ANTI-NUTRIENT AND PHYTOCHEMICAL EVALUATION OF 10 AMARANTH VARIETIES BEFORE AND AFTER FLOWERING

Abstract

Amaranth vegetable is widely consumed in Kenya and contributes to the alleviation of food insecurity. It is reported to have bioactive components such as antioxidants that help protect the body from long-term degenerative diseases. However, amaranth vegetable has also been shown to contain some anti-nutrients such as tannins, phytic acid, oxalates and nitrates which may bind nutrients and reduce their bioavailability in the body. There are many amaranth varieties and there is very little information about differences in the anti-nutrient and phytochemical levels among the varieties. The objective of this study was to determine the phytochemical and anti-nutrient content of ten amaranth varieties at two growth stages, before and after flowering. The study was in JKUAT. Ten amaranth varieties, eight of which are new varieties, were planted. Harvesting was done in two stages, at vegetative stage and post flowering stage. The leaves were analyzed for nitrates, tannins, vitamin C, total carotenoids, flavonoids and total antioxidant activity. Results showed increase in most anti-nutrients, except nitrates which reduced by about 40% as the plants matured. The leaves also increased in the total antioxidative activity as the plants matured with the concentration equivalent (IC50) with DPPH of 2mg/ml at vegetative stage and about 1mg/ml after flowering. In conclusion, as the plants grow older, there was increased accumulation of antinutrient and other plant chemicals. Antioxidative activity is however increased.