Composition, functional and nutritional quality of marama (Tylosema esculentum) storage root.

Abstract

Marama root is known to be the major source of nutrition for the first settlers (the Herero, Tswana and Khoisan people) of Sub-Sahara Africa, but it is not yet domesticated. The potential of Marama (Tylosema esculentum) root in food and nutrition security may pave way for the domestication of the plant in Sub-Saharan Africa. Marama storage roots collected from two locations, Omipanda and Okomumbonde in Namibia were analysed and compared to commercial potato and waxy potato tuber as well as sweet potato root. Fresh weight (FW) marama roots had mean water content, crude protein, fat, ash, and starch content of about 866, 24, 2, 22, and 56g/kg root, respectively. Marama root showed higher total soluble solids (4.3°) compared to potato, waxy potato and sweet potato. The swelling index (3g/g) and water absorption capacity (1.5g/g) of marama root were close to those of sweet potato, but lower than those of the potato and waxy potato. The soluble and insoluble dietary fibre of marama root (4.8, and 15%, db, respectively) were higher than those of the commercial potatoes; and the in vitro- starch digestibility of marama root was close to those of potatoes. Marama root has potential as prebiotic and its food value is similar to sweet potato in functional properties and nutritional composition. The high soluble solids of marama root can enhance the energy density of complimentary food, but will require compositing with high protein legume flour. There is a prospect of a protein-energy dense composite flour from a blend of the bean and root.