Structure and rheology of gelatin and collagen gels.

This paper undertakes a parallel analysis of the gelation mechanisms, structure and rheological properties of gelatin and collagen gels. Although the molecular compositions of collagen and gelatin are almost identical, gelation proceeds from distinct mechanisms and leads to different types of molecular assemblies. First are presented the properties of the solutions, based on their structural and rheological characterization; then the mechanisms of gelation in the networks, observed by Transmission Electron Microscopy, of three types of gels: gelatin gels, Type I collagen gels and gels made of cuticle collagen extracted from annelid worms. The rheological investigation of the sol-gel transition of gelatin is described within the context of the theories of percolation and scaling laws. Different experimental approaches to the kinetics of gelation are presented, combining dynamic light scattering and rheology in respect to gelatin gels.