Viscoelasticity of thermoreversible gelatin gels from mammalian and piscine collagens

In this article we describe the characterization of a number of gelatin sam ples extracted from both mammalian (bovine and porcine) and fish (cod) coll agens using oscillatory shear. The regime for gel formation and characteriz ation is discussed, and subsequent gel melting behavior is considered in li ght of both Eldridge-Ferry and Takahashi models for the concentration depen dence of the melting temperature. Frequency sweep data for some of the latt er samples suggest that, although the junctions are more complex than simpl e entanglements, they have some features in common with entanglement networ ks 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].