关键词: 黑米花色苷, β-乳球蛋白, 荧光光谱, 紫外吸收光谱, 抗氧化性, 分子对接

Abstract: In this work, we studied the interaction between black rice anthocyanin (BRA) and β-lactoglobulin (β-LG) by fluorescence spectroscopy, synchronous fluorescence spectroscopy, ultraviolet-visible spectroscopy, antioxidant capacity and molecular docking under simulated physiological conditions. The results showed that black rice anthocyanin had a strong ability to quench the fluorescence of β-lactoglobulin in a static mode. The binding constants (Ka) and site numbers (n) were obtained at different temperatures. The major interaction force was hydrophobic interaction in the binding of BRA to β-lactoglobulin based on the thermodynamic parameters. According to F.rster’s non-radiative energy transfer theory, the donor-acceptor proximity in BRA-β-LG complex was calculated as 3.14 nm. The synchronous fluorescence spectra revealed that interaction with BRA caused conformational changes in β-LG, but did not affect the microenvironment of tryptophan and tyrosine residues. Molecular docking indicated that the main driving force of the interaction between cyaniding-3-O-glucoside (the major component of black rice anthocyanin) and β-lactoglobulin was hydrophobic interaction, which was consistent with the result obtained from thermodynamic parameter analysis.

Key words: black rice anthocyanin (BRA), β-lactoglobulin (β-LG), fluorescence spectroscopy, ultraviolet spectroscopy, antioxidant capacity, molecular docking