ANTI-NUTRITIONAL CONSTITUENT OF COLOCASIA ESCULENTA ...

The phytate content of the Amadumbe tubers investigated is given in Table A3-4c.
Phy1ate concentration ranged between 2.2 - 3.2 mg/g. Results indicated that phy1ate
content was partially reduced by the cooking treatments. The phytate content of the
processed tubers was reduced by up to 74 per cent.
The cyanogen content ofAmadumbe tubers ranged from 12 - 2.5 mg HCN equivalent
per 100 g dry weight of tubers. The results, presented in Table A3-4c, showed low
variability of HCN content. The processing techniques employed were effective in
substantially reducing the cyanogens to low levels (0.1 - 0.8 mg HCN equivalent/lOOg).
Boiling for 30 minutes was found to be highly effective in reducing the HCN by up to 92
per cent in white and 68 per cent in purple Amadumbe. A loss ofHCN content (75 per
cent in white and 88 per cent in purple Amadumbe) was also observed when the tubers
were roasted for 30 minutes or fried for 15 minutes.
Phytochemical screening revealed the presence of alkaloids at different concentration
levels in all the unprocessed samples. A precipitate or flocculation in any ofthe samples
was regarded as a positive test result for alkaloids (Figure A3-3).
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