The storage (G') and loss (G '') moduli of transparent mixtures of l-c
arrageenan and gelatin have been measured during gelation and melting
and compared with those of gelatin and l-carrageenan systems alone. Th
e moduli of the mixtures were always higher than the sum of those of t
heir components alone. Gelatin and l-carrageenan seem to reinforce eac
h other. Three specific temperature domains can be distinguished, deli
mited by the melting and helix-coil transition temperatures of gelatin
and l-carrageenan. An interpretation based on conformational changes
and an attractive electrostatic interaction between the two biopolymer
s is suggested. The temperature dependence of G' and G '' for mixtures
has been studied as a function of thermal history (time and temperatu
re of gel ageing), sodium chloride concentration and molecular weight
of the l-carrageenan. Copyright (C) 1996 Elsevier Science Ltd.