Determination of Levels of Selected Essential and Non Essential Metals in Mango (Mangifera indica L.) Cultivated in Wolaita Zone, Southern Ethiopia

Abstract

Background: Mango (Mangifera indica L.) is one of the most important tropical fruits commercialized and consumed worldwide fresh or processed, having an attractive color and distinct taste and aroma. The main objective of this study is to determine the level of selected essential and non-essential metals in Mango. Methods: The levels of essential and non-essential metals were determined in mango (Mangifera indica L.) samples collected from four different sites (Boloso Bombe, Boloso Sore, Damot woyde and Humbo) in Wolaita Zone, Southern Ethiopia by flame atomic absorption spectrometry. A 0.5 g dried powdered mango sample was digested with 1 mL of nitric acid (HNO3), 3 mL of perchloric acid (HClO4) and 1 mL of hydrogen peroxide (H2O2) at 180°C for 2:00 hours. The study focused on two mango varieties, the Apple mango and the Keitt mango. Result: The metal contents in the apple mango in mg/kg were found in the following order: Mg (20.04-0.34) greater than Ca (1.49-6.78) greater than Zn (2.32-4.23) greater than Fe (2.77-2.85) greater than K (2.03-2.41) greater than Na (1.72-1.97) greater than Mn (0.47-1.36) mg/kg; and that of the Keitt mango samples in mg/kg were in the order of: Mg (2o.08_20.34) greater than Ca (0.95_5.84) greater than Zn (2.69_3.66) greater than Fe (2.69_2.90) greater than K (1.91_2.77) greater than Na (1.79_1.93) greater than Mn (0.38_0.72) mg/kg, respectively. The levels of Cd and Pb were below method detection limit. Analysis of variance (ANOVA) at 95% confidence level indicated that there is significant difference in the mean concentration of all metals between the four sample sites. There was good correlation between the levels of some metals (Mg, Ca, Zn, Fe K, Na and Mn) in both varieties of mango samples. From the results of this study it can be concluded that the studied mango varieties grown in the study area are good source of essential metals and free from the toxic metals: Cd and Pb.