[Evaluation of the possible technological uses of some dioscoreas tubers: name congo (Dioscorea bulbifera) and mapuey...

A comparison between the chemical composition and physical characteristics of ñame congo (Dioscorea bulbifera) and mapuey (Dioscorea trifida) white and purple varieties, was made. The tubers were evaluated for their physical attributes (morphology, size and weight). The chemical analysis was done according to AOAC methods (1990) and the pasting properties of the flours were evaluated using the Brabender Viscoamilograph. The mapuey tubers have an elongated shape, with one end wider while ñame congo presents a rounded shape. The results of the chemical analysis show that mapuey tubers have more proteins content (p < or = 0.05) than either purple mapuey tubers purple or ñame congo tubers. The flours overall viscosity, measured at the same concentration, was higher for white mapuey varieties. The gelatinization temperature range was similar among the flours. The negative breakdown datas suggest that the flours viscosity increases during the gelatinization process of all flours. Neither suspensions showed a viscosity peak. Set-back and consistency were lower in the ñame congo flour. The absence of a viscosity peak and the high temperature stability of the ñame congo flour make it an ideal ingredient for instant soup mixes. The flours high viscosity level developed by white and purple mapuey varieties should make it a suitable sauces thickener.