Abstract: Purpose: The objective of this research is to identify the factors affecting the formation of advanced glycation end products (AGEs) in 11S globulin-sugar model system and to shed light on the inhibitory mechanism of flavonoids on AGEs formation. Methods: Fluorescence spectrometry (λex/λem = 340 nm/465 nm) was used to detect the effects of sugar type and concentration, temperature, pH and flavonoids on the formation of AGEs, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was employed to characterize the glycation process and investigate the inhibitory effect of flavonoids. Changes in the concentrations of quercetin and products during the reaction process were determined by liquid chromatograph-tandem mass spectrometry (LC-MS/MS). Results: The reaction between 11S globulin at 2 mg/mL and fructose at 8 mg/mL at pH 9.2, 121 ℃ formed the greatest amount of fluorescent AGEs. The formation of AGEs was inhibited by all four flavonoids (quercetin, luteolin, genistein, or rutin). LC-MS/MS analysis showed that quercetin inhibited the generation of fluorescent cross-linked AGEs by trapping methylglyoxal as an intermediate of glycolysis. SDS-PAGE analysis confirmed that quercetin at 1 mmol/L significantly reduced the generation of cross-linked macromolecules but did not influence sugar modification and resulted in significant improvement of emulsifying properties. Conclusion: Application of high-molecular weight sugars, reduced sugar concentration, pH and reaction temperature, and addition of flavonoids can effectively inhibit the formation of harmful products AGEs during the glycosylation process of soybean protein.

Key words: 11S globulin, advanced glycation end products, flavonoids, protein glycosylation modification