title: Analysis of two bentonites of enological interest before and after commercial activation by solid Na(2)CO(3).
abstract: Two natural calcium-rich bentonites used for the removal of wine proteins, originating from Greece and Turkey, were studied by X-ray diffraction, thermal analysis, and solid state NMR, before and after activation by solid Na(2)CO(3). Exchange of Ca(2+) by Na(+) mainly occurs for cations located at the edge of layers and only weakly for interlayer cations. This Na(2)CO(3) activation process leads to an increased efficiency in the adsorption process of bovine serum albumin (BSA) used as a model protein for both bentonites. A direct correlation is observed between the extent of Ca(2+)/Na(+) exchange, the strength of adsorption of BSA, and the extent of unfolding of BSA backbone.
authors.affiliation: Laboratoire d'Oenologie, URVVC UPRES EA 2069, Université de Reims, Faculté des Sciences, Moulin de la Housse, B.P. 1039, 51687 Reims Cedex 2, France.
authors.forename: Régis D
authors.initials: RD
authors.lastname: Gougeon
authors.forename: Michel
authors.initials: M
authors.lastname: Soulard
authors.forename: Jocelyne
authors.initials: J
authors.lastname: Miehé-Brendlé
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Chézeau
authors.forename: Ronan
authors.initials: R
authors.lastname: Le Dred
authors.forename: Philippe
authors.initials: P
authors.lastname: Jeandet
authors.forename: Richard
authors.initials: R
authors.lastname: Marchal
mesh_terms: D000327:Adsorption; D001546:Bentonite / Q000737:chemistry*; D002118:Calcium / Q000032:analysis; D002254:Carbonates / Q000494:pharmacology*; D005524:Food Technology; D009682:Magnetic Resonance Spectroscopy; D012710:Serum Albumin, Bovine / Q000737:chemistry; D014920:Wine; D014961:X-Ray Diffraction
chemical_list: D002254:Carbonates; D001546:Bentonite; D012710:Serum Albumin, Bovine; C005686:sodium carbonate; D002118:Calcium