Abstract: The effect of Sanzan gum on the pasting, rheological and microstructural properties of modified corn starch was investigated. The results showed that the peak viscosity, trough viscosity, final viscosity and pasting temperature of the mixed system increased with increasing mass fraction of Sanzan gum, and there was a synergistic thickening effect between Sanzan gum and modified corn starch. The mixed system was a pseudoplastic fluid with shear-thinning properties. The addition of NaCl increased the viscosity of the mixed system, while the pseudoplastic properties were unaffected by changes in NaCl concentration and pH. The D50 value and gel strength of modified corn starch were increased by the addition of Sanzan gum. When the pH of the system was adjusted to 4.0, the D50 decreased and the gel strength increased. When the pH was fixed at 4.0, the D50 and gel strength of the mixed system decreased with the increase in NaCl concentration. The microstructure of mixed gels showed more homogeneous pore size distribution compared with that of modified corn starch gels. The pore size became slightly smaller when the pH of the mixed system was adjusted to 4.0, and it significantly decreased after further addition of 0.10 mol/L NaCl.

Key words: Sanzan gum; modified corn starch; pasting property; rheological property; microstructure