The fluorescence technique was employed to study gel-to-sol transitions in K-carrageenan systems with various carrageenan contents. Pyranine was used as a fluorescence probe for monitoring these transitions. Fluorescence, I-p and scattered light, I-sc intensities were measured against temperature to determine critical phase transition temperatures and exponents. It was observed that gel-to-sol transition temperatures, T-gs are found to be dependent to the carrageenan content. The measured critical exponents gamma' and beta' were found to be very close to the weight average degree of polymerization, DPw and gel fraction G, exponents (gamma and beta) of the classical Percolation Model. (C) 2004 Elsevier B.V. All rights reserved.