Data/hora: 13/06/2024 08:15:45

Provedor de dados: | 64
País: | Brazil
Título: | Thermodynamic properties of moisture desorption isotherms of ryegrass (Lolium multiflorum L.) seeds
Autores: | Zeymer,Juliana Soares; Corrêa,Paulo Cesar; Oliveira,Gabriel Henrique Horta de; Araujo,Marcos Eduardo Viana de; Magalhães,Diana Soares.
Data: | 2020-01-01
Ano: | 2020
Palavras-chave: | Gibbs free energy; Entropy; Enthalpy; Water activity; Chung Pfost.
Resumo: | ABSTRACT Studies about the thermodynamic properties of ryegrass seeds are necessary to improve post-harvest processes, relating the factors that affect product quality with the interaction between water and its chemical components. Given the importance of recognizing and understanding the intrinsic behavior of water in ryegrass seeds and providing data for the improvement of industrial drying equipment, this work aimed to calculate and evaluate the thermodynamic properties of moisture desorption of ryegrass seeds as a function of the equilibrium moisture content. Ryegrass seeds with initial moisture content of 10.4 (% d.b.) was used. The equilibrium moisture content of seeds was determined by static-gravimetric method at different temperatures (10, 20, 30, 40, and 50 °C) and water activity values (between 0.10 and 0.90), in three repetitions. The Chung Pfost model presented the best fit to the experimental data. It was observed that the integral isosteric desorption heat increased as the equilibrium moisture content decreased, ranged from 2499.95 to 4241.96 kJ kg-1 in the moisture content range 2.80 to 22.10 (% d.b.). Differential entropy also increased with decreasing equilibrium moisture content, as did Gibbs free energy, being positive for all temperature studied, indicating that ryegrass seeds desorption is a non-spontaneous process. The enthalpy-entropy compensation theory was satisfactorily applied to the sorption phenomenon, being controlled by enthalpy.
Tipo: | Info:eu-repo/semantics/article
Idioma: | Inglês
Identificador: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1413-70542020000100202
Editor: | Editora da Universidade Federal de Lavras
Relação: | 10.1590/1413-7054202044027619
Formato: | text/html
Fonte: | Ciência e Agrotecnologia  v.44 2020
Fonte: | info:eu-repo/semantics/openAccess