Some characteristics of the heat of water vapour sorption in dried foodstuffs

Abstract

Differential heat curves (obtained from adsorption and desorption isotherms) previously reported, were utilized for calculating 'integral' heats of water vapour sorption in dried foods. Foods examined amounted to almost thirty and included fruits, meats, vegetables and spices. 'Integral' heats were calculated by integrating the area under each differential heat curve in the moisture range of more practical interest. Calculated heats may be useful for estimating the heat requirements during dehydration. Average values of the heats of sorption were also reported which may be useful for the analysis of sorption rates.An empirical equation was obtained for expressing with very high accuracy, the differential (isoteric) heats of desorption as a function of moisture content.