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Determination
and comparison of vitamin C, calcium and potassium in four
selected conventionally and organically grown fruits and
vegetables
K. G. Masamba1*
and M. Nguyen2
1University
of Malawi, Bunda College, Department of Home Economics and
Human Nutrition, Box 219, Lilongwe, Malawi.
2University
of Newcastle, Ourimbah campus, New South Wales, 2258,
Australia.
*Corresponding author. E-mail:
kmasamba@yahoo.com.
Accepted 4 June, 2008 |
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It is evident that the growing interest in organically
grown produce has correspondingly necessitated the debate on
the nutritional supremacy between organically and
conventionally grown produce. A study was carried out to
determine and compare vitamin C, calcium and potassium in
organically and conventionally grown cabbage, carrots, Cos
lettuce and Valencia oranges. Samples were purchased from
local supermarkets within Central Coast, New South Wales in
Australia from late March to early April 2007. Vitamin C
content was determined by 2,6-dichloroindophenol titrimetric
method while calcium and potassium were determined by atomic
absorption spectroscopy. Results from the study showed
inconsistent pattern with respect to vitamin C, calcium and
potassium contents in the conventionally and organically
grown samples. No significant differences were observed in
vitamin C content in conventionally and organically grown
cabbage, carrots and Cos lettuce while significant
differences were observed in Valencia oranges which showed
higher vitamin C content in organic Valencia oranges as
compared to conventional ones (51.8 to 43.4 mg/100 g fresh
weight). Results on calcium and potassium contents showed
significant differences in all the samples with the trend of
higher values for organically grown cabbage, carrots and Cos
lettuce as opposed to their conventionally grown
counterparts. However, for Valencia oranges, results showed
that the calcium and potassium contents were significantly
higher in conventional Valencia oranges compared to the
organic Valencia orange (54.5 and192.0 mg to 51.8 and 189.5
mg/100 g, respectively).
Key words:
Organic, conventional, atomic absorption spectroscopy,
2,6-dichloroindophenol. |
