Interaction of barley β-glucan with food dye molecules - An insight from pulse dipolar EPR spectroscopy

The interactions between dietary fibers (DFs) and small molecules are of great interest to food chemistry and nutrition science. However, the corresponding interaction mechanisms and structural rearrangements of DFs at the molecular level are still opaque due to the usually weak binding and the lack of appropriate techniques to determine details of conformational distributions in such weakly organized systems. By combining our previ-ously established methodology on stochastic spin-labelling of DFs with the appropriately revised set of pulse electron paramagnetic resonance techniques, we present here a toolkit to determine the interactions between DFs and small molecules, using barley beta-glucan as an example for neutral DF and a selection of food dye molecules as examples for small molecules. The proposed here methodology allowed us to observe subtle conformational changes of beta-glucan by detecting multiple details of the local environment of the spin labels. Substantial vari-ations of binding propensities were detected for different food dyes.

Automated summary

The interactions between dietary fibers (DFs) and small molecules are of great interest in the fields of food chemistry and nutrition science. This study presents a methodology combining stochastic spin-labelling of DFs with pulse electron paramagnetic resonance techniques to determine the interactions between DFs and small molecules. The proposed methodology allows for the observation of subtle conformational changes and variations in binding propensities of DFs and small molecules.