A simple and effective method of isolating I I S-globulin (glycinin) from soybeans has bccn developed. which is based on the use of selective thermal denaturation of other components in globulin fraction. Glycinin content in the final preparation accounts for 9 7 "~. and its yield constitute about 1 g per 100 g ofdefatted flour (about 7 " o of glycinin content in flour). According to differential scanning microcalorimetry, the isolated preparation in terms of thermodynamics is identical with glycinin isolated by the method Of T~IASH-SHIBASAK~ with chromatography on hydroxyl apatite. The steady state viscosity of diluted solutions of the preparation, was studied in four solvents: A -phosphate buffer ptf 7.6, ionic strength 0.5; B --water pIi 7.1. ionic strength below 0.001 ; C -8 M guanidin . HCI; D -8 M guanidine HCI, containing 0.01 M 2-mercaptoethanol. Dependences of steady state viscosity on protein concentration (0.5 --7.0 g/dl) and temperature ( I M) 'C) were obtained. A study was also made on the fractional composition of the preparation in the indicated solvents by the sedimentation velocity method. According to the data of sedimentation velocity and viscosimetry, the molecular weights of various glycinin forms were determined. The values obtained are consistent with the published data. Analysis of the hydrodynamic properties of dodecameric and hexameric glycinin forms shows that they are similar to spheres of equal density, but of different size. In the investigated range of concentrations and temperatures, the intermolecular interactions play an insignificant role in the rheology of glycinin solutions (parameter of excluded voluhc according to MOONEY K = 0; excess cffectivc activation enthalpy in viscous flow Hf = H,(O Ho(C' = 0 ) = 0). Only in water of about 4 ' C , which is close to the temperature of glycinin precipitation. the role of intermolecular interactions is significant; this follows from the value flz = I I 7 kJ/mole.

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SummaryThermodynamic properties of aqueous solutions of both native and modified legumin of broad beans (Viciufuba L.) have been examined. A restricted trypsin-induced proteolysis was used to modify protein structure. Evaluation of protein affinity to ficoll in aqueous solutions showed that modified protein possessed higher hydrophilicity. Thermodynamic properties of diluted solutions were used to predict the phase behaviour in concentrated systems containing protein and ficoll. At specific concentrations of native legumin, the system can separate in two phases, whereas in the case of modified protein the single-phase behaviour of the system was predicted for any concentrations of both components. The experimental data obtained in concentrated systems confirmed predictions of thermodynamic analysis of diluted solutions.

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