Xanthan gumXanthan gum is microbial polysaccharide (gum) produced by a fermentation process. Xanthan builds viscosity at very low concentrations (0.1 to 1.0%) in a cold system. At high temps. this viscosity will drop but then return upon cooling. In baked goods its main functions are increased volume, moisture retention and air incorporation. Generally
$4 to $6 a pound.
Gum tragacanth is a plant exudate from low bushy shrubs found in regions of Iran, Syria and Turkey. Gum tragacanth swells in cold water to give highly viscous solutions. Used in many industries but in food for its thickening or stabilizing properties in jellies, etc. Not used so much for cake baking. Can be expensive.
Why not try guar gum. Much cheaper - $1/lb. Made from the seed of plants grown in India, Pakistan and southwest US. Seed are ground to a powder. Cold water swelling to add viscosity at very low concentrations (0.1 to 1.0%). Can be used in combo with xanthan for synergistic effect.
It's best to add gums to dry blends of sugar or flour. If water finds the gums too rapidly the gums will form lumps. Just hand blend well into the sugar. Start at 0.2 true % (total formula, not bakers %). The prices quoted are for large commercial purchases; the small shop will pay more per pound for smaller quantities.