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Properties of oil/water emulsions stabilized with the soluble casein-acid polysaccharide mixtures were investigated. Compared to initial protein solutions, higher emulsifying properties of the mixtures are dehonstrated. A study is made on the influence of the properties of the mixtures for obtaining thermostable emulsions of hard consistency which could be applied in production of a great variety of foodstuffs. The present work was aimed at the study of the emulsifying properties of casein-acid polysaccharide mixtures with respect to specific technological factors.This goal was primarily dictated by a task of practical importance. In the last few years application of emulsions in a great many branches of food industry is finding an ever increasing use. At the same time it is not always SO that the emulsifying action of proteins is sufficient to obtain highly stable emulsions ; it is undesirable to use chemical emulsifyers in food emulsions. Besides, many foodstuffs are subjected to the effect of high temperatures under relatively severe conditions (up to 120-130 "0, which often results in demulsification of emulsions stabilized with proteins thus rendering the foodstuff useless. These disadvantages can be avoided in stabilization of emulsions with soluble protein-acid polysaccharide mixtures.

The character of phase transformations and composition of the phases obtained during interaction of proteins precipitating in the vicinity of the isoelectric point with dextransulfate was investigated with the aid of nephelometric measurements and chemical analysis. Clearly expressed hysteresis of the acid‐base nephelometric titration which is not observed in the presence of 7‐M of urea was revealed. Composition of the phases obtained is determined by the system prehistory. The soluble protein‐dextransulfate complexes are highly stable to precipitation and destruction under action of the low molecular salts.

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A study has been made of surface pressure (pi) and maximum shear stress (Ps) (at a constant shear rate) of decane-water interface on which bovine serum albumin (BSA) and its complexes with dextran sulfate (DS) were adsorbed. The pi values have been monitored by the Wilhelmy plate technique. The Ps values have been measured with a surface viscoelastometer. The changes of pi with time for BSA and BSA-DS complexes in general takes place in two stages which can be attributed to two corresponding limiting factors: diffusion of molecules (or particles) to the interface, and rearrangements of adsorbed molecules. The diffusion-controlled stage for the BSA-DS complexes was found to be several times as long as for BSA. The relaxation time of the second stage is a function of protein concentration Cp, for the complexes having maximum value at Cp = 10(-3)-10(-2) g/l. These maxima are coincident with midpoints of the surface pressure isotherms. The latter one of the BSA-DS complexes is shifted towards greater protein concentrations in comparison with that of BSA. The Ps assumes maximum values at Cp corresponding to the midpoints of surface pressure isotherms. These values for the complexes are 15-20 times greater the that for free BSA.

It is common knowledge that most of vegetable proteins are precipitated in the vicinity of the isoelectric point. This circumstance hampers their being processed into food. The present work shows that interaction of some proteins with sulfonated dextran improves the solubility of those proteins in a wide range of pH values.