Xanthan gum is an anionic, extracellular heteropolysaccharide (glucose, mannose, glucuronic acid backbone). Its key property is pseudoplastic (shear-thinning) rheology: high viscosity at rest (suspending particles) but low viscosity under shear (pumpable). It is also stable over wide pH and temperature ranges and compatible with salts. Applications: food thickener (E415), enhanced oil recovery (EOR), pharmaceuticals, and personal care products.