Viscoelastic properties of l-carrageenan/gelatin mixtures

摘要

The storage (G′) and loss (G″) moduli of transparent mixtures of ι-carrageenan and gelatin have been measured during gelation and melting and compared with those of gelatin and ι-carrageenan systems alone. The moduli of the mixtures were always higher than the sum of those of their components alone. Gelatin and ι-carrageenan seem to reinforce each other. Three specific temperature domains can be distinguished, delimited by the melting and helix-coil transition temperatures of gelatin and ι-carrageenan. An interpretation based on conformational changes and an attractive electrostatic interaction between the two biopolymers is suggested. The temperature dependence of G′ and G″ for mixtures has been studied as a function of thermal history (time and temperature of gel ageing), sodium chloride concentration and molecular weight of the ι-carrageenan.