Abstract:

The effect of soy protein isolate-dextran grafted conjugates (SPI-g-DEXT) on the phase behavior and morphology
of SPI/DEXT blends was investigated. The results demonstrated that the apparent viscosity, viscoelastic modulus,
macroscopic phase separation time and polysaccharide dispersed phase of the blends was increased at first and then
decreased with increasing addition (0, 0.10, 0.20 and 0.30 g/100 mL) of SPI-g-DEXT with a graft degree of 49.92%. The
compatibility of SPI/DEXT blends was increased with increasing graft degree (0, 30.73%, 49.92%, and 62.84%) of SPI-g-
DEXT at an addition level of 0.20 g/100 mL. After incorporation of SPI-g-DEXT in SPI/DEXT blend, the changing trend of
the steady shear and dynamic viscoelastic rheology, macroscopic phase separation time and polysaccharide-dispersed phase
depends primarily on the competition between compatibilization and steric effects caused by SPI-g-DEXT.

Key words: soy protein isolate, DEXT, dextran, blend, phase behavior, morphology