Maillard-type glycoconjugates from dairy proteins inhibit adhesion of Escherichia coli to mucin

In this study, glycoconjugates of β-lactoglobulin (β-Lg) and sodium caseinate (SC) were obtained via Maillard reaction with galactose and lactose, and their ability to inhibit the adhesion of different Escherichia coli strains (CBL2, CBM1 and CBL8) to mucin was evaluated. The strains tested exhibited different interaction patterns with the glycoconjugates, suggesting the participation of different carbohydrate-recognition sites in adhesion. Galactosylation and lactosylation of both β-Lg and SC significantly decreased the adhesion values of E. coli CBL2 to mucin. Whereas the adhesion of E. coli CBM1 was preferably interfered by galactosylated glycoconjugates obtained under the harshest incubation conditions, the adhesion capacity of E. coli CBL8 was not affected. Competitive adhesion assays with lectins, which recognise different epitopes, supported the idea that galactose-reactive adhesins are partly responsible for the recognition of these glycoconjugates. The analysis of the presence of gene coding for several virulence factors in the E. coli strains by PCR revealed the absence of K88 gene in the CBL2 strain assayed. These findings suggest that the formation of Maillard-type neoglycoproteins under controlled conditions may be a simple and cost-effective method for producing new food ingredients with the potential ability to block pathogen adhesins involved in mucosal colonisation.