Nutrient and antinutrient components of Jatropha tanjorensis (J. lellis & Saroja), an unconventional vegetable in Nigeria

Abstract

The proximate composition, mineral composition (Ca, Mg, K, Na, Fe, and Zn), ascorbic acid and antinutrients (Tannin, Trypsin, phytate and oxalate) content of both raw and blanched Jatropha tanjorensis (J.L Ellis & Saroja) were reported. The crude protein, crude fibre, ether extract, carbohydrate and ash are 24.6, 9.7, 4.5, 58.8 and 8.1 g per 100 g respectively, for raw sample. The crude protein, crude fibre, and ether extract increased by 24.6, 30.5 and 37.8% respectively, on blanching while blanching reduced carbohydrate and ash by 9.6 and 19% respectively. The vegetable had highest level of calcium ( 1.14 g per 100 g) while zinc was the lowest (0.04 g per 100 g) among the elements analysed. Ascorbic acid was 502.2 mg per 100 g, which reduced by 64% on blanching. The levels of antinutrients are low (1.47 mg/g, 57.1 TIU/g, 0.43 mg/g and 2.46 g per 100 g) for  tannin, trypsin, phytate and oxalate respectively, compared with some conventional vegetables. Blanching reduced all these antinutritional factors with the exception of oxalate which was increased by 40%. This vegetable has potential for complementing conventional vegetables.

Keywords: Jatropha tanjorensis, proximate composition, mineral element, ascorbic acid, antinutritional factors.