Hysteresis during sol-gel and gel-sol phase transitions of kappa-carrageenan: A photon transmission study

Kara S., Tamerler C., Bermek H., Pekcan O.

JOURNAL OF BIOACTIVE AND COMPATIBLE POLYMERS, vol.18, no.1, pp.33-44, 2003 (SCI-Expanded) identifier identifier


Photon transmission techniques were used to study sol-gel and gel-sol transitions in kappa-carrageenan-water systems with various carrageenan contents. The photon transmission intensity, I-tr was monitored against temperature to determine critical phase transition temperatures and transition rates. It was observed that the sol-gel transition temperatures, T-sg, were found much lower than the gel-sol, T-gs, transition temperatures based on the hysteresis of the phase transition loops. Sol-gel and gel-sol activation energies were determined and it was found that a carrageenan-water system required less energy for the gel-sol transition than for the sol-gel transition.