Abstract:
Fruit juices are good source of carbohydrates, sugars, dietary fiber, proteins, fat, vitamins and
minerals. The main objective of this study was to determine the levels of heavy metals in five
brands of mango juices sold in Adama town, Oromia regional state, Ethiopia. In this thesis,
samples of industrially canned brands of mango juice were collected from Adama town around
Arada market using systematic random sampling method. A wet digestion procedure, using
mixtures of HNO3, HCl and H2O2 was developed for the decomposition of 5 mL of mango juice
samples and flame atomic absorption spectrometry (FAAS) was used to determine Cd, Mn, Cr,
Cu, Ni, Pb and Zn present in mango juice samples. The accuracy and precision of the optimized
procedure were evaluated by analyzing the digest of the spiked samples and the percentage
recoveries obtained varied from 85.0 to 112%. The precision of both the samples and spike
reagents which were tested by analyzing relative standard deviation were also between
acceptable ranges. The results revealed that the mean concentrations of Cr, Mn, Ni, Cu, and Zn
in the analyzed samples were ranged from ND – 1.004, ND – 0.429, 0.139 – 2.639, 0.418 –
1.597, 1.101 – 5.271 ppm, respectively while cadmium and lead were not detected in all the
selected samples. The results were compared with values reported in the literature and WHO
and it indicated that the mean concentrations of Mn, Cr, and Ni were above WHO guide line in
all brands of mango juices. The mean levels of metals in all mango juices collected were found to
decrease in the order of: Zn > Cu > Ni > Cr > Mn. In general, the results showed that the levels
of contamination of the mango juices by the heavy metals were somewhat high and the mango
juices were not polluted by toxic heavy metals (Cd and Pb).
