Characterization of lambrusco wines by means of Sr isotope ratio as provenance marker

Recently, geographical origin and authenticity of food are topics of great interest for consumers as well as for producers in the food industry. Furthermore, in the oenological field, these concepts are strictly tied with the quality of food. For different reasons, people are more focused towards food characterized by a well-established geographical origin. In the course of time, the symbiosis of quality and the geographical origin of products is certainly related to ethics of the producers and the whole determines the reputation of the territory. The present research is part of a project dealing with the development of authenticity and geographical traceability models of Italian wines, with particular reference on Lambrusco wines, which are one of the main typical products of the Modena district. Among the different indicators used for traceability studies, 87Sr, and in particular the 87Sr/86Sr isotopic ratio (I.R.), has provided excellent results for different types of food matrices. Aim of this work is to obtain a reliable fingerprint for Lambrusco wine on the basis of its 87Sr/86Sr isotopic value, linking it to its territory of provenance. Moreover, different analytical methods for the elimination of matrix interferences, before the Sr/Rb separation on resin, are also tested. In particular, the first method, widely used in literature, consists of the following step: i) ethanol elimination by means of HNO3 addition and ii) sample digestion through microwave assisted in acidic media. While, the second one merely consists in the addition of an aliquot of HNO3. Finally, as a preliminary study, wine samples were pre-treated according to the best procedure and 87Sr/86Sr measurements were accomplished with an high resolution multicollector inductively coupled plasma mass spectrometry (HR-MC-ICP-MS). The isotopic data of wines were compared with the isotopic range of Modena soils, with the aim to determine a correlation between soil and food, obtaining promising results as far as the potentiality of 87Sr/86Sr as geographical tracer is concerned. To the authors’ knowledge, this is the first report developing an easy analytical methodology for the pretreatment of the studied matrix, obtaining high precision and accuracy measurements, in terms of repeatability, reproducibility and time variability of the monitored indicator.