INTRODUCTION Electrodialysis treatment of whey is found to be the most effective method of targeted control of its mineral composition and acidity [1, 2]. It should be noted that the whey electrodialysis does not significantly affect the qualitative and quantitative properties of whey proteins, lactose content, and the content of vitamins in demineralized whey; in the meantime, its technological and organoleptic properties considerably improve [3]. The process of whey electrodialysis desalination or demineralization ends in demineralized whey and salt concentrate, namely, the whey mineralizate. The demineralized whey (especially when dry) is used in food production for children and for special purposes; in confectionery and bakery; for meat products; in pharmaceutical industry, etc. [1-5]. On the other hand, the whey mineralizates have not found the practical use. As shown in works [6, 7], whey mineralizates may be used as the basis for washing and disinfecting agents used in dairy enterprises. In this regard, the study of physical and chemical, surface-active properties and the composition of whey mineralizates, as well as the impact caused by the type of initial whey to such parameters are quite relevant. OBJECTS AND METHODS OF THE STUDY The targets of this research are the milk whey and whey mineralizates obtained by electrodialysis of unsalted cheese whey, curdy whey and casein whey. Milk whey was demineralized by the ED-mini electrodialysis device (manufactured by MEGA JSC, Czech Republic) using RALEXAMH-PES anion exchange membranes and RALEXSMH-PES cation exchange membranes. Samples were treated under the electrodialysis until 90% demineralization was achieved. Parameters of electrodialysis included the following: voltage U = 12.5 V; membrane area - 0.14 m2; steam of membranes - 10; diluate flow - 70 l/h; temperature t = 22.0 ± 2°C. The volume of experimental whey mineralizates was produced at the International R&D "Electro-and Baromembrane Technologies" Laboratory of MEGAProfiLine LLC (Stavropol Territory, Stavropol). The composition and properties of milk whey mineralizates were studied by laboratories of the Applied Biotechnology Department of the Institute of Living Systems and of the Department of Nanomaterial Technology of the Institute of Electric Power Engineering, Electronics and Nanotechnologies, Copyright © 2017, Khramtsov et al. This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/ ), allowing third parties to copy and redistribute the material in any medium or format and to remix, transform, and build upon the material for any purpose, even commercially, provided the original work is properly cited and states its license. This article is published with open access at http://frm-kemtipp.ru. Federal State Autonomous University of Higher Education North-Caucasian Federal University, as well as by the R&D Laboratory "Physical Methods of Research and Analysis" of the Center for Collective Use of Scientific Equipment (Stavropol Territory, Stavropol). The structure of the milk whey discontinuous phase was assessed by the photon-correlation spectroscopy method at the Photocor Complex unit (by Antek-97 LLC, Russia) [8]. The array of spectroscopic data was processed using the DynaLS software. The method of conductivity measurements at the EXPERT-002 conductometer [9, 10] was applied to measure the specific conductivity (SC) of milk whey and its mineralizates. The active acidity of whey and mineralized whey was determined by potentiometric method; the density was measured by the hydrometer [11]; the limiting wetting angle was measured by the sessile drop method that is the direct measurement of the angle by the shape of a drop on the solid surface; the surface tension was measured by stalagmometric method [12]; the kinematic viscosity was measured by the glass capillary viscosimeter VPZh-1 (Technocom NPO, Russia) [13]; the refractive index was measured by the refractometer; the titrated acidity of whey mineralizates was determined by titrimetry as per the procedure [14]. The structure of mineralizates the availability of certain vibrations of atomic group bonds was determined by the infrared spectroscopy (IR spectroscopy) using the IR Fourier spectrometer of FSM 1201 model listed with the No. 18895-99 in the National Register of Measuring Equipment of Russia. The phase composition of dry residues of whey mineralizates was evaluated by X-ray phase analysis by the method of powder diffraction at the PANanytical Empyrean X-ray diffractometer (manufactured by PANalytical BV, the Netherlands) as per the procedure [15]. The elemental composition of whey mineralizate dry residues was investigated using the energy- dispersive (elemental) analysis at the MIRA-LMH scanning electron microscope with the element determination system AZtecEnergy Standart/X-max 20 (standard) (manufactured by Tescan, Czech Republic) [16]. RESULTS AND DISCUSSION Physical and chemical properties of whey and whey mineralizates were studied at the first stage. The process of milk whey electrodialysis allowed obtaining dependences of specific conductivity (SC) and active acidity of curdy whey, cheese whey, casein whey and whey mineralizates on demineralization level. The results are shown graphically below. Fig. 1 shows the dependence of the specific conductivity of milk whey on the degree of its demineralization. As shown by the data analysis in Fig. 1, prior to the demineralization process, the initial milk whey had the values of specific conductivity as follow: the largest value obtained for the casein whey with SC = 9.54 ± 0.50 mS/cm, followed by the curdy whey with SC = 7.19 ± 0.55 mS/cm and the lowest value for the cheese whey with SC = 5.17 ± 0.52 mS/cm. The specific conductivity of all the whey samples studied in process of electrodialysis treatment decreased on a straight-line basis. The process of demineralization of milk whey was completed as the specific conductivity value was reached of about 1-1.5 mS/cm that corresponded to 90% of demineralization. Fig. 2 shows the dependence of specific conductivity of whey mineralizates on the extent of whey demineralization. Analysis of dependencies shown in Fig. 2 shows that the specific electrical conductivity of whey mineralizates increases as the extent of whey demineralization rises due to ion transition entering the dispersion medium of milk whey and to the salt concentrate influenced by the electromotive force (EMF). Upon completion of electrodialysis treatment, the casein whey mineralizate has the greatest specific conductance (SC) followed by the curdy and cheese whey that correlates with ion concentrations and SC of initial whey. In parallel with SC measurement, the active acidity (pH) was measured for both whey of various types and whey mineralizates. Fig. 3 shows the results of pH measurement of milk whey as it is demineralized. Specific conductivity, mS/cm 12 10 а 8 b 6 c 4 2 0 0 50 100 Demineralization level, % Fig. 1. Dependence of specific conductivity of milk whey on the extent of its demineralization: (a) casein, Specific conductivity, mS/cm (b) curdy, (c) cheese. 12 10 а 8 b 6 c 4 2 0 0 20 40 60 80 100 Demineralization level, % Fig. 2. Dependence of specific conductivity of whey mineralizates on the extent of whey demineralization: (a) casein, (b) curdy, (c) cheese. 7.5 7 6.5 рН 6 5.5 5 4.5 4 It was found that the process of electrodialysis treatment results in the decrease of mineralizate active acidity of casein and curdy whey due to c hydrochloric and lactic acid penetrated therein, respectively. The active acidity of the cheese whey mineralizate varies insignificantly and is within 6 ≤ pH ≤ 7.5; this is b apparently due to the order of ion passing to the а mineralizate. It is possible that at the beginning of electrodialysis, the ions with acidic properties pass into the mineralizate to explain the decrease in pH, 0 20 40 60 80 100 Demineralization level, % Fig. 3. Dependence of the milk whey active acidity on the extent of its demineralization: (a) casein, (b) curdy, (c) cheese. As per the analysis of dependencies shown Fig. 3, the active acidity values of tested whey species were as follow prior to demineralization: casein whey pH = 4.64 ± 0.11; curdy whey pH = 4.88 ± 0.12 and cheese whey pH = 6.86 ± 0.10. These active acidity values are well correlated with published data and are associated with processes to obtain these types of milk whey [2, 5]. For example, to produce the casein whey, the protein is coagulated using the hydrochloric acid (pH