In this paper, common millet protein (MP) was used as a control, and the physical and chemical properties, functional properties and structure of selenium-enriched millet protein (SMP) were analyzed by SDS-PAGE, Fourier infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), solubility (PS), water holding capacity (WA), and emulsification capability (EC). Results showed that the selenium contents of MP and SMP were 0.08 mg/kg and 0.63 mg/kg. The essential amino acid (EAA) content of MP and SMP accounted for 51.101% and 53.529% of the total amino acid content. The ratios of EAA to non-essential amino acids (NEAA) in MP and SMP were 1.045 and 1.152, respectively. Molecular weights of both millet proteins were distributed in the range of 10 kDa to 70.2 kDa. With the increase of pH, PS, WA, froth capability (FC), froth stability (FS), and EC of millet protein showed a trend of decreasing first and then increasing, while the emulsion stability (ES) was the opposite. PS, WA, oil-holding property (FA), FC, FS, EC, and ES of millet protein showed a trend of increasing first and then decreasing with the increasing temperature (P<0.05). SEM showed irregular bumps on the surface of MP, while the surface of SMP was smooth and flat. FT-IR showed that the peak patterns of the two millet proteins were the same, with the position of SMP slightly shifted back.Meanwhile, the α-helix, β-folding, and β-turning angle contents of SMP were 5.532, 2.885, and 5.506 percentage points higher than those of MP respectively, while the irregular curl content was lower than that of MP, indicating that the structural order of SMP was better than that of MP. The results of the study provide an important theoretical basis for the development and utilization of SMP products.
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