Molecular Origin of Thermal Stability of Rhamsan Gum in Aqueous Media

Tako, Masakuni

doi:10.1271/bbb.57.1182

Cited by 24 publications

(32 citation statements)

References 8 publications

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“…We proposed possible intramolecular associations for welan (Scheme 2) [51], rhamsan (Scheme 3) [52] [53], and S-657 (Scheme 4) [54], the structures of which are similar to that of gellan gum with the following exceptions; substitution at O-3 of every D-glucosyl residue next to the D-glucuronosyl residue by either α-L-rhamnosyl or α-L-mannosyl side-chains in a 2:1 ratio for welan [55], substitution at C-6 of every D-glucosyl residue next to the L-rhamnosyl residue by α-D-glucosyl disaccharide side-chains for rhamsan Scheme 1. Gelation mechanism of deacetylated gellan gum in aqueous solution.…”

Section: Introductionmentioning

confidence: 99%

Structure-Function Relationship of a Gellan Family of Polysaccharide, S-198 Gum, Produced by Alcaligenes ATCC31853

Tako¹,

Kitajima²,

Yogi³

et al. 2016

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The structure-function relationship of a gellan family of polysaccharides, S-198 gum produced by Alcaligenes ATCC31853 was investigated in terms of rheological aspects. The flow curves of S-198 gum showed plastic behavior above 0.3%. Gelation did not occur in S-198 gum solution at low temperature (0˚C), even at 0.8%. Both the viscosity and the elastic modulus remained constant with increasing temperature up to 80˚C. The elastic modulus decreased a little with the addition of CaCl2 (6.8 mM), but then once again remained constant up to 80˚C. The highest elastic modulus was observed for deacylated gellan gum with the addition of CaCl 2 and increased slightly with increasing temperature up to 80˚C, which was considered to be a transition temperature, after which it decreased rapidly. The elastic modulus of S-198 gum in the presence of urea (4.0 M) was lower than that in aqueous solution at low temperature (0˚C), but remained constant with increasing temperature up to 80˚C. The intramolecular associations, (hydrogen bonding and van der Waals forces of attraction), of S-198 gum molecules in aqueous solutions were proposed. The gellan family of polysaccharides, S-198, S-88, S-657, rhamsan, welan and gellan gum, provided a good opportunity to investigate the structure-function relationship for polysaccharides.

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Section: Introductionmentioning

confidence: 99%

Structure-Function Relationship of a Gellan Family of Polysaccharide, S-198 Gum, Produced by Alcaligenes ATCC31853

Tako¹,

Kitajima²,

Yogi³

et al. 2016

ABC

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“…The L-rhamnosyl residue plays a dominant role in gel-formation and thermostable processes in native [19] and deacylated [7] gellan gum, and native [30] and deacetylated rhamsan [18] gum solutions. Although the methyl groups of the L-rhamnosyl residues co-exist in 1 C 4 and 4 C 1 pyranose-ring conformations in native gellan and rhamsan gum molecules, resulting in soft-gel formation or thermal stability, they showed stiff and brittle gels on deacylation or deacetylation by treatment with a 0.2 M NaOH solution, where almost all of the L-rhamnosyl residues existed the 4 C 1 pyranose-ring conformation [7,18,19].…”

Section: Discussionmentioning

confidence: 99%

“…The transition temperature is the temperature above which the secondary association dissociates. The results indicate that rhamnan sulfate molecules have a thermostable characteristic in aqueous solution as in gellan family of polysaccharides [29][30][31][32][33].…”

Section: Elastic Modulusmentioning

confidence: 90%

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Structure-Function Relationship of Rhamnan Sulfate Isolated from Commercially Cultured Edible Green Seaweed, <i>Monostroma nitidum</i>

Tako¹

2017

AJAC

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Abstract:The green seaweed, Monostroma nitidum, is widespread in Japan. In Okinawa Prefecture, production of seaweed is performed using culture-nets that are seeded artificially. The annual production of the algae in Okinawa was approximately 100t in 2016. Recently, because Monostroma nitidum is used in salads, soups and other items, its utilization in the food industry increased. The algae contain a soluble polysaccharide, rhamnan sulfate. To estimate the applicability of a rhamnan sulfate as a food additive or non-food additives, we investigated the rheological properties of the polymer that was isolated from commercially cultured Monostroma nitidum using a rheogoniometer. A soft gelation occurred at a concentration of 4.0%, and the elastic modulus stayed at a constant value after the temperature to 50°C, which was estimated to be a transition temperature, then decreased rapidly with further increase in temperature. Although a small decrease in elastic modulus was observed with the addition of urea (4.0 M), it remained constant with an increase in temperature up to 60°C, and then decreased. An increase in the elastic modulus was observed in a 0.05 M NaOH solution and soft gelation occurred. The elastic modulus remained large during the increase in temperature even at 90°C. A soft gelation also occurred when rhamnan sulfate was dissolved in a Tris buffer (pH 8.0) solution. The possible mode of intra-and intermolecular associations within and between rhamnan sulfate molecules were discussed.

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“…Xanthan gum 15 28) Gellan gum 29,30) Welan gum 31,32) Rhamsan gum 33,34) The κ + form. , κ carrageenan alone; , with addition of KCl; _, with addition of NaCl.…”

Section: Bacterial Polysaccharidesmentioning

confidence: 99%

Studies on the Gelation Mechanism of Polysaccharides, and Development and Application of Fucoidan from Commercially Cultured Cladosiphon okamuranus

Tako¹

2009

J. Appl. Glycosci.

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The structure-function relationship of the polysaccharides from the view point of the rheological characteristics in aqueous solutions has been insighted into when I was listening to the first movement of the piano sonata No. 14, Op. 27 2, entitled Moon-light which was composed by Ludwig van Beethoven on July in 1973. At that time, I was a doctoral student at the Department of Food Science and Technology, Kyushu University. After getting job at the University of the Ryukyus in 1982, it has been investigated. Gelation mechanism for κ-carrageenan, ι-carrageenan, agarose (agar), gellan gum, alginic acid, curdlan and amylose has been analyzed, respectively, at the molecular level where sulfate oxygen, ring oxygen, hemiacetal oxygen, cations, hydroxyl groups oriented at axial, and methyl groups take part in the intra-and intermolecular associations with ionic bonding, electrostatic forces of attraction, hydrogen bonding and van der Waals forces of attraction. Co-gelation mechanism of xanthan with galactomannan (locust bean gum, tara bean gum, guar gum and Leucaena galactomannan), and with konjac glucomannan, where trisaccharide side-chains of the former molecules contribute with hydrogen bonding has also been analyzed, respectively. The structure-function relationship for non-gelling welan, rhamsan, S-657, S-88, S-198, shizophyllan and amylopectins (rice, potato and wheat), the structure of which is similar to that of gelling gellan, curdlan and amylose has been analyzed. The gellan family of the polysaccharides, as metioned above, have given a good opportunity to investigate the molecular origin for their rheological characteristics. Recently, we have analyzed a gelatinization and retrogradation mechanisms of rice, potato and wheat starches. From the results and discussions, the principles of the polysaccharide gels have been established. Though many investigations concerning the gelling properties of the polysaccharides have been done to discuss structure-function relationship, no one has established gelation mechanisms at the molecular level except the author. There is reasonable consistency in our investigations. Thus, rheological analysis is one of the most significant methods to realize the structure-function relationships of polysaccharides in aqueous solutions. We have isolated a novel fucoidan, which substituted an acetyl group, from commercially cultured Cladosiphon okamuranus in Okinawa, Japan and has been covered by a patent. The fucoidan has an excellent flow characteristics and immunological activity. The fucoidan has now been used in food and cosmetic industries, production of which increases year by year.

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Molecular Origin of Thermal Stability of Rhamsan Gum in Aqueous Media

Cited by 24 publications

References 8 publications

Structure-Function Relationship of a Gellan Family of Polysaccharide, S-198 Gum, Produced by Alcaligenes ATCC31853

Structure-Function Relationship of a Gellan Family of Polysaccharide, S-198 Gum, Produced by Alcaligenes ATCC31853

Structure-Function Relationship of Rhamnan Sulfate Isolated from Commercially Cultured Edible Green Seaweed, <i>Monostroma nitidum</i>

Studies on the Gelation Mechanism of Polysaccharides, and Development and Application of Fucoidan from Commercially Cultured Cladosiphon okamuranus

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Molecular Origin of Thermal Stability of Rhamsan Gum in Aqueous Media

Cited by 24 publications

References 8 publications

Structure-Function Relationship of a Gellan Family of Polysaccharide, S-198 Gum, Produced by Alcaligenes ATCC31853

Structure-Function Relationship of a Gellan Family of Polysaccharide, S-198 Gum, Produced by Alcaligenes ATCC31853

Structure-Function Relationship of Rhamnan Sulfate Isolated from Commercially Cultured Edible Green Seaweed, &lt;i&gt;Monostroma nitidum&lt;/i&gt;

Studies on the Gelation Mechanism of Polysaccharides, and Development and Application of Fucoidan from Commercially Cultured Cladosiphon okamuranus

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Structure-Function Relationship of Rhamnan Sulfate Isolated from Commercially Cultured Edible Green Seaweed, <i>Monostroma nitidum</i>