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 isreported to have bioactive components such as antioxidants that help protect the body from long-termdegenerative diseases. However, amaranth vegetable has also been shown to contain some anti-nutrients such astannins, 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 andphytochemical levels among the varieties. The objective of this study was to determine the phytochemical andanti-nutrient content of ten amaranth varieties at two growth stages, before and after flowering. The study was inJKUAT. 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, totalcarotenoids, flavonoids and total antioxidant activity. Results showed increase in most anti-nutrients, exceptnitrates which reduced by about 40% as the plants matured. The leaves also increased in the total antioxidativeactivity as the plants matured with the concentration equivalent (IC50) with DPPH of 2mg/ml at vegetative stageand about 1mg/ml after flowering. In conclusion, as the plants grow older, there was increased accumulation ofantinutrient and other plant chemicals. Antioxidative activity is however increased.