Amino Acid Composition of Dioscorea dumetorum Varieties

Abstract

The crude protein contents and amino acid compositions of two varieties of Dioscorea dumetorum (edible and wild) were determined. The crude protein (g/l00g) of the wild variety (11.37) was significantly higher (P<0.05) than the edible variety (7.0). The amino acid profiles showed both varieties to be limiting in lysine, methionine and cystine. The wild variety had tryptophan (0.60g/100g total aa), phenylalanine (3.01g/100g total aa), threonine (2.93g/100g total aa) and valine (3.6g/100g total aa) in substantial amounts when compared to the reference FAO pattern. Aspartic acid (4.47-9.28/100g total aa) was the most abundant amino acid in both varieties with the highest amount recorded for the wild variety. The chemical scores of the essential amino acids were tryptophan (60.0), threonine (43.5), valine (39.6), methionine (28.0) isoleucine (34.5), leucine (32.0), tyrosine and phenylalanine (39.0) and lysine (20.72) for the edible and tryptophan (117.0), threonine (73.25), valine (72.0), methionine (54.0) isoleucine (64.75), leucine (65.71), tyrosine and phenylalanine (83.67) and lysine (44.18) for the for the wild variety. This results being the first amino acid profiles recorded for this yam suggests that the wild D. dumetorum is richer in amino acid content than the edible variety and is likely to be of more benefit in human and animal nutrition.