Abstract:

In order to compare chemical properties of extruded oat bran and unextruded oat bran, they were hydrolyzed using alkaline or proteinases, and the hydrolysates were analyzed for protein isoelectric point, protein and b-glucan contents, and aromatic components in Maillard reaction product. Besides, IR spectral analysis and microstructure observation under scanning electron microscopy (SEM) were also conducted. Results showed that higher protein and β-glucan contents were exhibited in oat bran hydrolysates compared with extruded oat bran hydrolysates. There were obvious differences in microstructure between extruded oat bran and unextruded oat bran. Native oat bran revealed a simple dispersion microstructure with smooth and flat surface, while extruded oat bran exhibited a complex microstructure with rough surface and meanwhile obvious extrusion characteristics were observed. Totally 28 and 29 aromatic compounds were found in Maillard reaction product of native oat bran and extruded oat bran hydrolysates by GC analysis, respectively. Furthermore, the major aromatic compounds showed a great difference in content.

Key words: oat, extrusion, Fourier transform infrared spectroscopy, scanning electron microscopy, Maillard reaction, gas chromatography