Characterization of covalent, feruloylated polysaccharide gels by pulsed field gradient-stimulated echo (PFG-STE)-NMR.

Translational mobility of guest molecules such as water and glucose in gels that are based on feruloylated polysaccharides appears to be critical to understand their nutritional and functional properties. Here, the applicability of PFG-STE-NMR on feruloylated gels was proven, and relationships to rheological data were studied. Arabinoxylans and pectins were extracted from by-products using varying conditions. Laccase induced coupling of these chemically characterized polymers resulted for most of the feruloylated polysaccharides in homogeneous gels. Rheological studies confirmed that polysaccharide composition affects viscoelastic properties of the resulting gels. Generally, diffusion of water and glucose is hindered in gels. In the feruloylated polysaccharide gels, both polysaccharide concentration and extraction conditions affect the diffusion behavior of these molecules. A simple correlation between rheological data and mobility of guest molecules has not generally been found: although long time acid extracted pectins form highly elastic gels, water diffusion in these gels is less hindered.