scholarly journals Isotermas e calor isostérico de dessorção das sementes de tungue

2021 ◽  
Vol 1 (54) ◽  
pp. 163
Author(s):  
Lílian Moreira Costa ◽  
Osvaldo Resende ◽  
Weder Nunes Ferreira Junior ◽  
Daniel Emanuel Cabral de Oliveira ◽  
Igor Olacir Fernandes Silva
Keyword(s):  
Mathematical Model ◽  
Moisture Content ◽  
Information Criterion ◽  
Isosteric Heat ◽  
Static Method ◽  
Biodiesel Production ◽  
Salt Solutions ◽  
Equilibrium Water Content ◽  
Desorption Isotherms ◽  
Content Range

<p><span class="fontstyle0">The tung is a species that has potential for biodiesel production, so for safe storage there is a need to get to know its hygroscopicity. The objective of this work was to determine the desorption isotherms based on the recommendation of a mathematical model, to define the safe moisture content for storage, and to obtain the isosteric heat for the tung seeds. In order to obtain the hygroscopic equilibrium water content, the static method was used, with 20g of seeds surrounded by a permeable tissue, and placed inside the desiccators containing salt solutions, in a BOD chamber with temperatures of 20, 25, At 30 and 35 ºC, water activity ranged from 0.14 to 0.812 decimal.The Akaike information criterion (AIC) and Bayesian Schwarz information criterion (BIC) were used to adjust the mathematical models and to help choose the best one. Among the tested models, ChungPfost was  elected to represent the desorption isotherms of tung seeds. Integral isosteric desorption heat values in the equilibrium moisture content range from 2.08 to 8.35 (% b.s.) ranged from 3754 to 2555 kJ kg</span><span class="fontstyle0">-1</span> <br /><br /></p>

scholarly journals Desorption isotherms and isosteric heat of araticum (Annona crassiflora Mart.) seeds

2020 ◽  
Vol 24 (9) ◽  
pp. 630-636
Author(s):  
Weder N. Ferreira Junior ◽  
Osvaldo Resende ◽  
Kelly A. de Sousa ◽  
Melícia I. A. Gavazza ◽  
Juliana de F. Sales ◽  
...  
Keyword(s):  
Experimental Data ◽  
Moisture Content ◽  
Nonlinear Regression ◽  
Regression Models ◽  
Information Criterion ◽  
Isosteric Heat ◽  
Nonlinear Regression Models ◽  
Desorption Isotherms ◽  
Annona Crassiflora ◽  
Content Range

ABSTRACT The objective of this study was to determine the desorption isotherms and isosteric heat of Annona crassiflora Mart. seeds, using Akaike information criterion (AIC) and Schwarz’s Bayesian information criterion (BIC) to assist in the choice of the nonlinear regression model. The desorption isotherms were determined by indirect static method and water activity was obtained using the instrument HygroPalm; the product was put in the device in B.O.D. chamber set at 10, 20, 30 and 40 °C. Several nonlinear regression models were fitted to the experimental data by the Gauss-Newton method. The desorption isotherms of Annona crassiflora Mart. seeds can be represented by the models of Chung-Pfost, Copace, Modified GAB, Modified Henderson, Modified Oswin, Sabbah and Sigma Copace. However, the Sigma Copace model showed better fit to the experimental data, with lower AIC and BIC values, being chosen to represent the desorption isotherms of Annona crassiflora Mart seeds. Isosteric heat increased with decreasing moisture content, requiring a greater amount of energy to remove water from seeds, with values ranging from 2541.64 to 2481.56 kJ kg-1, for the moisture content range from 5.69 to 14.93% on a dry basis.

scholarly journals Desorption isotherms and isosteric heat of 'cajuzinho-do-cerrado' achenes

2016 ◽  
Vol 20 (5) ◽  
pp. 481-486 ◽  
Author(s):  
Karine F. Barbosa ◽  
Juliana de F. Sales ◽  
Osvaldo Resende ◽  
Daniel E. C. de Oliveira ◽  
Jacson Zuchi ◽  
...  
Keyword(s):  
Moisture Content ◽  
Water Activity ◽  
National Park ◽  
Linear Regression Analysis ◽  
Isosteric Heat ◽  
Static Method ◽  
Different Temperatures ◽  
Desorption Isotherms ◽  
The One ◽  
Content Range

ABSTRACT The objective of this study was to determine the desorption isotherms of 'cajuzinho-do-cerrado' achenes (Anacardium humile St. Hil.) in various conditions of temperature and water activity, as well as to select the one that best represents the phenomenon and to determine the isosteric heat of desorption. The fruits were collected at the Emas National Park, in the municipality of Mineiros-GO, Brazil, pulped and then subjected to drying in silica gel at temperature of 25 ± 2 °C until the moisture contents of 17.6, 13.6, 11.1, 8.7 and 5.3 (d.b.%). After drying, the desorption isotherms were determined by the indirect static method. The water activity (Aw) was determined at different temperatures, and the achenes were placed in a B.O.D. chamber, regulated at 10, 20, 30 and 40 °C. Data of hygroscopic equilibrium moisture content were fitted to different mathematical models through non-linear regression analysis, using the Gauss-Newton method. The Copace model was the one that best represented the hygroscopicity of 'cajuzinho-do-cerrado' achenes, while the integral isosteric heat of desorption of 'cajuzinho-do-cerrado' achenes for the moisture content range of 4.51 to 13.40 (% d.b.) varied from 2,734.82 to 2,548.49 kJ kg-1.

scholarly journals Isotherms and isostatic heat of foam-mat dried yellow mombin pulp

2018 ◽  
Vol 22 (6) ◽  
pp. 436-441
Author(s):  
Maisa D. Cavalcante ◽  
Geovana R. Plácido ◽  
Daniel E. C. de Oliveira ◽  
Bheatriz S. M. de Freitas ◽  
Caroline Cagnin ◽  
...  
Keyword(s):  
Water Content ◽  
Water Activity ◽  
Nutritional Value ◽  
Isosteric Heat ◽  
Agricultural Products ◽  
Equilibrium Water Content ◽  
Desorption Isotherms ◽  
Forced Air ◽  
Semi Solid ◽  
Content Range

ABSTRACT Yellow mombin has high nutritional value but is very perishable. Foam mat drying is a method that has been widely used to preserve liquid and semi-solid powdered foods. In this context, the aim of this study was to determine desorption isotherms and isosteric heat of yellow mombin (Spondias mombin L.) foam for different conditions of temperature and water activity. Powdered yellow mombin pulp was obtained by drying in forced-air oven regulated to 60 ° C. The indirect static method was used to determine the isotherms and isosteric heat, whereas water activity (aw) was determined using the Hygropalm-HP23AW-A analyzer. A B.O.D. incubator, set at 10, 20, 30 and 40 °C, was used to control the temperature, and the water activity for each temperature was between 0.220 and 0.832. The experimental data were fitted to mathematical models frequently used to represent the hygroscopicity of agricultural products, and the best model was the Modified Halsey. Integral isosteric heat of desorption of yellow mombin powder, within the water content range of 17.22 to 57.58 (% d.b.), ranged from 3198.56 to 2598.38 kJ kg-1. It was concluded that the equilibrium water content of yellow mombin pulp powder increased with the increment in water activity; desorption isotherms obtained for yellow mombin pulp powder showed sigmoid form and, with the reduction of water content, the isosteric heat increases.

scholarly journals Determination of desorption isotherms, latent heat and isosteric heat of pequi diaspore

2016 ◽  
Vol 20 (5) ◽  
pp. 493-498 ◽  
Author(s):  
Kelly A. de Sousa ◽  
Osvaldo Resende ◽  
Bruno de S. Carvalho
Keyword(s):  
Moisture Content ◽  
Latent Heat ◽  
Equilibrium Moisture Content ◽  
Sorption Isotherms ◽  
Isosteric Heat ◽  
Static Method ◽  
The One ◽  
Content Range ◽  
Water Sorption Isotherms

ABSTRACT The objective was to determine water sorption isotherms of diaspores of pequi fruits in order to obtain information on the amount of water that this product desorbs at the temperatures of 10, 20, 30 and 40 °C and water activities from 0.20 to 0.89, adjusting different mathematical models to experimental data, and to determine its latent heat and isosteric heat. The equilibrium moisture content was obtained through the indirect static method, using the device Hygropalm Model Aw 1. The Modified Henderson model was the one that best fitted the data and was selected to predict the equilibrium moisture content of pequi diaspore. It was observed that the higher the temperature for the same equilibrium moisture content (% d.b.), the higher the water activity values. As temperature values increased, there was a reduction in the vaporization latent heat of the product. Isosteric heat values of diaspores of pequi fruits in the moisture content range of 4.02 to 16.63 (% d.b.) varied from 2,776.49 to 2,558.39 kJ kg-1.

scholarly journals Isotherms and Isosteric Heat Desorption of Hymenaea stigonocarpa Mart. Seeds

2018 ◽  
Vol 10 (10) ◽  
pp. 504 ◽  
Author(s):  
Weder N. Ferreira Junior ◽  
Osvaldo Resende ◽  
Daniel E. C. de Oliveira ◽  
Lílian M. Costa
Keyword(s):  
Mathematical Model ◽  
Moisture Content ◽  
Equilibrium Moisture Content ◽  
Information Criterion ◽  
Isosteric Heat ◽  
Brazilian Cerrado ◽  
Harvest Management ◽  
Statistical Parameters ◽  
Modified Model ◽  
The One

The Brazilian Cerrado is one of the most important ecosystems and due to the extractivism it is necessary to recover the degraded areas. The tree of Hymenaea stigonocarpa Mart. is used in this reforestation system, so the study of post-harvest management of the seed is necessary for the propagation. The objective of this work was to determine the isotherms and the isosteric desorption heat of Hymenaea stigonocarpa Mart. Seeds, and to test the methodology of the Akaike&rsquo;s information criterion (AIC) and Schwarz&rsquo;s bayesian information criterion (BIC) for the choice of the best mathematical model. Different mathematical models were fitted to the experimental data and the model that best represents the phenomenon was selected, from the statistical parameters. To obtain the equilibrium moisture content was used static method using desiccants in incubators cameras with control of relative humidity by salt solution. The Oswin Modified model obtained better results according to analyzed parameters, being this model the one selected for prediction of the hygroscopic balance of the Hymenaea stigonocarpa Mart. seeds. It was found that the higher the temperature for the same equilibrium moisture content, the higher the water activity values. The AIC and BIC methodology contributed to the choice of the best mathematical model to predict the hygroscopicity phenomenon. The isosteric heat increased with the decrease in the equilibrium moisture content requiring a greater amount of energy to remove water from the seeds.

scholarly journals Hygroscopicity of ‘sucupira-branca’ (Pterodon emarginatus Vogel) fruits

2017 ◽  
Vol 21 (4) ◽  
pp. 285-289
Author(s):  
Daniel E. C. de Oliveira ◽  
Osvaldo Resende ◽  
Lílian M. Costa ◽  
Glicélia P. Silva ◽  
Juliana de F. Sales
Keyword(s):  
Moisture Content ◽  
Equilibrium Moisture Content ◽  
Dynamic Method ◽  
Sorption Isotherms ◽  
Isosteric Heat ◽  
Coefficient Of Determination ◽  
Chi Square ◽  
Mean Error ◽  
Technological Information ◽  
Desorption Isotherms

ABSTRACT ‘Sucupira-branca’ (Pterodon emarginatus Vogel) is a tree from ‘Cerrado’ and stands out mainly for its pharmacological properties; however, there are no technological information about its post-harvest operations. Thus, the aim of this study was to determine the sorption isotherms of ‘sucupira-branca’ fruits for different air conditions and obtain the values of desorption isosteric heat, depending on the equilibrium moisture content of the product. The equilibrium moisture content of ‘sucupira-branca’ fruits was determined by dynamic method for temperatures of 25, 30, 35 and 40 °C and water activities for each temperature between 0.270 and 0.775. The models Chung-Pfost, Copace, Modified Halsey, Oswin Modified and Sigma Copace obtained high coefficient of determination (R2) and low chi-square (χ2), relative mean error (P) and estimated mean error (SE), and the Copace model was selected to represent the desorption isotherms. The isosteric heat increases with the reduction of equilibrium moisture content and required more energy to remove water from the ‘sucupira-branca’ fruit.

scholarly journals Thermodynamic properties of water sorption of jackfruit (Artocarpus heterophyllus Lam.) as a function of moisture content

2013 ◽  
Vol 33 (1) ◽  
pp. 199-208 ◽  
Author(s):  
Ana Paula Prette ◽  
Francisco de Assis Cardoso Almeida ◽  
Harvey Alexander Villa-vélez ◽  
Javier Telis-Romero
Keyword(s):  
Thermodynamic Properties ◽  
Moisture Content ◽  
Water Activity ◽  
Water Sorption ◽  
Gravimetric Method ◽  
Isosteric Heat ◽  
Effect Of Temperature ◽  
Artocarpus Heterophyllus ◽  
Biological Damage ◽  
Desorption Isotherms

The Jackfruit tree is one of the most significant trees in tropical home gardens and perhaps the most widespread and useful tree in the important genus Artocarpus. The fruit is susceptible to mechanical and biological damage in the mature state, and some people find the aroma of the fruit objectionable, particularly in confined spaces. The dehydration process could be an alternative for the exploitation of this product, and the relationship between moisture content and water activity provides useful information for its processing and storage. The aim of this study was to determine the thermodynamic properties of the water sorption of jackfruit (Artocarpus heterophyllus Lam.) as a function of moisture content. Desorption isotherms of the different parts of the jackfruit (pulp, peduncle, mesocarp, peel, and seed) were determined at four different temperatures (313.15, 323.15, 333.15, and 343.15 K) in a water activity range of 0.02-0.753 using the static gravimetric method. Theoretical and empirical models were used to model the desorption isotherms. An analytical solution of the Clausius-Clapeyron equation was proposed to calculate the isosteric heat of sorption, the differential entropy, and Gibbs' free energy using the Guggenhein-Anderson-de Boer and Oswin models considering the effect of temperature on the hygroscopic equilibrium.

scholarly journals Desorption isotherms and isosteric heat of niger grains (Guizotia abyssinica (L. f.) Cass.)

2018 ◽  
Vol 12 (2) ◽  
pp. 124 ◽  
Author(s):  
Valdiney Cambuy Siqueira ◽  
Fernanda Pimentel Da Silva ◽  
Wellytton Darci Quequeto ◽  
Rodrigo Aparecido Jordan ◽  
Rafael Araujo Leite ◽  
...  
Keyword(s):  
Experimental Data ◽  
Moisture Content ◽  
Mathematical Models ◽  
Water Activity ◽  
Seed Oil ◽  
Oil Quality ◽  
Gravimetric Method ◽  
Isosteric Heat ◽  
Seed Moisture Content ◽  
Desorption Isotherms

Niger seed oil has excellent quality and quantity (30-50%) and is rich in polyunsaturated fatty acids, mainly linoleic acid (about 70%). Thus, control of environmental temperature and relative humidity, and of seed moisture content is essential to maintain seed oil quality during storage. Thus, the objective of this study was to determine the desorption isotherms of niger seeds under different temperature and water activity conditions, to test the experimental data with different mathematical models, and discover which best represents the phenomenon, as well as calculate the isosteric heat value for the product. Hygroscopicity was determined by the static gravimetric method, at temperatures of 30, 35 and 40 ºC, and water activity between 0.07 and 0.79 (decimal). For the experimental data, mathematical models commonly used to test hygroscopicity in agricultural products were evaluated. From the results obtained, it was concluded that: water activity increases as moisture content rises; based on the statistical parameters, the models of Chung and Pfost, modified Henderson, Oswin, Sabbah, Sigma Copace, Halsey, Smith and Copace appropriatrely represented the desorption phenomenon of niger seeds; total isosteric desorption heat increased with reduction of moisture content, with values varying from 2539.62 to 3081.48 kJ kg-1, within the range of equilibrium moisture content of 2.4 to 12.2 (% dry basis).

scholarly journals Desorption Isotherms and Isosteric Heats of Fermented Cocoa Beans (Theobroma cocoa)

2015 ◽  
Vol 4 (3) ◽  
pp. 138 ◽  
Author(s):  
Djedjro C. Akmel ◽  
Kouassi E. Kakou ◽  
Kisselmina Y. Kone ◽  
Nogbou E. Assidjo ◽  
Patrice Kouame
Keyword(s):  
Moisture Content ◽  
Energy Requirement ◽  
Isosteric Heat ◽  
Cocoa Beans ◽  
Water Desorption ◽  
Average Value ◽  
Desorption Isotherms ◽  
Monolayer Moisture ◽  
Isotherm Equations ◽  
Increasing Temperature

<p>Water desorption isotherms of fermented cocoa beans from Ivory Coast were determined using the gravimetric static method of saturated salts solutions at 30 °C, 40 °C and 60 °C, and isosteric heats of desorption were calculated from Clausius-Clapeyron equation. The experimental data were fitted to several isotherm equations. The best fittings were obtained for the BET equation for aw&lt;0.50 (with an average mean relative deviation (MRD) value of 1.56%) and for the Harkins-Jura equation for aw?0.50 (with an average value MRD equation of 4.17%). The isotherms obtained at 30 °C and 40 °C are practically coincident and overlapped for aw below 0.40. Fermented cocoa beans presented a monolayer moisture content of 0.083 dry basis (d.b.) at 30 °C and this value decreases with increasing temperature. The net isostheric heats of desorption for fermented cocoa beans for the temperature range studied (30-60 °C) were estimated as a function of moisture content. The maximum net isosteric heat of desorption for fermented cocoa beans was estimated at around 13.51 kJ/mol corresponding to a moisture content value of 2.85%. The energy requirement for maintaining the moisture content low of 8.7% (d.b.) or 8% wet basis (w.b.) for safe storage of this product or for reducing the moisture content during drying was estimated at around 9.58 kJ/mol.</p>

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.

Sign in / Sign up

Export Citation Format

Share Document