Investigation of mixed agarose-gelatin gels

Phase equilibria and mechanical properties of gel-like water-gelatin-locust bean gum systems

The establishment of phase equilibrium in aqueous gelatin-locust bean gum (LBG) systems in the process of cooling from 313 to 291 K in specific conditions, passes ahead of the gelation process(.) This allows the suggestion that macrostructure and mechanical properties of the system can be predicted on the basis of knowledge of its phase diagram, obtained for the liquid gelatin-LBG systems comprising gelatin molecular aggregates. Textural and rheological analysis of gel-like gelatin-LBG systems demonstrate the effect of two factors determining their mechanical properties and acting opposite each other when the concentration of LBG in the system increases: concentration of gelatin by LBG in the process of phase separation, and decrease in the density of the gel network.

Compositions and phase diagrams for aqueous systems based on proteins and polysaccharides

Limited thermodynamic compatibility of proteins with other proteins and proteins with polysaccharides is a fundamental phenomenon that has been demonstrated in more than 200 biopolymer pairs. These systems can undergo a liquid-liquid phase separation resulting in the different macromolecular components primarily concentrated in the different phases. This occurs under conditions (pH values and ionic strengths) inhibiting attraction between nonidentical biopolymers, i.e., the formation of interbiopolymer complexes. Generally, phase separation takes place when the total concentration of the macromolecular components exceeds a certain critical value. The excluded volume of the macromolecules determines both their thermodynamic activity and phase separation threshold. Phase diagrams of biopolymer mixtures and physicochemical features of biphasic systems are considered here. Attention is centered on the limited compatibility of the main classes of proteins and various polysaccharides and on the effects of variables such as pH, ionic strength, temperature and shear forces on the phase state, equilibrium and structure of these two-phase liquid systems. The general nature of the phenomenon of thermodynamic incompatibility of biopolymers accounts for its importance in structure formation in cytoplasm.