Effect of Processing on Some Physicochemical Composition and Antinutritional Factors of Locally Grown Cassava (Manihot Esculenta Crantz) Varieties
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2009-07
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Addis Ababa University
Abstract
The effect of boiling and natural fermentation on Qulle and Kello cassava varieties collected from southern Ethiopia were studied for their physicochemical composition and antinutritional factors. The moisture content of the samples was 9.47±0.47% for Qulle variety and 8.48±0.02% for Kello variety for raw samples. Based on dry weight basis, the ash, fat, protein, crude fibre and total carbohydrate were 3.45±0.20, 0.88±0.10, 1.32±0.06, 3.44±0.00, and 90.55±0.19 % respectively for the raw sample of Qulle variety and 2.43±0.13, 1.02±0.10, 1.47±0.02, 2.82±0.14, 91.76±0.84 % for the raw sample of Kello variety. The energy values are 376.86±1.28 and 386.55±1.93 Kcal/100g for the samples of Qulle and Kello variety respectively. Among the antinutritional factors analyzed, the level of cyanide, phytate, tannin and oxalate were determined to be 4.62±0.01, 543.97±0.74, 1.70±0.33 and 24.93±0.08 mg/100g in raw Qulle sample respectively and 5.04±0.02, 168.24±5.53, 1.82±0.03 and 86.18±0.10 mg/100g in raw Kello sample respectively. Significant difference (p<0.05) was observed in level of all the antinutrients of the two varieties. A reduction of 59.52%, 68.10%, 91.94% and 15.40% in the level of cyanide, phytate, tannin and oxalate was achieved by cooking process respectively and fermentation brought about 77.60%,%, 88.4%, 92.4% and 67.30%, in the level of cyanide, phytate, tannin and oxalates in Qulle samples. Cyanide, phytate, tannin and oxalate were reduced by 25.20%, 14.1%, 64.80% and 32.50% by cooking and a 43.70%, 37.90%, 90.70% and 87.50% reduction was achieved by fermentation for Kello samples. Natural fermentation has resulted in significant reduction in all types of antinutrients, particularly, phytates. Qulle variety is preferable where the antinutrients are significantly reduced more by processing as compared to Kello variety except for the oxalate content.
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Antinutrients, Particularly, Phytates