Investigation of Nutrient and Anti-Nutrient Composition of Dioscorea Cayenensis-D.rotundata complex
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Date
2011-03
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Addis Abeba University
Abstract
Dioscorea species (Yams) rank as the world’s fourth most important tuber crop in economic terms and make a significant contribution to diets in some rural areas of Ethiopia where Ethiopia is one of the major producers in East Africa. However, there is insufficient study on their nutritional value and anti-nutritional composition. This study was designed to evaluate the proximate, mineral and anti nutritional composition of yam tubers (Dioscorea cayenensis rotundata complex) collected from Sheko wereda, Bench Maji zone, South Nations, Nationalities and people’s Regional state. Effect of household processing methods namely boiling and frying on composition of Dioscorea was also investigated. To determine the proximate, mineral and anti nutritional composition chemical analysis were conducted using standard procedures. Data were analyzed using SPSS (SPSS Software for windows release 16.0; SPSS Inc., Chicago, IL, USA). In raw yam tubers, moisture was high 69.56 ± 0.2% for the yellow and 73.44±0.5% for the white tubers. Crude protein content was 1.85±0.04% for the yellow and 2.03±0.03% for the white tuber while ash was highest (4.10±0.01%) in the yellow 4.62±0.01% in the white tuber. Crude fat was low in both tubers 0.35±0.01% for the yellow and 0.18±0.01% for the white tuber while total carbohydrate was high in both tubers 20.95±0.1% and 19±0.06% for the yellow and white tubers respectively. The fiber contents were 3.19+0.05% for the yellow and 2.68+0.03% for the white tubers. Calcium and potassium were the major minerals found in both tubers. calcium contents of 52.55+ 0.01 and 60.52 + 0.01 and potassium contents of 53.33+ 0.33 and 45.73+ 0.01 were found for the yellow and white tubers respectively. Phytate, tannin and oxalate contents were 38.2+0.002, 22.2+ 0.001 and 0.006+ 0.001 for the yellow tuber and 34.8+ 0.002, 28.8+ 0.001 and 0.006+0.001 for the yellow tuber. There were no significant difference (p>0.05) in the proximate, mimeral, phytate, tannin and oxalate contents of the raw tubers of the yellow and white varities. Boiling and frying significantly reduced
Key words: D.cayenensis-D.rotundata complex, proximate composition, anti-nutritional factors
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Keywords
D.cayenensis-D.rotundata complex, proximate composition, anti-nutritional factors