Stable isotope ratios of H, C, and N – selected contributions to food authentication

Walter Vetter and Stephanie Krauß

University of Hohenheim, Institute of Food Chemistry (170b), Garbenstr. 28, 70593 Stuttgart, Germany

Stable isotope analysis of light elements by means of isotope ratio mass spectrometry (IRMS) is a well-established method in food authentication. Classic application fields are the differentiation of C3 and C4 plants by means of stable carbon isotope ratios, assignment of geographical origins of samples due to their stable hydrogen and/or oxygen isotope ratios, etc. After some background information, we will show and discuss novel applications and basic research, conducted in our group during the last years. Focus will be set to the exploration and understanding of the underlying factors leading to a given result. Examples will feature the differentiation of vegetables grown in green houses vs. open field cultivation, regional and year-to-year variations, and authentication of organic food. The usefulness of stable isotope analysis for the understanding of biochemical processes will be highlighted. Also, we will report on valuable findings we cannot explain at the moment and we will discuss advantages, limitations and potential amendments that will support the role of IRMS in food authentication.