In order to improve the added value of foxtail millet and the processing quality of foxtail millet noodles, the effect of different periods (0.5, 1, 2, 4, 6, and 8 h) of ball milling on the nutritional components, hydration properties, gelatinization properties, rheological properties and crystalline structure of foxtail millet flour and the quality of the resulting noodles was investigated. The correlation between some physicochemical properties and noodle quality was analyzed. The results showed that the crystalline structure of foxtail millet flour was damaged obviously, and the damaged starch content increased significantly with an increase in milling time. It was also found that the amylose content decreased continuously (except for 8 h), and the L* value rose from 77.27 to 81.37. The peak viscosity, trough viscosity, and final viscosity of foxtail millet flour increased from 1478, 665 and 1384 Pa·s to 3271 (ball milling 1 h), 982 (ball milling 2 h) and 2199 (ball milling 2 h) Pa·s (P < 0.05), respectively, and the hydration properties (water-holding capacity and swelling capacity) improved (P < 0.05). Ball milling for 4 h made the gel network structure of dough more compact and resulted in noodles with the best texture and cooking quality. Correlation analysis showed that noodle texture properties (elasticity, stickiness and chewiness) and sensory quality (color, appearance and stickiness) were significantly negatively correlated with amylose content (P < 0.01), but significantly positively correlated with damaged starch and amylopectin contents (P < 0.01). The cooking quality (breakage rate) of noodles was positively correlated with amylose content (P < 0.01), but significantly negatively correlated with damaged starch and amylopectin contents (P < 0.01) and gelatinization viscosity was also strongly correlated with noodle quality. Taken together, the modification of foxtail millet flour by ball milling can be used to produce high-quality foxtail millet noodles.

Millet bran with different degrees of milling was used as raw materials, the differences in nutritional composition, physicochemical properties, and volatile components of different foxtail millet bran fractions were explored by measuring nutritional composition, water distribution, hydration characteristics, chromaticity, gelatinization characteristics, and volatile components. The results showed there were significant differences in content of fat, protein, ash, starch, and water among the four types of foxtail millet bran (S1–S4). S3 millet bran contained 10.96% protein and 26.05% fat, with the highest nutritional value. Meanwhile, S3 millet bran had excellent characteristics such as strong fluidity, strong foaming ability (5.54%), and high stability (82.86%), but high content of water and oil were not conducive to the storage of S3 millet bran. Correlation analysis shows that starch and protein directly affected the processing properties of millet bran (hydration characteristics, foaming properties, etc.). In addition, 72, 47, 70, and 51 volatile substances were detected in the four types of millet bran (S1–S4), respectively. There were 10 different volatile substances in 4 types of millet bran. Six compounds including methyl hexanoate, hexanal, and methyl palmitic acid had the highest content in S1 millet bran, and the other 4 compounds including dodecane and n-hexanol had the highest content in S2 millet bran. The odor activity value (OAV) of nonanal in four types of millet bran was 702, 444, 110, and 51, respectively, which could be used to effectively distinguish these foxtail millet bran fractions. This study is conducive to the precision separation process and selective use, which can maximize the utilization of resources.