Guar gum is a polysacharide (a long chain made of sugars) made of the sugars galactose and mannose. Some other familiar polysacharides are starch and cellulose, which are made of long chains of the sugar glucose. Guar gum comes from the endosperm of the seed of the legume plant Cyamopsis tetragonolobus.
Cyamopsis tetragonolobus is an annual plant, grown in arid regions of India as a food crop for animals.
Guar gum is used as a thickener in cosmetics, sauces, salad dressings, as an agent in ice cream that prevents ice crystals from forming, and as a fat substitute that adds the "mouth feel" of fat. In pastry fillings, it prevents "weeping" (syneresis) of the water in the filling, keeping the pastry crust crisp. It has a very high viscosity (thickness) even when very little is used. When mixed with xanthan gum or locust bean gum, the viscosity is more than when either one is used alone,