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Whole milk powder (WMP) is a universal raw material component that can overcome the problem of seasonality of raw milk. It can be used to provide highnutritional products to remote areas experiencing a raw milk shortage. Its long shelf life depends on the conditions of storage and transportation, which are recommended to be carried out in a range from 0 to 10°C. At higher temperatures, the quality of WMP deteriorates because of a substantial increase in the degradation of fat and protein fractions. A range of low negative temperatures for storage have not been systematically investigated. Previous studies have shown that freezing WMP results in protein denaturation, crystallization of lactose, and extraction of free fat, all of which reduce the quality characteristics of the product, including deterioration of solubility, quick rancidification, and microbiological changes. However, these previous studies did not simulate the possible situations of transportation and storage of milk powder at low negative temperatures that occur in practice. Given the volume of transportation, distances and climatic characteristics of transportation routes play an important role in WMP preservation. In this study, we simulated storage and transport of WMP at −20°C. The samples were periodically thawed to 10 and 20°C and examined for physicochemical, functional-technological, thermodynamic, microbiological, and organoleptic parameters. Based on our results, storage of WMP at −20°C for 40 d did not have a significant effect on its qualitative characteristics. We observed some compaction of product structure and clustering or clumping, which was reversible by slight mechanical impact. Artificial contamination of the packaging surface with yeast and molds, followed by thawing of the samples, indicated the absence of the contaminants, which was explained by possible redistribution of moisture in the system.

During the last decade, research into genetic markers in the casein gene cluster has been actively introduced in cattle breeding programs. A special interest has been paid to the polymorphism of the CSN3 gene, responsible for the expression of the k-casein, playing a key role in protein coagulation, interaction with whey proteins, stabilization, and aggregation of casein micelles. This paper aimed to determine the effect of CSN3 genetic polymorphism on acid; rennet; acid–rennet; heat- and acid-induced as well as heat- and calcium-induced coagulation in skimmed milk; and protein-standardized milk systems (UF, NF, RO, VE). The influence of polymorphic variants of the CSN3 gene on the coagulation ability of milk proteins was assessed by the particle size of casein micelles, protein retention factor in the clot, and coagulation ability (duration of induction period, mass coagulation period, dynamic viscosity in gel point). The correlation between CSN3 gene polymorphism and protein coagulation was revealed. Milk systems obtained from CSN3 BB milk were found to have the shortest duration of coagulation, formation of better gel strength values, and increased yield compared to CSN3 AA. This study will improve the efficiency of milk processing and optimize the technology of dairy product production.

Providing the country’s population with quality food products in a demanded range and quantity is an important national economic task. A priori in the implementation of appropriate social and economic programs, an important place is taken by products of the dairy industry. Taking into account the geographical features and climatic conditions of Russia, strategic considerations, the existing fragmentation of the consumer market and economic factors, special importance is acquired by researches, aimed at improving traditional and developing new technologies for canned milk products, as  high-nutritional products with a pronounced priority of enhanced storage stability. The system of ensuring the stabilization of canned milk in storage is represented by two main blocks: technologically formed potential and post-technological requirements for its maintenance. The first forms the basic properties of the product and stabilizes them. The second one is to ensure the conditions under which the risks of initiation and/or intensity of the abiogenic and biogenic nature degradation reactions are minimized. To assess the canned milk quality and safety proposed and standardized a number of relevant indicators. However, taking into account the technology development, the expansion of the raw ingredients range, the requirements for the extension of shelf life and much more, the scope of the evaluation criteria for quality and safety indicators is constantly expanding, new methods of a priori and a posteriori analysis are being created, which is fixed in normative and technical documents, that are integrally reflected the level of modern technology. An analysis of the world tendencies in the development of canning, shows, that the reserves of improving the traditional technologies of dairy canned food, increasing their quality, are far from exhausted. Significant potential lies in the research of thermodynamic characteristics, functional and technological indicators of dairy products and further implementation of the obtained data, as system criteria of the technological operations rationality definition, the validity of production schemes, and the evaluation of product quality. The data, obtained over the last decades on the indicator of «water activity», inhibition of the degradation of micro and macro components, «barrier» conservation technologies and many other directions in various food systems can suggest, that it is possible to mediate most of the methodological approaches applied to canned milk technologies, to predict strategic, economic and social significance of such developments.

Introduction. Yoghurt has become one of the most popular acid-induced dairy products in the world. Consumers see yoghurt not only as a tasty, protein-rich, and calcium-fortified dessert, but also as a product that improves intestinal microflora and prevents obesity, metabolic syndrome, type II diabetes, and cardiovascular diseases. The stability of the structure and consistency of yoghurt directly depend on the composition and properties of raw materials, including genetic and technological factors and compliance with temperature storage conditions. Yoghurt formulations include various dairy raw materials, e.g. milk powder. The research objective was to assess the effect of κ-casein gene polymorphism in milk powder on the technological properties of acid-induced milk gels when simulating different temperature storage conditions. Study objects and methods. The research featured yoghurt samples prepared from milk powder of CSN3 gene (AA and BB). Model systems of yoghurt were prepared from dry bulk milk, mixed by mass fraction of protein in the ratio of AA2:BB2 as 75:25, 50:50, and 25:75%, respectively. The experiment involved standard methods, optical methods, dynamic viscometry, and PCR-RFLP. Results and discussion. As the mass fraction of BB dry bulk milk increased, the structural and mechanical properties, dimensional stability, and surface tension increased, too. As the storage temperature fell from 4 ± 2 to 12 ± 2°C, the structural and mechanical properties, dimensional stability, surface tension, and moisture-holding ability decreased while maintaining the previously established dependencies. The CSN3 gene polymorphism proved to have no effect on the curd tension after fermentation. Significant differences between the allelic variants AA and BB became obvious only after complete cooling and structuring of the product. Conclusion. The obtained experimental results and the analysis of related publications suggested an indirect effect of the κ-casein gene polymorphism on the structural and mechanical properties, associated with a genetic effect on the average diameter of casein micelles in the original milk and the resulting biochemical and isothermal processes. The research made it possible to assess the effect of the CSN3 gene polymorphism on the technological properties of dry milk during its processing into fermented milk products.

Всероссийский научно-исследовательский институт пивоваренной, безалкогольной и винодельческой промышленности-Федеральный научный центр пищевых систем им. В.М. Горбатова РАН,

No abstract

In this study the effect of k-casein gene polymorphism on the technological characteristics of milk powder obtained by spray (AA1:BB1) and freeze drying (AA2:BB2) was investigated. Standardized and generally accepted methods were used in the field of physical and chemical control of dairy products, as well as methods for assessing the heat stability and cheese making properties of milk. The most heat-resistant were the samples with a predominance of milk obtained from cows with the AA CSN3 genotype, in the pH range from 6.4 to 7.0 (36-91 minutes for AA1:BB1 and 37-101 minutes for AA2:BB2). In systems with a fraction of 25 % to 100 % of milk from cows with the AA CSN3 genotype obtained by freeze drying, higher (by 3-10 %) stabilization qualities of protein were revealed when heated in the pH range from 6.4 to 7.0 compared to spray drying. The analysis of the results regarding the cheese making properties showed that with an increase in the proportion of milk from cows with the BB CSN3 genotype from 0 % to 100 % in model systems, the rennet coagulation time decreases for all samples, regardless of the drying method. It was also found that when using freeze drying, coagulum of all samples were assigned to the highest class of milk quality in terms of cheese making properties, while during spray drying only the samples consisting of min. 75 % or completely of milk obtained from cows with genotype BB CSN3 corresponded to this category.