Studies of phase separation in soluble rice protein/different polysaccharides mixed systems

•Increase in protein size enhanced the demixing of SRP/polysaccharide systems.•Depletion and electrostatic interaction drove the phase separation of the systems.•Protein network-like structures were formed in the mixed systems.•Controlled phase separation and gelation of the systems can create novel rice food.

In present study, phase separation of soluble rice protein (SRP) and different polysaccharides were used to create specific structures with various structural and textural properties. The phase behavior and phase separation mechanism of mixtures of SRP and κ-carrageen/dextran (25 °C, pH 7.0 and 0.1 mol/L NaCl) were investigated by means of phase diagram construction, confocal laser scanning microscopy (CLSM) and stress-controlled rheometry. Phase diagrams combined with CLSM indicated that entropic effects of depletion interaction were the main driving force behind the phase separation of soluble rice protein and polysaccharides. Results also demonstrated that electrostatic interaction played an important role in the observed phase separation. CLSM and frequency sweeps revealed the effective association among rice proteins and formation of network-like structures in the mixed systems. These findings suggest that controlled phase separation and gelation of mixed SRP/polysaccharide systems have potential to create rice protein foods with novel textural characteristics.