The structure of soluble soybean polysaccharide

The chemical structure of soluble soybean polysaccharides (SSPS) was examined. SSPS was exhaustively degraded by three kinds of pectinase and four kinds of hemicellulase. The molecular structure of SSPS was examined using an enzymic-HPLC method. SSPS has three types of galacturonic main backbone, namely G-l, G-2 and G-3 unit, with longer homogeneous galactosyl and arabinosyl neutral sugar side chains than galacturonosyl main backbone. The G-l, G-2, and G-3 units consisted of rhamnogalacturonan (RG) subunits containing of rhamnose and galacturonic acid mainly as the sugar components, molecular ratio were nearly 1 : 1. Structural differences of main backbone between SSPS and citrus pectin were indicated by the analysis of the galacturonan region and galacturonate residues in the G-l, G-2, and G-3 units, using the polygalacturonase degradation. SSPS consisted of short-chain homogalacturonan (HG) and long-chain RG subunits. On the other hand, citrus pectin is made up of long-chain HG and short-chain RG subunits.