Properties of starches of some West African yams

The tuber starches of several species and varieties of yam (Dioscorea) grown as food crops in West Africa were examined. The granule sizes were investigated, and the forms of the starch granules are illustrated in photographs. Amylose contents were also measured, together with ‘pasting temperatures’, viscous properties and gel strength. The granules of D. rotundata and D. alata were large (10–70 μ) while those of D. esculenta and D. dumetorum were much smaller (1–5 μ). The starch of D. rotundata gave the most viscous solutions, but that of D. alata gave the strongest gel. Pasting temperatures ranged between 76° and 85°.