Kinetics of ion-induced gelation in carrageenan gels under physiologic conditions

✍ Scribed by Zhibing Hu; Yuanye Chen; John C. Lang

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 349 KB
• Volume: 60
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/(sici)1097-4628(19960411)60:2<221::aid-app9>3.0.co;2-u

✦ Synopsis

The kinetics of gelation of an ungelled carrageenan solution exposed to a gel-inducing ionic solution was studied using a turbidity technique. Alkali metal ions were allowed to diffuse through a dialysis membrane into the solution of biopolymer. Optical transmission was measured as a function of distance away from the membrane. In the early stage of 12 h, the transmission increases with distance. After 96 h, the transmission is independent of distance. This indicates that gelation is completed everywhere inside the gel and the gel's structure is homogeneous, in agreement with previous results. Time-dependent transmission indicates the presence of two relaxation processes occurring during ion-induced gelation: a primary relaxation process related to the gelling zone movement, and a secondary relaxation process related to local diffusion of polymer, bound ions, and water molecules.