Nutritional evaluation of wild yam (Dioscorea spp.) tubers of Nepal

Wild yams make a significant contribution to diets of tribal people in Nepal. However, there is insufficient study of their nutritional value. In this paper, four wild yam species: Dioscorea bulbifera, D. versicolor, D. deltoidea and D. triphylla, were studied. The dry matter ranged from 19.8 to 30.5% on a fresh weight basis. The ranges of crude protein, ash, crude fat and crude fibre contents were 1.6–3.1, 0.5–1.2, 0.2–0.3 and 0.6–1.5% of fresh weight, respectively. The ranges of minerals in mg per 100 g fresh weight were K (250–560), Na (4.15–17.8), P (33.1–61.6), Ca (14.3–46.9), Mg (18.3–27.3), Cu (0.10–0.21), Fe (0.39–2.92), Mn (0.14–0.35) and Zn (0.22–0.53). Sulfur-containing amino acids and lysine were the most limiting in all species studied. Nutritional compositions of wild yams were similar to those reported for most cultivated yams in several parts of the world except for the higher value of crude fibre found in our samples.