Nutritional Contents of Two Varieties of Sweet Potatoes (Ipomoea batatas (L.) Lam ) Cultivated IN North Western Nigeria

Abstract

Background and Objectives: Food shortages and nutritional imbalances are among the main food security problems in many countries around the world. In this study, the nutrients content of the yellow and red-fleshed sweet potatoes varieties cultivated in Nigeria were assessed. Materials and Methods: The proximate composition, mineral elements analysis, phytochemicals, and vitamins content of the red and yellow-fleshed sweet potatoes were determined using the standard methods of analysis. Results: The proximate analysis has shown that, the moisture (17.927%) and fat (2.703%) content of the yellow sweet potato were significantly (p<0.05) higher than in the red potato with a content of 16.68% and 1.693% respectively. The protein and fiber content of the red potato are 14.280% and 14.572% respectively, this is quite higher than in the yellow cultivar having 12.987% and 10.443% of the nutrients respectively. The ash and carbohydrate content were same in both. The red potato  exhibits high level of sodium (11.420 mg/l), potassium (1.206 mg/l), and magnesium (8.468 mg/l) in contrast to the red potato containing 10.270 mg/l, 1.035 mg/l and 6.127 mg/l of the respective elements. Iron and zinc content were comparable in both cultivars while the calcium content (1.444 mg/l) of the yellow cultivar is significantly higher than in the red variety (1.144 mg/l). The vitamin A, B and E content of the red potato are 8.740 µmol/L, 2.977 mg/dl, and 13.267 mg/dl respectively. These values are significantly (p<0.05) higher than in the yellow potato containing 6.047 µmol/L, 1.680 mg/dl, and 11.110 mg/dl of the respective vitamins. There is no significant difference with respect to the vitamin C content of both yellow (11.850 mg/dl) and red potato (12.520 mg/dl). The phytochemicals: tannins, flavonoids, phenols, terpenes, and anthocyanins content of the red sweet potato are 0.967 mg/g, 1.577 mg/g, 1.867 mg/g, 6.590 mg/g and 2.660 mg/g respectively. Terpenes and anthocyanins were not found in the yellow cultivar. However, saponins (0.823 mg/g) were found in the yellow variety but not in the red potato. Amount of the tannins, flavonoids and phenols observed in the yellow-fleshed potato are 0.667 mg/g, 1.027 mg/g and 1.287 mg/g respectively. These values are lower than in the corresponding red potato. Conclusion: In this study, the nutritional contents of sweet potato varieties have been assessed which will immensely contribute to reducing the menace of malnutrition bedeviling the Northwestern part of Nigeria.