The alleviating effects of vitamin B6 and choline on β-lactoglobulin Maillard reaction: Insight into the mechanisms via mass spectrometry and interaction analysis.

This study investigated the inhibition effects of vitamin B6 (VB6) and choline on β-lactoglobulin (β-Lg) Maillard reaction by characterizing reaction indicators, structural alterations, glycation sites, and intermolecular interactions. The results indicated that lactose-induced glycation led to a reduction in the free amino group content of β-Lg and promoted the formation of advanced glycation end products (AGEs). With VB6 and choline supplementation, the content of free amino groups increased by 1.5-fold and 0.7-fold, respectively, while the inhibition rates of AGEs reached 28.28% and 7.42%. Spectral analysis indicated that lactose-induced glycation exposed the fluorescent residues of β-Lg to a more polar environment, resulting in fluorescence quenching. The presence of VB6 further enhanced fluorescence quenching and was accompanied by a red shift of the maximum emission wavelength. In contrast, the addition of choline suppressed glycation-induced fluorescence quenching and stabilized the β-Lg structure. Furthermore, FITR analysis indicated that characteristic peaks shifted toward lower wavenumbers, accompanied by alterations in secondary structure. LC-MS/MS analysis demonstrated that VB6 and choline decreased the extent of glycation at specific sites, such as Lys75. Molecular docking revealed that VB6 and choline bound to β-Lg through hydrogen bonds and hydrophobic interactions. Restriction of Lys residues accessibility may represent a key mechanism underlying the inhibitory effects of VB6 and choline on glycation.