Italian tomato-based products authentication by multi-element approach: A mineral elements database to distinguish the domestic provenance

In this study, we propose a novel mineral elements database for the authentication of Italian processed tomato, able to discriminate the domestic provenance from the Chinese, US and Spanish ones. Multi-element analyses by Inductively Coupled Plasma orthogonal acceleration Time-of-Flight Mass Spectrometry (ICP-oa-TOF-MS) and Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) were used for quantifying 26 mineral elements (Li, Be, Na, Mg, Al, K, Ca, V, Cr, Mn, Co, Cu, Zn, Ga, As, Rb, Sr, Ag, Cd, In, Cs, Ba, Tl, Pb, Bi and U) in 183 tomato-based samples of different origin (Italy, China, US and Spain) collected in three different years of production (2013, 2015 and 2017). Linear Discriminant Analysis (LDA) applied to 28 variables (single elements + elemental ratios) allowed excellent separation between Italian and non-Italian tomato samples. Three elemental ratios (Li/Cu, Co/Rb and Sr/Cd) resulted highly effective in identifying the domestic provenance of tomato (100% prediction ability of the model and 98.8% in cross-validation). This result highlighted that ratios between elements were more important than single elements in discrimination.