Characteristics of Dynamics Sorption Isotherms of Date Flesh Powder Rich in Fiber

2016 ◽  
Vol 12 (5) ◽  
pp. 469-480 ◽  
Author(s):  
Mohammad Fikry ◽  
Alhussein M. Al-Awaadh
Keyword(s):  
Moisture Content ◽  
Water Activity ◽  
Sorption Isotherms ◽  
Isosteric Heat ◽  
Phoenix Dactylifera ◽  
Dynamic Vapor Sorption ◽  
Desorption Process ◽  
Adsorption And Desorption ◽  
Peleg Model ◽  
Wide Range

Abstract Dynamic vapor sorption equipment (AQUADVS) was used to determine adsorption and desorption isotherms for powder rich in fiber (PRF) produced from Palm Date flesh of Sifri cultivar (Phoenix dactylifera L.) at temperatures 25, 35 and 45 °C in a wide range of water activity (0.09–0.87). Equilibrium was achieved within 29 and 25 h for the adsorption and desorption process respectively. The obtained data were fitted to ten models (Peleg, GAB, BET, Halsey, Oswin, Smith, Modified Henderson, Adam and Shove, Modified Oswin and Modified Halsey). The results indicated that the PRF followed type III behavior. The empirical Peleg model was found to be the best to represent the experimental data in the water activity range 0.09–0.87. The isosteric heat of sorption and the differential entropy decreased by increasing the moisture content and can be predicted by polynomial functions. Glass transition temperatures (Tg) of PRF were determined. The Tg decreased as the moisture content increased and can be correlated using the Gordon and Taylor model (R2=0.976). The PRF should be stored at moisture less than 9 d.b.% and temperature less than 35 °C.

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 Moisture sorption isotherms and isosteric heat sorption of habanero pepper (Capsicum chínense) dehydrated powder

2018 ◽  
Author(s):  
Mario Luna-Flores ◽  
Mariana Gisela Peña-Juarez ◽  
Angélica Mara Bello-Ramirez ◽  
Javier Telis-Romero ◽  
Guadalupe Luna-Solano
Keyword(s):  
Moisture Content ◽  
Water Activity ◽  
Sorption Isotherms ◽  
Moisture Sorption ◽  
Isosteric Heat ◽  
Convective Drying ◽  
Hysteresis Phenomenon ◽  
Dynamic Vapor Sorption ◽  
Habanero Pepper ◽  
Moisture Sorption Isotherms

Moisture sorption isotherms of the habanero pepper powder were determined using the Dynamic Vapor Sorption (DVS) method at 20, 25, 35, 45 and 55 °C in a range of water activity from 0.10 to 0.90 at which the processes of drying, packing and storage of habanero pepper are developed. The sorption capacity decreased with increasing temperature at a given water activity and the sorption isotherms showed a sigmoid form (Type II). The hysteresis phenomenon was observed in the sorption isotherms at all temperatures studied and it was more pronounced at temperatures high. The experimental sorption curves were fitting to the GAB, BET and Oswin models. It was concluded that the models that best describe the adsorption and desorption data for habanero pepper dehydrated powder were the GAB and Oswin models.  The isosteric heat of water sorption was calculated with the moisture content data in equilibrium. The desorption isotherms present a higher isosteric heat in relation to the adsorption isotherms. In both, the isosteric heat decreased as the moisture content increased. Keywords: Habanero pepper dehydrated powder; Convective drying; Moisture sorption isotherms; Mathematic models

The prediction of moisture adsorption isotherm for sucrose powder in Côte d’Ivoire

2018 ◽  
Vol 6 (04) ◽  
Author(s):  
Yué Bi Yao Clément ◽  
Akmel Djédjro Clément ◽  
Tano Kablan
Keyword(s):  
Adsorption Isotherm ◽  
Moisture Content ◽  
Water Activity ◽  
Sorption Isotherms ◽  
Moisture Sorption ◽  
Least Square ◽  
Moisture Adsorption ◽  
Wide Range ◽  
Gab Model ◽  
And Storage

Moisture sorption isotherms play an essential role in preservation and storage of dehydrated food. To study the behavior of sucrose, it’s moisture adsorption isotherm was investigated using the static gravimetrique method at laboratory temperature (29 ±1°C) in a water activity range (aw) of 0.07-0.97. The results showed that the equilibrium moisture content of sucrose increase substantially above aw = 0.6. The moisture adsorption isotherm was sigmoid in shap, showing a type III BET isotherm. The data obtained were fitted to several models including two-parameter (BET, Hasley, Kuhn and Oswin), three parameter (GAB). A non-linear least square regression analysis was used to evaluate the models constants. The GAB model best fitted the experimental data in the wide range of water activity. The best fitted equation provide a sound basis for futur work on the drying and storage of sucrose. The accurate moisture content and the stability profile of sucrose were determined. The results of determination show that sucrose powder was stable below 7.7% RH at 29°C. The content of water adsorbed in the monomolecular layer was calculated (GAB Xm=0.950 g H2O/100 g solids; BET Xm= 1.072 g H2O/100 g solids).

scholarly journals Solar convective drying kinetics and sorption isotherms of Citrus aurantium flowers

2018 ◽  
Author(s):  
Naji Abdenouri ◽  
Hicham El Ferouali ◽  
Ahmed Zoukit ◽  
Said Doubabi
Keyword(s):  
Moisture Content ◽  
Sorption Isotherms ◽  
Isosteric Heat ◽  
Storage Conditions ◽  
Drying Kinetics ◽  
Convective Drying ◽  
Citrus Aurantium ◽  
Peleg Model ◽  
Drying Kinetic ◽  
Drying Curves

Citrus aurantium flowers are high value aromatic and medicinal plants. The storage conditions and quality of dried Citrus aurantium flowers depends on their hygroscopic stability. The equilibrium moisture content was determined at temperatures (from 30 to 60 °C), and the sorption phenomenon is well described by Peleg model. The optimal water activity for the storage of the product was estimated at awop=0.373. Afterwards, the net isosteric heat was evaluated in the range of 88 kJ.mol−1 for small values of the moisture content (Xeq=0.14kg water/kg d.b), and it decreased along with the increase of Xeq. The experimental drying curves showed only a falling rate period. Finally, Midilli-Kucuk model was found to be the more suitable to describe the drying kinetic of Citrus aurantium flowers. Keywords: Drying kinetics; Solar energy; Modeling; Citrus aurantium; Sorption isotherms; Conservation process

scholarly journals The Study of Sorption Characteristics of Dried Crab Stick Product Using Dynamic Vapor Sorption

2021 ◽  
Vol 18 (13) ◽  
Author(s):  
Traiphop PHAHOM
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Sorption Isotherm ◽  
Vapor Sorption ◽  
Dynamic Vapor Sorption ◽  
Adsorption And Desorption ◽  
Peleg Model ◽  
Monolayer Moisture Content ◽  
Monolayer Moisture ◽  
Sorption Characteristics

The research delved into the sorption characteristics of dried crab stick products using dynamic vapor sorption (DVS). The obtained sorption isotherm data, including equilibrium moisture content (Me) and water activity (aw), were fitted with 6 different sorption isotherm models, such as Brunauer-Emmett-Teller (BET), Guggenheim-Anderson-Boer (GAB), Pickett-Modified BET, Adam and Shove, Blahovec-Yanniotis, and Peleg. The results showed that the Peleg model was the best-describing model with a coefficient of determination (R2), chi-square (χ2), root mean square error (RMSE), and standard error of estimate (SEE) ranging from 0.988 to 0.998, 0.719 to 4.349, 0.431 to 2.609 and 0.692 to 1.703, respectively. According to the classification of the shape of moisture sorption isotherm, the isotherm type III and II were found in this research for adsorption and desorption, respectively. The GAB and BET models were used to estimate monolayer moisture content (M0) of the sample and it was found that the M0 ranged from 3.65 to 5.36 % dry basis and 4.57 to 4.83 % dry basis for GAB and BET models, respectively. Blahovec-Yanniotis’s model was applied in this work to investigate the contribution of water and the result showed that the contribution of solution water played a major in the moisture changes of the sample during the adsorption and desorption process. Moreover, sorption isotherm data were modeled with 0 and 1st order reaction kinetics, and the results demonstrated that 0 order and 1st order models were the most appropriate model to describe moisture changes behavior of the sample at each relative humidity step for adsorption and desorption, respectively. HIGHLIGHTS The construction of sorption isotherms of dried crab stick product using dynamic vapor sorption GAB and BET models were used to estimate monolayer moisture content Peleg model was the most appropriate model to describe sorption behaviors of dried crab stick product Blahovec-Yanniotis provided the contribution of water information of dried crab stick during adsorption and desorption processes The application of reaction order kinetics could provide the information of moisture changing behaviors at each relative humidity step for adsorption and desorption processes GRAPHICAL ABSTRACT

scholarly journals CURVAS DE SECAGEM E AVALIAÇÃO DA ATIVIDADE DE ÁGUA DA BANANA PASSA

2004 ◽  
Vol 22 (1) ◽  
Author(s):  
MILTON CANO-CHAUCA ◽  
AFONSO M. RAMOS ◽  
PAULO C. STRINGHETA ◽  
JOSÉ ANTONIO MARQUES ◽  
POLLYANNA IBRAHIM SILVA
Keyword(s):  
Experimental Data ◽  
Linear Regression ◽  
Moisture Content ◽  
Water Activity ◽  
Linear Regression Analysis ◽  
Sorption Isotherms ◽  
Exponential Model ◽  
Drying Time ◽  
Non Linear ◽  
Drying Curves

Curvas de secagem de banana passa foram determinadas, utilizando-se três temperaturas do ar de secagem. Os resultados indicaram que para reduzir o teor de umidade do produto até 23,5% foram necessários tempos de secagem de 51, 36 e 30 horas paras as temperaturas de 50, 60 e 70ºC, respectivamente. O modelo exponencial U/Uo = exp(-kt) foi ajustado para os dados experimentais mediante análise de regressão não-linear, encontrandose alto coeficiente de regressão linear. Determinou-se a atividade de água do produto ao longo do processo de secagem para as três temperaturas testadas. Estudou-se a correlação entre a atividade de água e o teor de umidade do produto, determinando-se as isotermas de dessorção da banana passa a 25ºC. Observou-se que a atividade de água diminuiu em função do tempo de secagem e do teor de umidade para as três temperaturas de secagem. Os dados experimentais foram ajustados mediante regressão não-linear ao modelo polinomial e a seguinte equação foi obtida: U = -1844,93 + 7293,53Aa – 9515,52Aa2 + 4157,196Aa3. O ajuste mostrou-se satisfatório (R2 > 0,90). DRYING CURVES AND WATER ACTIVITY EVALUATION OF THE BANANA-PASSES Abstract Banana drying curves were determined by utilizing three drying air temperatures. The results indicated that to reduce the moisture content of the product until 23.5% it were necessary drying times of 51, 36 and 30 hours for temperatures of 50, 60 and 70ºC, respectively. The exponential model U/Uo = exp(-kt) was adjusted for the experimental data by means of non linear regression analysis, and a high coefficient of linear regression was found. The water activity of the product was determined throughout the drying process for the three tested temperatures. The correlation between the water activity and moisture content of the product was studied, and the sorption isotherms were determined at 25º C. It was observed that the water activity decreased in function to the drying time and moisture content for the three drying temperatures. The experimental data were adjusted by means of non linear regression to the polynomial model and the following equation was obtained: U = - 1844.93 + 7293.53A a – 9515.52 Aa 2 + 4157.196A a 3. The final adjust was satisfactory (R2 > 0.90).

scholarly journals Sorption isotherms of Brazil nuts

2019 ◽  
Vol 23 (10) ◽  
pp. 776-781 ◽  
Author(s):  
Fernando M. Botelho ◽  
Nilso J. Boschiroli Neto ◽  
Silvia de C. C. Botelho ◽  
Gabriel H. H. de Oliveira ◽  
Michele R. Hauth
Keyword(s):  
Moisture Content ◽  
Equilibrium Moisture Content ◽  
Water Activity ◽  
Sorption Isotherms ◽  
Static Method ◽  
Acid Solutions ◽  
Brazil Nut ◽  
Brazil Nuts ◽  
Abstract Knowledge ◽  
Sorption Phenomenon

ABSTRACT Knowledge of the water sorption phenomenon in Brazil nut seeds will allow proper handling of this product, especially with regard to adequate conditions for safe storage. Thus, the present study aimed to determine the sorption isotherms (desorption and adsorption) of Brazil nuts, fitting different mathematical models to the experimental data, as well as to examine the hysteresis effect. To obtain the sorption isotherms, the static method was employed at temperatures of 25, 35, 45 and 55 °C and air relative humidities varying from 10 to 80%. The psychrometric conditions of the air were acquired with the aid of acid solutions and specific saturated saline left inside desiccators with the samples. It was verified that for a given isotherm, the equilibrium moisture content of Brazil nuts increases with water activity increment. In addition, at a constant water activity, equilibrium moisture content decreases with temperature increase. The Copace, Henderson and Oswin are the models that best describe the hygroscopicity of the Brazil nut seed for both the adsorption and desorption processes. Hysteresis was more pronounced at lower temperatures and higher values of water activity. The moisture content value for storage at temperatures less than 55 °C, without the risk of fungal development, must be lower than 8.2% (d.b.).

scholarly journals Moisture sorption isotherms of castor beans. Part 1: Mathematical modeling and hysteresis

2016 ◽  
Vol 20 (8) ◽  
pp. 751-756 ◽  
Author(s):  
André L. D. Goneli ◽  
Paulo C. Corrêa ◽  
Gabriel H. H. de Oliveira ◽  
Osvaldo Resende ◽  
Munir Mauad
Keyword(s):  
Moisture Content ◽  
Sorption Isotherms ◽  
Moisture Sorption ◽  
Environmental Condition ◽  
Adsorption And Desorption ◽  
Moisture Sorption Isotherms ◽  
Different Temperatures ◽  
The Difference ◽  
The Stability ◽  
And Storage

ABSTRACT Sorption isotherms are of great importance in post-harvest procedures, especially for predicting drying and storage, which help to establish the final moisture content of the product under certain environmental condition. Hysteresis is a phenomenon that occurs due to the difference between adsorption and desorption curves, which aids the evaluation of chemical and microbiological deteriorations, indicating the stability of stored products. Moisture sorption isotherms of castor beans were determined and hysteresis was analyzed. Static gravimetric technique at different temperatures (25, 35, 45 and 55 ± 1 °C) was used. Saturated salt solutions in the range of 37-87% ± 2% were utilized to create the required controlled relative humidity environment. Equilibrium moisture content data were correlated by different mathematical models and the Modified Halsey model presented good adjustment for the data, according to statistical procedures. Hysteresis between adsorption and desorption isotherms is present over the range of 0.2-0.9 of water activity, regardless of the temperature. This phenomenon decreases with temperature increase.

scholarly journals Moisture Sorption Behaviour and Mould Ecology of Trade Garri Sold in South Eastern Nigeria

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Tochukwu Samuel ◽  
J. Obeta Ugwuanyi
Keyword(s):  
Moisture Content ◽  
Water Activity ◽  
Central Africa ◽  
Sorption Isotherms ◽  
Moisture Sorption ◽  
Fungal Species ◽  
Temperature Dependent ◽  
Sorption Behaviour ◽  
Moisture Sorption Isotherms ◽  
West And Central Africa

Garri is a creamy white or yellow starchy grit produced by roasting to gelatinization and dryness of peeled, washed, mashed, and fermented dewatered cassava roots. It is the most important product of cassava in West and Central Africa. Mean moisture content of yellow and white garri was 11.11% and 10.81% within 24 hrs of sampling from the market, increasing to 17.27% and 16.14%, respectively, following 3 months of storage at room temperature. The water activity of samples varied from initial 0.587 to 0.934 following storage. Moisture sorption isotherms, determined by static gravimetric techniques at 20° and 30°C, showed temperature dependent BET Sigmoidal type II behaviour typical of carbohydrate rich foods but modulated very slightly by the content of palm oil. Equilibrium moisture content decreased with increase in temperature at constant water activity. A total of 10 fungal species belonging to the generaMucor,Penicillium,Cephalosporium,Aspergillus,Scopulariopsis,Rhizopus, and Paecilomyceswere identified, with range increasing with water activity of samples.

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.

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