Fractionation and Characterization of Commercial Low Acyl Gellan Gum

Abstract

Commercial low acyl gellan (LAG) is purified by the fractional dissolution method. An aqueous solution of purified commercial LAG exhibits polyelectrolyte character due to its high molar mass and carboxylic groups in glucuronic acid fragments. The empirical Fuoss equation determines the intrinsic viscosity of purified LAG in salt-less water. Fractionation of commercial LAG is carried out by ultrasound treatment. LAG fractions are characterized by ¹H NMR and FTIR spectroscopy. The intrinsic viscosities of ultrasonically treated LAG samples are measured in 0.025 m of tetramethylammonium chloride (TMACl). The molecular weights of LAG fractions are determined by the Mark–Kuhn–Houwink equation.