Dynamic rheological behavior of rice bran protein (RBP): Effects of concentration and temperature

The viscoelastic properties of rice bran protein (RBP) and the effect of temperature and concentration were investigated using small amplitude dynamic oscillatory shear measurements (SAOS). Linear viscoelastic region determined at 0.5% strain. Storage modulus (G') was greater than the loss modulus (G '') at all concentrations and increased by raising RBP concentration. Yield stress value was determined by stress sweep and it increased from 0.038 to 1.80 Pa, when concentration increased from 10% to 15%. Frequency sweep showed that REP solution had a typical fluid-gel behavior at low frequencies and complex viscosity (eta*) had linear correlation with frequency. Phase angle was remained relatively low (>10) over the 1-10 Hz frequency range, confirming weak network of REP. The effect of temperature on theological traits was investigated during heating (20-90 degrees C) and cooling (90-20 degrees C) phases. REP has a weak network and storage modulus was increased more during cooling phase. These rheological properties of RBP make it as a good candidate to apply with gelling materials in nutraceutical and food industries. (C) 2014 Elsevier Ltd. All rights reserved.