The combination of stable isotope abundance ratios of H, C, N and S with 87Sr/86Sr for geographical origin assignment of orange juices

Within the EU-project “Pure Juice” established stable isotope methods (δ2H, δ13C, δ15N) have been applied and improved in order to determine and verify the geographical origin of orange juices. In addition, new approaches employing analyses of δ34S and 87Sr/86Sr have been developed and tested. Approximately 150 authentic orange juice samples from several regions in North- and South-America, Africa and Europe have been analysed. A discrimination of orange producing regions, based on the results which ultimately depend on geographical, climatic and lithological differences was successfully performed. Furthermore, we demonstrate that blending of single strength juice by adding concentrate can be revealed by comparing 87Sr/86Sr of soluble and insoluble components of the juices. We conclude that regional assignment of orange juice samples is most successful when single parameters are combined in a “multi-element approach”.