A method to determine the apparent coordinates of critical points and effective values of the second virial coefficients in water-protein-neutral polymer systems enabling one to obtain the above values from data on the phase analysis within a restricted region of two-phase compositions has been proposed. The data obtained by this method for the coordinates of the critical points and binodals in water-bovine serum albumin-dextran (W-BSA-D) and waterbovine serum albumin-polyethylene glycol (W-BSA-PEG) systems are compared with experimentally determinated. Several peculiarities of the mechanism of the phase separation in above systems have been outlined in the course of this study.

AbstractThe effects of pH, calcium chloride concentration and coagulation temperature on the yield of sol‐fraction during the formation of fibrous texturates made of soya protein isolates (SPI) and their mixtures with casein were studied. The optimal conditions in terms of least protein loss were pH 7.0, 0.05 M calcium chloride and 99 °C. Also studied were functional properties of the fibrous texturates having different relative amounts of the protein components as well as organoleptic properties of combined meat products with a 24% substitution of meat for fibrous texturates. Combined meat products containing fibrous texturates with a casein‐SPI ratio of 1:1 had the best organoleptic and technological properties.

Conditions are established for limited thermodynamic compatibility of proteins of different classes, as distinguished by Osborne, in aqueous solutions. The result obtained are in good agreement with the concept known as Δx —effect.

The flow microcalorimetric method was used to determine the enthalpies of diluting solutions of ovalbumin, bovine serum albumin, casein, soybean globulin fraction, thermotropic aggregates of ovalbumin, mixtures of ovalbumin-bovine serum albumin, casein-soybean globulin fraction, and ovalbumin-thermotropic aggregates of ovalbumin in water. The calorimetric data obtained were compared with the data on phase equilibrium in the systems Water-Ovalbumin-Bovine serum albumin, Water-Casein-Soybean globulin fraction, Water-Ovalbumin-Thermotropic aggregates of ovalbumin. Intermolecular interactions have been shown to play a significant role in the thermodynamics of protein compatibility.

ABSTRACTThe phase state of mixture of gelatin and Broad Bean globulins in an aqueous medium has been studied. Phase diagrams were determined which demonstrated the compatibility of gelatin with total globulin and of gelation with 11S globulin of Broad Beans. Results indicate that compatibility of gelatin with total globulin differs only slightly from the compatibility with 11S globulin. The increase in compatibility of gelatin with 11S globulin with increasing ionic strength is particularly interesting. As a consequence it appears possible to extend the region of the one‐phase mixed compositions suitable for the production of mixed gels.

A study has been made on the effect of temperature, sodium chloride, pH and cysteine on the thermodynamic compatibility of casein and soybean globulin fraction in aqueous medium. The section of miscibility gap characterizing the influence of the indicated factors on the compatibility of proteins has been determined. Assessment has been made of the influence of pH and cysteine on a) the effective molecular weights of casein and soybean globulin fraction and b) the difference in the intensity of interaction between each protein and a solvent. The experimental data obtained on the compatibility of proteins were found in good agreement with the theoretical concepts which establish the dependence of the compatibility of polymers on the ratio of their molecular weights, the intensity of interactions between polymers, as well as on the difference in the intensities of interaction between each of them and a solvent, i.e. on the difference of protein hydrophilicities.

The possibility of using the phase-volume method for determining phase diagrams of polymer mixtures in a common solvent has been ascertained. The above method was used to determine a phase diagram of water-casein-soybean globulins system.