THE RHEOLOGICAL PROPERTIES OF POLYSACCHARIDES FROM RAPESEED

摘要

Two polysaccharides fractions (RPM1 and RPM2) were extracted from rapeseed. The rheological properties are the basis for the application of polysaccharides in functional foods, and can be used to predicate the microstructure of the natural polymers. Then the rheological properties of the polysaccharides from rapeseed were determined by a rotational rheometer. Results showed that their apparent viscosities increased with the increase of concentrations, and decreased with the increase of temperatures. And it indicated that the solutions of lower concentration were approximately Newton fluid, while solutions of higher concentrations were similar to pseudoplastic fluid. When concentration and temperature were fixed, pH weakly affected the apparent viscosity of RPMI. On the contrary, pH remarkably affected the apparent viscosity of RPM2. As the pH rose from 5 to 9, the viscosity of RPM2 solutions was increased accordingly, however, the viscosity decreased instead when the pH was above 9. Meanwhile, the influence of metal ions (K+ and Ca2+) on the viscosity was also different. For RPM1, the higher concentrations of Ca2+ could obviously increase its apparent viscosity, while K+ only had a weak effect. But for RPM2, K+ of higher concentrations could increase its apparent viscosity, while influence of Ca2+ was relatively weak.