Gelation of Konjac glucomannan crosslinked by organotitanium chelated with different ligands

Abstract

Konjac Glucomannan (KGM) gels can be formed in the presence of organotitanium as crosslinkers which were chelated by different organic compounds. Organotitanium cross-linking agent is a chelate formed by coordination between tetrabutyl titanate and different organic compounds. The gel network was formed through the crosslinking reaction between titanium ions dissociated from organotitanium crosslinkers and the cis-diol hydroxyl groups on the mannose units of polysaccharide chains. Effect of concentration and species of ligands on rheological properties of the complex gels was studied by dynamic viscoelastic measurements. The gelation kinetics of the gels were investigated and the critical gelation points of the gels were accurately determined according to the Winter-Chambon criterion. The effects of kinds and concentrations of ligands on the shear storage modulus (G’), the loss modulus (G”), and the sol-gel transition points were studied. The sol-gel transition time varies with different ligands in the organotitanium crosslinkers. The sol-gel transition time and temperature were obviously observed and in good agreement with Winter–Chambon criterion.