Viscoelasticity of thermoreversible gelatin gels from mammalian and piscine collagens

In this article we describe the characterization of a number of gelatin samples extracted from both mammalian (bovine and porcine) and fish (cod) collagens using oscillatory shear. The regime for gel formation and characterization is discussed, and subsequent gel melting behavior is considered in light of both Eldridge-Ferry and Takahashi models for the concentration dependence of the melting temperature. Frequency sweep data for some of the latter samples suggest that, although the junctions are more complex than simple entanglements, they have some features in common with entanglement networks compared to true gel networks (those with an equilibrium modulus). This has consequences on the longer-term behavior of the gels, and suggests, for example, the possibility of gel healing. (C) 2000 The Society of Rheology. [S0148-6055(00)00304-7].