Alkali-modification of carrageenans: mechanism and kinetics in the kappa/iota-, mu/nu- and lambda-series

Ciancia, Marina; Noseda, Miguel D.; Matulewicz, Marı́a C.; Cerezo, Alberto S.

doi:10.1016/0144-8617(93)90083-g

Cited by 86 publications

(47 citation statements)

References 8 publications

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“…In vivo cyclization of the mu and nu precursors is similar to what occurs in chemical processes involved in the laboratory and/or industrial alkali-extraction (Ciancia et al, 1993). However, contrary to that stated by these authors, cycling derivatives of lambda-carrageenan (e.g.…”

Section: Carrageenan Compositioncontrasting

confidence: 51%

“…In practice, the alkaline treatment used is not sufficient to promote transformation of lambda to theta-carrageenan. Industrially, most of the extracted carrageenans from Chondrus and Gigartina tetrasporophytes are mixtures of lambda and theta because, in this case, the cyclization is incomplete and slower than that which occurred during the alkali-treatment of the kappa family carrageenans (Ciancia et al, 1993;Falshaw et al, 2003).…”

Section: Carrageenan Compositionmentioning

confidence: 99%

“…The process of moderate alkaline extraction is used, at the industrial level, when cold soluble carrageenans and/or with the ability to increase the viscosity are required (Falshaw et al, 2003). The method of alkaline extraction used in this study Pereira & Mesquita, 2004) allowed for extraction of carrageenan types with a low degree of degradation (Ciancia, Noseda, Matulewicz & Cerezo, 1993) and thus with higher molecular weights. It has been confirmed that the carrageenan extraction of kappa family carrageenans, even under "soft" (low pressures and temperatures), promotes the cyclization of carrageenan precursors.…”

Section: Carrageenan Compositionmentioning

confidence: 99%

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Portuguese carrageenophytes: Carrageenan composition and geographic distribution of eight species (Gigartinales, Rhodophyta)

Pereira

Velde

2011

Carbohydrate Polymers

100

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a b s t r a c tEight carrageenophytes from the Centre and North coast of Portugal, representing seven genera and three families of Gigartinales, were studied in 15 different coastal stations in a geographic study, from Baleal (Peniche), in the central zone, to Moledo, in the northern zone.In order to characterize the different carrageenan types, 1 H NMR spectroscopy was used to identify and quantify the different carrageenan fractions in the extracted phycocolloids (both water and alkali extractions). Thereby, detailed information concerning the properties and structure of these polysaccharides at molecular level was revealed.Based on the results of the analysis of the carrageenan types, the following conclusions were made: female gametophytes and non-fertile thalli of Chondrus crispus, Mastocarpus stellatus, Chondracanthus teedei var. lusitanicus, Gigartina pistillata, Chondracanthus acicularis and Gymnogongrus crenulatus, presented a varying degrees of kappa-iota hybrid carrageenan (co-polymers of kappa-iota carrageenan). The kappa/iota ratio ranged from 0 to 2.2. The carrageenans extracted from Ahnfeltiopsis devoniensis were mainly iota-carrageenan, but some geographic variations in the composition of carrageenans were found. Calliblepharis jubata contained carrageenans of iota-type in all reproductive stages. Lambda-family carrageenans were found in tetrasporophytes of C. cripus (lambda), M. stellatus (lambda), C. teedei var. lusitanicus (hybrid xi-theta), C. acicularis (hybrid xi-theta) and G. pistillata (hybrid xi-lambda).

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Section: Carrageenan Compositioncontrasting

confidence: 51%

Section: Carrageenan Compositionmentioning

confidence: 99%

Section: Carrageenan Compositionmentioning

confidence: 99%

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Portuguese carrageenophytes: Carrageenan composition and geographic distribution of eight species (Gigartinales, Rhodophyta)

Pereira

Velde

2011

Carbohydrate Polymers

100

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“…An alkaline hydrolysis is usually applied, both in laboratory and in industrial processes, as a pre-treatment in the extraction of agar from Gracilaria to convert the L-galactose 6-sulphate into the 3,6-anhydro form, and consequently enhance their gel forming ability Craigie & Leigh,1978;Armisen & Galatas, 1987). The treatment of agar molecules with alkali at 80-95 °C eliminates, if the hydroxyl group on C-3 is free, the energetically unstable axial sulphate ester at C-6 of the L-galactopyranose unit, giving rise to the more stable 3,6-anhydro-L-galactose (Rees, 1969;Percival, 1980;Ciancia et al, 1993). The resulting change of conformation in the whole molecule is important for the formation of a three-dimensional gel network and hence for the gelling capacity of agar extracts (Norton et a, 1986;Morris, 1986).…”

Section: Sulphatesmentioning

confidence: 99%

Chemical structure and quality of agars from Gracilaria

Murano

1995

J Appl Phycol

110

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Agar polymers synthesized by species of the genus Gracilaria constitute a complex mixture of molecules, containing several extremes in structure. Sulphate hemi-esters, methyl ethers and pyruvic ketals can alter in a number of ways the structural regularity of agar based on strictly 3-O-linked /I-L-galactopyranose and 4-O-linked a-L-galactopyranose residues. In comparison with agars from Gelidium and Pterocladia, agars from Gracilaria can have higher degrees of sulphation, methoxylation and pyruvylation. The gelling ability of agars from most of Gracilaria species is considerably improved by adopting, before extraction, an alkali pretreatment which converts a-L-galactose 6 sulphate into 3,6-anhydro-a-L-galactose. Native agars obtained from Gracilaria cannot be classified, with few exceptions, as bacteriological grade agar as they have a high content of methoxyls and consequently high gelling temperatures. On the contrary, the genus Gracilaria is considered the most important source of food and sugar-reactive grade agars.Among techniques which can be used to study algal polysaccharides, combined H and 3 C nuclear magnetic resonance spectroscopy represent the most effective and powerful method for the investigation of the chemical structure of agarocolloids.

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“…The rheological aspects of the gelling or thickening properties presented by several of these polysaccharides, which are useful in food industry, have been related to the sulfate content and positioning [39,40]. Moreover, the cyclization reactions of agarans and carrageenans, which are utilized in industry to enhance gelation properties of these polymers, are also influenced by the sulfation positioning [41][42][43][44][45]. More importantly, highly sulfated red seaweed galactans have shown antiviral properties against enveloped virus, such as HSV [46 -50] and dengue virus [51][52][53].…”

mentioning

confidence: 99%

ESI-MS differential fragmentation of positional isomers of sulfated oligosaccharides derived from carrageenans and agarans

Gonçalves

Ducatti

Grindley

et al. 2010

J. Am. Soc. Mass Spectrom.

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We have prepared a number of isomeric red seaweed galactan-derivative sulfated oligosaccharides to determine whether there were diagnostic differences among the isomeric mass spectra obtained using ESI CID MS/MS (triple quadrupole instrument). Fragmentation of the single or multicharged molecular ions from di-, tetra-, and hexasaccharides indicated that the relative positioning of the sulfate groups and type of monosaccharide unit affect the rate of cleavage of the glycosidic bonds. We also performed a comparative [M-Na] Ϫ fragmentation study of positional isomers of sulfated disaccharides that present all four monosulfation possibilities on the galactopyranosidic ring. In this case, negative-ion ESI CID MS/MS approach gave diagnostic product ions from cross-ring cleavages along with the same main B 1 ion (from sulfated Galp), at m/z 241, for all isomers. The isomeric disaccharides were also submitted to increased spray energy conditions inducing in-source fragmentation; preformed B 1 ions were then fragmented to give similar product ions as those found in [M-Na] Ϫ analysis. [4,5]. It is now recognized that the regiochemistry and stereochemistry of the positions of the sulfates are highly significant for their recognition, the "sulfation code" [6,7]. Thus, the development of diverse tools for the structural determination of sulfated sugars has become extremely important. In this context, a high number of publications have been focused on the study of sulfated sugar-containing macromolecules through the mass spectrometric analysis of their enzymatically or chemically produced oligosaccharides [8 -12]. The earlier studies [13,14] [8,9], and mucopolysaccharides [24] have served as models for the improvement of the knowledge of mass spectrometric methods involving these types of molecules.Many of the aforementioned studies have been dedicated to determine the sulfation position of isomeric oligosaccharides. Evaluation of the losses of monosaccharide units by sequencing mass spectrometry is normally sufficient to determine the sulfation pattern of isomers bearing sulfate groups on different monosaccharide units [10,17]. In cases where the differences are only related to the position occupied by the sulfate groups in the same monosaccharide ring, the determination of the positional isomer is more difficult. Most of the studies carried out with this aim have been performed to determine the location and degree of sulfation for 4-and/or 6-sulfated HexNAc of chondroitin sulfate-oligosaccharides. For this purpose, control of the charge state of the parent ion followed by determination of the relative abundance of the product ions generated from the cleavage of the glycosidic linkage Address reprint requests to Dr. M. D. Noseda,

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Alkali-modification of carrageenans: mechanism and kinetics in the kappa/iota-, mu/nu- and lambda-series

Cited by 86 publications

References 8 publications

Portuguese carrageenophytes: Carrageenan composition and geographic distribution of eight species (Gigartinales, Rhodophyta)

Portuguese carrageenophytes: Carrageenan composition and geographic distribution of eight species (Gigartinales, Rhodophyta)

Chemical structure and quality of agars from Gracilaria

ESI-MS differential fragmentation of positional isomers of sulfated oligosaccharides derived from carrageenans and agarans

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