB equations and evaluated by residual sum squares, standard error of estimate and mean relative deviation. The modified Halsey and GAB equations were found to be the most suitable for describing the relationship among equilibrium moisture content, relative humidity and temperature. There was no significant difference between the equilibrium moisture content of the Russian and French tarragon.

Equilibrium Moisture Content Models for Lafun

2008 ◽  
Vol 4 (2) ◽  
Author(s):  
Olusegun J Oyelade
Keyword(s):  
Moisture Content ◽  
Equilibrium Moisture Content ◽  
Adsorption Isotherms ◽  
Gravimetric Method ◽  
Sorption Isotherms ◽  
Moisture Sorption ◽  
Keeping Quality ◽  
Moisture Sorption Isotherms ◽  
Process Operation ◽  
The Relationship

Insights into the relationship between the air relative humidity (water activity (aw)) and equilibrium moisture content of food materials is essential to maintain good keeping quality and optimize process operation. The adsorption isotherms for cassava flour (lafun) were investigated with the static gravimetric method. Concentrated acid (H2SO4) solutions were used to vary the micro-climate in the study and presented in an easy-to-use template-like format over the range of temperature (27- 40oC) and aw (0.10-0.80) usually experienced in the tropical environment. The experimental data were compared with five widely recommended models in the literature for food sorption isotherms (GAB, modified GAB, modified Oswin, modified Henderson & modified Chung-Pfost). The moisture sorption isotherms were sigmoidal in shape and were influenced by temperature. The modified Oswin model was found to be most adequate whilst the modified GAB appears not suitable to model the adsorption isotherms for lafun.

Experimental Study and Modelling of Moisture Sorption Isotherms of Salted Largehead Hairtail (Trichiurus lepturus) at 25 and 35°C

2014 ◽  
Vol 1033-1034 ◽  
pp. 681-689
Author(s):  
Zhong Yang Ren ◽  
Yan Yan Wu ◽  
Zhen Hua Duan ◽  
Lai Hao Li ◽  
Xian Qing Yang
Keyword(s):  
Experimental Data ◽  
Moisture Content ◽  
Equilibrium Moisture Content ◽  
Water Activity ◽  
Gravimetric Method ◽  
Sorption Isotherms ◽  
Moisture Sorption ◽  
The Body ◽  
Trichiurus Lepturus ◽  
Moisture Sorption Isotherms

The moisture sorption characteristics of salted largehead hairtail (Trichiurus lepturus) were investigated within the limits of water activity (0.11-0.98) at 25 and 35°C using a self-made instrument for the measurement of the equilibrium moisture content according to the static gravimetric method. The shape of the sorption isotherms was sigmoidal. The moisture sorption isotherms exhibited significant hysteresis. The hysteresis of salted fish may be due to the salt permeating into the body of the fish as a result of desorption and adsorption processes. Seventeen mathematical models were fit to the experimental data for the equilibrium moisture content at different water activity levels. The Ferro-Fontan equation provided the best fit for the experimental data of the equilibrium moisture content among the 17 models assessed for the sorption isotherms at 25 and 35°C. The net isosteric heats of sorption decreased gradually with increases in moisture content. The isosteric heats of sorption ranged from 44.59 kJ/mol to 45.61 kJ/mol between the moisture contents of 22.22% and 43.25% for salted largehead hairtail.

Sorption Isotherms and Isosteric Heat of Peanut Pods, Kernels and Hulls

2007 ◽  
Vol 13 (3) ◽  
pp. 231-238 ◽  
Author(s):  
P.C. Corrêa ◽  
A.L.D. Goneli ◽  
C. Jaren ◽  
D.M. Ribeiro ◽  
O. Resende
Keyword(s):  
Experimental Data ◽  
Relative Humidity ◽  
Moisture Content ◽  
Mathematical Models ◽  
Equilibrium Moisture Content ◽  
Sorption Isotherms ◽  
Isosteric Heat ◽  
Statistical Parameters ◽  
Peanut Hulls ◽  
Pass Through

This study was carried out to evaluate the sorption isotherms of peanut pods, kernels and hulls for several temperature and humidity conditions and to fit different mathematical models to the experimental data, selecting the one best fitting the phenomenon. The dynamic method was applied to obtain the hygroscopic equilibrium moisture content. The environmental conditions were provided by means of an atmospheric conditioning unit, in which removable perforated trays were placed to allow air to pass through peanut mass, each one containing 50 g of the product. The mathematical models frequently used for the representation of hygroscopicity of agricultural products were fit to the experimental data. Based on those results, it was concluded that peanut pods, kernels and hulls presented differentiated hygroscopicity. The equilibrium moisture content for peanut pods, kernels and hulls increased with an increase in the relative humidity at any particular temperature and decreased with increase in temperature at constant relative humidity. At a constant water activity, peanut hulls samples had higher equilibrium moisture content than the pods and kernels samples. Based on statistical parameters, the modified Henderson and Chung-Pfost models were found to adequately describe the sorption characteristics of peanut pods, kernels and hulls. Isosteric heat of desorption were evaluated by applying the Clausius—Clapeyron equation to experimental isotherms and decreased with increasing moisture content. The peanut hulls had higher isosteric heat of sorption than that peanut pods and kernels.

Moisture Sorption Characteristics of Dakuwa (Nigerian Cereal/Groundnut Snack)

2013 ◽  
Vol 9 (4) ◽  
pp. 499-504 ◽  
Author(s):  
Ocheme Boniface Ocheme ◽  
Chukwuma Charles Ariahu ◽  
Emmanuel Kongo Ingbian
Keyword(s):  
Moisture Content ◽  
Equilibrium Moisture Content ◽  
Goodness Of Fit ◽  
Sorption Isotherms ◽  
Moisture Sorption ◽  
Sorption Data ◽  
Moisture Contents ◽  
Monolayer Moisture ◽  
Increasing Temperature ◽  
Sorption Characteristics

AbstractThe moisture sorption characteristics of dakuwa at 10, 20, 30 and 400°C were studied. The experimental sorption data obtained were applied to BET, GAB, Oswin and Henderson equations to test fitness of the equations to moisture sorption of dakuwa. The sorption isotherms of dakuwa were type III isotherms (J shaped), and the equilibrium moisture content increased with increasing water activity but decreased with increasing temperature. The BET and GAB monolayer moisture contents all decreased with increasing temperature. For adsorption, the BET monolayer was higher (3.163–4.158 g/100 g solid) than that of GAB (2.931–3.728 g/100 g solid), but for desorption, the GAB monolayer (4.792–7.741 g/100 g solid) was higher than that of BET (3.962–4.480 g/100 g solid). Evaluation of goodness of fit of models revealed that moisture sorption of dakuwa was best modelled by GAB equation.

Moisture Sorption Isotherms and Net Isosteric Heats of Sorption of Green Soybean

2012 ◽  
Vol 8 (3) ◽  
Author(s):  
Zhao Yang ◽  
Enlong Zhu ◽  
Zongsheng Zhu
Keyword(s):  
Moisture Content ◽  
Equilibrium Moisture Content ◽  
Sorption Capacity ◽  
Water Activity ◽  
Sorption Isotherms ◽  
Moisture Sorption ◽  
Isosteric Heat ◽  
Model Parameters ◽  
Desorption Process ◽  
Moisture Sorption Isotherms

Abstract Moisture sorption isotherms of green soybean seeds were determined by static gravimetric method and water activity ranging from 0.11to 0.94 at 20, 30 and 40°C. The optimal sorption model of green soybean was determined by using nonlinear regression method. Modified BET multilayer sorption theory model parameters at different temperatures were calculated, isosteric sorption heat was derived by the water activity sorption isosteric model. Results indicated that sorption isotherms were belong to type III behaviour, a notable hysteresis effect was observed, Green soybean monolayer saturated sorption capacity was greater in desorption process than that of adsorption. The monolayer saturated sorption capacity decreased with increasing temperature, while the number of multilayer had a reverse trend with the monolayer saturated sorption capacity, the optimal sorption isotherm model for green soybean is Halsey model, The thermodynamic parameters including net isosteric heat of adsorption and desorption calculated at 40°C were 105.2-1865.4 kJ/kg and 111.62-1939.0 kJ/kg with equilibrium moisture content between 5% and 32% (d.b.), respectively. The net isosteric heat of sorption decreased with increasing equilibrium moisture content.

scholarly journals Water sorption properties of Dutch type semi-hard cheese edge in the range of common storing temperatures

2011 ◽  
Vol 59 (5) ◽  
pp. 203-208 ◽  
Author(s):  
Maria Carolina Soares Pereira ◽  
Jiří Štencl ◽  
Bohumíra Janštová ◽  
Václav Vlášek
Keyword(s):  
Moisture Content ◽  
Equilibrium Moisture Content ◽  
Pure Water ◽  
Free Water ◽  
Sorption Isotherms ◽  
Moisture Sorption ◽  
Water Evaporation ◽  
Adsorption And Desorption ◽  
Moisture Sorption Isotherms ◽  
Hard Cheese

Moisture sorption isotherms of Dutch type semi-hard cheese edge in the temperature range of 10–25 ºC and water activity (Aw) from 0.11 to 0.98 were determined using manometric method. The sorption curves had a sigmoid shape. The equilibrium moisture content (EMC) of cheese samples increased with an increase in Aw at a constant temperature both for water adsorption and desorption. An increase in temperature caused an increase in Aw for the same moisture content (MC) and, if Aw was kept constant, an increase in temperature caused a decrease in the amount of absorbed water. Critical values of equilibrium moisture content, corresponding to the Aw = 0.6, were between 11 % MC (w.b.) and 17 % MC (w.b.) both for moisture adsorption and desorption. Values of sorption heat were calculated from moisture sorption isotherms by applying the Clausius-Clapeyron equation. Values of the heat of desorption are higher than those of adsorption and the difference increases with the MC decrease. Heat of sorption decreased from 48.5 kJ/mol (~5.5 % MC w.b.) to the values approaching the heat of vaporization of pure water, free MC. The critical value for free water evaporation is about w = 27 % (w.b.) for the range of temperature 10–25 ºC.

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.

Estimation of Equilibrium Moisture Content of Pistachio Powder through the ANN and GA Approaches

2014 ◽  
Vol 10 (4) ◽  
pp. 747-755
Author(s):  
Hamid Tavakolipour ◽  
Mohsen Mokhtarian
Keyword(s):  
Experimental Data ◽  
Moisture Content ◽  
Equilibrium Moisture Content ◽  
High Performance ◽  
Gravimetric Method ◽  
Sorption Isotherms ◽  
Moisture Sorption ◽  
Similar Data ◽  
Intelligent Tools ◽  
Artificial Neural Network Ann

Abstract In this study, two intelligent tools of genetic algorithm (GA) and artificial neural network (ANN) were employed to use experimental data to predict equilibrium moisture content (EMC) of Persian pistachio powder. Initially the moisture sorption isotherms of pistachio powder were determined by gravimetric method at different temperatures (15, 25, 35 and 40°C) and constant relative humidity’s (0.11, 0.23, 0.36, 0.49, 0.62, 0.75 and 0.88 aw values) and then traditional mathematical models including BET, Iglesias and Chirife, GAB, Caurie and Freundlich were used to check the fitness of experimental data. Later the experimental data were compared with similar data obtained from GA and ANN models. The overall results showed that the Caurie model had high performance to predict EMC and revealed that GA model had greater accuracy to predict EMC of pistachio powder with very high R2 values (equal to 0.9996).

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