Mechanisms of astringency: Structural alteration of the oral mucosal pellicle by dietary tannins and protective effect of bPRPs
Résumé
The interaction of tannins with salivary proteins is involved in astringency. This paper focussed on saliva lining
oral mucosae, the mucosal pellicle. Using a cell-based model, the impact of two dietary tannins (EgC and EgCG)
on the mucosal pellicle structure and properties was investigated by microscopic techniques. The role of basic
Proline-Rich-Proteins (bPRPs) in protecting the mucosal pellicle was also evaluated.
At low (0.05 mM) tannin concentration, below the sensory detection threshold, the distribution of salivary
mucins MUC5B on cells remained unaffected. At 0.5 and 1 mM, MUC5B-tannin aggregates were observed and
their size increased with tannin concentration and with galloylation. In addition, 3mM EgCG resulted in higher
friction forces measured by AFM. In presence of bPRPs, the size distribution of aggregates was greatly modified
and tended to resemble that of the “no tannin” condition, highlighting that bPRPs have a protective effect
against the structural alteration induced by dietary tannins.
