Abstract:
The proximate, macro and trace-elements, vitamins A and C, and oxalate
compositions were determined in onion bulbs and their stalks from three agricultural fields in
Aliero, Kebbi state. The bulbs and stalks contained closely related mean values of 93.11g/100g
and 91.70g/100g, 6.48g/100g and 6.74g/100g as moisture and crude protein contents
respectively. Values of 4.26g/100g (bulbs) and 13.56g/100g (stalks) were observed as ash
content, while their fibre contents were 13.56g/100g (bulbs) and 9.33g/100g (stalks). The macro
element concentration in the bulbs was in the order Ca>Mg>K>P>Na while that of the stalks was
Mg>Ca>K>P>Na. For the trace elements, the order was Fe>Zn>Mn>Cu>Pb>Ni>Cd for the
bulbs and Fe>Mn>Zn>Cu>Ni>Pb>Cd for the stalks. Only Iron concentrations were observed to
be higher than (100-500μgg-1) the normal Fe concentrations in plants. There were significant
differences (p<0.05) in the mean concentrations of Fe, Mn and Pb with stalks having higher
values for Fe and Mn. Both the oxalate and vitamins A and C contents of the bulbs were
significantly (P<0.05) high when compared to other reported values. The presence of oxalate in
both the bulbs and stalks could affect the bioavailability of some nutrient elements. The results
generally indicate that the bulbs are more nutritious than the stalks. With the current problem of
Fe deficiency as identified by WHO, onions could be another source of helping the situation
