Nutrient content of water spinach (<i>Ipomoea aquatica</i>) under different harvesting stages and preservation methods in Zimbabwe

Abstract

Water spinach is very perishable and it does not store well even in the refrigerator. It requires special processing treatments to reduce post-harvest losses. Nutrient content analysis of the water spinach ( Ipomoea aquatica ) was carried out at different harvest stages and under different preservation methods. Standard methods of food analysis were used. Water spinach was harvested at 3, 4 and 5 weeks after transplanting (WAT). The preservation methods used were freezing after blanching, sun drying of vegetable samples without any pre-treatment and sun drying samples after blanching. Fresh water spinach samples were used as the control. The Ca concentrations were remarkably high in all preservation methods. Blanching increased the concentration of Ca, P, Fe, K, Na and Mg and decreased the concentration of Pb. Freezing increased the concentration of Ca, P, Na and Mg and decreased the concentration of Fe, Pb and K. Sun drying increased the concentration for Ca, P, Fe, K, Na and Mg and decreased the concentration of Pb. Blanching and sun drying of water spinach could be the best method of preserving it without conceding on its quality. Keywords : Ipomoea aquatica , blanching, sun-drying, freezing, nutrient analysis, different harvest stages.