Level of Nutritious and Non- Nutritious Elements in Banana Grown in Zanzibar

Banana play important role in providing dietary needs to the individuals from vitamins, iron, calcium, potassium, sodium and some others nutritious elements that are needed in the daily food as dietary supplementation, or as an important elements that form some hormones or enzymes in small concentration. However, if they exist beyond the recommended levels they can pose bad health effects. This study aims at assessing level of selected nutritious and non-nutritious elements in banana grown in different areas of Unguja-Zanzibar using Energy Dispersive X- Ray Fluorescence (EDXRF) machine. Nutritious elements (NEs) included sodium (Na), potassium (K), iron (Fe), manganese (Mn), zinc (Zn), and selenium (Se), while non-nutritious elements (NNEs) were; cadmium (Cd), lead (Pb), and chromium (Cr). These elements were observed and recorded from Jumbi (six sampling sites), Ndijani (six sampling sites), Masingini (four sampling sites), as well as Mpigaduru (four sampling sites). Concentration of elements investigated in all banana samples were above limit recommended by FAO/WHO and USDA. The sound reason for the elevated levels of the analyzed parameters is suggested to be due to solid wastes dumped at the study sites. From the statistical data analysis, the levels (in mg/kg) of the analyzed elements in their decreasing order were; K: 10537.62; Na: 8723.50; Pb: 106.151; Cr: 90.747; Fe: 61.548; Mn: 58.949; Cd: 14.995; Zn: 9.478; and Se: 2.01. This order is summarized as; K > Na > P b> Cr > Fe > Mn > Cd > Zn > Se. Elevated levels of these elements in banana might had been attributed to the repeated use, and addition of wastes as fertilizers in banana agricultural areas. The data analysis showed that the levels of some elements namely, Cr, Fe, Pb and Na in banana were significantly different (p <0.05). Nevertheless, the present study remarkably pointed out the age of the dumping site has a positive correlation with the levels of both NEs and NNEs found in the analyzed samples. These findings will provide the baseline information about the presence of nutritious and non-nutritious elements in banana grown in different areas of Unguja- Zanzibar. Moreover, it is important for nutritional classification, compliance with the standard of identification and ensuring that the products meet human consumption specification.