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| Registros recuperados: 13 | |
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| Zeymer,Juliana S.; Corrêa,Paulo C.; Oliveira,Gabriel H. H. de; Baptestini,Fernanda M.; Faria,Igor L.. |
| ABSTRACT This study aimed to determine the thermodynamic properties of sorption processes (desorption and adsorption) of rice in the husk, cv. Urucuia. A static-gravimetric method was used to reach equilibrium moisture content at different temperatures (10, 20, 30, 40, and 50 °C ± 1°C) and relative humidity levels (10, 30, 50, 70, and 90 % ± 2%). A decrease in moisture content led to an increment of the integral isosteric heat of sorption, indicating a higher demand for energy to remove moisture from the product. Differential entropy of sorption decreased along with a moisture content increment, with higher values for desorption. This indicates a higher mobility of water molecules during desorption if compared to adsorption. Gibbs free energy decreased... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Equilibrium moisture content; Integral isosteric heat of sorption; Differential entropy; Gibbs free energy; Enthalpy-entropy compensation theory. |
| Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162018000300369 |
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| Campos,Renata C.; Corrêa,Paulo C.; Fernandes,Lara S.; Baptestini,Fernanda M.; Costa,Cristian F.; Bustos-Vanegas,Jaime D.. |
| ABSTRACT This study aimed to evaluate the effect of mechanical damage on the hysteresis of beans with induced mechanical damage under different conditions of temperature and relative humidity. Beans (Phaseolus vulgaris L.) harvested manually with 35% water content (w.b.) were used. Part of this product was subjected to induced mechanical damage by Stein Breakage Tester and controlled drying (damaged and control sample), for sorption processes. The sorption isotherms of water were analyzed for different temperature conditions: 20, 30, 40 and 50 oC; and relative humidity: 0.3; 0.4; 0.5; 0.7 and 0.9 (decimal). Equilibrium moisture content data were correlated with six mathematical models, and the Modified Oswin model was the one that best fitted to the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Mechanical damage; Equilibrium moisture content; Sorption isotherms; Mathematical modeling; Phaseolus vulgaris L.. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662016001000930 |
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| Oliveira,Daniel E. C. de; Resende,Osvaldo; Costa,Lílian M.; Ferreira Júnior,Weder N.; Igor O. F.,Silva. |
| ABSTRACT With the knowledge on the hygroscopic equilibrium of the baru (Dipteryx alata Vogel) fruit, the product can be adequately handled to maintain the moisture content at the levels recommended for safe storage. Thus, this paper aimed to determine the water desorption isotherms of baru fruits at temperatures of 20, 25, 30 and 35 °C, and water activity between 0.14 and 0.80, and obtain the values of isosteric heat of desorption as a function of the equilibrium moisture content of the product. The equilibrium moisture content was obtained using the static-gravimetric method. Modified Halsey was the best model recommended to represent the hygroscopicity of baru fruits. The recommended moisture contents for safe storage of baru fruits are not more than... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Equilibrium moisture content; Mathematical modeling; Desorption isotherms. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662017000400279 |
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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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| Goneli,André L. D.; Corrêa,Paulo C.; Oliveira,Gabriel H. H. de; Resende,Osvaldo; Mauad,Munir. |
| 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.... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Ricinus communis L.; Equilibrium moisture content; Mathematical modeling. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662016000800751 |
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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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| Ade, Ayokanmi Remi; Ajav, E A; Raji, Abdulganiy O; Adetayo, Seun Ayodele; Arowora, Kayode Adebisi. |
| Moisture profoundly influences product attributes such as quality and safety. The knowledge of moisture sorption isotherm is essential to determine products stability, and needed for design of storage, packaging and drying systems for extension of shelf lives. This study is to develop sorption isotherms of Prosopis africana.The moisture sorption isotherms of the seed were determined at temperatures of 20ºC, 25ºC and 30ºC, over a relative humidity range of 11%-100% using the static gravimetric technique. A linear regression programme was used to fit five isotherm models; GAB, Oswin, Halsey, Henderson, and Chung Pfost to the experimental data and compared using the root mean standard error, regression coefficient, standard error of estimate, and randomness... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Agrricultural Engineering Prospis africana; Equilibrium moisture content; Water activity; Adsorption; And desorption. |
| Ano: 2016 |
URL: http://www.cigrjournal.org/index.php/Ejounral/article/view/3727 |
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| Amankwah, E.A.; Straten, G. van; Boxtel, Ton van. |
| The experimental equilibrium moisture content of yam (Dioscorea rotundata; cultivar: Dente) at temperatures of 25 and 50°C were determined at relative humidities from 0 to 95% employing the Dynamic Vapour Sorption analyzer. Wet yam samples with about 68% initial moisture content were used, first for desorption and subsequently for sorption. Water activity decreased with increased temperature at constant equilibrium moisture content. The desorption and adsorption isotherms were fitted by the GAB, Henderson, Halsey, Oswin, Smith, BET and Peleg models. On the basis of the fit the Peleg, GAB and Oswin models were most suitable for describing the observed data. When the focus is on drying, the GAB (3 parameters) and empirical Peleg model (4 parameters)... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Post-harvest processing; Drying Sorption isotherm; Yam; Equilibrium moisture content; GAB. |
| Ano: 2018 |
URL: http://www.cigrjournal.org/index.php/Ejounral/article/view/4428 |
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| Corrêa,Paulo Cesar; Zeymer,Juliana Soares; Oliveira,Gabriel Henrique Horta de; Araujo,Marcos Eduardo Viana de; Silva,Camilla Sena da. |
| ABSTRACT It is necessary to determine the sorption isotherms of seeds to develop adequate systems of storage and drying. The chemical composition of a product affects the sorption process; products with a high oil content adsorb a lower amount of moisture from the environment than products with a high carbohydrate content. Given the importance of the hygroscopicity of different agricultural products, this work aimed to determine, model and evaluate the difference between desorption isotherms of ryegrass and flax seeds grown at different temperature and relative humidity conditions. Ryegrass and flax seeds, which contained initial moisture contents of 10.4 and 8.7% (db), respectively, were used. The equilibrium moisture content of the seeds was determined... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Equilibrium moisture content; Chemical composition; Mathematical modeling; Chung Pfost; Smith.. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1413-70542020000100215 |
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| Registros recuperados: 13 | |
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