Keywords: moisture sorption, Bambara nuts, Tiger nuts, water activity, modelling, storage stability, monolayer, adsorption, desorption, moisture content, postharvest storage
Moisture-sorption isotherms of Bambara nut and Tiger nut
Moisture sorption characteristics of Bambara nut [Voandzeia subcerranea (L.) thouars] and Tiger nut (Cyperus esculentus L.) were investigated at 34°C and 0.10-0.98 water activity. Both the adsorption and desorption modes for the nuts followed the Brunauer-Emmet-Teller (BET) Type 2 model. Five moisture sorption models, namely Bradley, Smith, Henderson, BET and GAB (Guggerhein-Anderson-de Boer) were tested for their predictive capability on the data. The coefficients of determination varied from 0.7825-0.9949. The Henderson and Bradley models gave the closest moisture content estimates to the experimental data under the adsorptive and desorptive modes. The monolayer moisture contents were calculated using both the GAB and BET models, providing useful data for assessing the storage stability of the nuts.