Characterization of molar mass and conformation of relevant (non-)starch polysaccharides in cereal-based beverages

Arabinoxylans, beta-glucans, and dextrins influence the brewing industry's filtration process and product quality. Despite their relevance, only a maximum concentration of beta-glucans is recommended. Nevertheless, filtration problems are still present, indicating that although the chemical concentration is essential, other parameters should be investigated. Molar mass and conformation are important polymer physical characteristics often neglected in this industry. Therefore, this research proposes an approach to physically characterize enzymatically isolated beer polysaccharides by asymmetrical flow field-flow fractionation coupled to multi-angle light scattering and differential refractive index detector. Based on the obtained molar masses, root-mean-square radius (r(rms) from MALS), and hydrodynamic radius (r(hyd)), conformational properties such as apparent density (rho app) and r(rms)/r(hyd) can be calculated based on their molar mass and size. Consequently, the rho app and r(rms)/r(hyd) behavior hints at the different structures within each polysaccharide. The r(rms)/r(hyd) 1.2 and high rho app values on low molar mass dextrins (1-2 & sdot;10(5) g/mol) indicate branches, while aggregated structures at high molar masses on arabinoxylans and beta-glucans (2 & sdot;10(5) -6 & sdot;10(6) g/mol) are due to an increase of rho app and a r(rms)/r(hyd) (0.6-1). This methodology provides a new perspective to analyze starch and non-starch polysaccharides in cereal-based beverages since different physical characteristics could influence beer's filtration and sensory characteristics.