Multi-element and multi-isotopic profiles of Port and Douro wines as tracers for authenticity

Port and Douro wines are produced in the Douro Demarcated Region using different wine making processes. This works aims at evaluating the influence of the geographical origin and the wine making process in their multielement (Li, Be, B, Al, Cr, Mn, Co, Ni, Cu, Zn, As, Se, Rb, Sr, Mo, Ag, Cd, Sn, Tl, Pb, Fe, Mg, P, Ca, Na, K) and isotopic compositions (87Sr/86Sr, δ11B, xPb/yPb, δ18O). Fifteen samples of each were analysed. ANOVA identified significant differences for Ca, Na, Rb, Zn, Cu, Cr, Se, 206Pb/204Pb, 207Pb/204Pb, 206Pb/207Pb and δ11B. PCA revealed that Cr, Se and Cu are the main contributors for discrimination by type of wine. 87Sr/86Sr and δ18O are region specific and not influenced by the winemaking process or storage. Thus, make good natural tracers for geographical origin of this region. HCA suggested a common profile in Port and Douro in white wines, for Sr and K, which should be further investigated.

Highlights: Inorganic analysis was used to study the geographical authenticity of wines; Port and Douro wines have different inorganic signatures; The wine making process influences the multielement fingerprint; Cr, Se and Cu are the main contributors for discrimination by type of wine; 87Sr/86Sr and δ18O are specific to the region.