Impact of Lactobacillus plantarum fermentation on the structural, physicochemical, emulsification, and digestibility properties of foxtail millet protein.

The digestibility of foxtail millet protein is greatly limited by its intrinsic structure. This study was aimed to assess the effect of fermentation on the structural, physicochemical, and digestibility properties of foxtail millet protein. Results showed that fermentation increased the porosity and roughness of protein particles, while producing small-molecule proteins and peptides. Compared with original protein, the α-helix of protein decreased by 17.34 %-36.07 % after fermentation, while the content of β-sheet increased by 28.95 %-67.94 %, indicating changes in the secondary structure of proteins. Additionally, fermentation enhanced the hydrogen bonding interactions, increased air-water and oil-water interfacial tensions, and weakened disulfide bonds and electrostatic interactions. These changes reduced the surface hydrophobicity and emulsification capacity of proteins by 1.19 %-56.32 % and 13.31 %-49.26 %, respectively. Notably, fermentation increased protein digestibility from 68.63 % to 78.55 %. Thus, fermentation has great potential as a processing technology to improve the digestive properties of foxtail millet protein.