Polysaccharides

Cellulose is a linear polysaccharide of β 1-4 linked glucose residues. The polysaccharide chains are bundled as microfibrils in cell walls and provide the essential structural components within growing plants. Each microfibril exhibits a high degree of three-dimensional internal bonding resulting in a crystalline structure that is insoluble in water, resistant to reagents and very strong. The crystalline region of cellulose is isolated to produce microcrystalline cellulose. Microcrystalline cellulose is a term for refined wood pulp and is used as a texturizer, an anti-caking agent, a fat substitute, an emulsifier, an extender, and a bulking agent in food production.

Water thickener; rheological control additive; has industrial appplications

Starch is a two component polysaccharide mixture of amylose and amylopectin. Amylose is a linear polysaccharide of α (1,4)-linked glucose residues and averages 20 to 30% of the total in most native starches. Amylopectin is a highly branced glucan containing both a (1,4) and a (1,6) linkages. The number of glucose residues in a single starch molecule can vary from five hundred to several hundred thousand, depending on the type of starch. Starch is the major storage form of energy in plants, just as glycogen is the storage form of energy for animals. The plant directs the starch molecules to the amyloplasts, where they are deposited to form granules. Thus, both in plants and in the extracted concentrate, starch exists as granules varying in diameter from 2 to 130 μm.

A sulphated galactan from the red seaweeds (Gelidium spp.). The major gel-forming component agarose consisting of a linear chain of sequences of (1,3) linked β -D-galactopyranosyl units and (1,4 ) linkages to 3,6-anhydro-α-D-galactopyranosyl units. Gelation is via the formation of double helices. Both Gelidium latifolium and Gelidium amansii are sources of both Agar (mixture of agarose and agaropectin) and Agarose. The images were kindly provided by Prof Mike Guiry from Cork who runs ‘The Seaweed Site’.

Chitin forms the tough fibrous exoskeletons of insects, crustaceans and other arthropods, and, in addition to its presence in some fungi, it occurs in at least one alga. The structure of chitin is similar to that of cellulose but with glucose replaced with N-acetyl-D-glucosaminyl units linked β-D-(1,4) in a linear chain. Chitin is normally produced from the shells of lobster, crab or shrimp.

Galactomannan, food additive, fracking fluids, complex formation with Xanthan

Starch is a two component polysaccharide mixture of amylose and amylopectin. Amylose is a linear polysaccharide of α (1,4)-linked glucose residues and averages 20 to 30% of the total in most native starches. Amylopectin is a highly branced glucan containing both a (1,4) and a (1,6) linkages. The number of glucose residues in a single starch molecule can vary from five hundred to several hundred thousand, depending on the type of starch. Starch is the major storage form of energy in plants, just as glycogen is the storage form of energy for animals. The plant directs the starch molecules to the amyloplasts, where they are deposited to form granules. Thus, both in plants and in the extracted concentrate, starch exists as granules varying in diameter from 2 to 130 μm.

Fluorescein isothiocyanate carboxymethyl dextran (FITC-CM Dextran) has been reported to provide a valuable carrier for nanoparticles of iron oxide.  These products provide a potent tool for contrast enhancement in magnetic resonance imaging.