Nutritional quality and antinutritional composition of four non-conventional leafy vegetables

The leaves of Xanthosomas mafaffa, Ipomoea involucrata, Launaea taxaracifolia and Euphorbia hirta were analysed for their nutritive value and antinutritional factors. Protein content of the leaves ranged between 2.60 and 3.42%, while fibre and mineral (ash) contents were 1.15-7.73% and 1.48-2.86%, respectively. The amino acid spectrum revealed that the leaf proteins were generally deficient in more than one amino acid. Methionine was the most limiting amino acid in X. mafaffa, E. hirta and L. taxaracifolia, while lysine was most limiting in I. involucrata. The highest chemical score was recorded for the E. hirta protein while L. taxaracifolia registered the lowest scores. Therefore, L. taxaracifolia leaf protein was the poorest in quality. E. hirta leaves contained the highest concentration of calcium (175 mg%), copper (14.7 mg%), iron (45.8 mg%) and lead (26.4 mg%). A high level of phosphorus (34.1 mg%) was observed in I. involucrata. In terms of antinutritional principles, all the leaves studied had comparatively lower concentrations of oxalate, phytate, tannins, alkaloids and saponins. (C) 1998 Elsevier Science Ltd. All rights reserved.