Cadmium distribution in mature durum wheat grains using dissection, laser ablation-ICP-MS and synchrotron techniques *

Bofang Yan (1) , M.-P. Isaure (2) , Sandra Mounicou (2) , Hiram Castillo-Michel (3) , Wout de Nolf (3) , Christophe Nguyen (1) , Jean-Yves Cornu (1)

1 UMR ISPA - Interactions Sol Plante Atmosphère
2 IPREM - Institut des sciences analytiques et de physico-chimie pour l'environnement et les materiaux
3 ESRF - European Synchrotron Radiation Facility

Understanding how essential and toxic elements are distributed in cereal grains is a key to improving the nutritional quality of cereal-based products. The main objective of this work was to characterize the distribution of Cd and of nutrients (notably Cu, Fe, Mn, P, S and Zn) in the durum wheat grain. Laser ablation inductively coupled mass spectrometry and synchrotron micro X-ray fluorescence were used for micro-scale mapping of Cd and nutrients. A dissection approach was used to quantitatively assess the distribution of Cd and nutrients among grain tissues. Micro X-ray absorption near-edge spectroscopy was used to identify the Cd chemical environment in the crease. Cadmium distribution was characterized by strong accumulation in the crease and by non-negligible dissemination in the endosperm. Inside the crease, Cd accumulated most in the pigment strand where it was mainly associated with sulfur ligands. High-resolution maps highlighted very specific accumulation areas of some nutrients in the germ, for instance Mo in the root cortex primordia and Cu in the scutellum. Cadmium loading into the grain appears to be highly restricted. In the grain, Cd co-localized with several nutrients, notably Mn and Zn, which challenges the idea of selectively removing Cd-enriched fractions by dedicated milling process.

Mots clés: Cadmium; durum wheat grain; LA-ICP-MS; µXRF; µXANES

Domaines: Chimie analytique; Ingénierie des aliments; Sciences de l'environnement

Bofang Yan, M.-P. Isaure, Sandra Mounicou, Hiram Castillo-Michel, Wout de Nolf, et al.. Cadmium distribution in mature durum wheat grains using dissection, laser ablation-ICP-MS and synchrotron techniques *. Environmental Pollution, 2020, 260, pp.1-9. ⟨10.1016/j.envpol.2020.113987⟩. ⟨hal-03018958⟩