In modern conditions the food industry of the Russian Federation needs high quality natural emulsifiers, for example, lecithins. It should be noted that the carp caviar, in particular, the sazan caviar contains a large amount of lecithin. Analysis of the positive and negative aspects of different approaches to the freezing process and its structural design leads to the conclusion that it is reasonable to use (both from the point of view of technology, power consuming and economy) a conductive energy removal from the product that is in contact with the working surface of the cooling unit made in the form of a drum with a refrigerant supplied inside it. Given that it is difficult to empirically determine the temperature over the volume of the frozen object, it is advisable to simulate the processes of internal transfer of thermal energy and its exchange at the interfaces between the sample and the external environment, as well as the cooling surface of the drum. The aim of the study was a mathematical model solution about internal heat transfer during sazan caviar freezing under heterogeneous boundary conditions. The object of the study is a thin layer of the sazan caviar. Putting into practice the mathematical model of heat transfer, which describes freezing a 5 mm thick caviar product by the contact method by means of the finite difference method was realized by using the Mathcad Professional software product. In the process of solving the mathematical model of freezing, it was revealed that at the end of the freezing procedure, the average volumetric temperature of the caviar reaches its rational value of –7.5°C, after which the caviar product can be transported to the storage places. Rational operating parameters of the caviar product freezing process are: ambient air temperature up to 20°C; initial product temperature –10 ± 1°C; drum surface temperature up to –18°C; thickness of the frozen layer – 5 ± 0.5 mm; freezing time = 10 minutes.

No abstract

Increasing the raw materials deep processing efficiency for commercial fish farming, including freshwater fish caviar of the carp family that demonstrates low demand on the Russian market, is an important and urgent task. In the modern context, Russian food industry needs high quality natural emulsifiers, for example, lecithin. The research aim is to determine the thermophysical characteristics, cryoscopic temperature, refrigeration object density and the amount of frozen moisture in it, depending on its temperature variation. The study object is carp caviar. A man found the temperature variation during carp caviar freezing using an experimental stand, containing a specialized ThermoChart program for constructing thermograms. The authors determined caviar material density dependence on its temperature in the range from −18 to 5 °C: with an increase in temperature, its density raised to 1,071 kg/m³ monotonously at Tcr = −0.91 °C and then changed up to 5 °C ordinary. An obtained thermophysical characteristics values analysis of carp caviar, which is a high-moisture product, demonstrates that its freezing is accompanied by the latent crystallization heat release, depending on a decrease in the study object temperature and due to the proton bonds presence at the sample microlevel. A man can use obtained data in the freezing processes calculation and refrigeration equipment design; and utilize the semi-finished product to extract lecithin.