Amino acid profile of raw and locally processed seeds of Prosopis africana and Ricinus communis: potential antidotes to protein malnutrition

Abstract

Background: Increasing incidence of malnutrition occasioned by high incidence of hunger, worsening food situation in the world, insufficient availability and high cost of animal protein sources, has necessitated extensive research into and use of alternative plant protein sources especially underexploited leguminous seeds.Methods: Flours from raw, boiled and fermented seeds of Prosopis africana and Ricinus communis were evaluated for crude protein and amino acid (AA) profiles, and their protein qualities determined. Results: Fermentation improved the protein contents of raw seeds of P. africana and R. communis by 18.70% and 3.95% respectively. In the raw and fermented P. africana seeds, glutamate at 132.60 ± 1.30 and 182.70 ± 3.02 mg/g crude protein (mg/gcp) was the most abundant amino acid (AA), while leucine (62.80 ± 0.60 and 79.50 ± 2.01 mg/gcp) was the most concentrated essential amino acid (EAA). Aspartate (151.90 ± 2.01 and 170.10 ± 2.00 mg/gcp) and arginine (72.80 ± 2.01 and 78.60 ± 2.00 mg/gcp) were the most concentrated and abundant non-essential amino acid (NEAA) and EAA in the raw and fermented samples of R. communis respectively. The total AA concentrations (mg/gcp) of raw and fermented P. africana were 733.00 and 962.60 respectively, while those of R. communis were 823.50 and 894.10 respectively. The total EAA contents (mg/gcp) for P. africana were 311.00 (raw) and 404.50 (fermented), and for R. communis; 401.10 (raw) and 430.30 (fermented). Threonine was the limiting EAA in raw and fermented P. africana, whereas lysine was the limiting EAA in R. communis raw sample. Fermentation significantly (p<0.05) increased the individual AA compositions of P. africana and R. communis by 94% and 53% respectively, while boiling reduced these parameters significantly (p<0.05) by 47% and 82% respectively.Conclusion: P. africana and R. communis seeds are potentially important plant sources of protein and essential amino acids, and so could be of great importance in combating malnutrition and food security problems generally.Key words: Amino acid score; condiments; crude protein; fermentation; legumes; nutrition