Nutrients, Anti-Nutrients and Phytochemical Evaluation of Ten Vegetable Amaranth (Amaranthus Spp.) Varieties at Two Stages of Growth

Abstract

Nutrients, Anti-Nutrients and Phytochemical Evaluation of Ten Vegetable Amaranth (Amaranthus Spp.) Varieties at Two Stages of Growth

Vegetable amaranth is widely consumed in Kenya and contributes to the alleviation of food insecurity and malnutrition. Malnutrition is a major challenge facing Kenya in particular and Africa as a whole and the most affected are women and children. Vegetable amaranth has been shown to contain many nutrients and can contribute to the alleviation of malnutrition, and is also reported to have phytochemicals with antioxidant activity that help protect the body from long-term degenerative diseases. However, amaranth vegetable has also been shown to contain some anti-nutrients which may bind nutrients and reduce their bioavailability in the body. There hundreds of amaranth varieties in existent, and new varieties are still being produced, but there is very little information about differences in the nutrients, anti-nutrient and phytochemical levels among the varieties. The objective of this study was to determine the nutrients, anti-nutrient and phytochemical content of ten vegetable amaranth varieties at two growth stages, before and after flowering. The study was carried out in JKUAT. Ten amaranth varieties, eight of which were new varieties, were planted in the JKUAT farm. Harvesting was done at vegetative stage and post flowering stage. The leaves were analyzed for nutrients, anti-nutrients and phytochemicals including total flavonoids, carotenoids and total antioxidant activity. There were significant differences (P≤0.05)in the nutrient content among the amaranth varieties and at the two stages of maturity. Similarly there was also significant variation(P≤0.05) in antinutrient and phytochemicals among the ten amaranth varieties and between the maturity stages with the total antioxidant activity increasing significantly at post flowering stage. It was established that various components vary differently as the plant grows older.Variety 5 (Amaranthus hybridus), variety 7 (Amaranthus dubius) and variety 8 (Amaranthus hypocandracus) were found to be highest in minerals, while variety 5 (Amaranthus hybridus), variety 6 (Amaranthus hybridus), variety 8 (Amaranthus hypocandracus) and variety 10 (Amaranthus dubius) are the highest in proteins and vitamins.