Introduction. Canning requires thermophysical calculations for thermal or cold processing. These calculations are based on thermophysical characteristics of raw materials. The research objective was to analyze the thermophysical characteristics of tropical fruits. Study objects and methods. The study featured kiwi, papaya, avocado, and figs. Their thermal conductivity was analyzed with the help of stationary fiber plate method. The cryoscopic temperature was determined from the flat area of the thermogram obtained during freezing. The heat capacity and the amount of frozen moisture were determined by calculation based on the available data on the chemical composition of the fruits. The density was defined by using the hydrostatic weighing method, the sugar content – by the refractometric method, the moisture content – by drying to constant mass. Results and discussion. The research revealed the physicochemical parameters of kiwi, avocado, papaya, and figs. Papaya demonstrated the highest moisture content – 86.32 ± 0.02%, while kiwi appeared to have the highest density – 1,065 ± 1 kg/m3. Figs had the highest sugar content – 16.0 ± 0.1%. The thermal conductivity coefficient of fresh and frozen tropical fruits was determined experimentally and increased after freezing. Frozen avocado showed only a slight increase in thermal conductivity coefficient because of its low moisture content while frozen figs demonstrated a significant increase in the thermal conductivity coefficient – by 3.3 times. This product possessed the highest thermal conductivity: 0.63 ± 0.02 W/(m·K) for the fresh samples and 2.06 ± 0.02 W/(m·K) for the frozen samples. The thermal conductivity coefficient of kiwi and papaya increased by 2 and 4.2 times, respectively. The experiment also examined the effect of protective plastic wrap and ripeness on the thermal conductivity coefficient. The film proved to have a negative effect on the reliability of thermophysical analysis. The cryoscopic temperature was determined empirically. Such thermophysical properties as heat capacity, thermal diffusivity, and frozen moisture were based on the available chemical composition. Conclusion. The research revealed the physicochemical parameters of kiwi, avocado, papaya, and figs. It included a set of experiments on the thermal conductivity coefficient of fresh and frozen tropical fruits. The obtained values can be used to develop the optimal parameters of thermal processing, refrigeration, and thermal treatment of new products. They can also be useful for fortifying dairy and bakery products with exotic fruits.

A significant problem in the food industry is the lack of raw materials. At the same time, a significant part of the resources is not used for obtaining food products. This kind of food raw material includes whey, which contains a large amount of valuable components, in particular whey proteins and lactose. The article discusses the results of research devoted to the development of industrial technology for separating freezing (cryoconcentration) of skim milk and curd whey to obtain concentrated skim milk, as well as whey protein concentrate in low-tonnage production conditions. The research was carried out on products manufactured by dairy enterprises in Kemerovo, Russia.

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.

Consumer properties of chocolate depend largely on the quality of cocoa butter, which affects the technological processes of chocolate production. This article introduces a new method of calorimetry-based mathematical modeling applied to polymorphic forms of cocoa butter. The authors studied various samples of cocoa butter from different manufacturers using the method of differential scanning calorimetry. The results of experimental studies were processed as a Gaussian distribution. The new method of cocoa butter quality assessment relied on experimental data processed as distribution dependencies of polymorphic cocoa butter forms. The latter were identified as follows: 1) a low-melting form (10–18 °C); 2) polymorphic form α (17–24 °C); 3) metastable form β' (27–29 °C); 4) polymorphic form β (28–30 °C). The authors also calculated the proportion of polymorphic forms of cocoa butter according to their melting point. The method facilitated the quality assessment of cocoa butter, which renders good prospects for the chocolate industry.

The most important issue when working with nuts is their processing from the shell and peel. Previously, this process was carried out entirely by hand, but today with a higher demand and developed logistics services, the scale of production of the finished product has increased, which entails an increase in the productivity of lines for the destruction of walnut shells. The purpose of this work is to study the effect of low temperatures on the load exerted on the hazelnut shell during its destruction. The tasks to be solved in this work are the development of an experimental stand that allows you to control all the necessary parameters, the receipt of experimental material, its description with further recommendations when introducing the proposed technology into the industry. The maximum effect on the destruction of the hazelnut shell is achieved by freezing it in nitrogen for 15 minutes, the load being about 208.3 N. This duration is optimal when using liquid nitrogen, because during this period of cryogenic freezing, the limiting deformations of destruction are reduced, the hazelnut shell becomes as fragile as possible and is easily destroyed when the nuts are exposed to shock deformations, and the integrity of the nut kernels is preserved as much as possible. So the load for the destruction of the shell of a hazelnut after treatment with liquid nitrogen is reduced by 39%, compared with untreated, which in production conditions will make significant energy savings for the drive of equipment for the destruction of walnut.