Rheological properties of matrix-particle gellan gum gel: effects of calcium chloride on the matrix

The effects of particle gel (PG) on the rheological properties of gellan gum gels were investigated. Samples were 1.2% gellan gum gels with 5 mM CaCl2 (MG-CaCl2) or without CaCl2 (MG), to which various amounts a particle gel of 1.2% gellan gum containing 5 mM CaCl2 (PG-CaCl2) was added. Breaking stress and storage Youngʹs modulus of MG containing PG-CaCl2 increased with increased PG-CaCl2 content, while those of MG-CaCl2 containing PG-CaCl2 decreased. PG-CaCl2 behaved as an active filler in MG and as an inactive filler in MG-CaCl2. Activation of PG-CaCl2 may be the result of interaction between calcium ions in the particles and carboxyl groups in the gellan gum molecules of the matrix.