Critical Exponents of Kappa Carrageenan in the Coil-Helix and Helix-Coil Hysteresis Loops


Tari O., KARA S., Pekcan O.

JOURNAL OF MACROMOLECULAR SCIENCE PART B-PHYSICS, cilt.48, sa.4, ss.812-822, 2009 (SCI-Expanded) identifier identifier

Özet

The steady-state fluorescence technique was used to study coil-helix (sol-gel) and helix-coil (gel-sol) transitions of the kappa carrageenan-water system with various carrageenan contents. Fluorescence (I) and scattered light (I-sc) intensities were measured against temperature to determine critical phase transition temperatures and exponents. It was observed that the coil-helix transition temperatures, T-ch were much lower than the helix-coil (T-hc) transition temperatures due to the hysteresis of the phase transition loops. The gel fraction exponent (beta) was measured and found to be in accord with the classical Flory-Stockmayer model.