Evaluating Nanofiltration Effect on Wine 87Sr/86Sr Isotopic Ratio and the Robustness of this Geographical Fingerprint

When aiming to use the strontium isotopic ratio 87Sr/86Sr for the traceability and authentication of wine, it is crucial to understand the impacts of anthropogenic factors and technological processes on this parameter.  A study was developed to evaluate the effect of nanofiltration (NF), a membrane process with several applications in oenology, on the isotopic ratio 87Sr/86Sr of wine, testing its robustness as geographical tracer.  NF assays, for dealcoholisation, were carried out at laboratory scale with model solutions and white and red wines from Portuguese DO. High rejections to strontium (97%) and tartaric acid (> 70%) and low rejection to ethanol (< 10%) at 15 bar were observed in model solutions. Wines and NF-processed wines (17 bar; 2.1 L/min) were evaluated for physicochemical composition (including phenolic composition, chromatic characteristics and polysaccharides), multi-elemental composition and 87Sr/86Sr ratio by Q-ICPMS.  The preferential membrane permeation of ethanol was associated with a slight increase in the quality parameters of the wine (anthocyanins and polysaccharides). High rejections to mineral elements, including heavy metals, were observed. Rejection to Sr was mostly higher than 95%. No significant differences in the 87Sr/86Sr of wines and corresponding permeate fractions were observed, suggesting that NF does not preclude the use of this parameter for wine traceability purposes.

Automatic flow systems based on sequential injection analysis for routine determinations in wines

Sequential injection systems for wine analysis have been developed in recent years for determination of more than 20 species. Several aspects of these systems are reviewed in the present paper. Special focus is given to implementation of in-line sample treatment and adaptation of system operation through software control to enable determination in different types of wine. The strategies used to enhance selectivity and the capacity for multi-parameter determination are also addressed

Use of ion exchange resins for tartrate wine stabilization

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

⁸⁷sr/⁸⁶sr ratio in vineyard soils from Portuguese denominations of origin and its potential for origin authentication

Aim: 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. Methods and results: 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. Conclusion: The results show clearly that 87Sr/86Sr ratio may represent a suitable fingerprint for these Portuguese DO. Significance and impact of the study: This study highlights the relevance of setting up an international databank of 87Sr/86Sr values for use for geographical identification and authentication

Effect of new and conventional technological processes on the terroir marker 87Sr/86Sr

Aiming to use the strontium isotopic ratio 87Sr/86Sr for traceability and authentication of wine, it is crucial to understand the impacts of anthropogenic factor and technological processes on this parameter. In this study the effect of two technologies: nanofiltration (NF), applied for wine dealcoholisation (1), and ageing with oak wood staves (2), on 87Sr/86Sr ratio of wines from Portuguese Designations of Origin (DO), was assessed. Control wines, NF processed wines and wooden aged wines were evaluated for chemical composition, multi-elemental composition and 87Sr/86Sr ratio by Q-ICP-MS. Regarding NF experiments, high rejections to mineral elements, including heavy metals, were observed. Bearing in mind the several roles played by these elements in wine, this knowledge is of strategic importance in order to guarantee that NF process does not adversely affect product quality. Concerning wood ageing experiment, results indicate the influence of this technological process on metal physical-chemical stability. In the experimental conditions of this study, no significant effect of NF process and wood ageing on 87Sr/86Sr ratio was observed, suggesting that the application of these technologies in wine production is not a limitative factor for the use of 87Sr/86Sr ratio as a geographical origin marker

Effect of new and conventional technological processes on the terroir marker

Aiming to use the strontium isotopic ratio 87Sr/86Sr for traceability and authentication of wine, it is crucial to understand the impacts of anthropogenic factor and technological processes on this parameter. In this study the effect of two technologies: nanofiltration (NF), applied for wine dealcoholisation (1), and ageing with oak wood staves (2), on 87Sr/86Sr ratio of wines from Portuguese Designations of Origin (DO), was assessed. Control wines, NF processed wines and wooden aged wines were evaluated for chemical composition, multi-elemental composition and 87Sr/86Sr ratio by Q-ICP-MS. Regarding NF experiments, high rejections to mineral elements, including heavy metals, were observed. Bearing in mind the several roles played by these elements in wine, this knowledge is of strategic importance in order to guarantee that NF process does not adversely affect product quality. Concerning wood ageing experiment, results indicate the influence of this technological process on metal physical-chemical stability. In the experimental conditions of this study, no significant effect of NF process and wood ageing on 87Sr/86Sr ratio was observed, suggesting that the application of these technologies in wine production is not a limitative factor for the use of 87Sr/86Sr ratio as a geographical origin marker