Investigation of Changes in Element Contents of Different Citrus Fruit Peel and Flesh Parts by Microwave-Assisted Digestion and ICP-OES

In this study, the concentrations of toxic elements as well as macro- and microelements accumulated in the peel and flesh of different Citrus fruits were investigated by inductively coupled plasma optical emission spectroscopy (ICP-OES). The toxic element found in the highest amounts in the peel and flesh parts of citrus fruits was arsenic (As), followed by barium (Ba), chromium (Cr), and cadmium (Cd) in decreasing order. The quantity of As in citrus fruit peel and flesh parts varied between 5.42 (lemon) and 10.59 mg/kg (grapefruit) to 4.62 (lemon) and 12.25 mg/kg (grapefruit), respectively. The aluminum (Al) and As contents of the peels of citrus fruits (except grapefruit) were high in the flesh parts. The quantities of phosphorus (P) and potassium (K) in the peels of citrus fruits were between 1012.35 (lemon) and 1159.82 mg/kg (grapefruit) to 4340.07 (lemon) and 8695.24 mg/kg (grapefruit), respectively. In addition, while the quantity of P in the fruit flesh parts was between 460.13 (orange) and 1486.49 mg/kg (grapefruit), the quantity of K in the flesh of citrus fruits was between 11082.51 (lemon) and 14585.65 mg/kg (grapefruit). In general, the P contents of the flesh parts of grapefruit and lemon fruits were higher than the peel parts. In addition, while the K contents of the flesh parts of the fruits were established to be high in the shell parts, the amounts of calcium (Ca) and magnesium (Mg) in the flesh parts were found to be low. While the quantity of iron (Fe) in the peel parts of grapefruit, lemon, mandarin, and orange fruits was higher than in the flesh parts, the quantity of zinc (Zn) in the fruits was found to be low. The microelement found in the highest amounts in fruit parts was B, followed by Fe, Mn, and Zn in decreasing order. The toxic element found in the highest amounts in the peel and flesh of citrus fruits was As, followed by Ba, Cr, and Cd in decreasing order.