Extraction and physicochemical characterization of Sargassum vulgare alginate from Brazil
Alginate fractions from Sargassum vulgare brown seaweed were characterized by 1 H NMR and fluorescence spectroscopy and by rheological measurements. The alginate extraction conditions were investigated. In order to carry out the structural and physicochemical characterization, samples extracted for...
| Autores: | , , , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2007 |
| País: | Brasil |
| Institución: | Universidade Federal do Ceará (UFC) |
| Repositorio: | Repositório Institucional da Universidade Federal do Ceará (UFC) |
| Idioma: | portugués |
| OAI Identifier: | oai:repositorio.ufc.br:riufc/5606 |
| Acceso en línea: | http://www.repositorio.ufc.br/handle/riufc/5606 |
| Access Level: | acceso abierto |
| Palabra clave: | Feófitas Espectroscopia de Ressonância Magnética |
| Sumario: | Alginate fractions from Sargassum vulgare brown seaweed were characterized by 1 H NMR and fluorescence spectroscopy and by rheological measurements. The alginate extraction conditions were investigated. In order to carry out the structural and physicochemical characterization, samples extracted for 1 and 5 h at 60 C were further purified by re-precipitation with eth- anol and denoted as SVLV ( S. vulgare low viscosity) and SVHV ( S. vulgare high viscosity), respectively. The M/G ratio values for SVLV and SVHV were 1.56 and 1.27, respectively, higher than the ratio for most Sargassum spp. alginates (0.19–0.82). The homopolymeric blocks F GG and F MM of these fractions characterized by 1 H NMR spectroscopy were 0.43 and 0.55 for SVHV and 0.36 and 0.58 for SVLV samples, respectively, these values typically being within 0.28–0.77 and 0.07–0.41, respectively. There- fore, the alginate samples from S. vulgare are much richer in mannuronic block structures than those from other Sargassum species. Values of M w for alginate samples were also calculated using intrinsic viscosity data. The M w value for SVLV (1.94 · 10 5 g/mol) was lower than that for SVHV (3.3 · 10 5 g/mol). Newtonian behavior was observed for a solution concentration as high as 0.7% for SVLV, while for SVHV the solutions behaved as a Newtonian fluid up to 0.5%. The optimal conditions for obtaining the alginates from S. vulgare were 60 C and 5 h extraction. Under these conditions, a more viscous alginate in higher yield was extracted from the seaweed biomass |
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