Food Hydrocolloids, 2018, vol 79pp. 218-227
DOI:10.1016/j.foodhyd.2017.12.036
Abstract
Several health benefits have been established for cereal mixed-linkage β-glucan of high molar mass (M), and are said to be attributed to the ability of β-glucan to form viscous slurries in the gut. As no comprehensive understanding exists yet, the characterization of β-glucan solution behavior is crucial. β-Glucan was characterized in terms of M, molecular size and conformation characteristics in aqueous solutions utilizing asymmetric flow field-flow fractionation (AF4) coupled to multi-angle light scattering (MALS) and differential refractive index (dRI) detectors. Polymers and aggregates were investigated using conformational data from comparing hydrodynamic radii (rhyd, from AF4) and root-mean-square radii (rrms, from MALS), Kratky plots (from MALS) and persistence length determination (from small-angle x-ray scattering (SAXS)). The aggregated structures were also analyzed with cryo-transmission electron microscopy (cryo-TEM). The results show the presence of highly aggregated structures in aqueous solution, in addition to dissolved, highly polydisperse polymers. The structural and conformational properties of the aggregates are different between oat and barley β-glucan. While oat β-glucan seems to be aggregated in a widely distributed, loose structure, barley β-glucan showed surprisingly dense and well-defined aggregates.
