Nutritional and antinutritional characteristics of seven South Indian wild legumes

Seeds from seven species of wild legumes of the South India were analyzed for proximate composition, mineral profiles, amino acid profiles of total seed protein, in vitro protein digestibility, and certain antinutritional factors to assess their potential as alternative sources of protein crops. The major findings of the study were as follows: crude protein ranged from 20.3 to 35.0%, crude lipid 3.1-9.6%, crude fiber 5.9-12.1%, ash 2.7-5.1%, and carbohydrates 49.2-61.8%. Minerals viz., sodium, potassium, calcium, magnesium, phosphorus, iron, copper, zinc, and manganese occurred in the range 42.9-135.9, 556.2-1639.5, 304.5-572.2, 174.9-686.7, 98.4-947.8, 3.6-16.4, 0.2-1.2, 2.0-30.0, and 1.0-3.9 mg/100 g seed flour, respectively. Profiles of amino acids of total seed proteins detected in the present study revealed that levels of valine, phenylalanine, tyrosine, isoleucine, and histidine of all the seven wild legume seed samples, threonine of Canavalia ensiformis and C. gladiata, leucine of Mucuna pruriens var. pruriens, and lysine of Cassia floribunda and C. obtusifolia were found to be higher than FAO/WHO (1991) requirement pattern. The in vitro protein digestibility of the legumes under study ranged from 63.39 to 83.32%. Antinutritional factors such as total free phenolics ranged from 0.41 to 5.96%, tannins from 0.04 to 0.60%, L-DOPA from 1.34 to 8.37% and trypsin inhibitor activity from 13.48 to 65.43 TIU/mg protein. The detected antinutritional factors probably have little nutritional significance if the seeds are properly processed.