Evaluation of the Antinutrients, Nutrients, Phytochemicals and Metals Content of Five Leafy Vegetables in Dengi Metropolis

Aim: To quantify the levels of amino acids, some metals, and phytochemicals/antinutritional factors in leafy vegetables: Cucurbita pepo, Vitex doniana, Hibiscus cannabinus, Leptadenia hastata, Balanites aegyptiaca.

Study Design: The research work is descriptive.

Place and Duration of Study: Department of Biochemistry, University of Jos between March 2016 and September 2016.

Methodology: Five samples each of the vegetables were collected at random from different locations in the area of study. Atomic Absorption Spectrophotometry was applied to analyse for metals. Levels of amino acids in samples were determined using the PTH amino acids analyser. Antinutrients were quantified using standard methods. One way ANOVA was used to analyse the data obtained at 95% level of significance.

Results: Mean levels of Pb and Cd were 0.030 ±0.01 ppm and 0.004 ± 0.001 ppm respectively (P>0.05) relative permissible limits. Mean Mg, Mn and Fe content were 1.084 ± 0.02 ppm, 0.069 ± 0.01 ppm and 1.534±0.10 ppm respectively (P=.05). Amino acids profile indicated mean values (g/100 g proteins) of Glutamate 8.34, Aspartate 8.14, Leucine 8.34, Lysine 4.03, Isoleucine 3.30, Phenylalanine 4.17, Tryptophan 2.25, Valine 4.6, Methionine 1.12, Proline 2.84, Arginine 4.99, Tyrosine 2.75, Histidine 2.23, Cysteine 1.09, Alanine 3.71, Glycine 4.08, Threonine 2.88, Serine 2.99. Mean range of antinutrients were: tannins (g/100 g), 0.51±0.13 to 0.60±0.12, oxalates (mg/100 g), 0.14±0.14 to 0.60±0.20, phytates (mg/100 g), 1.70±0.01 to 4.10±0.01, saponins (g/100 g), 11.85±1.85 to 15.13±1.50, cyanogenic glycosides (mg/100 g), 4.82±1.30 to 7.59±1.20, total alkaloids and total flavonoids (g/100 g) were 16.22±1.61 to 19.37±1.23 and 9.87±1.32 to 14.71±2.30 respectively.

Conclusion: Although samples analysed contained significant amounts of antinutrients, they are very good sources of amino acids; especially Lysine, Methionine, Leucine, tryptophan which are essential; and mineral elements. Levels of lead and cadmium in the samples were lower than safe limits. These vegetables are good sources of nutrients. Their consumption will replenish nutrients to the cell thereby improving the well being of consumers.