Effects of additional fibrils on structural and rheological properties of rice bran albumin solution and gel

The effects of additional heat-induced fibrils on the viscosity and gel strength of rice bran albumin (RBA) were studied. The structure and morphology of the fibrils were strongly affected by extent of heating time. The mean contour length and particle size of RBA fibrils increased with increasing heating time. The conversion of RBA monomers into linear aggregations at pH 2.0 and 90 °C increased with increasing heating time and protein concentration. Adding mature fibrils to RBA solutions can modify the structural properties and make this system rather complex. Rheological results showed that adding fibrils could promote solution thickening and gel hardening behavior and result in a significant increase in solution viscosity and gel strength. Interestingly, adding the longer heating time fibrils exhibited a higher viscosity values and elastic modulus. Significant difference in gel structure obtained by scanning electron microscopy between fibrils/RBA and RBA was observed. The former has more loose mesh structure than the latter. These results would be of great importance for understanding the physicochemical properties of RBA fibril assembly.