Water sorption thermodynamic properties applied to persimmon skin and pulp

Telis, Vânia Regina Nicoletti; Gabas, Ana Lúcia; Menegalli, Florência Cecília; Telis‐Romero, Javier

doi:10.1016/s0040-6031(99)00379-2

Cited by 109 publications

(120 citation statements)

References 20 publications

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“…the GAB parameter K increased as the temperature increased. For all jackfruit items, the values for constant K were below one, indicating that there was a difference in free enthalpy between the sorbate molecules in the pure liquid and those in the second sorption stage in the layer above the monolayer (RIZVI, 2005 The results of equilibrium moisture content reported in the literature for products such as persimmon skin (TELIS et al, 2000), pectin (TSAMI; KROKIDA; DROUZAS, 1998), Tunisian olive leaves (BAHLOUL; BOUDHRIOUA; KECHAOU, 2008), tomato pulp (GUOLA et al, 2008), and sesame seeds (AVIARA; AJIBOLA; DAIRO, 2002) showed similarities between the experimental values and the sorption isotherms obtained for the peel, peduncle, mesocarp, pulp, and seed, respectively.…”

Section: Thermodynamic Properties Of Water Sorptionmentioning

confidence: 96%

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

et al. 2013

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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.

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Section: Thermodynamic Properties Of Water Sorptionmentioning

confidence: 96%

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

et al. 2013

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“…Changes in ∆G values provide a criterion to evaluate whether water sorption is a spontaneous (∆Gβ < 0) or non-spontaneous process (∆Gβ > 0) (RIZVI, 2005;TELIS et al, 2000).…”

Section: Enthalpy-entropic Mechanism Of Water Sorptionmentioning

confidence: 99%

Study of the enthalpy-entropy mechanism from water sorption of orange seeds (C. sinensis cv. Brazilian) for the use of agro-industrial residues as a possible source of vegetable oil production

Rosa¹,

Vélez²,

Telis‐Romero³

2013

Ciênc. Tecnol. Aliment.

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Study of the enthalpy-entropy mechanism from water sorption of orange seeds (C. sinensis cv. Brazilian) for the use of agro-industrial residues as a possible source of vegetable oil production Estudo do mecanismo entálpico-entrópico de sorção da água de sementes de laranja (C. sinensis cv. Brasileira), para a utilização de resíduos agroindustriais como uma possível fonte de produção de óleo vegetal

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“…Para valores de energia livre de Gibbs negativos, o processo é espontâneo, enquanto para valores positivos é não-espontâneo (Telis et al, 2000). Mudanças na energia livre de Gibbs durante a troca de água entre o produto e o meio são a energia requerida para transferir moléculas de água do estado de vapor para uma superfície sólida ou vice-versa.…”

Section: Introducãounclassified

Modelagem matemática e determinação das propriedades termodinâmicas do café (Coffea arabica L.) durante o processo de secagem

et al. 2010

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Mathematical modeling and determination of thermodynamic properties of coffee (Coffea arabica L.) during the drying processThe aim of the present work was to model the drying process and to obtain the thermodynamic parameters of coffee beans (Coffea arabica L.), cultivar Catuaí Amarelo, for three different conditions of temperature and relative humidity (35 ºC and 32.1 %; 45 ºC and 15.7 %; 55 ºC and 10.2 %). Coffee beans were hand picked with an initial moisture content of 1.25 (d.b.) and dried to a mean moisture content of 0. 13 (d.b.). Six mathematical models commonly used to represent the drying process of agricultural products were fit to the experimental data. Fick's second law was used to obtain the diffusion coefficients of coffee beans using the drying kinetics. The activation energy for the drying process of coffee beans, as well as the entropy, enthalpy and Gibbs free energy were determined. The modified Midili model best represented the drying phenomenon of coffee beans. The calculated diffusion coefficients were 2.99 x 10 -11 , 2.39 x 10 -11 and 5.98 x 10 -11 m 2 s -1 , to the temperatures of 35, 45 and 55 ºC, respectively. Enthalpy decreased with the increase in the drying air temperature, as well as the entropy. The Gibbs free energy increased with the temperature.Key words: Arrhenius, moisture diffusion, enthalpy, activation energy. Modelagem matemática e determinação das propriedades termodinâmicas do café (Coffea arabica L.) durante o processo de secagem A secagem de produtos agrícolas é largamente utilizada no mundo para o controle e a manutenção da qualidade dos produtos agrícolas. O objetivo do presente trabalho foi modelar o processo de secagem e obter os parâmetros termodinâmicos de frutos de café (Coffea Arabica L.), cultivar Catuaí Amarelo, para três diferentes condições de temperatura e umidade relativa (35 ºC e 32,1%; 45 ºC e 15,7%; e 55 ºC e 10,2%). Foram utilizados frutos de café colhidos manualmente com teor inicial de água de 1,25 (b.s.) e submetidos à secagem até atingirem o teor médio de 0,13 (b.s). Seis modelos matemáticos usualmente utilizados para a representação do processo de secagem de produtos agrícolas foram ajustados aos dados experimentais. A segunda lei de Fick foi utilizada para obter os coeficientes de difusão dos frutos de café por meio da cinética da secagem. A energia de ativação para a secagem dos frutos de café, bem como a entropia, entalpia e energia livre de Gibbs, foram obtidas. O modelo de Midili modificado foi o que melhor representou o fenômeno de secagem de frutos de café. Os valores do coeficiente de difusão obtidos foram 2,99 x 10 -11 , 2,39 x 10 -11 e 5,98 x 10 -11 m 2 s -1 para as temperaturas de 35, 45 e 55 ºC, respectivamente. A entalpia diminuiu com o aumento da temperatura do ar de secagem, bem como a entropia. A energia livre de Gibbs aumentou com o aumento da temperatura.Palavras-chave: Arrhenius, difusão de umidade, entalpia, energia de ativação.

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Water sorption thermodynamic properties applied to persimmon skin and pulp

Cited by 109 publications

References 20 publications

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

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

Study of the enthalpy-entropy mechanism from water sorption of orange seeds (C. sinensis cv. Brazilian) for the use of agro-industrial residues as a possible source of vegetable oil production

Modelagem matemática e determinação das propriedades termodinâmicas do café (Coffea arabica L.) durante o processo de secagem

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