EVALUATION OF NUTRITIONAL COMPOSITION AND In-VITRO GLYCEMIC INDEX OF THREE VARIETIES OF UNDERUTILIZED LEGUMES

Abstract

Legumes provide basic nutrition, rich sources of bioactive phytochemicals which are beneficial in various health conditions. The samples of Urad bean (Vigna mungo), Yard bean (Phaselous vulgaris), and Black (Phaselous vulgaris), bean were brought from Abuja, prepared and analyzed for their chemical compositions using standard methods. The results of the chemical composition of the samples, Urad bean, Yard bean and Black bean respectively for proximate composition (%) were moisture content (11.49, 8.87 and 9.41), crude protein (46.25, 35.98 and 31.91), carbohydrate (37.13, 48.27 and 45.89), crude fat (1.28, 1.20 and 1.26), ash (4.83, 5.64 and 5.13), crude fiber (0.39, 0.33 and 0.33) and energy (345.74 kcal/100g, 360.31 kcal/100g and 347.17 kcal/100g). Mineral composition in mg/L were Sodium (31.23, 30.46, and 29.19), Calcium (593.27, 587.11 and 595.09), Potassium (41.68, 46.07 and 52.11) Magnesium (18.06, 32. 51 and 20.62), Iron (7.55, 13.13 and 11.06) Zn (2.61, 7.71, and 3.79), Copper (0.15, 0.93, and 0.75), Ni (1.02, 2 .87 and 1.01) and Cadmium (0.14, and 0.01). However, Cadmium was below detection limit in black bean and lead was also below detection limit in Urad bean, Yard bean and Black bean. Phytochemical screening for both water and ethanol extract showed the presence of cardiac glycoside, protein and saponin in the three samples. The antioxidant properties were total phenol (42.24, 6.64 and 11.75 mg/g), ferric reducing antioxidant (28.18, 31.04 and 37.41 mg/g), iron chelating (63.80, 67.26 and75.30 mg/g) and DPPH (2, 2 –diphenyl-1-picryhydrazyl) (47.28, 53.42 and 58.46 %).The anti-nutritional composition were oxalate (0.00 mg/g, 0.00 mg/g and 0.00 mg/g). Phytate (5.01, 4.88 and 5.96%), alkaloid (8.61, 5.21 and 11.20%) and saponin (6.02, 5.57 and 6.78%). The amino acid profile (g/100g protein) were total amino acids (114.65, 90.74 and 112.39), total essential amino acids (51.23, 35.00 and 48.82), total non-essential amino acids (63.40, 55.73 and 63.96) and total sulpur amino acids (11.78, 2.36 and 9.96). The glycemic index were 34.17, 24.69 and 36.38% respectively The finding revealed that the three seeds possessed good nutritional quality required in human diet together with adequate antioxidant properties that could help in fighting various cardiovascular and other diseases .The low glycemic index in the seeds prove them to be a good source of food required by diabetic patients.