WATER PURIFICATION BY SEPARATE FREEZING IN RECONSTITUTED MILK PRODUCTION

Milk and dairy products play an important role in human diet due to their high nutritional and biological value, as well as to their easy digestibility. Milk powder makes it possible to improve the seasonal character of dairy foods. As a solvent in the production of reconstituted milk, water can significantly affect the quality of the finished product. In this regard, the problem of water quality and its preparation for the production of reconstituted milk is highly relevant. The method of separate freezing allows one to reduce the number of pre-treatment stages and energy costs. The research objectives were 1) to establish the effect of separate freezing on water quality indicators, 2) to determine the solubility index of milk powder in water prepared by the method in question, 3) to definethe energy costs. The research was carried out on the basis of the Department of Heat, Ventilation, and Air Conditioning Equipment (Kemerovo State University). The study was conducted with the help of a tank crystallizer with a controlling and measuring complex for registration of temperatures at temperatures from minus 2 to minus 10 C. In defining the quality of water and reconstituted milk, the authors used standard methods for determining its organoleptic and physico-chemical parameters. The study made it possible to define the organoleptic and physico-chemical parameters of water before and after separate freezing, the solubility index of dry milk, and the quality of reconstituted milk obtained by the method. The research revealed that it is energetically more advantageous to carry out the procedure at the temperature of minus 2 C. The present paper describes the numerous advantages of the method in that it reduces: 1) the dry residue content in tap water by 8 times, 2) the overall hardness of water by 2.5 times, 3) the content of chlorides and fluorides by 1.7 and 1.9 times, respectively, 4) the solubility index of milk powder from 0.35 to 0.1 cm3. All these factors improve the quality of reconstituted milk.