This work was undertaken in order to study the effects of the addition of foxtail millet flour on the rheological properties of dough and the textural properties of steamed bread. The damage starch content and pasting characteristics of waxy and non-waxy foxtail millet flours with different particle sizes were analyzed using a damaged starch tester and a rapid viscosity analyzer. The rheological characteristics of doughs made from blends of wheat and foxtail millet flour were measured using a rheometer and the microstructure was observed using a scanning electron microscope (SEM). The texture characteristics of steamed breads made from wheat-foxtail millet doughs were measured using a texture analyzer. The results showed that the iodine absorption rate of damaged starch increased with decreasing millet flour particle size for most cultivars (except Jigu 39 and Huihua Jinmi). The peak viscosity, trough viscosity, final viscosity and setback value of nonwaxy millet flour were larger than those of waxy millet flour at the same particle size, depending on the ratio of amylopectin to amylose. Rheological studies showed that the storage and loss moduli generally increased with increasing angular frequency for most cultivars except Huihua Jinmi and Jigu 39. SEM observation revealed that the addition of millet flour made the dough structure looser. The addition of millet flour negatively affected the hardness, chewiness and springiness of steamed bread to a certain extent. Principal component analysis (PCA) showed that the chewiness of steamed bread and the damaged starch, peak viscosity, trough viscosity, final viscosity, disintegration value and setback value of millet flour are useful indicators to distinguish foxtail millet flours and steamed breads from waxy and non-waxy cultivars.

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.

Heat-moisture treatment (HMT) was evaluated for its effects on the antioxidant, nutritional and dough properties of different legume flours. The results showed that the contents of total phenols and flavonoids and the antioxidant capacity of adzuki bean and pea flour initially increased and then decreased with the increase in HMT time, reaching the maximum at 0.5 and 1.0 h, respectively; whereas the contents of total phenols and flavonoids of white kidney bean flour increased with HMT time up to 8.0 h. HMT had consistent effects on the scavenging activity against 2,2’-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) cation radical and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and the contents of total phenols and total flavonoids. The major fatty acids in all three legume flours were palmitic acid, stearic acid, linoleic acid, cis-11-eicosatetraenoic acid and oleic acid. HMT for 2.0 h and longer had a significant effect on the contents of oleic acid, linoleic acid and cis-11-eicosatetraenoic acid in white kidney bean flour. After HMT, the contents of free amino acids in red and white kidney bean flour decreased significantly due to its involvement in the Maillard reaction, while bound amino acids in pea flour were released, thereby increasing the amount of free amino acids. Scanning electron microscopy (SEM) showed pores in and protein adhesion on the starch granules due to protein denaturation and partial gelatinization of starch with increasing HMT time. The recrystallization of starch resulted in a decrease in peak, trough and setback viscosity, and poorer shear resistance of legume flour. The results of dough water distribution showed that the relaxation times T₂₁ and T₂₂ of adzuki bean flour increased after HMT, and the dough formation of adzuki bean flour was better than that of the other two flours. Thermomechanical analysis showed that HMT enhanced protein weakening in mixed legume-wheat flour doughs and inhibited starch retrogradation, thus improving product quality.