Amino acid composition, available lysine content and in vitro protein digestibility of selected tropical crop seeds

As the search for alternative sources of food to alleviate hunger continues, this study was undertaken to determine nitrogen and amino acid content, chemical score, protein digestibility corrected amino acid score, available lysine and in vitro digestibility of 8 lesser known, wild tropical seeds, gathered in Nigeria. Results were contrasted with a tropical soybean variety (Glycine max, TGX 1660-15F). The investigated seeds were Millettia thonningii, Gliricidia sepium, Lonchocarpus sericeus, Albizia zygia, Daneillia ogea and Afzella bella from the family of Leguminosae, Diospyros mespiliformis (Ebenaceae) and Entandrophragma angolense (Meliaceae). The crude protein content, based on nitrogen determination, was found to be lower in the wild seeds compared to soybean, which was partly due to the relatively high content of non-protein nitrogen. With reference to amino acid requirement and digestibility in most seed samples, lysine, followed by sulphur amino acids and threonine, were the limiting amino acids. It was concluded, that these less familiar wild seed plants may be used as valuable food or feed complements. However, further investigation is necessary to elucidate potential toxic and antinutritional factors.