This review is devoted to the analysis of various aspects of gelation in gelatin and multicomponent gelatin-containing systems.Gelation mechanisms in gelatin-water systems upon varying polymer content in the solution are discussed in detail.New data concerning a sol-gel transition at gelatin concentrations above the gelation threshold are presented,and models describing gelation in highly concentrated solutions are outlined.Principal phenomena related to the effect of various modifying additives (glycerol,electrolytes,hydrocarbon- and fluorine-containing surfactants,high-molecular-mass compounds,and tanning agents) are reviewed,and the effect of microheterogeneous additives on the properties of gels based on gelatin-containing multicomponent systems is considered.A crucial problem concerning thermal stability of gels is discussed separately.Special attention is focused on the effect of structuring processes in gelatin (tanning) that lead to the chemical modification of polypeptide gelatin chains,as well as on the influence of the above processes on the properties of gels and their surfaces.In addition to traditional rheological parameters,characterizing structural and mechanical properties of gelatin gels,the presented analysis involves the data on durability of gelatin gels and its variations under the action of added components with various modifying potency.
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