ANTI-NUTRITIONAL CONSTITUENT OF COLOCASIA ESCULENTA ...

Colocasta esculenta (L.) Schott is an ancient crop grown throughout Africa for its edible
corms and leaves, as well as for its traditional uses. Matthews (2004, cited in Oscarsson
and Savage, 2007) surmised that Colocasta esculenta (L.) Schott had its origins in the
tropics between India and Indonesia and the Food and Agricultural Organization [FAO]
(1992, cited in Oscarsson and Savage, 2007) commented that this plant had been grown
in the South Pacific for hundreds ofyears.
According to Bradbury and Nixon (1998), many Colocasia esculenta cultivars have a
sharp, pungent taste and should not be eaten raw, because they can cause swelling oflips,
mouth and throat. To enable comfortable ingestion, the tubers have to be thickly peeled
and cooked over a long period (Saikai 1979; Crabtree and Baldry, 1982). Onayemi and
Nwigwe (1987) identified the following constituents in Colocasia esculenta, once the
causticity had been removed: digestIole starch, high-quality protein, essential amino
acids, vitamin C, thiamin, riboflavin and niacin.
In the rural areas ofKwazulu-Natal (SA), Amadumbe is the main starch source in cooked
meals. Considered traditional African fare, the tubers are used in the same way as
potatoes: fried as chips (Figure Al-3), mashed or barbequed whole (African affair, 2005).
The young Amadumbe (cocoyam or taro) leaves can also be used as a vegetable
(Aregheore and Perera, 2003): they are boiled for 15 minutes like spinach and are utilized
as a supplement to maize. Leaves may be used in making salad and the Indian delicacy
puripatha, often created in Durban, SA, is wrapped in Amadumbe leaves (Cultivation,
food and health: arnadumbe, n.d). Lee (1999) observed that taro (Arnadumbe or
cocoyam) is one ofthe only major staple foods where both the leafand underground parts
are used and have equal importance for human consumption. The excellent digestibility
(98.8%) of the small starch grains of taro suggests efficient release of nutrients during
digestion and absorption ofthis food (Lee, 1999).
Much work has been done on Colocasta esculenta (L.) var. Schott. As mentioned before,
cocoyam and taro are the other common names used for these edible aroids. Cocoyarns
are grown for local consumption in West Africa and their corms and cormels are used in
the same manner as yarns or potatoes for local dishes (Onayemi and Nwigwe, 1987).
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