Abstract: A method for producing derivatized microfibrillar polysaccharide, including but not limited to cellulose, derivatized by steric and/or electrostatic forces, where the electrostatic forces are provided by anionic charge or by a combination of both anionic and cationic charge, by stabilizing and/or microfibrillating a polysaccharide starting material. A method of modifying the rheological properties of a composition of matter using derivatized microfibrillar polysaccharide. Method of improving coatings, paper manufacture, and the stability of emulsions, dispersions, and foams using a derivatized microfibrillar polysaccharide. Compositions that include derivatized microfibrillar polysaccharide, including paper compositions, comestible compositions, non-comestible spreadable compositions, and emulsions, dispersion, and foams.