Abstract: The study assessed the sorption isotherm characteristics of water yam flour. This was in the view to predict the stability of the water yam flour under different humid conditions. The sorption isotherm of water yam flour obtained from blanched and un-blanched water yam cubes was determined by the static gravimetric method using sulphuric acid solution at 25, 35 and 45°C in the water activity range of 0.09-0.96.The un-blanched samples had higher equilibrium moisture content values than the blanched samples at the same water activity level and same temperature for both the adsorption and desorption processes. They also exhibited hysteresis loop over considerable levels of water activity. GAB model gave the overall best description to the sorption characteristics of the water yam flour out of the five sorption models fitted to the experimental data. The isosteric heat of adsorption and desorption decreases with increasing temperature. The study would be useful in the design and selection of adequate packaging materials and establishment of preferred humidity level during storage.
A.F. Okeleye, T.A. Morakinyo and C.T. Akanbi, 2019. Sorption Isotherm Characteristics of Water Yam (Dioscorea alata) Flour. Journal of Food Technology, 17: 46-52.