Abstract: There were significant differences in the content of fat, protein, ash, starch and water for four foxtail millet bran fraction(S1-S4) (P<0.05). S3 had the highest nutritional value with 10.96% protein and 26.05% fat. At the same time, S3 had larger stacking density(326.07g/L) and a smaller angle of repose (36.75°), which indicated that S3 showed stronger liquidity and easier to be packaged and transported. However, higher moisture and oil content in S3 was not conducive to storage. In terms of processing properties, S3 with strong hydrophilicity was more easily soluble in water, result in higher water solubility index. The foaming ability is the strongest (5.54%) and the stability of foam is the highest (82.86%) in four millet bran, which could form a large number of compact and uniform foam. Using GC-MS technology, 72, 47, 70, and 51 volatile substances were detected from S1-S4. Loading Plot of PCA showed most of the volatile components are located on the right side of the axis, and they contribute significantly to the S1 and S2 samples, while ethylbenzene and toluene are located on the left side, making a significant contribution to the S3 and S4 samples. Among the 10 different volatile substances, six compounds (Methyl hexanoate, hexanal, 2,2,4-trimethyl-1,3-pentanediol di Isobutyric acid, methyl Palmitic acid, nonaldehyde, and methyl Linoleic acid) have the highest content in S1, while four compounds(dodecane, n-hexanol, Undecane, 2-n-pentylfuran) have the highest content in S2. The higher the OAV value, the greater the contribution of odor. The OAV values of nonanal in S1-S4 were 702, 444, 110 and 51, respectively, which can effectively distinguish the foxtail millet bran fraction.

Key words: foxtail millet bran farction, degree of processing, physical and chemical properties, application