Characterizations of stable carbon and nitrogen isotopic ratios in wheat fractions and their feasibility for geographical traceability: A preliminary study

The study aims to investigate the characterization of stable isotopic ratios in wheat milling fractions (bran, wheat shorts, and flour) and extracts (defatted flour, gluten, lipid, starch, and crude fiber) and correlations among different matrices for each isotope, which could provide some references for the development and application of stable isotopes for geographical traceability of wheat and its milling products. Wheat samples with three genotypes were collected from three regions in China. δ13C and δ15N values in wholemeal, milling fractions and extracts were determined. Results showed that δ13C varied significantly among milling fractions and extracts, while no significant difference was found among δ15N values of different milling fractions or extracts. Each isotope shows significantly positive correlations among wheat fractions (p < 0.01). The variations of δ13C and δ15N were most contributed by fraction and region, respectively. Therefore, δ15N is suitable for geographical traceability of wheat and its milling products.