Yam is a significant and highly prized starchy crop in West and Central Africa, but largely underutilized industrially. Functional and physicochemical properties of starches extracted from forty‐three varieties of Dioscorea rotundata, Dioscorea alata, Dioscorea dumetorum, Dioscorea cayenensis, and Dioscorea bulbifera were investigated for their potential industrial utilization. Water binding, swelling, gelation capacity, granule size, amylose/amylopectin, pasting characteristics, paste clarity, and syneresis were determined. Results showed that starches from D. rotundata, D. alata, D. cayenensis, and D. bulbifera had large starch granules (25–50 µm) while D. dumetorum had small granules (7–12 µm). There was variability in the starch granule shapes, which were mostly oval, round, and triangular. The least gelation concentration of the starches was between 4 and 16%. Paste clarity of the starches decreased as storage days increased and all the starches exhibited high syneresis indicating tendencies to retrograde on low storage temperature. There were differences in the pasting characteristics of the yam starches with D. rotundata and D. bulbifera having high peak viscosities compared to others. These differences in functional and physico‐chemical properties of the yam starches are discussed as indicators of the various products for which they can be utilized in both food and non‐food applications.

The aim of this study was to characterize 43 genotypes from five yam species [ (Poir), (Linn), (Linn), (Lam) and (Kunith) Pax] which are major land races in Nigeria in terms of their chemical composition, nutritional, anti-nutritional and mineral bioavailability. Findings showed that there was genotypic variation in terms of chemical composition, mineral profile and bioavailability of the minerals among the germplasm. had the highest cell wall carbohydrates, (cellulose: 3.2%, hemicelluloses, 2.1%, lignin, 1.1%, acid detergent fibre (ADF) 3.2%, neutral detergent fibre (NDF) 6.4%), had the highest oxalate (606 mg/kg). In conclusion, intra and inter-species variations exist among the yam germplasm in terms of their chemical composition, anti-nutritional and mineral bioavailability. Phytate content of the yam genotypes did not affect the bioavailability of Zn but Ca was affected significantly. The Ox:Ca ratio in most of the yam varieties were below one, thus bioavailability of Ca in yam by oxalate is variety dependent.