Concentration of curd whey by separating freezing

Separating freezing is one of the gentlest ways of liquid food products processing, allowing them to increase their concentration to extend shelf life, or to separate certain components. The purpose of the study was to investigate the processes occur-ring during the cryoconcentration of milk whey. The experiments on separating freezing were carried out at the temperatures of heat exchange surface from -2 to -10 ° C. It was established that the high-est rate of ice formation was observed during the first minutes of separation freezing. At the tempera-ture of -2 ° C after 5 minutes of the process, the rate of ice formation was 22 mm / h, and at heat exchange surface temperature -10 ° C this value was 72 mm / h. It was found out that the higher the temperature of the heat exchange surface, the gen-tler the graph of the change in the content of dry substances in the concentrate. The same applies to the concentration of dry matter in formed ice. In all cases the highest rate of increase in the concentra-tion of dry substances was observed during the first 5-10 minutes. At the temperatures of heat ex-change surface below -6 ° C, 30 minutes after the start of the process, significant decrease in the rate of increase in the concentration of solids was ob-served. The value of losses of dry substances at various temperatures of freezing was calculated. It was established that the greatest efficiency of the process had been at the surface temperature of the crystallizer -2 ° С. At the temperature about 30 % of initial solution was frozen out, and the concentra-tion of dry matter in the unfrozen solution was 9.78.