MOISTURE SORPTION STUDY ON NIGERIAN FOODS - KUKA

Kuka is an important vegetable in the Nigerian food chain. The moisture sorption characteristics of the vegetable studied at 34, 37 and 45-degrees-C between a(w) 0.10-0.96, revealed a BET type II behaviour. The Kuka exhibited hysteresis and an increase in EMC with increase in a(w) and decrease in temperature. Four sorption models (Oswin, Halsey, Kuhn, and GAB) were studied and the Oswin model was the most suitable. The constants in the Oswin model and GAB monolayer moisture contents were obtained and found to be temperature-dependent. Heats of sorption were greater for desorption than adsorption and in either mode, they reduced with an increase in moisture content. An exponential equation was obtained to relate heat of sorption with moisture content.