PROTEIN EXTRACTABILITY, FRACTIONATION AND AMINO ACID COMPOSITION OF SOME LEGUMINOUS SEEDS FOUND IN NIGERIA

Abstract

Protein content in eight minor legume seeds grown in Nigeria was determined, and protein was fractionated into albumin, globulin, prolamin and glutelin. Seed protein concentrates (SPC) were prepared from legume seeds; and extractabilities of protein N, total N content, yield and the amino acid profiles are reported. The globulins and glutelins were the major fractions. Mucuna seeds (velvet bean) appear to be the most promising species for obtaining SPC based on the high values for extractability of SPC, protein N and total N. Amino acid composition shows that the sulfur-containing amino acids, methionine + cysteine, were the most limiting amino acids in the seed proteins. Lysine content (9.12 g/100 g) of Mucuna seeds was high. Prosopis africana (mesquite bean) contains remarkably high levels of methionine and lysine (3.55 and 6.50 g/100 g protein, respectively), which make it a good potential supplement to the starchy tuber and cereal diets of the local population. It was concluded that Milletia thonningii, Adenanthera pavonina (coral seeds), Lonchocarpus sericeus and Mucuna seeds have a promising potential as sources of low-cost protein for possible use as food/feed supplements.