ANTI-NUTRITIONAL CONSTITUENT OF COLOCASIA ESCULENTA ...

.\.4.2.2 Mineral analysis
Diet is responsible for several existing problems relating to human health. Deficiency
diseases could be prevented by sufficient intake of specific micronutrients that are
involved in many biochemical processes. Vegetables and fruits are particularly important
sources ofminerals (Milton, 2003; Smolin and Grosvenor, 2000). Diets high in fruits and
vegetables are also linked to decreased risk ofdiseases such as diabetes and cancer and
daily consumption of these foods is being encouraged (Bernstein et aI., 2002; Leterme,
2002).
The mineral profile ofAmadumbe species is comparable to that of taro, cocoyam, potato
and sweet potato (Sefa-Dedeh and Agyir-Sackey, 2004 and Huang et al., 2000; Noman et
al. 2007). It is apparent that the Zulu1and variety ofColocasia esculenta is rich in mineral
nutrients, especially in potassium and magnesium. It is thought that potassium might play
an important role in the control of hypertension and in lowering the risk of strokes (NRC
1989). Magnesium plays a marked role in maintaining good health: for example, lowering
of blood pressure, acting as an antacid, (Yamori, et al., 1994) and counteracting asthma
(Britton et al., 1994).
Very few aspects with regard to the enviroumental and physiological processes that are
responsible for the uptake of minerals in plants have been identified. This notwithstanding,
substantial variations in mineral concentration in Amadumbe were generally observed. The
discrepancies have been reported to be due to the influence of species, the age ofthe plant
and environmental differences such as concentration of minerals in the soil, pH, water
supply and climate variations (Underwood and SchuttIe, 1999; Hofinan et al., 2002; AIfaia
et al., 2003).
Cooked samples of Amadumbe tubers were higher in sodium, calcium, magnesium, zinc
and iron, while the potassium content was relatively lower than in the raw samples. The
cooking process, which allows extraction of nutrients from the tissues, may have increased
the mineral nutrient levels while reducing moisture content (Booth etat. 1992).
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