Résumé
Mannoproteins are an important group of carbohydrate macromolecules in wines. Numerous functional properties are attributed to these bio-copolymers which are related to the stability and sensory characteristics of wines. However, neither the exact mechanisms involved in these properties nor the impact of mannoprotein structural characteristics are well known. Focusing on mannoproteins property of modulating astringency, the objective of this work was to evaluate mannoproteins capacity to affect tannin-protein interactions and/or the consequent particle formation. In the mouth, tannin interactions with salivary proteins are associated to the puckering sensation and the lost of lubricity; characteristic of the astringent mouth-feel5. Mannoproteins differing in their polysaccharide structure were employed to also elucidate the impact of particular features of the generic polysaccharide structure of mannoproteins (mannosyl-phosphorylation and molecular compactness). They were extracted through an specific and exclusive enzymatic activity, purified and thoroughly characterized to preserve to uttermost extent the native structure of the macromolecule.