Studies on the interaction of -epigallocatechin-3-gallate from green tea with bovine β-lactoglobulin by spectroscopic methods and docking

The binding interaction between-epigallocatechin-3-gallate (EGCG) and bovine beta-lactoglobulin (beta LG) was thoroughly studied by fluorescence, circular dichroism (CD) and proteinligand docking. Fluorescence data revealed that the fluorescence quenching of beta LG by EGCG was the result of the formation of a complex of beta LGEGCG. The binding constants and thermodynamic parameters at two different temperatures and the binding force were determined. The binding interaction between EGCG and beta LG was mainly hydrophobic and the complex was stabilised by hydrogen bonding. The results suggested that beta LG in complex with EGCG changes its native conformation. Furthermore, preheat treatment (90 degrees C, 120 degrees C) and emulsifier (sucrose fatty acid ester) all boosted the binding constants (Ka) and the binding site values (n) of the beta LG-EGCG complex. This study provided important insight into the mechanism of binding interactions of green tea flavonoids with milk protein.