The effects of MgSO4, d-glucono-δ-lactone (GDL), sucrose, and urea on gelation properties of pectic polysaccharide from soy hull

The monosaccharide composition of pectic polysaccharide extracted from soy hull under assistance of microwave was firstly analyzed. Soy hull pectic polysaccharide (SHPP) mainly contains galactose, xylose, galacturonic acid, arabinose, glucose and rhamnose with a molar ratio of 4.7:2.5:1.5:3.8:3.2:3.0. The gelation properties of SHPP as a function of Mg2+, GDL, sucrose, and urea concentration were then systematically studied. Mg2+ can induce the gelation of SHPP but low concentration Mg2+ require more time to cross-linking SHPP molecular chains. GDL can strengthen the elasticity of SHPP/Mg2+ gel, while sucrose can also strengthen the network through hydrophobic interaction, however 30 wt% sucrose can weaken the SHPP/Mg2+ gel network. 2 mol/L urea can collapse the gel network formed by 3 wt% GDL with 0.1 mol/L Mg2+, which suggests that the junction zone of SHPP/GDL/Mg2+ system is formed through hydrogen bonding.