Synergistic inhibition of advanced glycation end products and enhancement of flavor by the combination of oligomeric proanthocyanidins and glycated yeast proteins.

Abstract

The application of yeast protein (YP) in food industry is often limited by its undesirable flavor. While the Maillard reaction (MR) enhances protein flavor effectively, excessive glycation can also promote the development of advanced glycation end products (AGEs). This study elucidated the mechanism by which oligomeric proanthocyanidins (OPCs) inhibit AGE formation in glycated YP (GYP) and synergistically enhance flavor. The results showed that OPC synergistic MR reduced the content of bitter flavor in YP, changed the distribution of volatile compounds, and decreased the content of bitter amino acids. Furthermore, OPC binding dose-dependently reduced the formation of early, intermediate, and AGEs in GYP. Structural analysis revealed that OPC binding modified the secondary and tertiary structures of YP, which effectively reduced protein carbonylation, protected thiol groups, and inhibited protein aggregation, thereby contributing to the improved flavor. The anti-glycation activity of OPC was achieved by scavenging reactive free radicals (O₂-· and OH·), chelating metal ions (Fe2+), and trapping of α-Dicarbonyl compounds. Moreover, OPC has a stronger affinity for YP than glucose (Glu), and it inhibited the glycation process by competing with Glu for the occupation of glycation sites. These findings provide critical insights for developing OPC as natural anti-glycation agents to improve the flavor and safety of protein-based foods.