scholarly journals Moisture sorption characteristics of pistachio

2018 ◽  
Author(s):  
Banu Koç ◽  
Gamze Atar ◽  
Nazan Çağlar
Keyword(s):  
Experimental Data ◽  
Adsorption Isotherm ◽  
Water Activity ◽  
Linear Regression Analysis ◽  
Gravimetric Method ◽  
Moisture Sorption ◽  
Moisture Adsorption ◽  
Wide Range ◽  
Predicted Values ◽  
Best Fit

In this study, the moisture adsorption isotherm of pistachio was determined at 25°C and relative humidity (10-90%), using the standard static, gravimetric method. Eleven sorption models were tested to fit the experimental data. A non-linear regression analysis method was used to evaluate the constants of the sorption equations. The GAB equation gave the best fit to the experimental data for a wide range of water activity, while BET gave the best fit for a water activity range of 0.1-0.5. The agreement between experimental and predicted values of these models was found to be satisfactory. Keywords: Moisture adsorption isotherm; Sorption model; Pistachio 

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.

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).

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.

scholarly journals Moisture Adsorption Isotherm Model for Edible Food Film Packaging – A Review

2020 ◽  
Vol 17 (2) ◽  
pp. 221
Author(s):  
Aqila Zulaikha Nazreen ◽  
Junaidah Jai ◽  
Sherif Abdulbari Ali ◽  
Norasmah Mohamed Manshor
Keyword(s):  
Adsorption Isotherm ◽  
Food Packaging ◽  
Sorption Isotherms ◽  
Moisture Sorption ◽  
Moisture Adsorption ◽  
Surrounding Environment ◽  
Moisture Sorption Isotherm ◽  
Moisture Sorption Isotherms ◽  
Physical And Chemical ◽  
Best Fit

Bioplastic has been extensively studied due to its ability to replace synthetic plastics. Its biodegradability is seen as a significant advantage to be used as edible food film packaging. As a food packaging, the film should be able to retain moisture from the food and the surrounding environment. The ability of the film to retain moisture varies with the type of material the film is made of. Moisture sorption isotherms are used to study the moisture content and water activity of food or film packaging at a given temperature. There are many models to describe moisture sorption isotherm. Some researchers modified the models to account for varying temperatures. The purpose of this paper is to review types of adsorption isotherms and the most common models used for film packaging. The general and modified models are described in this paper as well as its best-fit use on film packaging. The advantages of studying adsorption isotherm include shelf-life determination, physical and chemical stability, and others.

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 Modelagem matemática da desidratação osmo-convectiva da palma forrageira (Opuntia fícus-indica Mill) utilizando soluções mistas

2015 ◽  
Vol 10 (4) ◽  
pp. 39
Author(s):  
E. T. Silva ◽  
E. C. O. Silva ◽  
R. P. Gusmão ◽  
J. D. Lopes ◽  
T. A. S. Gusmão
Keyword(s):  
Experimental Data ◽  
Water Activity ◽  
Osmotic Dehydration ◽  
Convective Drying ◽  
Human Consumption ◽  
Cactus Pear ◽  
Opuntia Ficus Indica ◽  
Mixed Solutions ◽  
Cut Resistance ◽  
Best Fit

<p>Objetivou-se nesse estudo avaliar a influência de pré-tratamentos osmóticos utilizando secagem convectiva complementar no processo de perda de água, ganho de sólidos e nos parâmetros de qualidade (cor, atividade de água e textura) de cladódios de palma forrageira. O Cladódio foi submetido à desidratação osmótica utilizando soluções mistas contendo 5% de NaCl e concentrações de sacarose de 50 e 60 °Brix, em diferentes proporções palma/solução (1:1, 1:4 e 1:10) a 40°C. Posteriormente foi realizada secagem convectiva a 50 e 60 °C. Foram utilizados, para ajuste aos dados experimentais da secagem, os modelos matemáticos de Page, Henderson &amp; Pabis, Cavancanti Mata, Exponencial de Dois Termos e Midilli. O cladódio de palma <em>in natura</em> e desidratado foi caracterizado quanto aos parâmetros de cor, atividade de água e textura. O aumento da perda de massa foi proporcional ao aumento da proporção cladódio/solução utilizada na desidratação osmótica e o ganho de sólidos foi maior para a concentração de 50 °Brix. O modelo matemático de Midilli foi o que melhor se ajustou aos dados experimentais. Os parâmetros de cor, atividade de água e textura foram modificados pelas condições de desidratação osmótica e de secagem as quais o cladódio de palma foi submetido. O cladódio desidratado a 50 °C apresentou melhor preservação da cor, maior resistência ao corte e menor atividade de água.<strong> </strong></p><p><strong> </strong></p><p align="center"><strong><em>Mathematical modeling of osmo-convective dehydration of the cactus pear (Opuntia ficus-indica Mill) using mixed solutions</em></strong><strong><em></em></strong></p><p><strong>Abstract</strong><strong>: </strong>The objective of this study was to evaluate the influence of osmotic pre-treatments with complementary convective drying in the water loss process and solids gain of cactus pear cladodes, to obtain palm for human consumption. The cladode was subjected to osmotic dehydration using mixed solutions containing 5% NaCl and sugar concentrations of 50 and 60 °Brix in different proportions palm/solution (1:1, 1:4 and 1:10) at 40 °C. Subsequently convective drying was performed at 50 and 60 °C. Were used to fit to the experimental data of drying, the mathematical models for Page, Henderson &amp; Pabis, Cavancanti Mata, Exponential of Two Terms and Midilli. The spineless cactus in natura and dehydrated was characterized as the parameters: color, water activity and texture. The study noted that the increased of weight mass was proportional to the increased of proportion cladode/solution used in osmotic dehydration and the solids gain was higher for concentration of 50 °Brix. The Midilli mathematical model was the best fit to the experimental data. The parameters of color, water activity and texture were modified by the conditions of osmotic dehydration and drying which spineless cactus cladodes was submitted. The cactus cladode dehydrated at 50 °C presented better preservation of the color, increased cut resistance and lowest water activity.</p>

scholarly journals Non-linear Regression Analysis for the Adsorption Kinetics and Equilibrium Isotherm of Phenacetin onto Activated Carbons

2019 ◽  
pp. 1-18 ◽  
Author(s):  
Christian Sadeu Ngakou ◽  
Gabche Solomon Anagho ◽  
Horace Manga Ngomo
Keyword(s):  
Experimental Data ◽  
Activated Carbon ◽  
Activated Carbons ◽  
Linear Regression Analysis ◽  
Xrd Analysis ◽  
Strong Interactions ◽  
Isotherm Models ◽  
Linear Isotherm ◽  
Non Linear ◽  
Best Fit

Activated carbon obtained from ayous sawdust, Cucurbitaceae (egussi) peelings and the mixture of the two were studied for the adsorption of phenacetin. Characterisation of activated carbon by SEM and XRD analysis shows that the mixture of precursors combine the properties of activated carbon obtained separately. The well-knownbatch sorption models– Langmuir (one and two sites), Freudlich, Tempkin, Elovich, Langmuir-Freudlich, Redlich Peterson, Radke-Prausnitz, Fritz Shlunder)—were tested with experimental data for the adsorption of phenacetin to estimate adsorption equilibrium parameters—rate constantsand adsorption capacities. The model with the best fit was identified from extensive statistical analysis of the results of nonlinear regression of the experimental data. Comparison of the statistical errors in parameter estimation between linear and non-linear isotherm models shows that transformation of non-linear isotherm equations to linear forms implicitly alter their error structure. The much smaller size of the various error indicators —Determination Coefficient, R2; Sum of Square Errors, SSE; Chi Test, χ2; Average Relative Errors, ARE—, calculated for the case of non linearization when compared to linearization, indicate the greater accuracy in the application of non linearization. The Langmuir model (one site) gave the best fit and thus the values of adsorption capacity for each activated carbon were calculated from it. Kinetic models show that weak and strong interactions are involved in the adsorption process and that the controlling mechanism may not be limited to intra particle diffusion. The lower value of the boundary layer thickness in the case of activated carbon obtained from the mixture, justified the higher adsorbed quantity of this activated carbon compared to those of activated carbon from each precursor.

scholarly journals Moisture Adsorption and Thermodynamic Properties of California Grown Almonds (Varieties: Nonpareil and Monterey)

2012 ◽  
Vol 1 (1) ◽  
Author(s):  
Li Zuo Taitano ◽  
R.P. Singh
Keyword(s):  
Diffusion Coefficient ◽  
Thermodynamic Properties ◽  
Moisture Content ◽  
Water Activity ◽  
Gravimetric Method ◽  
Isosteric Heat ◽  
Moisture Adsorption ◽  
Constant Weight ◽  
Differential Enthalpy ◽  
Monolayer Moisture

Moisture adsorption characteristics of California grown almonds (Nonpareil: pasteurized and unpasteurized almonds; Monterey: pasteurized, unpasteurized and blanched almonds) were obtained using the gravimetric method over a range of water activities from 0.11 to 0.98 at 7-50ºC. The weights of almonds were measured until samples reached a constant weight. The relationship between equilibrium moisture content and water activity was established using the Guggenheim-Anderson-de Boer model. The diffusion coefficient of water in almond kernels was calculated based on Ficks second law. The monolayer moisture value of almonds ranged from 0.020 to 0.035 kg H2O kg-1 solids. The diffusion coefficient increased with temperature at a constant water activity, and decreased with water activity at a constant temperature. The thermodynamic properties (net isosteric heat, differential enthalpy and entropy) were also determined. The net isosteric heat of adsorption decreased with the increasing moisture content, and the plot of differential enthalpy versus entropy satisfied the enthalpy-entropy compensation theory. The adsorption process of almond samples was enthalpy driven over the range of studied moisture contents.

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.

MOISTURE SORPTION ISOTHERM CHARACTERISTICS OF AWARA FOOD

2020 ◽  
Vol 4 (2) ◽  
pp. 620-626
Author(s):  
K. A. Maigalura ◽  
J. Suleiman
Keyword(s):  
Storage Stability ◽  
Linear Regression Analysis ◽  
Gravimetric Method ◽  
Moisture Sorption ◽  
Coefficient Of Determination ◽  
Safe Water ◽  
Temperature Range ◽  
Moisture Sorption Isotherm ◽  
And Storage

Moisture sorption and storage stability of Awara were evaluated using gravimetric method. Guggenhein-Anderson-de boer (GAB) and Brunauer Emmett and Teller (BET) were used in evaluating sorption and desorption isotherm at temperature range of 30, 40 and 50oc in the range of water activity (0.1-0.9).Sigmoid moisture isotherm shapes were obtained at various temperatures. Lowest level EMC was obtained at highest temperature (500c).A non-linear regression analysis was used to fit both BET and GAB. GAB was found to generate higher coefficient of determination R2 (0.9986, 0.9959 and 0.9933) and lowest mean of relative percentage p% (0.231, 0.0061 and 0.0017) at temperature range (30, 40 and 500c) respectively. Safe % water and storage stability were all predicted from adsorption isotherm curve. 3.14, 3.19 and 3.10 were found to be the safe % water which corresponds to the 3.8aw for GAB adsorption graphs at 30, 40 and 500c temperatures respectively. This safe % water will be useful in packaging and determination of shelf- life of Awara.

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