scholarly journals Study of adsorption isotherms of green coconut pulp

2013 ◽  
Vol 33 (1) ◽  
pp. 68-74 ◽  
Author(s):  
Fábia Carolina Gonçalves Lavoyer ◽  
Ana Lúcia Gabas ◽  
Wanderley Pereira Oliveira ◽  
Javier Telis-Romero
Keyword(s):  
Moisture Content ◽  
Adsorption Isotherms ◽  
Cocos Nucifera ◽  
Isosteric Heat ◽  
Water Industry ◽  
Tropical Fruits ◽  
Heat Of Sorption ◽  
Production And Consumption ◽  
Gab Model ◽  
Cocos Nucifera L

Brazil is considered one of the largest producers and consumers of tropical fruits. Green coconut (Cocos nucifera L.) stands out not only for its production and consumption, but also for the high amount of waste produced by coconut water industry and in natura consumption. Therefore, there is a need for utilization of this by-product. This study aims to study the adsorption isotherms of green coconut pulp and determine its isosteric heat of sorption. The adsorption isotherms at temperatures of 30, 40, 50, 60, and 70 °C were analyzed, and they exhibit type III behavior, typical of sugar rich foods. The experimental results of equilibrium moisture content were correlated by models present in the literature. The Guggenheim, Anderson and De Boer (GAB) model proved particularly good overall agreement with the experimental data. The heat of sorption determined from the adsorption isotherms increased with the decrease in moisture content. The heat of sorption is considered as indicative of intermolecular attractive forces between the sorption sites and water vapor, which is an important factor to predict the shelf life of dried products.

Identification prediction moisture content of Thai coconut sugar (Cocos nucifera L.) using FT-NIR spectroscopy

Food Research ◽  
2021 ◽  
Vol 5 (4) ◽  
pp. 382-385
Author(s):  
D. Thumrongchote
Keyword(s):  
Moisture Content ◽  
Cocos Nucifera ◽  
Nir Spectroscopy ◽  
Grocery Stores ◽  
Absorbance Spectrum ◽  
Coconut Tree ◽  
Cocos Nucifera L ◽  
The Cost ◽  
Non Destructive ◽  
Low Glycemic Index

Coconut sugar is a local sugar from the blossoms of a coconut tree. It has been considered a healthy sugar due to its low glycemic index. There is an attempt to add other sugar to it to lower the cost. Thus, this research aimed to identify Thai coconut sugar and to establish models for predicting the moisture content of coconut sugar by using FT-NIR spectroscopy. Thai coconut sugar samples were purchased from local grocery stores in four provinces, online, and the community market. Their moisture contents were varied and equilibrated for 24 hrs prior to the measurements of moisture and FT-NIR spectra. The results showed that FT-NIR spectra of Thai coconut sugar differ from sucrose, glucose and fructose at the absorbance spectrum of 5379-5011 cm-1 . FT-NIR spectroscopy of 54 known moisture samples of Thai coconut sugar was used to obtain a model to predict moisture content. The predicted equation, using the PLS technique with the Spectrum Quant program, was found to give a standard error of prediction (SEP) 0.077% (less than 0.10%), indicating a non-destructive method of accurately and precisely predicting moisture levels in the coconut sugar. The results obtained suggested that FTNIR spectroscopy has the potential to be used as a tool to identify Thai coconut sugar accurately. It can rapidly predict the moisture content in the sample which will be useful in quality control standards.

scholarly journals MODELING DYNAMIC ADSORPTION ISOTHERMS AND THERMODYNAMIC PROPERTIES OF SPECIALTY GROUND ROASTED-COFFEE (Coffee Arabica L.)

2019 ◽  
Vol 14 (1) ◽  
pp. 93 ◽  
Author(s):  
Gentil Andres Collazos-Escobar ◽  
Nelson Gutiérrez-Guzman ◽  
Henry A. Vaquiro Herrera
Keyword(s):  
Thermodynamic Properties ◽  
Moisture Content ◽  
Equilibrium Moisture Content ◽  
Adsorption Isotherms ◽  
Sorption Isotherms ◽  
Isosteric Heat ◽  
Roasted Coffee ◽  
Sorption Data ◽  
Specialty Coffee ◽  
Sensorial Attributes

Specialty coffee is highly differentiated product because of  its sensorial attributes: aroma, body and brand reputation. In specialized markets, these products are highly valued, and sometimes up to six times their commercial value is paid. Thus, it is essential to preserve their freshness. Sorption isotherms are necessary for determining and studying water sorption changes in specialty coffee during storage. This study aimed to determine the adsorption isotherms of specialty ground roasted-coffee at temperatures of 25 °C, 30 °C and 40 °C and water activities between 0.1 and 0.8 using the dynamic dewpoint method (DDI). The experiment sorption data were modeled using 12 different equations with non-linear regression to represent the dependence of the equilibrium moisture content with both water activity and temperature. In addition, the thermodynamic properties were determined with the experiment adsorption data. The results showed that type III isotherms were obtained according to the Brunauer classification, and the Weibull equation satisfactorily modeled the effect of the temperature on the hygroscopic equilibrium in the specialty ground roasted-coffee. The results of thermodynamic analysis showed that the net isosteric heat of adsorption and Gibbs free energy decreased as the equilibrium moisture content increased, indicating the amount of energy released, a strong bond energy between water molecules in the product components and spontaneity in the adsorption process. The entropy of the adsorption increased with the moisture content, leading to product stability conditions during storage. The results were similar to those reported for the roasted and ground coffee of others cultivars.

Determination of Isosteric Heat and Entropy of Sorption of Air Dried Sheet Rubber Using Artificial Neural Network Approach

2014 ◽  
Vol 541-542 ◽  
pp. 374-379 ◽  
Author(s):  
Kiattisak Suntaro ◽  
Supawan Tirawanichakul ◽  
Yutthana Tirawanichakul
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Moisture Content ◽  
Water Activity ◽  
Research Work ◽  
Isosteric Heat ◽  
Neural Network Approach ◽  
Heat Of Sorption ◽  
Artificial Neural

Equilibrium moisture contents (EMC) of air dried sheet (ADS) rubber were determined by commonly gravimetric-static method with saturated salt solution among surrounding temperatures of 40-70°C correlated to water activity (aw) ranges between 0.10 and 0.9. The experimental results was analyzed by 5 commonly EMC model. The results showed that equilibrium moisture content of ADS rubber decreased with increase of surrounding temperature at constant water activity and the simulated data using Chung-Pfost model has a good relation to experimental data with R2, RMSE and χ2 equal 0.9565, 0.0235 and 0.0006, respectively. However some physical property of ADS rubber sample affects to evaluate EMC modeling. Due to avoid this effect, thus the aim of this research work was to determine EMC value by using Artificial neural network (ANN) method and also evaluate the isosteric heat of sorption by following the Clausius-Clapeyron equation. The results showed that simulated results using ANN approach has relatively high accuracy compared to common EMC model. Finally determination of isosteric heat of sorption and entropy of sorption of ADS rubber were carried on. The results stated that the enthalpy and entropy of heat sorption was power function and polynomial function of moisture content respectively. These two parameters of ADS rubber can be used for prediction suitable storage condition and drying condition for ADS rubber drying in the near future work.

Moisture Sorption Isotherms, Isosteric Heat of Sorption and Glass Transition Temperature of Murtilla (Ugni molinae T.) Berry

2014 ◽  
Vol 10 (4) ◽  
pp. 583-594 ◽  
Author(s):  
Kong S. Ah-Hen ◽  
Roberto Lemus-Mondaca ◽  
Karen A. Mathias-Rettig ◽  
Antonio Vega-Gálvez ◽  
Jessica López
Keyword(s):  
Experimental Data ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Moisture Content ◽  
Sorption Isotherms ◽  
Isosteric Heat ◽  
Sorption Data ◽  
Heat Of Sorption ◽  
Ugni Molinae

Abstract Adsorption and desorption isotherms of fresh and dried murtilla (Ugni molinae Turcz) berries were determined at 20, 40 and 60°C using a gravimetric technique. The experimental data obtained were fitted to eight models, namely GAB, BET, Henderson, Caurie, Smith, Oswin, Halsey and Iglesias–Chirife. A non-linear least square regression analysis was used to evaluate the models. The GAB model best fitted the experimental data. Isosteric heat of sorption was determined from the equilibrium sorption data using the Clausius–Clapeyron equation and was found to decrease exponentially with increasing moisture content. The enthalpy–entropy compensation theory applied to the sorption isotherms indicated an enthalpy controlled sorption process. Glass transition temperature of murtilla was determined by differential scanning calorimetry and modelled as a function of moisture content by the Gordon–Taylor equation and as function of water activity by Roos and Khalloufi models, which proved to be excellent tools for predicting glass transition of murtilla.

scholarly journals PENGARUH SUHU REAKSI, KECEPATAN PENGADUKAN DAN WAKTU REAKSI PADA PEMBUATAN SABUN PADAT DARI MINYAK KELAPA (Cocos nucifera L.)

2019 ◽  
Vol 8 (1) ◽  
pp. 11-17
Author(s):  
Rosdanelli Hasibuan ◽  
Fransiska Adventi ◽  
Rahmad Parsaulian Rtg
Keyword(s):  
Reaction Time ◽  
Moisture Content ◽  
Reaction Temperature ◽  
Ph Value ◽  
Cocos Nucifera ◽  
Coconut Oil ◽  
Operating Conditions ◽  
Animal Fats ◽  
Cocos Nucifera L ◽  
Impeller Type

Soap is a cleanser made by chemical reactions between sodium hydroxide or potassium hydroxide with fatty acids from vegetable oils or animal fats. Soaps can be made by several methods, namely saponification and neutralization methods, in this study carried out by saponification method. In the saponification method there are several problems namely operating conditions which include reaction temperature, stirring speed and stirring time. Therefore, need to do research to determine the best conditions of saponification reaction, namely reaction speed, operating temperature and reaction time using an impeller type multiple pitch blade turbine with research variables reaction temperature 60 oC, 70 oC, and 80 oC, stirring speed 300 rpm,400 rpm and 500 rpm and reaction time of 45minutes, 60 minutes, and 75 minutes. Saponification reaction is carried out by heating coconut oil and inserting 30% NaOH slowly and then stirring with a multiple pitch blade stirrer. The product will be analyzed by testing alkaline levels, moisture content and pH of the soap. The best operating conditions obtained from this study were at a temperature of 70 oC, reaction time of 60 minutes, stirring speed of 400 rpm with a pH value of 9.4 and an alkaline level of 0.073 and a moisture content of 9.8.

scholarly journals Hygroscopic Behavior and Thermodynamic Properties of Ziziphus joazeiro Mart. Kernel Flour

2020 ◽  
Vol 8 (3) ◽  
pp. 50
Author(s):  
Hanndson Araujo Silva ◽  
Josivanda Palmeira Gomes ◽  
Alexandre José de Melo Queiroz
Keyword(s):  
Experimental Data ◽  
Thermodynamic Properties ◽  
Moisture Content ◽  
Isosteric Heat ◽  
Type Ii ◽  
Differential Entropy ◽  
Differential Enthalpy ◽  
Gab Model ◽  
Hygroscopic Behavior ◽  
Best Fit

The hygroscopic and thermal behavior of kernel flour from Ziziphus joazeiro fruits were investigated. Adsorption isotherms were obtained at temperatures of 293, 303 and 313 K and adjusted to GAB, Oswin and Peleg models. The best fit of the experimental data was obtained with the GAB model with R² values> 0.994 and mean percentage deviation P <10%. The isotherms obtained were sigmoidal type II. Isosteric heat and other thermodynamic properties were calculated as a function of moisture content. Adsorption isosteric heat decreased exponentially with increasing moisture content and differential entropy increased with moisture content, while differential enthalpy decreased. The theory of compensation confirmed that these properties are dependent on moisture content. The isotherms presented a spontaneous and enthalpy process.

Modeling Desorption Isotherms and Thermodynamic Properties of Fresh Tea Leaves (Camellia sinensis var. assamica)

2012 ◽  
Vol 8 (4) ◽  
Author(s):  
W. Sarath Botheju ◽  
K. Sanath P. Amaratunge ◽  
I. Sarath B. Abeysinghe
Keyword(s):  
Thermodynamic Properties ◽  
Moisture Content ◽  
Pure Water ◽  
Gravimetric Method ◽  
Isosteric Heat ◽  
Differential Entropy ◽  
Tea Leaves ◽  
Heat Of Sorption ◽  
Compensation Theory ◽  
Tea Leaf

Abstract Desorption isotherm of fresh tea leaves was studied using static gravimetric method of saturated salt solutions at temperatures of 15, 20, 25 and 30ºC and water activities of 0.07 to 0.97. Data were fitted to five mathematical equations. Using the best-fit mathematical model, thermodynamic properties of fresh tea leaves including net isosteric heat of sorption, differential entropy were estimated. The applicability of enthalpy – entropy compensation theory for fresh tea leaves was also evaluated. Results showed that the modified Oswin model was best fitted with the experimental data. Thermodynamics properties like net isosteric heat of sorption and differential entropy were found to decrease exponentially with the increase in moisture content. Net isosteric heat of sorption and differential entropy increased exponentially with decreasing moisture content of fresh tea leaves. Isosteric heat of sorption of fresh tea leaves was very close to heat of vaporization of pure water when the moisture content of tea leaves exceeded 40% (d.b.). The enthalpy-entropy compensation theory could be successfully applied for the moisture desorption behavior of fresh tea leaf samples and it was enthalpy driven spontaneous process.

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.

Determination of Moisture Sorption Isotherms of Jasmine Rice Crackers Using BET and GAB Models

2006 ◽  
Vol 12 (6) ◽  
pp. 459-465 ◽  
Author(s):  
U. Siripatrawan ◽  
P. Jantawat
Keyword(s):  
Moisture Content ◽  
Water Activity ◽  
Sorption Isotherms ◽  
Moisture Sorption ◽  
Sorption Data ◽  
Heat Of Sorption ◽  
Moisture Sorption Isotherms ◽  
Jasmine Rice ◽  
Gab Model ◽  
Best Fit

Moisture sorption isotherms of Thai Jasmine rice crackers were determined at 30, 45 and 60°C over a water activity range of 0.10 to 0.95 using a static gravimetric technique. Moisture sorption isotherms of rice crackers exhibited the sigmoid (Type II) shape. The moisture content of rice crackers decreased as temperature increased at a given water activity of the storage environment. The Brunauer, Emmett and Teller (BET) and Guggenheim-Anderson-de Boer (GAB) models were applied to fit the experimental data. The isosteric heat of sorption at different moisture levels was also determined using the Clausius–Clapeyron thermodynamic equation. A nonlinear regression analysis method was determined to evaluate the parameters of sorption equations. The criteria used to evaluate the goodness of fit of each model were the mean relative percentage deviation modulus (E) and the percentage root mean square error (RMSE). The more extended range of application of the GAB equation over the BET equation was evident. The GAB model gave the best fit to the experimental sorption data for a wide range of water activity (0.10–0.95) while the BET model gave the best fit for a water activity range of less than 0.60. The GAB model is considered suitable to predict the moisture sorption isotherm of rice crackers since it gave low E and RMSE values. The heat of sorption values of rice crackers were found to be large at low moisture content and decreased with an increase in food moisture content.

scholarly journals Modeling sorption isotherms and isosteric heat of sorption of roasted coffee beans

2018 ◽  
Author(s):  
Gentil Andres Collazos-Escobar ◽  
Nelson Gutiérrez-Guzmán ◽  
Henry Alexander Vaquiro-Herrera ◽  
Erika Tatiana Cortes-Macias
Keyword(s):  
Moisture Content ◽  
Equilibrium Moisture Content ◽  
Sorption Isotherms ◽  
Isosteric Heat ◽  
Dew Point ◽  
Roasted Coffee ◽  
Sorption Data ◽  
Heat Of Sorption ◽  
Coffee Beans ◽  
Roasted Coffee Beans

The aim of this work was determine the sorption isotherms in roasted beans of specialty coffee at temperatures of 25, 30 and 40 °C and water activities between 0.1 and 0.8 using the dynamic dew point method. The experimental sorption data were modeled using 12 different equations to represent the dependence of equilibrium moisture content with aw and temperature. The net isosteric heat of sorption was determined from the experimental sorption data using the Clausius-Clapeyron equation. The Weibull model satisfactorily modeled the effect of the temperature on the hygroscopic equilibrium in roasted coffee beans (R2adj =0.902 and RMSE = 0.00550 kg·kg-1d.b.). The net isosteric heat of sorption increase with increased moisture content. Keywords: water activity; sorption properties; equilibrium moisture content; hygroscopicity

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