Estimation of Nutrients and Anti-nutrients Components of Three Nigerian Leafy Vegetables.

Abstract

Three Nigerian leafy vegetable species were analyzed for their proximate composition, mineral constituents, energy values and their anti-nutritional factors. The mean values for the proximate composition were 19.04, 13.62, 7.07, 1.84 35.68, 22.74 and 77.26% for crude protein, crude fibre, Ash, fat, carbohydrate, moisture and dry matter  contents respectively, and the mean gross energy value was 235.47 Kcal/100g. Moderate variations were observed in the proximate composition of the vegetables analyzed as indicated by the moderately high coefficient of variation, except for moisture which was high 82.59%. The ten minerals analyzed (Na, K ,Ca, P, Fe, Mg, Cu, Zn, Mn and Co) were all present in all the three samples, with Cu been least in Ugwu (Telfaria occidentalis) (0.24+0.01), Ebolo (Crassocephalum crepidiodes) (0.20+0.01) and Mn least in Manihot esculenta (0.10+0.01) mg/100g. Phosphorus was the most abundant in Ugwu (14.60+0.04) and Ebolo (6.23+0.04)mg/100g, while K was the most abundant (7.73+0.05) mg/100g in Manihot esculenta. The Na/K ratio was less than one (<1) in all the samples but the Ca/P ratio was very high for Manihot esculenta 6.20. Marked variations were observed in the mineral composition of the samples as indicated by the high co-efficient of variations. The anti-nutrients analyzed Tannin, Saponin, Phytic acid, oxalate and HCN were significantly present with tannin been the most abundant in Manihot esculenta (4108. 67+0.90) mg/100g and HCN been the least abundant in Ugwu (3.10+0.02) mg/100g. There were distinct familial differences in these anti-nutrient constituents as indicate by the high co-efficient of variation of 160.78, 145.36, 139.80, 90.20 and 67.28% for Tannin, Saponin, oxalate, phytic acid, and HCN, respectively. The nutritive potentials of the samples are highlighted, dietary implications of the anti-nutrients are also mentioned, and the need to develop food/feed safe programmes involving these inherent factors discussed.

Key words: Proximate composition, minerals, anti-nutritional constituents.