Polysaccharides

Stability Hygroscopic
Applications Sugar composition of sake.
References Giri, N.Y., et al.: Arch. Biochem. Biophysics, 145, 505 (1971a

Applications Scleroglucan is a natural polymer produced by fungi, especially those of the genus Sclerotium. Scleroglucan fluids have been used to trap and treat Cr(VI) in environmental applications.
References Brigand, G.: Industrial Gums (Third Edition), pp. 461 (1993); Pensini, E.; et al.: Colloids Surf., A, 559, 191 (2018);

Laminaran is a polysaccharide that co-occurs with fucoidan and alginate in brown seaweeds such as Laminaria digitata, Laminaria cloustoni, Eisenia bicyclis and Thallus laminariae. It is a β-1,3-linked glucan which it is claimed stimulates the immune system in mammals and fish.
The image was kindly provided by Prof Mike Guiry from Cork who runs ‘The Seaweed Site’.

Nigeran is a polysaccharide found in the cell wall of lower fungi. In certain Aspergillus and Penicillium spp., nigeran was first isolated from Penicillium expansum and Aspergillus niger (illustrated). The polysaccharide contains unbranched α-D- glucopyranose residues linked 1,3 and 1,4. Nigeran is part of the hyphal cell wall, where it can contribute up to 40 % of the cell dry weight. The polysaccharide occupies several domains or location on the hyphal wall and is highly crystalline in vivo. Deposition of nigeran is primarily at the outer surface of the hyphal wall.

Dextran is α-(1,6)-linked α-D-glucan with α-(1,3)-linked glucose branch points produced by fermentation of Leuconostoc mesenteroides via the action of the enzyme dextransucrase on sucrose.  The main use for native dextran is as an extender in blood transfusions and products having a range of sharp cutoff molecular weights are produced commercially for this and other applications.  A complex of iron with dextran, known as iron dextran, is used as a source of iron for baby piglets which are often anaemic at birth.

Amylopectin is composed of between 2,000 to 200,000 glucose residues linked α (1→4) with α (1→6) branching. The molecule is highly branched, every 24 to 30 glucose units, resulting in a soluble molecule with many terminal residues. Starch is made of about 70% amylopectin by weight, though it varies depending on the source (higher in medium-grain rice to 100% in glutinous rice, waxy potato starch, waxy corn, and lower in long-grain rice, amylomaize, and russet potatoes).

Dextran sulphate is a dextran derivative whose ulcer (colitis) -causing properties were first reported in hamsters and extrapolated a few years later to mice and rats. The exact mechanisms through which dextran sulphate induces intestinal inflammation are unclear but may be the result of direct damage of the monolayer of epithelial cells in the colon, leading to the crossing of intestinal contents (e.g., commensal bacteria and their products) into underlying tissue and therefore induction of inflammation.  The dextran sulphate sodium induced ulceration model in laboratory animals has some advantages when compared to other animal models of colitis, due to its simplicity and has many similarities to human inflammatory bowel disease.

PolyGlycopleX (PGX) is produced from a mixture containing proprietary proportions of three polysaccharides, konjac glucomannan, xanthan gum and sodium alginate.  Recent hydrodynamic, rheological and analytical studies have shown that the unexpectedly high viscosity of solutions of PGX is consistent with an interaction between a konjac glucomannan, xanthan gum complex and sodium alginate to form a new, ternary complex in solution. Human and animal feeding studies have shown that PGX can be used to control weight, lower the glycaemic index of foods and postprandial glycaemia.

Colominic acid (polysialic acid) is a linear small polysaccharide containing α-2,8-linked sialic acid (neurominic acid) with (n = 8 to >100) residues. Polysialic acid is an unusual post translational modification polysaccharide that is widely expressed in nature in bacterial capsules, fish, sea urchin eggs, embryonic tissues, amphibians, animal and human brains, and in a various cancers.  The major carrier of polysialic acids in mammals is the neural cell adhesion molecule (a glycoprotein that belongs to the immunoglobulin superfamily).Average molecular weight for this product is :50000-60000

Sodium carboxymethyl dextran is a white, odourless and tasteless powder, which is freely soluble in water or electrolyte solutions. Applications that have been described for carboxymethyl dextran include carriers of paramagnetic contrast agents, preparation of conjugates of pharmacologically active compounds and carboxymethyl dextrans in biosensors.  A number of other uses in cosmetics, agriculture, foods, paints and textiles have been the subject of patent applications.

Food additive, applied in pharmaceuticals and beauty products.

A linear β-(1,4)-galactan from potato tubers. Other linear β-(1,4)-galactans have been isolated from lemon peel, potato tubers and Norwegian acacia gum.