Effect of variety and processing method on functional properties of traditional sweet potato flour (“elubo”) and sensory acceptability of cooked paste (“amala”)

"Amala" is a generic term in Nigeria, used to describe a thick paste prepared by stirring flour ("elubo") from yam, cassava or unripe plantain, in hot water, to form a smooth consistency. In order to overcome its high perishability and increase the utilization of sweet potato roots, three varieties of sweet potato roots were processed into flour using two methods. The interactive effect of variety and the processing method had a significant effect (P < 0.05) on all the functional properties of the flour except yellowness, setback viscosity, and peak time. Acceptable sweet potato "amala" with average sensory acceptability score of 7.5 were obtained from yellow-fleshed varieties irrespective of the processing method. Flour that produced acceptable "amala" were characterized by lower values of protein (2.20-3.94%), fiber (1.30-1.65%), total sugar (12.41-38.83 μg/mg), water absorption capacity (168-215 g/100 g), water solubility (8.29-14.65%), swelling power (0.52-0.82 g/g), and higher peak time (6.9-8.7 min).