The development of temperature conditions of vacuum concoction of milk

Vacuum concentration contributes to the preservation of quality indicators of the product due to the low temperature level of heating. One of the technological modes of the vacuum concentration is the process temperature. The aim of this work was to study the influence of heating temperature on the efficiency of the vacuum concentration of milk. The objects of research were skim milk and milk fat mass fraction of 3 and 5 %. The concentra-tion of these products was carried out at the tem-perature in the chamber from 50 to 100 °C in in-crements of 10 °C. The change in the solids con-tent in the milk during the process of vacuum con-centrating was found out. It was discovered that with increasing temperature the concentration and the duration of the process the mass fraction of dry substances of milk increased. However, at temper-atures concentration at 90 and 100 °C, the reduc-tion in the organoleptic evaluation of the product took place. Skimmed milk had a maximum organo- leptic score (38-39 points) at the temperature of concentration of not more than 70 °C. Similar de-pendence was observed when the concentration of milk with fat mass fraction was 3 and 5 %. It was established that in the process of vacuum concen-trating the solids content of skim milk, milk with fat mass fraction of 3 and 5% increased to 5.6; 4. 1; 3.6-fold respectively. The increase in unit cost of heat in the concentration with increasing tempera-ture in the chamber. The unit cost of heat increases with temperature especially hard under the concen-tration of more than 70 to 80 °C. On the basis of the conducted researches the rational temperature and duration of the process of concentration of re-search facilities. Milk to the concentration of solids 48-50 % is necessary to thicken at the temperature of 70±3 °C for 5 hours. This temperature range is selected based on organoleptic and physical and chemical parameters, and kinetics of the process and the unit cost of heat per a kilogram of removed moisture.