Nutritional and anti-oxidant properties of yam (Dioscorea schimperiana) based complementary food formulation

Abstract

Childhood malnutrition is a current and perpetual public health concern in many African countries. Challenges remain the difficulty in formulating nutritionally adequate diets. This study was carried out to investigate the effect of Dioscorea schimperiana flesh color on nutritional composition and antioxidant activity of formulated yam based complementary food. Flours from dried yam slices bought on local market were fortified with soybean and groundnut paste to develop a balanced diet. Carrot and egg shell were added as reinforcing sources of micronutrients. The nutritional content and antioxidant properties of the flour blends were then assessed. Results indicate the flour blendes satisfy the recommended energy and macronutrients requirements according to set standards. Thus the flour blends can be used for managing protein-energy malnutrition. They can also offer health benefits due the composition of many bioactive compounds. The amount of carotenoids, α tocopherol, total phenols, zinc and iron in yam-based formulations depended on the color of the yam flesh. Βeta carotene was the major carotenoid present. The yellow-fleshed yam flour blend had the highest content (10 mg/100 g) of polyphenolic compounds but comparatively lower antioxidant activity. In contrary, yellow-fleshed with red dots flour blend had the highest antioxidant activity (0.218 M Trolox equivalents/100 g) and the lowest content (8 mg/100 g) of the responsive bioactive compounds. The red-fleshed yam based complementary food had the highest content in these micronutrients. Feeding 6–11 months old children with yam-based complementary food would satisfy 23–77.4% of the 200 µg daily minimum suggested reference retinol activity intake of vitamin A and 8.20–30.48% of the 2.5 mg α-tocopherol requirement. At this stage of growth, yam based complementary food would satisfy 68–100% of the average daily minimum reference intake of zinc and 63–100% of iron daily requirements according to the daily serving portion needed to satisfy the 200–550 energy requirement. Taking into consideration their contribution in meeting the micronutrients daily intake suggested reference values; the weaning flour is most suitable for a 12–23 month old child. Keywords: Childhood malnutrition, Balanced diet, Dioscorea schimperiana