The concentration dependence of the rheological properties were investigated for simple gels of κ-carrageenan (C) and gelatin (G) in concentration ranges of 0.45-0.9% (w/v) and 2-4% (w/v), respectively. Mixed carrageenan-gelatin gels of various mixing ratios were prepared, i.e., C-G (3:1), C-G (1:1) and C-G (1:3), and the effects of mixing ratio were examined by measuring the rupture properties, dynamic viscoelasticity values and melting temperature. The temperature dependence of the simple gels and mixed gels was also determined.
The mixed gels generally exhibited hindrance toward gelation. The melting temperature of carrageenan gels had high concentration dependence, that of the mixed gels being nearly equal to the equivalent simple carrageenan gel. The rupture stress, rupture energy and dynamic viscoelastic constants showed temperature dependence above 20°C, while they tended to remain constant or slightly increase because of entropic behavior below 15°C.