Physical, chemical, and mineralogical characteristics of six bentonites were assessed and related to their elemental release to wine. Extraction essays of bentonites in wine at three pH levels were carried out. The multielemental analysis of bentonites and wines was performed by atomic absorption spectrometry (AAS) and inductively coupled plasma mass spectrometry (ICP-MS). Bentonite addition resulted in significantly higher concentrations of Li, Be, Na, Mg, Al, Ca, Sc, V, Mn, Fe, Co, Ni, Ga, Ge, As, Sr, Y, Zr, Nb, Mo, Cd, Sn, Sb, Ba, W, Tl, Bi, and W. In contrast, the concentrations of B, K, Cu, Zn, and Rb significantly decreased. A strong correlation between Na concentrations of treated wines and its content in bentonite exchange complex was observed. Al and Fe contents reflected bentonite extractable aluminous and ferruginous constituents, while Be, Mg, Ca, V, Mn, Ni, Ge, Zr, Nb, Mo, Sn, Sb, Tl, Pb, and U concentrations reflected the elemental composition of bentonites. Several nonconformances with OIV specifications demonstrated the need for an effective control.

<p style="text-align: justify;"><strong>Aim</strong>: The control of geographical origin is one of the most challenging topics regarding wine authenticity. The aim of the present study was to assess the ⁸⁷Sr/⁸⁶Sr ratio of vineyard soils from Portuguese Denominations of Origin (DO) and evaluate its suitability as a tool for origin authentication.</p><p style="text-align: justify;"><strong>Methods and results</strong>: An analytical protocol was optimized (chromatographic separation of Sr and Rb, followed by inductively coupled plasma-mass spectrometry (ICP-MS) analysis) for ⁸⁷Sr/⁸⁶Sr isotopic ratio determination in soil-wine system. The ⁸⁷Sr/⁸⁶Sr ratios of soils from four vineyards located in three Portuguese DO (Dão, Óbidos and Palmela), established on distinct soil types, were determined. Significant differences were found between soils of different DO regions. The soil in the Dão DO, developed on granites, showed a statistically higher ⁸⁷Sr/⁸⁶Sr ratio than the other soils, which were developed on sedimentary formations.</p><p style="text-align: justify;"><strong>Conclusion</strong>: The results show clearly that ⁸⁷Sr/⁸⁶Sr ratio may represent a suitable fingerprint for these Portuguese DO.</p><p style="text-align: justify;"><strong>Significance and impact of the study</strong>: This study highlights the relevance of setting up an international databank of ⁸⁷Sr/⁸⁶Sr values for use for geographical identification and authentication.</p>

<p style="text-align: justify;">The application of the cation exchange and double cation-anion exchange resins, regarding the wine tartrate stabilization, without previous treatment of wine by cold has been studied as well as their influence in phenolic, mineral and organic acid composition. The R1 resin was used in Mg2+, Na+ and H+ form, the R2 resin was always used in H+ form, and the R3 was used in OH- form. The eluted wine was assembled with untreated wine to obtain stable wine. The R2 resin showed to be more efficient to enhance the tartrate stabilization than R1 in Mg2+ form; however in H+ form, the behaviour of both resins was quite similar. The tartrate stabilization results to double cation anion exchange were similar to the results obtained with cation exchange.</p>

The control of geographic origin is one of a highest priority issue regarding traceability and wine authenticity. The current study aimed to examine whether elemental composition can be used for the discrimination of wines according to geographical origin, taking into account the effects of soil, winemaking process, and year of production. The elemental composition of soils, grapes, musts, and wines from three DO (Designations of Origin) and for two vintage years was determined by using the ICP-MS semi-quantitative method, followed by multivariate statistical analysis. The elemental composition of soils varied according to geological formations, and for some elements, the variation due to soil provenance was also observed in musts and wines. Li, Mn, Sr and rare-earth elements (REE) allowed wine discrimination according to vineyard. Results evidenced the influence of winemaking processes and of vintage year on the wine’s elemental composition. The mineral composition pattern is transferred through the soil-wine system, and differences observed for soils are reflected in grape musts and wines, but not for all elements. Results suggest that winemaking processes and vintage year should be taken into account for the use of elemental composition as a tool for wine traceability. Therefore, understanding the evolution of mineral pattern composition from soil to wine, and how it is influenced by the climatic year, is indispensable for traceability purposes.

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