Secagem de tamara (Phoenix dactylifera L.) para obtenção de tamara passa
Monica Elisabeth Torres Prado
TESE
Português
T/UNICAMP P882s
Campinas, SP : [s.n.], 1998.
[230]f. : il.
Orientador: Kil Jin Park
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
Resumo: Estudou-se o comportamento do processo de secagem de tâmaras da variedade Zahidi, a fim de se obter uma tâmara-passa deste fruto, que vem apresentando boas perspectivas de cultivo e comercialização no Brasil. Os dados experimentais das ísotermas de sorção nas temperaturas de 60, 70 e 80 °C,...
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Resumo: Estudou-se o comportamento do processo de secagem de tâmaras da variedade Zahidi, a fim de se obter uma tâmara-passa deste fruto, que vem apresentando boas perspectivas de cultivo e comercialização no Brasil. Os dados experimentais das ísotermas de sorção nas temperaturas de 60, 70 e 80 °C, com umidade relativa variando de 10,51% a 80,25% obtida através de soluções saturadas de sais , foram ajustadas pelos modelos de BET, GAB, Halsey e Oswin. Os melhores ajustes foram obtidos peias equações de BET e GAB. O encolhimento foi determinado e correlacionado com a perda de umidade através dos modelos propostos por SUZUKI et al. (1978). Para a caracterização da geometria do fruto foram testadas quatro formas geométricas distintas: cilindro com tampa, cilindro sem tampa, elipse oblata e elipse proiata. Os resultados mostraram que a tâmara pode ser considerada um cilindro sem tampa. As corridas experimentais de secagem foram conduzidas em um secador vertical convectivo, nas temperaturas de 60, 70 e 80 ° C, com umidade relativa variando de 6,68 a 11,59%. As curvas de secagem foram ajustadas peia equação de difusão líquida para geometria esférica e geometria cilíndrica do material, considerando ou não o encolhimento. A melhor correlação das curvas de secagem foi obtida utilizando o modelo difusional de Fick para a geometria cilíndrica da tâmara considerando o encolhimento. Os valores de difusividade efetiva foram de 1,02 .10-7 a 4,52 . 10-7 m2/s para curvas de secagem sem encolhimento e de 0,71 .10-7 a 3,81 . 10-7 m2/s para curvas com encolhimento. A energia de ativação de Arrhenius foi calculada para os valores de difusividade sem e com a consideração do encolhimento, variando de 41,23 kj/mol. K a 60,98 kj/mol. Ke de 36,35 kj/mol. K a 69,59 kj/mol. K, respectivamente
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Abstract: Drying process behavior of date was studied to obtain dried date (passa). The production and commerciaiization of date are successfully growing in Brazil. The experimentai values of sorption isotherms at 60, 70 and 80°C were obtained at relative humidity ranging from 10,51 % to 80,25% and...
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Abstract: Drying process behavior of date was studied to obtain dried date (passa). The production and commerciaiization of date are successfully growing in Brazil. The experimentai values of sorption isotherms at 60, 70 and 80°C were obtained at relative humidity ranging from 10,51 % to 80,25% and were correlated by BET, GAB, HALSEY and OSWIN model. BET and GAB models presented the best
correlation. The shrinkage during drying was observed and verified by SUZUKí et ai (1978) equations'. Date geometric forms were characterized by four different shapes-cylinder with caps, cylinder without caps, oblate ellipse and prolate ellipse. The results indicate that the date may be considered as a cylinder without caps. The experimental drying curves were obtained to 60, 70 and 8Q°C in a convective vertical dryer. The relative humidity ranged from 6.66% to 11.59%. The drying curve was using Fick's second law for liquid diffusion solved for spherical and cylindrical boundaries, with and without shrinkage. The best correlation was obtained to cylindrical geometry with shrinkage. Effective diffusivity obtained ranged from 1.02 . 10-7 to 4,52 . 10-7 m2/s without shrinkage and from 0.72 . 10-7 to 3,81 . 10-7 m2/s with shrinkage. Arrenious type activation energy was calculated using the effective diffusivities, ranging from 41,23 kJ/mol. K to 60,98 kJ/mol. K without and from 36,35 kJ/mol. K to 69,59 kj/mol. K with shrinkage
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correlation. The shrinkage during drying was observed and verified by SUZUKí et ai (1978) equations'. Date geometric forms were characterized by four different shapes-cylinder with caps, cylinder without caps, oblate ellipse and prolate ellipse. The results indicate that the date may be considered as a cylinder without caps. The experimental drying curves were obtained to 60, 70 and 8Q°C in a convective vertical dryer. The relative humidity ranged from 6.66% to 11.59%. The drying curve was using Fick's second law for liquid diffusion solved for spherical and cylindrical boundaries, with and without shrinkage. The best correlation was obtained to cylindrical geometry with shrinkage. Effective diffusivity obtained ranged from 1.02 . 10-7 to 4,52 . 10-7 m2/s without shrinkage and from 0.72 . 10-7 to 3,81 . 10-7 m2/s with shrinkage. Arrenious type activation energy was calculated using the effective diffusivities, ranging from 41,23 kJ/mol. K to 60,98 kJ/mol. K without and from 36,35 kJ/mol. K to 69,59 kj/mol. K with shrinkage
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Park, Kil Jin, 1950-2020
Orientador
Tobinaga, Satoshi, 1936-
Avaliador
Hubinger, Miriam Dupas, 1957-
Avaliador
Jardine, Jose Gilberto
Avaliador
Martucci, Enny Therezinha, 1930-2016
Avaliador
Honório, Sylvio Luís, 1950-
Avaliador
Secagem de tamara (Phoenix dactylifera L.) para obtenção de tamara passa
Monica Elisabeth Torres Prado
Secagem de tamara (Phoenix dactylifera L.) para obtenção de tamara passa
Monica Elisabeth Torres Prado
Exemplares
Nº de exemplares: 2
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