Nutritional diversity of leafy amaranth (Amaranthus) species grown in Kenya

Abstract

Malnutrition is a major problem in Kenya affecting about 50% of the population. Utilization of nutritious food crops of African origin in mitigating malnutrition has been hindered by production and farming practices. Amaranth is one of the underutilized but nutritious food crops. Despite the large genetic diversity of the amaranth species grown in Kenya, there is inadequate information on their nutritional differences and how they can be tapped in mitigating hidden hunger. The current study aimed at determining the nutritional diversity of the most common amaranth species grown in Kenya. A baseline survey was conducted in Bondo, Kieni East, Lugari, Luanda and Sabatia regions of Kenya to identify the most popular amaranth varieties. Five of the most popular varieties namely; A. dubius, A. hybridus, A. cruentus, A. albus and A. hypochondriacus were selected and planted in the Jomo Kenyatta University of Agriculture and Technology experimental farm under the same agronomic conditions. Leaves from the 5 varieties were harvested at 4-6 weeks after planting. The samples were analyzed for their proximate composition, vitamin C, β carotene, antinutrient and phytochemical content. The samples were subjected to blanching (80 o C for 3 minutes and 65 o C for 25 minutes) prior to solar-drying. The effect of processing on vitamin C and β carotene was determined. The protein (3.37%), zinc (1.67mg/100g), β carotene (23.66mg/100g) and total phenolics (3.59GAE/100mg) content, were significantly (p<0.05) high in A. cruentus than in the other species. The, calcium (336.47mg/100g) and iron (18.64mg/100g) content were significantly (p<0.05) higher in A.dubius than in the other species. The antinutrient content in all the species was not significantly different (p<0.05). Blanching at 80o C for 3 minutes prior to solar drying led to better retention of vitamin C and β carotene than solar drying without prior blanching. According to this study, the most nutritious amaranth species is A. cruentus. .