Agar group, polysaccharides

Scheme 2. Structural diversity in the polysaccharides of die agar group.

A. S. Shashkov, A. I. Usov, and S. V. Yarotsky, Polysaccharides of algae. 24. Application of 13C-NMR spectroscopy for structural analysis of polysaccharides of the agar group, Sov. J. Bioorg. Chem., 4 (1978) 57-63 (English translation from Bioorg. Khim., 4 (1978) 74-81). 

If branching is (1 —> 3), no glycol grouping will be present in any central unit and it may be seen that reaction will only occur on the terminal units. Such is the case with the polysaccharide laminarin, with the glucan of yeast membrane, and with a galactose-containing polysaccharide isolated from agar.146-148... 

As with agar and carrageenan, substitution in the Xanthomonas polysaccharide structure inhibits the interaction with galactomannan. Thus, removal of the acetyl groups by saponification yields a product that interacts much better with galactomannans.211 Less locust-bean gum is required to gel deacetylated Xanthomonas polysaccharide, and mixtures of locust-bean gum and deacetylated Xanthomonas polysaccharide form a gel at lower, total-polysaccharide concentrations. 

Stabilizers and Thickeners. Many food products receive their textural properties from a group of compounds known as hydrocolloids. Hydrocolloids fall into Iwo classes polysaccharides and proteins. They include loeust bean gum. guar gum, gum arabic. carrageenan, xanthan gum. cellulose. agar, starch, pectin, alginates, and gelatin. See also Stablizer. 

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