• 食品化学 •

### 大豆分离蛋白与染料木素共价交联对蛋白表征和结构的影响

1. （1.吉林农业大学食品科学与工程学院，吉林 长春 130118；2.吉林农业大学 国家大豆产业技术体系加工研究室，吉林 长春 130118）
• 发布日期:2022-07-01

### Effect of Covalent Crosslinking of Soybean Protein Isolate with Genistein on Protein Characterization and Structure

LÜ Siyao, ZHU Dengzhao, BAO Yunxiang, ZHANG Debin, YU Hansong, GU Chunmei

1. (1. School of Food Science and Engineering, Jilin Agricultural University, Changchun 130118, China; 2. Processing Laboratory, National Soybean Industrial Technology System, Jilin Agricultural University, Changchun 130118, China)
• Published:2022-07-01

Abstract: In order to explore the effects covalent crosslinking between soybean protein isolate (SPI) and genistein on protein characterization and structure, covalent complexes between SPI and genistein, prepared by adding different concentrations (0, 1.2, 1.5 and 2.0 mg/mL) of genistein to SPI solution, were characterized by measuring particle size, zeta potential, turbidity and surface hydrophobicity, and the structural changes of SPI were analyzed by using an ultraviolet spectrophotometer, a fluorescence spectrophotometer and a Fourier transform infrared spectrometer. The results showed that the median particle size of SPI declined from 135.6 to a minimum value of 98.0 μm, the absolute value of zeta potential increased from 15.0 mV to a maximum value of 21.4 mV, the surface hydrophobicity decreased from 216.0 to a minimum value of 115.5, and the total sulfhydryl group content decreased from 31.5 μmol/g to a minimum value of 20.4 μmol/g after covalent complexation with genistein. Compared with the control group, the turbidity of the covalent complexes increased, and the turbidity of the SPI-Ge-1.2 complex was lower than that of the SPI-Ge-1.5 and SPI-Ge-2.0 complexes. Spectral analysis showed that genistein had a quenching effect on SPI. After covalent cross-linking, the hydrophobicity of the microenvironments of tryptophan and tyrosine residues in SPI decreased, the contents of α-helix and β-turn increased, and the contents of β-sheet and random coil decreased. The addition of 1.2 mg/mL genistein had a better effect on the characterization and structure of SPI. The results indicated that the covalent cross-linking of genistein with SPI can affect the characterization and structure of the protein.