.beta.-1,3-glucan polysaccharides, compositions, and their preparation and uses

An aqueous gel which is the product of the process of a) mixing a 20 to 80 weight percent aqueous solution of a chaotropic salt with a 0.5 to 10 weight percent aqueous sol of at least one .beta.-1,3-glucan polysaccharide which polysaccaride will form a clear, aqueous 1% by weight sol having essentially a baseline UV adsorption at 260 nm;

• b) heating the mixture until a a homogeneous sol is formed;
• c) cooling the heated mixture to form a gel which has essentially no background fluorescence when stained with ethidium bromide;
• and d) washing the gel with water thereby removing the chaotropic agent.

An aqueous gel which is the product of the process of the process of a) mixing a 20 to 80 weight percent aqueous solution of a chaotropic salt with a 0.5 to 10 weight percent aqueous sol of at least one substantially pure hydroxyalkylated derivative of a .beta.-1,3-glucan polysaccharide having a degree of substitution of 0.01 to 10 or a coprocessed mixture with at least one other hydrocolloid;

• b) heating the mixture until a homogeneous sol is formed;
• c) cooling the heated mixture to form a gel.

An aqueous gel which is the product of the process of a) mixing a 20 to 80 weight percent aqueous solution of a chaotropic salt with a 0.5 to 10 weight percent aqueous sol of curdlan which curdlan will form a clear, aqueous 1% by weight sol having essentially a baseline UV adsorption at 260 nm;

• b) heating the mixture until a homogeneous sol is formed;
• and c) cooling the heated mixture to form a gel which has essentially no background fluorescence when stained with ethidium bromide.

An aqueous gel which is the product of the process of a) mixing a 20 to 80 weight percent aqueous solution of a chaotropic agent selected from the group consisting of urea, lithium bromide, lithium iodide or guanidinium isothiocyanate with a 0.5 to 10 weight percent aqueous sol of at least one .beta.-1,3-glucan polysaccharide which polysaccaride will form a clear, aqueous 1% by weight sol having essentially a baseline UV adsorption at 260 nm;

• b) heating the mixture until a homogeneous sol is formed;
• and c) cooling the heated mixture to form a gel which has essentially no background fluorescence when stained with ethidium bromide.

A water-soluble alkali metal salt of a substantially pure .beta.-1,3-glucan polysaccharide providing gel-forming sols which are clear gels which exhibit essentially no background fluorescence when stained with ethidium bromide and which exhibit essentially baseline UV absorption at 260 nm.

A hydroxylated .beta.-1,3-glucan polysaccharide, wherein its degree of substitution is about 0.01 to about 1 and its hydroxyalkyl moiety is a C.sub.2 -C.sub.4 monohydroxyalkyl or C.sub.3 -C.sub.4 dihydroxyalkyl providing gel-forming sols which are clear gels which exhibit essentially no background fluorescence when stained with ethidium bromide and which exhibit essentially baseline UV absorption at 260 nm.

A partially depolymerized substantially pure .beta.-1,3-glucan polysaccharide providing gel-forming sols which are clear gels which exhibit essentially no background fluorescence when stained with ethidium bromide and which exhibit essentially baseline UV absorption at 260 nm.

A partially depolymerized hydroxyalkylated .beta.-1,3-glucan polysaccharide providing gel-forming sols which are clear gels which exhibit essentially no background fluorescence when stained with ethidium bromide and which exhibit essentially baseline UV absorption at 260 nm, the partial depolymerization being equivalent to the exposure caused by 200 Krad to 800 Krad of gamma radiation from Cobalt 60.

A coprocessed hydrocolloid composition comprising:

• a) from about 10 to 90 parts by weight of a compound selected from the group consisting of a substantially pure .beta.-3-1, 3-glucan polysaccharide, a substantially pure hydroxyalkylated .beta.-1,3-glucan polysaccharide, a partially depolymerized substantially pure .beta.-1,3-glucan polysaccharide, or a hydroxyalkylated derivative thereof, and b) the remainder to 100 parts by weight of at lease one hydrocolloid other than any of the above, wherein the partial depolymerization is equivalent to the exposure of 200 Krad to 800 Krad of gamma radiation from Cobalt 60 and wherein the substantially pure glucan polysaccharides will form clear, aqueous 1% by weight s01s having essentially a baseline UV absorption at 260 nm, and gels from the sols have essentially no background fluorescence when stained with ethidium bromide.

An aqueous gel prepared by the process of a) mixing a 20 to 80 weight percent aqueous solution of a chaotropic salt with a 0.5 to 10 weight percent aqueous sol of at least one .beta.-1,3-glucan polysaccharide which polysaccaride will form a clear, aqueous 1% by weight sol, has essentially a baseline UV adsorption at 260 nm;

• b) heating the mixture until a homogeneous sol is formed;
• and c) cooling the heated mixture to form a gel which has essentially no background fluorescence when stained with ethidium bromide.

A clear, substantially pure curdlan comprising a 1% by weight aqueous sol having essentially no background fluorescence when stained with ethidium bromide;

• and essentially baseline UV absorption at 260 nm.