Unveilling the role of technological processes on the strontium isotopic ratio, fingerprint of wines' geographical origin

Mestrado Vinifera Euromaster - Instituto Superior de Agronomia - UL / Institut National d'Études Supérieurs Agronomiques, MontpellierBased on the close relationship of strontium isotopic ratio 87Sr/86Sr between soil and plants, this isotopic ratio has been reported as fingerprint tool to verify wine geographical origin and its authenticity In the last decade, some studies suggested that winemaking applications do not alter the 87Sr/86Sr isotopic ratios from vineyard to the wine despite the variations of mineral concentration. However, information about wood impact on 87Sr/86Sr is lacking in the literature. In this study, we investigated the wood ageing effect on 87Sr/86Sr, and also on the multi-elemental compositon of wine, which to our best knowledge are novelties, thus representing important advances to this field of knowledge. A red wine from Castelão grape variety was aged in stainless steel vats (34,000 L) with oak wood staves, in triplicate. The wines were sampled after 30, 60 and 90 days of ageing and evaluated in terms of: 87Sr/86Sr, by Q-ICP-MS after Sr and Rb separation by ion exchange chromatography; multi-elemental analysis (Be, Mg, Al, Sc, Ti, V, Mn, Co, Ni, Cu, Zn, Ga, Ge, As, Rb, Sr, Y, Zr, Mo, Sb, Cs, Ba, Pr, Nd, Sm, Eu, Dy, Ho, Er, Yb, Lu, Tl, Pb) by Q-ICP-MS; Na, K, Ca, Fe by FAAS. Wood ageingWood ageing effect on total polysaccharides concentration , chromatic characteristics and phenolic composition was also evaluated. Statistical analysis showed that there was no significant difference of the 87Sr/86Sr between the control wine and wine aged with wood. The results show that strontium isotopic ratio of wines was not altered even after ageing with wood (0.710 at initial time and 0.709 after 90 days) despite having a significant increase in Sr concentration by wood stage. This suggests that 87Sr/86Sr might be used as a reliable geographical indicator. Time had significant impact on Al, V, Zn, Ni, Cs, Pb and also on Na, K, Ca and Fe while wood stage only altered concentrations of Mg, V, Co, Ni and Sr. Our study suggests that wood ageing does not impact the 87Sr/86Sr, accordingly it will shed some light for further studies.N/