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Equilibrium moisture content and heat of desorption of saffron
Author(s) -
Gazor Hamid Reza,
Chaji Hossein
Publication year - 2010
Publication title -
international journal of food science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.831
H-Index - 96
eISSN - 1365-2621
pISSN - 0950-5423
DOI - 10.1111/j.1365-2621.2010.02321.x
Subject(s) - equilibrium moisture content , desorption , chemistry , gravimetric analysis , relative humidity , water activity , water content , thermodynamics , moisture , sorption , crocus sativus , humidity , chromatography , analytical chemistry (journal) , botany , organic chemistry , adsorption , physics , geology , geotechnical engineering , biology
Summary The equilibrium moisture contents of saffron ( Crocus sativus L.) stigmas were determined experimentally using the standard gravimetric method at temperatures 30, 45 and 60 °C and water activity ranging from 11% to 83%. The sorption isotherm curves of saffron were sigmoidal in shape and decreased with increased temperature at constant relative humidity. Five selected isotherm models GAB, modified Henderson, modified Chung‐Pfost, modified Halsaey and modified Oswin were tested to fit the experimental isotherm data. Modified Oswin and modified Henderson models were found acceptable for predicting desorption moisture isotherms and fitting to the experimental data, respectively. The isosteric heats of desorption, determined from equilibrium data using the Clausius‐Clapeyron equation, were found to be a function of moisture content. The net isosteric heat of desorption of saffron varied between 1.38 and 5.38 kJ mol −1 at moisture content varying between 2% and 20% (d.b).