Formation and rupture of Ca2+ induced pectin biopolymer gels

摘要: When calcium salts are added to an aqueous solution of polysaccharide pectin, ionic cross-links form between pectin chains, giving rise a gel network in dilute solution. In this work, dynamic light scattering (DLS) is employed study the microscopic dynamics fractal aggregates (flocs) that constitute gels, while rheological measurements carried out process rupture. As salt concentration increased, DLS experiments reveal polydispersity flocs increase simultaneously with characteristic relaxation times network. Above critical concentration, become interlinked reaction-limited Rheological studies demonstrate limits linear response and stresses required rupture these networks both decrease concentration. These features indicate ion-mediated gels studied here lie ‘strong link’ regime characterised by inter-floc links stronger than intra-floc links. A scaling analysis experimental data presented demonstrates elasticities individual exhibit power-law dependences on We conclude when concentrations number increases density crosslinks, very large values bulk elastic modulus.