title: Influence of wine pectic polysaccharides on the interactions between condensed tannins and salivary proteins.
abstract: Alpha-amylase, a major human salivary protein, and IB8c, a representative of the proline-rich proteins, were obtained by isolation from saliva and by solid-phase synthesis, respectively. The interactions between these proteins and condensed tannins isolated from grape seeds were studied at different protein and tannin concentrations by measuring their aggregation. Pectic polysaccharides were isolated from wine, and their effect on protein tannin aggregation was assessed. The results presented in this study showed that the most acidic fractions of arabinogalactan proteins have the ability to inhibit the formation of aggregates between the grape seed tannins and the two different salivary proteins. Rhamnogalacturonan II has the same ability toward alpha-amylase but not IB8c under the conditions of the present study. Polysaccharides show effects at concentrations at which they are present in wine, which could mean an influence in wine astringency. The interaction between condensed tannins and alpha-amylase is differently affected by ionic strength when compared with IB8c.
authors.affiliation: Centro de Investigação em Química, Universidade do Porto, Faculdade de Ciências, Departamento de Química, Rua do Campo Alegre 687, 4169-007 Porto, Portugal.
authors.forename: Elisabete
authors.initials: E
authors.lastname: Carvalho
authors.forename: Nuno
authors.initials: N
authors.lastname: Mateus
authors.forename: Benoit
authors.initials: B
authors.lastname: Plet
authors.forename: Isabelle
authors.initials: I
authors.lastname: Pianet
authors.forename: Erick
authors.initials: E
authors.lastname: Dufourc
authors.forename: Victor
authors.initials: V
authors.lastname: De Freitas
mesh_terms: D000595:Amino Acid Sequence; D008027:Light; D008969:Molecular Sequence Data; D010368:Pectins / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry; D011134:Polysaccharides / Q000737:chemistry*; D055232:Proline-Rich Protein Domains; D012471:Salivary Proteins and Peptides / Q000737:chemistry*; D012542:Scattering, Radiation; D012639:Seeds / Q000737:chemistry; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013634:Tannins / Q000737:chemistry*; D027843:Vitis / Q000737:chemistry; D014920:Wine; D000516:alpha-Amylases / Q000737:chemistry*
chemical_list: D010455:Peptides; D011134:Polysaccharides; D012471:Salivary Proteins and Peptides; D013634:Tannins; D010368:Pectins; D000516:alpha-Amylases