Impact of different preparation methods on the properties of brown rice flour and the cooking stability of brown rice noodles and the underlying mechanism: Microstructure, starch-protein distribution, moisture migration

Abstract

Brown rice flour (BRF) and corresponding brown rice noodle (BRN) were prepared by different methods and the mechanism of impact of extruded rice bran on cooking stability of BRN was investigated. The particle size distribution, damaged starch content and pasting properties of BRFs were evaluated and the texture properties, microstructure and moisture distribution during cooking of BRNs were investigated. The average particle size and damaged starch of brown rice flour refilled with extruded rice bran (BRF-E) and brown rice flour refilled with nonextruded rice bran (BRF-NE) were obviously less than that of the brown rice flour by fully crushed brown rice (BRF-F). The peak viscosity (PV), setback viscosity (SV) and pasting temperature (PT) of BRF-E and BRF-NE were significantly higher than that of BRF-F. The results of scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) showed that the microstructure of BRN-E was most compact, which indicated that using BRF refilled with extruded rice bran to produce BRN could promote BRN formed a compact texture structure. Meanwhile, water migration and texture properties analysis demonstrated that BRN-E had better cooking stability and chewiness.