Agar from Gracilaria gracilis (Gracilariales, Rhodophyta) of the Patagonic coast of Argentina - Content, structure and physical properties

Milled summer thalli of Gracilaria gracilis from Argentina were sequentially extracted with water at room temperature (RTW1-3), 70 °C (W701-3) and 90 °C (W901-2). Both W701 and W901 consisted of high molecular weight polysaccharides (ca. 540,000 Da), but polydispersity was higher for the major produ...

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Autores principales:	Rodriguez, María Cecilia, Matulewicz, María Cristina, Noseda, Miguel D.
Publicado:	2009
Materias:	Agarose Cell wall Gracilaria gracilis Structure determination Sulfated galactans Biopolymers Chemical properties Colloids Debris Gelation Microscopic examination Molecular weight Nuclear magnetic resonance Nuclear magnetic resonance spectroscopy Photodegradation Polydispersity Polysaccharides Solvent extraction Walls (structural partitions) Water Extraction agar agarose hot water polysaccharide sulfate carbon isotope chemical composition extraction method methylation nuclear magnetic resonance physical property red alga starch ultrastructure article carbon nuclear magnetic resonance cell wall dispersion extraction Gracilaria gracilaria gracilis molecular weight nonhuman priority journal qualitative analysis room temperature stratification structure analysis transmission electron microscopy Agar Argentina Elasticity Hardness Molecular Weight Viscosity Gracilariales Rhodophyta
Acceso en línea:	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_09608524_v100_n3_p1435_Rodriguez http://hdl.handle.net/20.500.12110/paper_09608524_v100_n3_p1435_Rodriguez
Aporte de:	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires

id	paper:paper_09608524_v100_n3_p1435_Rodriguez
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spelling	paper:paper_09608524_v100_n3_p1435_Rodriguez2023-06-08T15:57:44Z Agar from Gracilaria gracilis (Gracilariales, Rhodophyta) of the Patagonic coast of Argentina - Content, structure and physical properties Rodriguez, María Cecilia Matulewicz, María Cristina Noseda, Miguel D. Agarose Cell wall Gracilaria gracilis Structure determination Sulfated galactans Biopolymers Chemical properties Colloids Debris Gelation Microscopic examination Molecular weight Nuclear magnetic resonance Nuclear magnetic resonance spectroscopy Photodegradation Polydispersity Polysaccharides Solvent extraction Walls (structural partitions) Water Agarose Cell wall Gracilaria gracilis Structure determination Sulfated galactans Extraction agar agarose hot water polysaccharide sulfate agar carbon isotope chemical composition extraction method methylation nuclear magnetic resonance physical property red alga starch ultrastructure article carbon nuclear magnetic resonance cell wall chemical composition dispersion extraction Gracilaria gracilaria gracilis methylation molecular weight nonhuman priority journal qualitative analysis room temperature stratification structure analysis transmission electron microscopy ultrastructure Agar Argentina Elasticity Gracilaria Hardness Molecular Weight Viscosity Gracilaria gracilis Gracilariales Rhodophyta Milled summer thalli of Gracilaria gracilis from Argentina were sequentially extracted with water at room temperature (RTW1-3), 70 °C (W701-3) and 90 °C (W901-2). Both W701 and W901 consisted of high molecular weight polysaccharides (ca. 540,000 Da), but polydispersity was higher for the major product W701 (yield, 72% of the recovered). Structural analyzes by methylation and 13C NMR spectroscopy revealed that W701 was mainly agarose. Alkaline treatment, together with structural analyzes, indicated a negligible proportion of precursor l-galactose 6-sulfate residues in this product, while they were clearly detected in the 13C NMR spectra of RTW2-3. The presence of floridean starch in W901 had an antagonistic effect on its gel strength, which resulted nearly three times lower than that of fraction W701. Ultrastructural observation by transmission electron microscopy showed that, after extraction with hot water, a partial loss of cell wall stratification and disorganization of the cuticle had occurred. Final cellular debris exhibited swelling in the microfibrillar component. After this first thorough study of the chemical composition and physical properties of the products of G. gracilis from Bahía Bustamante we conclude that a good quality agarose is obtained in high yield after extraction with water at 70 °C without the requirement of alkaline pretreatment, which usually produces degradation of the polysaccharide. © 2008 Elsevier Ltd. All rights reserved. Fil:Rodríguez, M.C. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Matulewicz, M.C. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Noseda, M.D. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2009 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_09608524_v100_n3_p1435_Rodriguez http://hdl.handle.net/20.500.12110/paper_09608524_v100_n3_p1435_Rodriguez
institution	Universidad de Buenos Aires
institution_str	I-28
repository_str	R-134
collection	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic	Agarose Cell wall Gracilaria gracilis Structure determination Sulfated galactans Biopolymers Chemical properties Colloids Debris Gelation Microscopic examination Molecular weight Nuclear magnetic resonance Nuclear magnetic resonance spectroscopy Photodegradation Polydispersity Polysaccharides Solvent extraction Walls (structural partitions) Water Agarose Cell wall Gracilaria gracilis Structure determination Sulfated galactans Extraction agar agarose hot water polysaccharide sulfate agar carbon isotope chemical composition extraction method methylation nuclear magnetic resonance physical property red alga starch ultrastructure article carbon nuclear magnetic resonance cell wall chemical composition dispersion extraction Gracilaria gracilaria gracilis methylation molecular weight nonhuman priority journal qualitative analysis room temperature stratification structure analysis transmission electron microscopy ultrastructure Agar Argentina Elasticity Gracilaria Hardness Molecular Weight Viscosity Gracilaria gracilis Gracilariales Rhodophyta
spellingShingle	Agarose Cell wall Gracilaria gracilis Structure determination Sulfated galactans Biopolymers Chemical properties Colloids Debris Gelation Microscopic examination Molecular weight Nuclear magnetic resonance Nuclear magnetic resonance spectroscopy Photodegradation Polydispersity Polysaccharides Solvent extraction Walls (structural partitions) Water Agarose Cell wall Gracilaria gracilis Structure determination Sulfated galactans Extraction agar agarose hot water polysaccharide sulfate agar carbon isotope chemical composition extraction method methylation nuclear magnetic resonance physical property red alga starch ultrastructure article carbon nuclear magnetic resonance cell wall chemical composition dispersion extraction Gracilaria gracilaria gracilis methylation molecular weight nonhuman priority journal qualitative analysis room temperature stratification structure analysis transmission electron microscopy ultrastructure Agar Argentina Elasticity Gracilaria Hardness Molecular Weight Viscosity Gracilaria gracilis Gracilariales Rhodophyta Rodriguez, María Cecilia Matulewicz, María Cristina Noseda, Miguel D. Agar from Gracilaria gracilis (Gracilariales, Rhodophyta) of the Patagonic coast of Argentina - Content, structure and physical properties
topic_facet	Agarose Cell wall Gracilaria gracilis Structure determination Sulfated galactans Biopolymers Chemical properties Colloids Debris Gelation Microscopic examination Molecular weight Nuclear magnetic resonance Nuclear magnetic resonance spectroscopy Photodegradation Polydispersity Polysaccharides Solvent extraction Walls (structural partitions) Water Agarose Cell wall Gracilaria gracilis Structure determination Sulfated galactans Extraction agar agarose hot water polysaccharide sulfate agar carbon isotope chemical composition extraction method methylation nuclear magnetic resonance physical property red alga starch ultrastructure article carbon nuclear magnetic resonance cell wall chemical composition dispersion extraction Gracilaria gracilaria gracilis methylation molecular weight nonhuman priority journal qualitative analysis room temperature stratification structure analysis transmission electron microscopy ultrastructure Agar Argentina Elasticity Gracilaria Hardness Molecular Weight Viscosity Gracilaria gracilis Gracilariales Rhodophyta
description	Milled summer thalli of Gracilaria gracilis from Argentina were sequentially extracted with water at room temperature (RTW1-3), 70 °C (W701-3) and 90 °C (W901-2). Both W701 and W901 consisted of high molecular weight polysaccharides (ca. 540,000 Da), but polydispersity was higher for the major product W701 (yield, 72% of the recovered). Structural analyzes by methylation and 13C NMR spectroscopy revealed that W701 was mainly agarose. Alkaline treatment, together with structural analyzes, indicated a negligible proportion of precursor l-galactose 6-sulfate residues in this product, while they were clearly detected in the 13C NMR spectra of RTW2-3. The presence of floridean starch in W901 had an antagonistic effect on its gel strength, which resulted nearly three times lower than that of fraction W701. Ultrastructural observation by transmission electron microscopy showed that, after extraction with hot water, a partial loss of cell wall stratification and disorganization of the cuticle had occurred. Final cellular debris exhibited swelling in the microfibrillar component. After this first thorough study of the chemical composition and physical properties of the products of G. gracilis from Bahía Bustamante we conclude that a good quality agarose is obtained in high yield after extraction with water at 70 °C without the requirement of alkaline pretreatment, which usually produces degradation of the polysaccharide. © 2008 Elsevier Ltd. All rights reserved.
author	Rodriguez, María Cecilia Matulewicz, María Cristina Noseda, Miguel D.
author_facet	Rodriguez, María Cecilia Matulewicz, María Cristina Noseda, Miguel D.
author_sort	Rodriguez, María Cecilia
title	Agar from Gracilaria gracilis (Gracilariales, Rhodophyta) of the Patagonic coast of Argentina - Content, structure and physical properties
title_short	Agar from Gracilaria gracilis (Gracilariales, Rhodophyta) of the Patagonic coast of Argentina - Content, structure and physical properties
title_full	Agar from Gracilaria gracilis (Gracilariales, Rhodophyta) of the Patagonic coast of Argentina - Content, structure and physical properties
title_fullStr	Agar from Gracilaria gracilis (Gracilariales, Rhodophyta) of the Patagonic coast of Argentina - Content, structure and physical properties
title_full_unstemmed	Agar from Gracilaria gracilis (Gracilariales, Rhodophyta) of the Patagonic coast of Argentina - Content, structure and physical properties
title_sort	agar from gracilaria gracilis (gracilariales, rhodophyta) of the patagonic coast of argentina - content, structure and physical properties
publishDate	2009
url	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_09608524_v100_n3_p1435_Rodriguez http://hdl.handle.net/20.500.12110/paper_09608524_v100_n3_p1435_Rodriguez
work_keys_str_mv	AT rodriguezmariacecilia agarfromgracilariagracilisgracilarialesrhodophytaofthepatagoniccoastofargentinacontentstructureandphysicalproperties AT matulewiczmariacristina agarfromgracilariagracilisgracilarialesrhodophytaofthepatagoniccoastofargentinacontentstructureandphysicalproperties AT nosedamigueld agarfromgracilariagracilisgracilarialesrhodophytaofthepatagoniccoastofargentinacontentstructureandphysicalproperties
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Agar from Gracilaria gracilis (Gracilariales, Rhodophyta) of the Patagonic coast of Argentina - Content, structure and physical properties

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