Modeling of desorption isotherm of black tea

In this paper the relationship between the moisture content of black tea an d the relative humidity at different temperature conditions is interrogated . The equivalent moisture contents was measured using the static gravimetri c method under the relative humidity range of 10% to 90% and under the temp erature range of 25 degreesC to 80 degreesC. The obtained data was analysed using statistical data processing techniques and the results fitted to the different sorption isotherm equations like GAB, Oswin, Henderson, and Hals ey at various temperatures. The G.A.B. and Oswin equations show good agreem ents with the obtained results. The results indicate that the desorption is otherms of black tea are sensitive to the temperature. At constant water ac tivity, an increase in temperature decreases the equivalent moisture conten t of black tea.