Colloidal dispersions of tannins in water-ethanol solutions
The molecular interactions of grape-seed tannins dissolved in water-ethanol solutions have been studied through small angle neutron scattering, light scattering, and physical separation techniques. Through selective precipitation in different solvent mixtures, three populations of tannin macromolecu...
| Veröffentlicht in: | Langmuir : the ACS journal of surfaces and colloids. - 1992. - 23(2007), 20 vom: 25. Sept., Seite 9949-59 |
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| 1. Verfasser: | |
| Weitere Verfasser: | , , , , , |
| Format: | Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2007
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| Zugriff auf das übergeordnete Werk: | Langmuir : the ACS journal of surfaces and colloids |
| Schlagworte: | Journal Article Colloids Solutions Tannins Water 059QF0KO0R Ethanol 3K9958V90M |
| Zusammenfassung: | The molecular interactions of grape-seed tannins dissolved in water-ethanol solutions have been studied through small angle neutron scattering, light scattering, and physical separation techniques. Through selective precipitation in different solvent mixtures, three populations of tannin macromolecules have been identified: T1 (2% of the total tannin), which forms colloidal particles when the ethanol content of the solvent is brought below phiA = 0.6; T2a (33% of the tannin), which phase-separates below phiA = 0.08 in ionic conditions that are typical of wine; and T2b (65% of the tannin), which remains in solution regardless of ethanol content. Each population remains molecularly dissolved (i.e., it does not form any association structures such as stacks or micelles) until the threshold where dense colloidal particles are formed through nucleation and growth. The colloidal dispersions are metastable, due to the adsorption of organic acids on the particle surfaces; increasing ionic strength and reducing ethanol content cause the loss of this metastability and the aggregation of the particles |
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| Beschreibung: | Date Completed 13.11.2007 Date Revised 21.11.2013 published: Print-Electronic Citation Status MEDLINE |
| ISSN: | 1520-5827 |