Effects of cation properties on sol-gel transition and cel properties of kappa-carrageenan

The phase transition temperatures, rheological properties and gel-network c haracteristics for gelation of kappa -carrageenan-salt (NaCl, KCl and CaCl2 ) solutions and their aged gels were investigated. The effectiveness of inc reasing gelling and gel-melting temperatures at the salt concentrations exa mined followed the sequence of K+ > Ca2+ > Na+. This sequence was also true for the gel strength and the melting enthalpy (DH) of the most crosslinked junction zones of aged gels at low salt concentrations. Nonetheless, a dif ferent order (Ca++ > K+ and Na+) was found for increasing storage modulus a nd gelation rate during early-stage gelation, thermal hysteresis and the DH of aged gels in some salt-carrageenan systems.