Effect of purple red rice bran anthocyanins on pasting, rheological and gelling properties of rice starch

Abstract

Purple red rice bran (PRRBA), a by-product of the rice polishing process, is frequently thrown away, resulting in a waste of resources. This study investigated the effects of PRRBA on the pasting, rheological property, chemical structure, microstructure, and water migration of rice starch. The results demonstrated that the peak viscosity (PV), final viscosity (FV), and activation energy (retrogradation energy) of rice starch were all decreased by a dose of PRRBA. Furthermore, the gel strength and hardness of rice starch were positively correlated with the addition of PRRBA. Rice starchs particle size distribution can be improved by PRRBA, which may be a result of the non-covalent bonds that exist between PRRBA and rice starch. The addition of PRRBA resulted in a decrease in the spin relaxation time (T2) of rice starch, from 259.7 to 143.6 ms. This can be attributed to that PRRBA improved the water-holding capacity of rice starch. These results could contribute to the development of high-value-added products of PRRBA and facilitate the application of anthocyanins in starch-based foods.