Comparative Assessment Of Proximate, Macro Mineral, Phytochemical And Heavy Metal Contents Of Leafy Vegetables Sourced From Two Major Markets In Umuahia

ABSTRACT

Fresh samples were used for moisture content analysis. Standard methods were used to determine in triplicate the proximate, macro minerals, phytochemical and heavy metal levels. Proximate composition of samples revealed that moisture content for all the samples studied was appreciably high and ranged from51.09±0.57% to 92.32±0.06%. Talinum triangulare in Orie-Ugba sample recorded the highest (92.32±0.06%) while Gnetum africanum in Ubani market recorded the lowest (51.09±0.57%). Ash content for the samples was between 1.14±0.07% and 6.53±0.28% with Pterocarpus soyanxii in Ubani market recording the highest while Telfairia occidentalis in Orie-Ugba market gave the least. Crude protein values ranged from 9.24±0.04% in Gnetum africanum in Orie-Ugba market to 24.48±0.02% in Telfairia occidentalis also in Orie-Ugba market. However, crude fibre content was maximum in Pterocarpus soyanxii (12.25±0.06%) obtained from Ubani market and minimum in Talinum triangulare (3.54±0.19%) obtained from Ubani market. A low ( crude lipid composition was observed in the vegetable leaves obtained from the two markets. For carbohydrate content, values ranged from, 56.24±0.23% to 74.69±0.37% with Talinum triangulare in Orie-Ugba market recording the highest and Vernonia amygdalina also in Orie-Ugba market recording the lowest. The result for calorific values of the vegetables revealed that Talinum triangulare from Orie-Ugba market had the highest value (425.95 kcal) although all the other samples also showed a high percentage of energy content. The phytochemical screening results showed amounts of alkaloids (0.63±0.02% - 5.13±0.01%), saponins (1.30±0.02% - 9.13±0.06%), flavonoids (2.51±0.01% to 7.79±0.03%), tannins (0.05±0.01% - 0.14±0.01%) and phenols (0.05±0.00% - 0.26±0.00%) in all the leafy vegetables. The macro mineral analysis showed the leafy vegetables in both markets contain amounts of calcium (0.05±0.00% - 0.26±0.00%), magnesium (0.06±0.00% to 0.55±0.00%), potassium (2.40±0.00% - 10.33±0.00%), sodium (0.29±0.00% - 0.92±0.00%) and phosphorus (2.70±0.00% - 9.40±0.00%). No mercury was detected in any of the leafy vegetables from the two markets while lead, arsenic and chromium levels were below the FAO/WHO limits. Mean cadmium concentrations in Telfairia occidentalis, Gnetum africanum, Pterocarpus soyanxii in Orie-Ugba market and Gnetum africanum, Pterocarpus soyanxii in Ubani market were either above or equal to the limit.