Galacturonic acid tragacanth

The gum consists of a mixture of water-insoluble and water-soluble polysaccharides. Bassorin, which constitutes 60-70% of the gum, is the main water-insoluble portion, while the remainder of the gum consists of the water-soluble material tragacanthin. On hydrolysis, tragacanthin yields L-arabinose, L-fucose, D-xylose, D-galactose, and D-galacturonic acid. Tragacanth gum also contains small amounts of cellulose, starch, protein, and ash. 

The crude gum tragacanth is a mixture of the salt of a complex acid polysaccharide and a neutral polysaccharide composed principally of L-arabinose residues. Starch is also present in the gum. The acid character of this gum is due to units of D-galacturonic acid and not D-glucuronic acid and it is of interest to note that in its ability to form gels it resembles pectin and the plant mucilages, which also contain D-galacturonic acid. 

Tragacanthin A complex mixture of polysaccharides containing some galacturonic acid residues The soluble component of the natural (plant origin) tragacanth gum Binder (in tablets) and demulcent... 

Tragacanthic acid, the main component of gum tragacanth, contains interior chains that approximate most closely to those of a galactu-ronan.14,18 4-0-(a-D-Galactopyranosyluronic acid)-D-galacturonic acid (59) and the polymer-homologous trisaccharide 60 have been isolated... 

Tragacanth is a plant exudate from certain legumes. It is a mixture of various polysaccharides, predominantly with D-galacturonic acid residues. It is used as a thickener in foods, e.g., in salad sauces, ice cream, etc. 

Karaya gum (sterculia gum, Indian tragacanth) plant (sterculia urens) mixture of D-galactose, L-rhamnose and D-galacturonic acid. The galacturonic acid units are the branching points of the molecule... 

The water insoluble part, tragacanthic acid, includes D-galacturonic acid, D-xylose, L-fructose, D-galactose, and other sugar units [3]. It has a main chain of a-D-galacturonopyranosyl bonded with (1 4) linkages. The main chain has randomly substituted xylosyl branches [24]. The water-soluble and the water-insoluble part components can be separated from each other through an easy procedure [4]. 

Figure 14.9 Main monomers of tragacanth gum (a) p-D-xylose, (b) L-arabinose, (c) a-D-galacturonic acid, (d) a-D-galacturonic acid methyl ester, (e) p-D-galactose, (0 a-L-fucose. Adapted with permission from [60] Copyright 2007 Springer.

Gum Tragacanth E413 Plant exudate Astragalus species Iran, Turkey L-arabinose, D-galactose, D-galacturonic acid, L-rhamnose Confectionery icings, dressings, flavour oil emulsions... 

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