Nutrients, the Bioavailability of Micronutrients and Antinutrient Composition of African Yam Bean Tubers

Abstract

Despite the huge nutritional and nutraceutical benefits associated with the consumption of African yam bean (AYB) seeds, AYB tubers are still underutilized in Nigeria, they are left to rot in farmers’ fields. To create awareness about their nutrient density and provide information on the bioavailability of micronutrients in the tubers of AYB accessions, raw tubers of TSs 9, TSs 60 and TSs 93 were analyzed using standard laboratory procedures. The AYB tubers had the following composition on a fresh weight basis: crude protein (7.55-8.27%), carbohydrate (9.36-11.12%), crude fat (0.18-0.22%), crude fibre (0.33-0.750%), crude ash (0.44-0.59%), and moisture (79.76-80.82%). The fresh tubers were rich in minerals: potassium (532.88-557.80 mg/100 g), calcium (205.75-467.50 mg/100 g), magnesium (124.75-168.50 mg/100 g), iron (15.71-27.30 mg/100 g), zinc (8.57-14.80 mg/100 g), and manganese (0.68-1.98 mg/100 g). The phytate: Zn and the phytate: Fe molar ratios indicated the bioavailability of Fe and Zn in the raw AYB tubers. The results of this study indicate that AYB tubers are good sources of protein, energy and bioavailable Fe and Zn and should be utilized for human diets and livestock feed. With good processing, AYB tubers could contribute to food and nutrition security. There is a need for research on food products developed from AYB tubers to enhance their utilization and large-scale production in Nigeria.&nbsp