MOISTURE ADSORPTION ISOTHERMS OF COPRA AT DIFFERENT TEMPERATURES

Abstract

The moisture adsorption isotherms of tapahan dried copra were determined at 22, 30 and 38°C. The isotherm of copra at different temperatures were of type III according to the BET classification. Equilibrium moisture content of copra at a given water activity increased as temperature decreased. The Henderson equation gave better fit of the adsorption isotherms of copra at each given temperature, followed by Oswin and Caurie equations, respectively. A modified Henderson equation can describe the effect of temperature on the adsorption isotherms of copra. The critical moisture contents of copra with respect to mold growth and aflatoxin production decreased as temperature increased. Aflatoxin production had higher critical moisture content than mold growth only.