ANTI-NUTRITIONAL CONSTITUENT OF COLOCASIA ESCULENTA ...

The study showed that Amadumbe tubers also contain essential fatty acids, linoleic
(omega-6) and linolenic (omega-3) acid Therefore, from a nutritional viewpoint, it may
be concluded that, apart from the good starch content in Amadumbe, this food is a fine
source ofessential fatty acids.
Ithas been reported that several anti-nutritional factors are present in root and tuber crops
(Bhandari and Kawabata, 2004). The levels of anti-nutritional factors in locally grown
Amadumbe are important in the assessment ofits nutritional status. In this investigation,
the Amadumbe tuber was found to contain a-amylase and trypsin inlnbitors, lectins, total
phenols, alkaloids, oxalates, phylates, cyanogens and saponin. When the valnes recorded
for Amadumbe were compared with those of taro, cocoyam, yam and other roots and
tubers investigated in other studies, the oxalate (Holloway et al., 1989; Hnang et al.,
2007) and phytate (Marfo et aI., 1990) content were observed to be low, while total
phenols (Njingtang et aI., 2006) and cyanogens (Bhandari and Kawabata, 2004) were
considered high.
A.S.2 Processing and anti-nutritional factors
The different cooking methods studied had diverse effects on reducing the levels of the
a-amylase inhibitor, total phenols, taunin, flavonoids, alkaloids, oxalates, phytates,
cyanogens and saponins.
Boiling appeared to be the most effective processing method to reduce most anti­
nutrients in Amadumbe tubers. The reduction of anti-nutrient levels on processing this
foodstuff enhances the nutritional value of Amadumbe tubers. Thus, it may be stated
from the results of this study that the anti-nutritional factors, though present in raw
tubers, should not pose a problem with regard to human consumption if the tubers are
properly processed.
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