Affiliations: Department of Food and Nutrition, Faculty of Human Life Science, Osaka City University, Sumiyoshi, Osaka 558‐8585, Japan | Department of Biological and Chemical Engineering, Gunma University, Kiryu, Gunma 376‐8515, Japan
Note: [] Address for correspondence: Dr. K. Nishinari, Department of Food and Nutrition, Faculty of Human Life Science, Osaka City University, Sumiyoshi, Osaka 558‐8585, Japan. Tel.: +81 6 6605 2818; Fax: +81 6 6605 3086; E‐mail: nisinari@life.osaka‐cu.ac.jp.
Abstract: It was found that solutions of calcium hyaluronate (CaHA) (0.1∼0.5 wt%) could form a gel by mixing with solutions of sodium type gellan (0.1∼0.5 wt%), although neither polymer by itself forms a gel at low concentrations (0.1∼0.5 wt% in this experiment). The rheological properties of CaHA–gellan mixtures were investigated by dynamic and steady shear measurements. Both storage shear modulus G′ and loss shear modulus G″ for CaHA–gellan mixtures increased with increasing time, and tended to an equilibrium value after 1 h. After reaching steady values of G′ and G″, the frequency dependence of G′ and G″ was observed. G′ was always larger than G″ in the accessible frequency range from 10−2 to 102 rad/s. The effects of pH and calcium ions were examined. Gel formation of the mixtures was promoted by decreasing pH and adding from 0.01 to 0.1 M calcium ions, but excessive calcium ions weakened the gel.
Journal: Biorheology, vol. 37, no. 5-6, pp. 401-408, 2000
