ANTI-NUTRITIONAL CONSTITUENT OF COLOCASIA ESCULENTA ...
ANTI-NUTRITIONAL CONSTITUENT OF COLOCASIA ESCULENTA ... 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. 79
In conclusion, Section A ofthis study indicates the potential ofthe Amadumbe tuber as an unconventional dietary carbohydrate source for rural people living in Zululand. However, the principal problems that could undermine this potential are the presence of anti-nutrients typified by oxalate, cyanogeus, tannin and phytate. Two of the anti nutritients (a-amylase inhibitor, saponin) are further characterized in Section B. In order to reduce the effects of these anti-nutrients, which may be a potential health-hazard, proper processing before cousurnption is recommended. Supplementation from other sources, such as vegetables eaten with the cooked Amadurnbe, could improve the nutritional value ofthese tubers. 80
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In conclusion, Section A ofthis study indicates the potential ofthe Amadumbe tuber as<br />
an unconventional dietary carbohydrate source for rural people living in Zululand.<br />
However, the principal problems that could undermine this potential are the presence of<br />
anti-nutrients typified by oxalate, cyanogeus, tannin and phytate. Two of the anti<br />
nutritients (a-amylase inhibitor, saponin) are further characterized in Section B. In order<br />
to reduce the effects of these anti-nutrients, which may be a potential health-hazard,<br />
proper processing before cousurnption is recommended. Supplementation from other<br />
sources, such as vegetables eaten with the cooked Amadurnbe, could improve the<br />
nutritional value ofthese tubers.<br />
80
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