Static and dynamic light scattering studies of heteroxylans from maize bran in aqueous solution

Macromolecular features of four heteroxylan samples extracted from maize bran under different conditions of temperature, type and concentration of alkali were determined by light scattering measurements in 80 mM NaNO3 after elimination of the aggregates by filtration through 0.2 mu m pore size filters. The macromolecular parameters were similar for all four samples, with a slight molecular weight dependence on extraction conditions. Static and dynamic results were confirmed by SEC-MALLS measurements. The radii of gyration were approximate to 40 nm and the hydrodynamic radius approximate to 20 nm for a weight-average molecular weight of approximate to 2.8 x 10(5) g/mol and a polydispersity approximate to 2. The structural parameter rho (=1.6-2.1), calculated from these results, was characteristic of a branched rather rigid polymer. The hydrodynamic parameter nu(1) (=0.3) indicated a compact structure, which could be due to the side chains or to a 'fringed micelle' organisation of the macromolecules. Copyright (C) 1996 Elsevier Science Ltd