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Epidemiological studies have recognized that daily consumption of dietary fiber-containing foods reduces the incidence of developing many chronic diseases, for example, by interacting with nutritionally relevant compounds. The low affinity nature that some of these interactions can have make the development of an analytical detection system for their study particularly difficult. Therefore, the mechanism of action of binding compounds, by which a dietary fiber exerts its potential health benefits, remains largely unknown. Here, a novel method based on glyco-nanotechnology is proposed for studying the interaction between galactomannan and target molecules. Starting from a bottom-up approach, gold nanoparticles and thiolated galactomannans of two different sizes were synthesized separately, and then mixed for auto-assembly of the two glyconanoparticle materials. In addition, a preliminary interaction study between the prepared glyconanoparticles and Concanavalin A was carried out using transmission electron microscopy (TEM) from which it could be deduced that the molecular weight and ligand density on the gold core play an important role in the interaction. Therefore, dietary fiber-tethered gold nanoparticles are a valuable tool to elucidate key parameters underlying dietary fiber interactions.

Optimizing human diet by including dietary fibers would be more efficient when the fibers' chain interactions with other molecules are understood in depth. Thereby, it is important to develop methods for characterizing the fiber chain to be able to monitor its structural alterations upon intermolecular interactions. Here, we demonstrate the utility of the electron paramagnetic resonance (EPR) spectroscopy, complemented by simulations in probing the atomistic details of the chain conformations for spin-labeled fibers. Barley β-glucan, a native polysaccharide with linear chain, was utilized as a test fiber system to demonstrate the technique's capabilities. Pulse dipolar EPR data show good agreement with results of the fiber chain modeling, revealing sinuous chain conformations and providing polymer shape descriptors: the gyration tensor, spin-spin distance distribution function, and information about proton density near the spin probe. Results from EPR measurements point to the fiber aggregation in aqueous solution, which agrees with the results of the dynamic light scattering. We propose that the combination of pulse EPR measurements with modeling can be a perfect experimental tool for in-depth structural investigation of dietary fibers and their interaction under such conditions, and that the presented methodology can be extended to other weakly ordered or disordered macromolecules. [Display omitted] • EPR data augmented by modeling describe conformational distributions of dietary fiber. • Heterogeneities in fibers result in strong T m -filtering in pulse EPR data. • The proposed methodology can have broad applications to polymer solutions. [ABSTRACT FROM AUTHOR]