ABSTRACT

 This study was carried out to determine the macro elements (Ca, K, P, Mg, Na, N), micro elements (Zn, Fe, Al, Cu and Mn) and heavy metals (Pb, Ni, As, Cd and Cr) in oranges, pawpaw and pineapples artificially ripened with different amounts of calcium carbide (0g/5kg, 10g/5kg, 20g/5kg, 30g/5kg) in Umudike, Ikwuano L.G.A, Abia State. The samples were digested using the wet acid multiple Nutrient Digestion Method, heavy metals were determined by the Atomic Absorption Spectrophotometer. It was found that Ca (30.37%) Pb (10.52 mg/kg), Mg (3.80 %), P (1.89 %) were the predominant elements in calcium carbide. The fruits treated with 30g/5kg calcium carbide/fruit were quicker to ripen, 2 days (48 hours) for pawpaw, 6 days (144 hours) for oranges and 7 days (168 hours) for the pineapples. The concentration of macro elements as Ca, Mg, K, P and Na, micro elements as Zn, Cu, and Mn, and all the heavy metals ( Pb, Ni, As,Cr and Cd,) increased with increased amount of calcium carbide applied while N, Fe and Al decreased. The results of macro mineral in the artificially ripened fruits obtained showed highest concentration of Ca in pineapple at 30g/5kg (8.40%), K in pawpaw at control (0.62%), Na in pineapples at 30g/5kg(0.60 %), P in pineapples at 30g/5kg (1.42%) and N in unripe oranges (0.98 %). For the micro minerals, data obtained showed highest value for Zn in unripe oranges (4.44mg/kg), Cu in 30g/5kg pineapples (0.26 mg/kg), Fe in the unripe pawpaw (60.15mg/kg), Mn in pawpaw at 30g/5kg (2.86 mg/kg) and Al in pineapples at control (0.35 mg/kg). While for the heavy metals, data obtained showed highest value for Pb in 30g/5kg pawpaw (0.56mg/kg), Ni in 30g/5kg oranges (0.67 mg/kg), As in the 30g/5kg oranges (0.55mg/kg), Cr in the unripe oranges (0.12 mg/kg) and Cd in the 30g/5kg pineapples (0.16 mg/kg). The application of calcium carbide showed significant difference on the heavy metal, macro and micro minerals in the treated fruits at p<0.05.