Abstract:

Soluble soybean polysaccharides (SSPS) were modified by dynamic high pressure microfluidization (DHPM) at
80, 120 and 170 MPa, respectively. Differences in surface topography and molecular structure between SSPS and DHPMmodified
SPSS (MSSPS) were analyzed by scanning electron microscope (SEM) and Fourier transform infrared spectroscopy
(FTIR). The results indicated that the hydrogen bond and internal order of samples were decreased while the major structure
of SSPS was not changed by DHPM treatment. In addition, the surface topography of samples became loose as SSPS was
ruptured and some cellular structures were formed. Rapid visco analyzer (RVA), differential scanning calorimetry (DSC)
and FTIR were employed to investigate the effect of MSSPS on the retrogradation properties of rice starch (RS). The results
showed that the peak viscosity, final viscosity, gelatinization enthalpy and setback value were significantly decreased
(P ＜ 0.05) in the gelatinization of RS with the addition of MSSPS. FTIR spectrum showed that the ratios of the peak intensities at
1 047 cm-1and 1 022 cm-1 were significantly decreased (P ＜ 0.05) with the addition of MSSPS. These results demonstrated that the
retrogradation extent of RS was decreased significantly (P ＜ 0.05) with the addition of MSSPS. Moreover, the inhibitory effect of
MSSPS on the retrogradation of RS was significantly (P ＜ 0.05) enhanced with increasing DHPM pressure.

Key words: dynamic high pressure microfluidization, soluble soybean polysaccharides, rice starch, retrogradation