Determining the geographical origin of durum wheat samples by combining strontium isotope ratio and multielemental analyses

Background and objectivesDetermining the geographical origin of durum wheat is an important and emerging challenge because consumers perceive added value of final products (e.g., pasta) depending on the origin. Declaration of geographical origin is also an emerging requirement of specific national regulations. Among analytical strategies for determining geographical origins of samples, isotopic techniques based on both light and radiogenic isotope targets stand out, despite limitations of applicability, validation and assessment of interyear variability. FindingsIn this study, Sr-87/Sr-86 isotopic analysis was successfully used to discriminate Italian (ITA) samples versus rest-of-the world (RoW) samples and subsequently integrated with an elemental analysis (ICP-MS) on 75 elements. A tiered approach was finally adopted in which the results of the Sr-87/Sr-86 analysis were input to a second step of support vector machine classification modeling (SVMC) based on the Al, Mn, Mo, P, S, Ti, Y, and Zn percentages in each sample. This model was tested against a blind group of samples with overall satisfactory performance. ConclusionValuable information from multielemental and stable isotope ratio analyses was collected for authentic samples from different Italian, European, and non-European regions harvested during different years. Significance and noveltyThis study demonstrates the potential and validity of an innovative combined multielemental and strontium isotope ratio approach for the geographic discrimination of durum wheat on a global scale: the developed predictive model has already been routinely employed to control industrial lots.