Abstract:
In this study, nutritional, anti-nutritional, and mineral compositions of yam tubers (Dioscorea
alata) commercialized in the local markets of Jimma City, Ethiopia were investigated. The study
was on red and white yam varieties, which are commonly commercialized in the city. For each
variety 1kg sample was separately collected in plastic bags. Their nutritional compositions such
as moisture, crude protein, total ash, crude fiber, crude fat, total carbohydrates and gross
energy were determined using the standard, Association of Official Analytical Chemists (AOAC)
method. The obtained results for the red and white yam samples, respectively, were (59 and 60
mg/100g) moisture content; (2.42 and 6.12 mg/100 g) crude protein; (3.23 and 3.74 mg/100 g)
total ash; (1.36 and 1.31 mg/100 g) crude fiber; (0.16 and 0.09 mg/100 g) crude fat; (33.83 and
28.74 mg/100 g) carbohydrate content; (146.44 and 140.25 mg/100 g) gross energy. The antinutritional components, i.e., oxalate and phytate components were determined by titrimetric
method. The obtained values were 0.47 and 0.34mg/100 phytate and 1.80and 1.76 mg/100 g
oxalate, respectively. Mineral compositions such as Ca, Mg, Fe and Zn were determined using a
flame atomic absorption spectroscopy. The mineral contents of the yam samples were Fe (6.96
and 16.52 mg/100g), Ca (121.26 and 221.73 mg/100g), Mg (104.54 and 118.37 mg/100g) and Zn
(44.44 and 56.30 mg/100g) in red and white yam samples, respectively. Student t-test (p<0.05)
demonstrated that there was significant difference between the two yams (red and white) in the
studied nutritional, anti-nutritional, and metal compositions.
