The gelation of proteins

This chapter describes the process of the gelation of proteins. Gelation is a phenomenon; therefore, its definition and that of its product, a gel, is dependent on the perspective of the observer and the technique(s) used to observe it. For example, gels may be defined by their ability to immobilize a liquid, their macromolecular structure, or their textural or rheological properties. The chapter reviews a variety of protein gel systems with a broad perspective stressing similarities between them, yet not without mentioning the important differences that make each unique. It describes the multicomponent protein gels. The rheological and optical properties of thermally irreversible gels are the outcome of two events. First, a change in protein structure is needed that permits protein–protein interactions. The subsequent aggregation process, which is highly influenced by the solvent environment, may produce the gel microstructure, which is responsible for the optical and rheological properties. The physical integrity of a gel is maintained by counterbalancing forces of attraction and repulsion among polymer molecules and between the polymer network and the surrounding solvent