EP0134649A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Gel-forming polysaccharides
Assignee: National Research Development Corp UK
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Filing: 1984-07-03
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Granted: —
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Expires: 2004-07-03
Abstract
Abstract The invention provides a polysaccharide which undergoes cation-induced gelation to form gels of useful strength at relatively low concentration of cation, and which melt and set sharply and reversibly. It has a marked preference in terms of gel strength for cations of sodium rather than other group la elements and calcium rather than other Group Ila elements. It contains D-glucose, L-fucose and D-glucuronate residues in the approximate molar ratio of 3:1:1. The polysaccharide can be isolated from the bacterium NCIB 11870. Its gels are useful in food and medicine for addition to a variety of foodstuffs and pharmaceuticals. They can be prepared simply by adding the appropriate cations to a dilute aqueous solution of the polymer at ambient temperature, whereupon the gel forms rapidly. If desired the gel initially formed can be melted and re-set.
Inventors
- 👤 Ian Wishart Sutherland
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 05:30
CPC Classifications
C; C12; C12N; C12N1/00; C12N1/20; C12N1/205; C12P; C12P19/00; C12P19/04; C12R; C12R2001/00; C12R2001/01
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
206 words
A polysaccharide characterised in that (1) it contains D-glucose, L-fucose and D-glucuronate residues in the approximate molar ratio of 3:1:1; (2) when oxidised by periodate it gives a product containing some only of the D-glucose residues of the unoxidised polymer, substantially all the L-fucose residues of the unoxidised polymer and substantially no D-glucuronate; (3) it forms gels when cations of at least any one of the elements lithium, sodium, potassium, rubidium and caesium of Group Ia of the Periodic Table and magnesium, calcium, strontium and barium of Group IIa of the Periodic Table are added to an aqueous solution of the polymer; (4) the gels thus formed melt on heating and set on cooling reversibly; (5) the strength of the gels increases with increasing concentration of the polymer in aqueous solution; (6) the polymer forms stronger gels with Group Ia and IIa cations of a particular ionic radius than with other Group Ia and IIa cations; and (7) the polymer is obtainable by isolation from the bacterium NCIB 11870 deposited as a patent deposit at the National Collection of Industrial Bacteria, Torry Research Station, P 0 Box 31, 135 Abbey Road, Aberdeen, Scotland AB9 8DG on 10 June 1983 or from a variant or mutant thereof.
Claim 2
Dependent Claim
206 words
A polysaccharide characterised in that (1) it contains D-glucose, L-fucose and D-glucuronate residues in the approximate molar ratio of 3:1:1; (2) when oxidised by periodate it gives a product containing some only of the D-glucose residues of the unoxidised polymer, substantially all the L-fucose residues of the unoxidised polymer and substantially no D-glucuronate; (3) it forms gels when cations of at least any one of the elements lithium, sodium, potassium, rubidium and caesium of Group Ia of the Periodic Table and magnesium, calcium, strontium and barium of Group IIa of the Periodic Table are added to an aqueous solution of the polymer; (4) the gels thus formed melt on heating and set on cooling reversibly; (5) the strength of the gels increases with increasing concentration of the polymer in aqueous solution; (6) the polymer forms stronger gels with Group Ia and IIa cations of a particular ionic radius than with other Group Ia and IIa cations; and (7) the polymer is obtainable by isolation from the bacterium NCIB 11870 deposited as a patent deposit at the National Collection of Industrial Bacteria, Torry Research Station, P 0 Box 31, 135 Abbey Road, Aberdeen, Scotland AB9 8DG on 10 June 1983 or from a variant or mutant thereof.
Claim 3
Dependent Claim
33 words
A polysaccharide according to Claim 1 further characterised in that in item (6) of the definition the cations of Group Ia and IIa of a particular ionic radius are sodium or calcium ions.
Claim 4
Dependent Claim
50 words
A polysaccharide according to Claim 1 or 2 further characterised in that the gel formed by addition of 0.17 M aqueous sodium chloride solution to a 0.3X w/v (g/100 ml) aqueous solution of the polymer at ambient temperature has a yield stress at 25°C of at least 10 g/cm .
Claim 5
Dependent Claim
18 words
The bacterium NCIB 11870 deposited in the manner set forth in Claim 1 and variants and mutants thereof.
Claim 6
Dependent Claim
11 words
A biologically pure culture of a bacterium defined in Claim 4.
Claim 7
Dependent Claim
17 words
A gel comprising a polysaccharide defined in Claim 1, 2 or 3 and a gel-forming cation therefor.
Claim 8
Dependent Claim
31 words
A gel according to Claim 6 wherein the ratio of cation to polymer is selected to impart to the gel the property of melting at or just below human body temperature.
Claim 9
Dependent Claim
18 words
A gellable aqueous composition containing a polysaccharide defined in Claim 1, 2 or 3 and a gel-forming cation.
Claim 10
Dependent Claim
22 words
A method of preparing a gel claimed in Claim 6 or 7 which comprises setting a gellable composition defined in Claim 8.
Claim 11
Dependent Claim
14 words
A method according to Claim 9 wherein the gel is set at ambient temperature.
References Cited (Backward Citations)
No citation records indexed.
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