Sorption Properties of Cape Gooseberry (Physalis peruviana L.)

2012 ◽  
Vol 8 (1) ◽  
Author(s):  
Farid B. Cortés ◽  
Veronica López ◽  
Benjamin A. Rojano
Keyword(s):  
Free Energy ◽  
Moisture Content ◽  
Gibbs Free Energy ◽  
Isosteric Heat ◽  
Sorption Equilibrium ◽  
Physalis Peruviana ◽  
Different Temperatures ◽  
Gab Model ◽  
Monolayer Moisture ◽  
Cape Gooseberry

The sorption equilibrium of water for cape gooseberry at different temperatures (25, 35, 50 and 60°C) over a range of relative humidity levels, from 0.10 to 0.90, were determined using a gravimetric static method. The isosteric heat and Gibbs free energy were calculated from the sorption equilibrium. GAB, BET, SMITH, modified de Halsey, modified de Chung-Pfost, modified Oswin and modified Henderson models were tested to fit the experimental data. The GAB model was found to be the most suitable for describing the sorption curves. The monolayer moisture content values for the sorption at different temperatures were calculated using the BET model. The sorption curves show a Type III behavior. The isosteric heat decreased with increases in moisture content, while the Gibbs free energy increased.

scholarly journals Some Thermodynamic Properties of White Yam (Dioscorea rotundata) Slices Dehydrated in a Refractance WindowTM Dryer

2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Akinjide A Akinola ◽  
Stanley N Ezeorah
Keyword(s):  
Activation Energy ◽  
Free Energy ◽  
Moisture Content ◽  
Gibbs Free Energy ◽  
Moisture Diffusivity ◽  
Process Conditions ◽  
Dioscorea Rotundata ◽  
History Data ◽  
White Yam ◽  
Different Temperatures

The objective of this study is to estimate the changes in Enthalpy, Entropy and Gibbs Free Energy of yam slices dehydrated at different temperatures using a Refractance WindowTM dryer. Dehydration of 1.5, 3.0 and 4.5 mm thick yam slices, was performed with water temperatures of 65, 75, 85 and 95oC in the flume of a Refractance WindowTM dryer. During the dehydration operations, the moisture-content history data were recorded. For the process conditions considered, the moisture content history data was used to calculate the moisture diffusivity and the activation energy of dehydration of the samples. Subsequently, changes in Enthalpy, , Entropy, , and Gibbs Free Energy, ), were calculated. For the process conditions studied, the changes in, , , and, varied from 20,381.33 to 25,217.05 J.mol-1., -140.69 to -122.29 J.mol-1.K-1.and 67,934.80 to 70,220.15 J.mol-1, respectively. This study is essential as knowledge of these thermodynamic parameters are useful for the optimal design and sizing of preservation dryers for argo-products. Keywords— Enthalpy; Entropy; Gibbs Free Energy; Refractance WindowTM Dryer; Yam 

Analysis of Moisture Desorption Isotherms of Eggplant (Solanum melongena)

2010 ◽  
Vol 16 (5) ◽  
pp. 417-425 ◽  
Author(s):  
R. Moreira ◽  
F. Chenlo ◽  
M.D. Torres ◽  
N. Vallejo
Keyword(s):  
Moisture Content ◽  
Solanum Melongena ◽  
Gravimetric Method ◽  
Sorption Isotherms ◽  
Isosteric Heat ◽  
Integral Enthalpy ◽  
Differential Enthalpy ◽  
Different Temperatures ◽  
Enthalpy And Entropy ◽  
Monolayer Moisture

Sorption isotherms of eggplant were determined employing, as experimental technique, a static gravimetric method, using saturated salt solutions to achieve the equilibrium. The experiments were carried out at different temperatures (20, 35, 50 and 65 °C). The sorption isotherms can be classified, according to Brunauer’s classification, as type II or III depending on temperature. Equilibrium moisture content data were correlated by two models usually applied to foodstuffs (Brunauer-Emmet-Teller (BET) and Halsey). BET model was employed to determine monolayer moisture content (0.121 kg/kg d.b.). Halsey model was selected by the goodness of fitting. Experimental data were analyzed by a thermodynamic approach to obtain some properties as net isosteric heat, equilibrium heat and differential and net integral entropy. The differential enthalpy and entropy decreased with increasing moisture content and satisfied the compensation theory. The net integral enthalpy and entropy showed maximum values (~31 kJ/mol and ~88 J/mol.K) at 0.093 (kg/kg d.b.) of moisture content.

Predicting Sorption Isotherms and Net Isosteric Heats of Sorption of Maize Grains at Different Temperatures

2014 ◽  
Vol 10 (3) ◽  
pp. 393-401 ◽  
Author(s):  
André Talla
Keyword(s):  
Moisture Content ◽  
Sorption Isotherms ◽  
Isosteric Heat ◽  
Sub Saharan Africa ◽  
Maximum Deviation ◽  
Different Temperatures ◽  
Sub Saharan ◽  
C 50 ◽  
The Stability ◽  
Monolayer Moisture

Abstract In Sub-Saharan Africa, drying maize on their stem was the traditional technique frequently used; this technique must be improved to avoid contaminations and to increase the quality of drying. However, the method of storage is accountable for the most significant losses after harvest, because mildew develops when the conditions of storage (too high temperature and moisture of the air) do not tally with the final content of the dried product. Sorption isotherms of products are most important to model moisture uptake during storage and distribution. Sorption isotherms of intermediate moisture content maize grains were determined using the gravimetric static method of saturated salt solutions at 30°C, 40°C, 50°C, and 60°C, and GAB equation was applied to discuss the results. This model correctly describes the evolutions of maize sorption isotherms, with maximum deviation of 0.0080 kg water/kg db. The net isosteric heat of sorption was determined also, using the Clausius–Clapeyron equation, and it was varied from 463 kJ/kg to 1,264 kJ/kg, decreasing with increasing moisture content. This effect was well described by an exponential function with a regression coefficient R2 > 97%. The monolayer moisture content was found to decrease with increasing temperature. These results can be used to predict the potential changes in the stability of maize grains and later for the development of a system of suitable drying.

scholarly journals Modelling Thermodynamic Properties of Banana Waste by Analytical Derivation of Desorption Isotherms

2012 ◽  
Vol 8 (1) ◽  
Author(s):  
Harvey A. Villa-Vélez ◽  
Henry A. Váquiro ◽  
José Bon ◽  
Javier Telis-Romero
Keyword(s):  
Moisture Content ◽  
Water Activity ◽  
Isosteric Heat ◽  
Effect Of Temperature ◽  
Agricultural Product ◽  
Different Temperatures ◽  
Desorption Isotherms ◽  
Gab Model ◽  
Processing And Storage ◽  
The Relationship

Banana is an agricultural product of great economic importance for various developing countries. The relationship between moisture content and water activity provides useful information for the processing and storage of banana waste. The water activity and moisture content of three banana (Mussa spp. Haploid AAB cv. Nanica) waste items were analyzed to determine the desorption isotherms at six different temperatures (20, 30, 40, 50, 60 and 70°C). The desorption isotherms of the peel, pedicel and pulp of overripe bananas were determined in wide ranges of moisture content (0.001–6.360 kg kg-1 d.b.) and water activity (0.02–0.907). The theoretical GAB model was used for modelling the desorption isotherms. An analytical solution of the Clausius-Clapeyron equation was proposed to compute the isosteric heat of sorption, the differential entropy and Gibbs’ free energy by way of the GAB model when the effect of temperature on the hygroscopic equilibrium was considered.

scholarly journals Kinetics and thermodynamic properties related to the drying of 'Cabacinha' pepper fruits

2016 ◽  
Vol 20 (2) ◽  
pp. 174-180 ◽  
Author(s):  
Hellismar W. da Silva ◽  
Renato S. Rodovalho ◽  
Marya F. Velasco ◽  
Camila F. Silva ◽  
Luís S. R. Vale
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Free Energy ◽  
Thermodynamic Properties ◽  
Gibbs Free Energy ◽  
Removal Rate ◽  
Effective Diffusion ◽  
Drying Time ◽  
Three Samples ◽  
Different Temperatures

ABSTRACT The objective of this study was to determine and model the drying kinetics of 'Cabacinha' pepper fruits at different temperatures of the drying air, as well as obtain the thermodynamic properties involved in the drying process of the product. Drying was carried out under controlled conductions of temperature (60, 70, 80, 90 and 100 °C) using three samples of 130 g of fruit, which were weighed periodically until constant mass. The experimental data were adjusted to different mathematical models often used in the representation of fruit drying. Effective diffusion coefficients, calculated from the mathematical model of liquid diffusion, were used to obtain activation energy, enthalpy, entropy and Gibbs free energy. The Midilli model showed the best fit to the experimental data of drying of 'Cabacinha' pepper fruits. The increase in drying temperature promoted an increase in water removal rate, effective diffusion coefficient and Gibbs free energy, besides a reduction in fruit drying time and in the values of entropy and enthalpy. The activation energy for the drying of pepper fruits was 36.09 kJ mol-1.

Note: Estimation of Sorption Isotherm and the Heat of Sorption of Quinoa (Chenopodium quinoaWilld.) Seeds

2004 ◽  
Vol 10 (6) ◽  
pp. 409-413 ◽  
Author(s):  
C. Rohvein ◽  
E. Santalla ◽  
M. C. Gely
Keyword(s):  
Moisture Content ◽  
Pure Water ◽  
Absolute Temperature ◽  
Sorption Data ◽  
Statistical Adjustment ◽  
Exponential Trend ◽  
Gab Model ◽  
Sorption Heat ◽  
Monolayer Moisture ◽  
Negative Exponential

A modified Guggenheim-Anderson-de Boer (GAB) equation of four parameters was obtained to adjust the experimental sorption data for washed quinoa seeds. From the original GAB equation, only the monolayer moisture resulted in a dependence-temperature parameter showing a negative exponential trend with the absolute temperature. The results of the statistical adjustment showed that the new four parameters GAB equation adequately represented the experimental data in the range of 20 to 30°C with a corrected correlation coefficient of 0.999. The sorption heat of washed quinoa seeds was estimated by combining the GAB model with the Clapeyron equation and it resulted approximately 32% higher than the sorption heat of pure water in the temperature ranges between 20 and 60°C for temperature and 0.003 and 0.30 for moisture content. Using Othmer method the ratio of latent heats varied from 1.18 to 1.0474 in the range of moisture content studied.

scholarly journals Thermodynamic Properties of Water Adsorption on Gaplek Flour Fortified with Red Bead Tree Seed

Molekul ◽  
2018 ◽  
Vol 13 (2) ◽  
pp. 114
Author(s):  
Margareta Novian Cahyanti ◽  
Alvama Pattiserlihun
Keyword(s):  
Free Energy ◽  
Moisture Content ◽  
Moisture Sorption ◽  
Maximum Level ◽  
Isosteric Heat ◽  
Clapeyron Equation ◽  
Spreading Pressure ◽  
Moisture Sorption Isotherm ◽  
Adsorption Entropy ◽  
Tree Seed

The moisture sorption isotherm data of gaplek flour fortified with red bead tree seed stored in a chamber, the relative humidity of chamber ranging from 10% to 97% regulated using a saturated salt solution, was determined at three temperatures 25°, 35°, and 45 °C. The experimental data used to determine the thermodynamic functions were isosteric heat of sorption, sorption entropy, and free energy changes. The sorption isosteric heats were determined by the application of the Clausius–Clapeyron equation. Isosteric heats of adsorption increased to maximum level and then declined with increase of moisture content. Adsorption entropy increased to maximum level and then declined with the increase of moisture content. The free energy changes increased with increase in moisture content. The spreading pressure increased with increasing water activity.

scholarly journals MATHEMATICAL MODELS AND THERMODYNAMIC PROPERTIES OF MOISTURE SORPTION ISOTHERMS OF FERMENTED CASSAVA FLOUR BY RED YEAST RICE

2017 ◽  
Vol 13 (1) ◽  
pp. 29 ◽  
Author(s):  
Mutiara Nur Alfiah ◽  
Sri Hartini ◽  
Margareta Novian Cahyanti
Keyword(s):  
Thermodynamic Properties ◽  
Moisture Content ◽  
Sorption Isotherm ◽  
Moisture Sorption ◽  
Red Yeast Rice ◽  
Cassava Flour ◽  
Red Yeast ◽  
Moisture Sorption Isotherm ◽  
Gab Model ◽  
Monolayer Moisture

<p>This research aims to determine moisture sorption isotherm curves, moisture sorption isotherm models and thermodynamic properties of fermented cassava flour by red yeast rice. The moisture sorption isotherm model used are Guggenheim Anderson deBoer (GAB), Brunauer Emmet Teller (BET) and Caurie. Meanwhile, the test of modelling accuray by Mean Relative Deviation (MRD) and Root Mean Square Error (RMSE). The thermodynamic properties, i.e., enthalpy and entropy were calculated by Clausius - Clapeyron equation. The result shows that the moisture sorption isotherm curve on fermented cassava flour in a sigmoid form (type II). The GAB model is the best model for moisture sorption isotherm of fermented cassava flour by red yeast rice. The MRD and RMSE values at 30˚C, 35˚C and 40˚C are 3.12%, 2.71%, 3.81%, and 1.01, 0.35, 0.42, respectively. The monolayer moisture content at 30˚C, 35˚C and 40˚C are 6.61%, 6.27% and 6.91%, based on GAB model. Meanwhile, when the BET model was used, the monolayer moisture content are 4.92%, 4.86% and 5.19%, while by Caurie model are 6.37%, 6.18% and 5.30%, at 30˚C, 35˚C and 40˚C, respectively. The enthalpy and entropy of water sorption process were decreased when moisture content increased.</p>

scholarly journals Modeling of Moisture Adsorption Isotherm of Selected Commercial flours of Bangladesh

2018 ◽  
Vol 16 (02) ◽  
pp. 35-42 ◽  
Author(s):  
Md Wadud Ahmed ◽  
Mohammad Gulzarul Aziz ◽  
Md Nazrul Islam
Keyword(s):  
Moisture Content ◽  
Water Activity ◽  
Adsorption Behavior ◽  
Stable Region ◽  
Moisture Adsorption ◽  
Sorption Data ◽  
Bet Model ◽  
Monolayer Moisture Content ◽  
Gab Model ◽  
Monolayer Moisture

The moisture adsorption behavior is a fundamental knowledge in the processing and storage of food materials. In this paper, the experimental adsorption behavior of wheat, rice and corn flours were compared with five widely recommended adsorption models (BET, GAB, Oswin, Smith and Halsey) in the literature. From the sorption data, monolayer moisture content of wheat, rice and corn flours were estimated as per BET and GAB models. For all flours, GAB model gave higher monolayer moisture content compare to the BET model. Linear regression analysis was done to determine the model constants where all models were compared using regression coefficient and standard error of the estimate. It was observed that there is no single model that could describe accurately the sorption isotherm over the whole range of water activity (aw) and for all types of flours. BET model was found as the best model for the prediction of equilibrium moisture content (EMC) of the most stable region (i.e. EMC corresponding to aw range below 0.52) but it was not suitable at aw above 0.52. The GAB model was found to be the most suitable to predict the EMC for wide range of water activity (0.11 to 0.93). The Agriculturists 2018; 16(2) 35-42

Study of Chemical Quench of High Temperature Syngas

2011 ◽  
Vol 9 (1) ◽  
Author(s):  
Zhen Yang ◽  
Yinhe Liu ◽  
Zidong Cao
Keyword(s):  
Free Energy ◽  
High Temperature ◽  
Moisture Content ◽  
Gibbs Free Energy ◽  
Energy Minimization ◽  
Feeding Rate ◽  
Energy Utilization ◽  
Quench Temperature ◽  
Gibbs Free Energy Minimization ◽  
Minimization Approach

Quench of high temperature raw syngas to a certain degree is of great importance for the availability of a gasifier, and it influences the economical running of whole energy utilization system. Chemical quench is one of the best choices for high temperature syngas quench. Based on the Gibbs free energy minimization approach, thermodynamic analyses are carried out to elucidate the quench process of high temperature syngas. The optimal quench temperature and optimal feeding rate of coal are achieved with the consideration of effects such as inlet syngas temperature, steam input and moisture content in the coal. The results show that chemical quench is an effective way for high temperature syngas quench. The higher the temperature of syngas is, the better the chemical quench effect is. Steam input to the syngas can enhance the chemical quench reaction for the same coal feeding rate, while the effect of moisture content in coal on chemical quench is negligible.

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