EVALUATION OF MOISTURE SORPTION ISOTHERM FOR SHEA NUTS, VITELLARIA PARADOXA

Highlights Equilibrium moisture content models were assessed for shea nuts. The Modified Halsey and Modified Oswin EMC/ERH models were found to be most appropriate in describing the sorption behavior of shea nuts. Critical moisture content for storage of shea nuts in the Sahel region was determined to be 5.08% to 6.68%. The study provided a basis for developing a calibration equation for a commercially available, hand-held, low-cost moisture meter for adoption in the shea nut value chain. Abstract. Shea nuts (Vitellaria paradoxa) are prone to mold deterioration during post-harvest handling, drying and storage. Evaluating the moisture sorption characteristics provides the basis to better understand their drying and storage behavior for prevailing climatic conditions during growing, harvesting and storage periods in shea-producing communities. Thus, this study sought to evaluate the moisture sorption isotherm of whole shea nuts across a temperature range of 20°C to 35°C, as is typical in the Sahel region. A series of goodness-of-fit indices were assessed to evaluate five moisture sorption models. The Modified Halsey and Modified Oswin EMC/ERH models were found to be most appropriate in describing the sorption behavior of shea nuts. The critical moisture content determined at 0.65-0.70 water activity across the 20°C to 35°C temperature range was 5.08% to 6.68%. Therefore, this study provided a recommendation for the safe storage moisture content of shea nuts and a basis for developing a calibration equation for a commercially available, hand-held, low-cost moisture meter to monitor effective drying, safe storage, and improved handling in the shea nuts value chain. Keywords: Keywords.,Equilibrium moisture content, Post-harvest handling, Safe storage moisture content, Shea nuts, Sorption isotherm.