Elemental concentration of tomato paste and respective packages through particle-induced X-ray emission

The elemental concentrations of three brands of Brazilian tomato paste packed in cans and Tetra Pak® cardboard boxes were determined through the Particle-Induced X-ray Emission (PIXE) technique. The elements Na, Mg, Al, Si, P, S, Cl, K, Ca, Ti, Mn, Fe, Ni, Cu, Zn, Br and Rb were identified in the tomato pastes. The metallic cannisters are characterized primarily by the presence of Fe and Sn, while several elements including Al, Cl, Ti, Fe and Zn showed up in Tetra Pak® boxes. The elemental concentrations of tomato paste varied significantly among different brands and packages. The major elements present in tomato paste are Na, Cl and K with concentrations ranging from 1700 mg/kg up to 7500 mg/kg, while trace elements like Br and Rb had average concentrations around 2 mg/kg. Tomato paste from different brands and packages stored for long periods of time were evaluated as well. Canned tomato paste showed distinct rising and decreasing trends of Fe and Al concentrations as a function of the storage time respectively. Possible transfer mechanisms are discussed.