Macro and Micro Elements in Sweet Potatoes Cultivated in Senegal and Risk Assessment

Abstract

Once relegated to the background, sweet potatoes are a staple food crop that is gaining increasing popularity in Senegal to combat malnutrition in both rural and urban areas. Given its increasingly widespread use, it is essential to establish scientific foundations for its safe use for the population. Leaves and tubers of sweet potatoes were harvested from a white sweet potato plantation located in a rural area in Senegal. The macro (Na, K, Mg, Ca) and micro (Fe, Ni, Cu, Zn and Cd) elements contents in the leaves, peels, and flesh of sweet potatoes were analyzed. The samples were wet digested, and the metals were analyzed by atomic absorption spectroscopy. The results showed that macro element concentrations were highest in leaves (I), followed by peels (II). Sweet potato flesh (III) was less rich in macro elements. It was also found that potassium content was higher than all macro elements in all samples, with values ​​of 19682.14 ± 0.72 (I), 12876.53 ± 0.17 (II), and 10326.44 ± 0.10 mg/kg (III). The iron concentrations were 126.53 ± 0.09 (I), 21.94 ± 0.042 (II) and 91.31 ± 0.04 mg/kg (III). Nickel contents are 6.13 ± 0.08 (I), 3.74 ± 0.07 (II) and 9.09 ± 0.07 mg/kg (III). Copper and zinc concentrations were found between 5.38 ± 0.02 and 2.11 ± 0.01 mg/kg (II) and 15.80 ± 0.02 and 6.01 ± 0.01 0.72mg/kg (II) for Zn. Cadmium contents are 2.48 ± 0.01 (I), 1.80 ± 0.02 (II) and 1.90 ± 0.01 mg/kg (III). According to this study, sweet potato leaves have higher contents of all elements than peels and flesh. Na/K being less than 1, which is the recommended value in the three parts of the plant studied (0.129 (I), 0.084 (II) and 0.070 (III)). Thus the consumption of sweet potato and its leaves and peels could prevent high blood pressure. The Ca/Mg ratios for leaves and peels, which are 1.01 and 1.84, are within the recommended values ​​(between 1 and 2) to be beneficial for consumers. For the flesh, the Ca/Mg ratio value is 2.25 and is outside the recommended limits. For all heavy metals, the hazard quotient (THQ) values ​​are less than 1, suggesting that there are no health risks associated to the consumption of leaves, peels or flesh of sweet potato. In addition, the health index (HI) values ​​for all samples are less than 1, indicating that the combined effects of the heavy metal contaminants pose no health risk in long terms for consumers.