Preparation and characterization of sulfated galactomannan from guar gum: Optimization of reaction conditions by BBD and molecule conformational studies

Sulfated polysaccharides exert significant biological activity which is depend on degree of substitution (DS), weight average molecular weight (MW), substitution position and molecular conformation. In the present study, commercial guar gum was purified and its sulfated derivate (SGG) was prepared by Box–Behnken statistical design. Results of FT-IR and X-ray photoelectron spectroscopy (XPS) indicated that SO3− groups were widely present in SGG molecules. A conformation transition from a compact chain conformation of branched clusters to a random coil conformation was observed in size exclusion chromatography (SEC) combined with laser light scattering (SEC–LLS) analysis. It could be attributed to a comprehensive effect of molecule weight, sulfo groups and galactose substitution pattern in the sulfated derivatives.

► An efficient model of polysaccharides modification was studied in the present work. So far, there are no similar reports in this area.
► In addition, the current study is focused on structure characterization and molecule conformation of sulfated polysaccharides.
► The originality of this work is obvious. We hope it would provide valuable information in polysaccharides research.