The nutritional and antinutritional attributes of sword bean [Canavalia gladiata (Jacq.) DC.]: an under-utilized tribal pulse from south India

Six accessions [three with maroon-coloured seed coat and three with white-coloured seed coat) of sword bean (Canavalia gladiata (Jacq.) DC.], were collected from six different locations in south India. They were analysed for their proximate and mineral composition, amino acid profiles of total seed proteins, in vitro protein digestibility (IVPD) and certain antinutritional factors. The essential amino acid profile of total seed proteins compared favourably with FAO/WHO requirements, except that there were deficiencies of sulphur containing amino acids in all the six accessions and also the leucine, lysine and tryptophan contents were low in maroon-coloured seed coat accessions. The IVPD of the accessions ranged from 63.39 to 76.92%. Antinutritional substances like total free phenolics, tannins, l-DOPA (3,4-dihydroxyphenylalanine), trypsin inhibitor activity and phytohaemagglutinating activity were also investigated. The antinutritional factors that were detected were thought to have little nutritional significance if the beans are properly processed.