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| Registros recuperados: 12 | |
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| Sousa, Kelly Aparecida; Resende, Osvaldo; Goneli, André Luis Duarte; Smaniotto, Thaís Adriana de Souza; Oliveira, Daniel Emanuel Cabral de. |
| The purpose of this study was to determine the thermodynamic properties of the process of water sorption in forage turnip seeds. The equilibrium moisture content of forage turnip seeds was determined by the gravimetric-dynamic method for different values of temperature and water activity. According to the results, increasing the moisture content increases the energy required for the evaporation of water in forage turnip seeds, and the values of integral isosteric heat of desorption, within the moisture content range of 3.33 to 11.30 (% d.b.), varies from 4,222.70 to 2,870.34 kJ kg-1. With the elevation in the equilibrium moisture content, there is an increase in differential entropy and Gibbs free energy, which has positive values, demonstrating... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Ciências Ágrarias; Armazenamento de produtos agrícolas hygroscopic equilibrium; Isosteric heat; Gibbs free energy; Compensation theory Ciências Ágrarias; Armazenamento de produtos agrícolas. |
| Ano: 2014 |
URL: http://periodicos.uem.br/ojs/index.php/ActaSciAgron/article/view/19333 |
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| Baptestini, Fernanda Machado; Corrêa, Paulo Cesar; Oliveira, Gabriel Henrique Horta de; Cecon, Paulo Roberto; Soares, Nilda de Fátima Ferreira. |
| The objective of this study was to model the kinetics of water sorption in roasted and ground coffee. Crude Arabica coffee beans with an initial moisture content of 0.1234 kgwkgdm-1 were used. These beans were roasted to a medium roast level (SCCA # 55) and ground at three particle sizes: coarse (1.19 mm), medium (0.84 mm) and fine (0.59 mm). To obtain the water sorption isotherms and the isosteric heat, different conditions of temperature and relative humidity were analyzed using the dynamic method at 25ºC (0.50, 0.60, 0.70, and 0.80 of RH) and 30°C (0.30, 0.40, 0.50, 0.60, 0.70, and 0.80 of RH) and using the static method at 25ºC (0.332 and 0.438 of RH). The GAB model best represented the hygroscopic equilibrium of roasted coffee at every particle size.... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Particle size; Specific surface; Isosteric heat. |
| Ano: 2017 |
URL: http://periodicos.uem.br/ojs/index.php/ActaSciAgron/article/view/32576 |
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| Amiri Chayjan,Reza; Esna-Ashari,Mahmood. |
| Sorption isotherm of soya bean (Glycine max (L.) Merr.) was obtained by the dynamic experimental method. Artificial Neural Networks (ANNs) were used for modeling soya bean equilibrium moisture content (EMC). Thermodynamic equations and trained ANN for prediction of two thermodynamic properties of net isosteric heat and entropy of soya bean were utilized. The ANN models were better compared with mathematical models. In this study, the isosteric heat and entropy of sorption of soya bean were separately predicted by two power models as a EMC function. Predictive power of the models was high (R² ≈ 0.99). At the moisture content above 11% (dry basis, db), isosteric heat and entropy of sorption of soya bean were smoothly decreased, while they were... |
| Tipo: Journal article |
Palavras-chave: Back propagation; Entropy; Isosteric heat; Sorption isotherm; Soya bean. |
| Ano: 2010 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392010000400012 |
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| Molina Filho,Lucídio; Gonçalves,Ana Karla Rebes; Mauro,Maria Aparecida; Frascareli,Elen Cristina. |
| Moisture desorption isotherms of fresh and heat blanched pumpkins (Cucurbita moschata) were determined at three temperatures (30, 50 and 70 °C), using the standard, static-gravimetric method. The GAB, Oswin, BET, Halsey, and Henderson models were tested and, with the exception of the Henderson model, showed satisfactory fits to the experimental data. The GAB model was used to analyze the fitting ability to describe the isotherm type. The shape of the desorption isotherms of fresh and blanched pumpkin at 30 and 50 °C was intermediate to types II and III, and at 70 °C it was of type II for the blanched pumpkin and close to type II for the fresh sample. The influence of blanching on the decrease in equilibrium moisture was very small compared to the fresh... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Blanching; Pumpkin; Desorption isotherms; Isosteric heat; GAB model. |
| Ano: 2011 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0101-20612011000300025 |
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| Oliveira,Daniel E. C. de; Resende,Osvaldo; Costa,Lílian M.; Silva,Glicélia P.; Sales,Juliana de F.. |
| 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... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Equilibrium moisture content; Isotherms; Water activity; Isosteric heat; Copace. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662017000400285 |
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| Cavalcante,Maisa D.; Plácido,Geovana R.; Oliveira,Daniel E. C. de; Freitas,Bheatriz S. M. de; Cagnin,Caroline; Oliveira,Déborah de S.. |
| 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... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Water activity; Isosteric heat; Hygroscopicity; Mathematical modeling; Spondias mombin L.. |
| Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662018000600436 |
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| Valente,Maria da Conceição da Costa; Nascimento,Rafael Alves do; Santana,Elza Brandão; Faria,Lênio José Guerreiro de; Costa,Cristiane Maria Leal. |
| ABSTRACT Sorption isotherms of flaxseeds were determined by static gravimetric method at temperatures 40, 60, and 80 ºC, over a relative moisture range of 10-95%. Six mathematical models were applied to analyze the experimental data. The modified GAB model showed the best fitting to the experimental data. The isosteric heat and differential entropy were determined by applying the Clausius-Clapeyron and Gibbs-Helmholtz equations, respectively. The isosteric heat and the entropy of desorption isotherm presented similar behavior, with a sharp change of 10% in the equilibrium moisture content. The enthalpy-entropy compensation theory was applied to the isotherms, indicating that they are enthalpy-controlled. |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Equilibrium moisture content; Drying; Isosteric heat. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1806-66902020000200401 |
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| Registros recuperados: 12 | |
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