Water sorption isotherms and thermodynamic properties of pearl millet grain

The water sorption isotherms of pearl millet grain and the thermodynamic properties obtaining during the process of drying pearl millet were examined. Equilibrium moisture content (Xeq) was determined under several temperature (T) and relative humidity (RH) conditions. The Xeq data were correlated b...

Full description

Saved in:
Bibliographic Details
Published in:International journal of food science & technology 2010-04, Vol.45 (4), p.828-838
Main Authors: Goneli, André Luis Duarte, Corrêa, Paulo Cesar, de Oliveira, Gabriel Henrique Horta, Gomes, Cassandra Ferreira, Botelho, Fernando Mendes
Format: Article
Language:English
Subjects:
Biological and medical sciences
Cereal and baking product industries
enthalpy-entropy compensation theory
Entropy
Food industries
Fundamental and applied biological sciences. Psychology
hygroscopicity
isosteric heat of sorption
mathematical modelling
mathematical models
pearl millet
Pennisetum glaucum
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The water sorption isotherms of pearl millet grain and the thermodynamic properties obtaining during the process of drying pearl millet were examined. Equilibrium moisture content (Xeq) was determined under several temperature (T) and relative humidity (RH) conditions. The Xeq data were correlated by six mathematical models. The modified Henderson was the model that best fitted the experimental data. The Xeq decreased with an increase in T at constant RH. Hysteresis was also studied; increasing T led to a decrease in this phenomenon. Integral isosteric heat of sorption (Qst), differential entropy (ΔS) and the enthalpy-entropy compensation theory were studied. Qst values decreased when Xeq increased because the Qst values of adsorption were lower than Qst desorption values. The values of ΔS decreased with increases in Xeq, because ΔS values were higher for desorption than for adsorption. The enthalpy-entropy compensation theory is valid for describing the water sorption processes of pearl millet grain.
ISSN:0950-5423
1365-2621
DOI:10.1111/j.1365-2621.2010.02208.x