The aim of the research was to study the regularity of the influence of the culture medium (substrate) on the development of microflora on the pre -fermentation stage of a model medium made from white cabbage «Parus», using strains of lactic acid microorganisms Leuconostoc mesenteroides VKPM B-8818. The main task in the research process was to perform a stepby-step mathematical processing of experimental data and analyze them, to obtain functional dependencies adequately approximating the experimental data for the base (BMS) and modified (MMC) model media. Analysis of the experimental data showed that, depending on the type (composition) of the medium, the same species of microorganisms exhibit different dynamics of titer growth. In connection with this, an algorithm was developed to determine the optimal duration of pre-fermentation – «stop points». The results of the research showed that modification of the model medium with the addition of table salt and ascorbic acid to it promotes the formation of positive dynamics of the comparison indicator. This dynamics has three extreme extremes, but only extremes are of practical significance, which are in the interval of the monotonic decrease of the titer. One of the conditions for successful development of the starting culture at the main stage of fermentation is a relatively small amount of the first culture's titer at the end of the preliminary fermentation stage in order to exclude competition. Consequently, the position of the "stoppoint" corresponds to the period after the last peak of the comparison indicator. These studies on the regularity of the effect of the pre-cultivation of gram-positive microorganisms on the activity of lactic acid microorganisms in the process of fermentation are relevant, since the whole process and the production of high-quality products depend on this approach in full.

Relevance. The use of certain single or mixed cultures of lactic acid microorganisms and the mandatory control of the fermentation process of white cabbage are of great importance to ensure that the product is of stable quality without the need for any chemical preservatives or harsh processing conditions. Carbohydrates contained in raw materials play an important role in this process, since carbohydrates are the main source of maintaining the viability of lactic acid microorganisms. By adjusting the carbohydrate component of raw materials at different stages of fermentation, it is possible to maintain a high titer of microorganisms, while obtaining not only a high-quality product, but also giving it, along with prebiotic (a source of fiber) and probiotic properties. Materials and methods. The purpose of this research work was to ensure the direction of the biotechnological process in the direction of stabilization of the concentration of functional microflora (starting systems of lactic acid microorganisms), under the influence of introduced carbohydrate nutrients. In this work, we studied two fermentation systems of microorganisms that are fundamental microorganisms in the fermentation of cabbage, namely, systems consisting of a pre-fermentation culture of Leuconostoc mesenteroides and one of the cultures of lactobacilli: Lactobacillus plantarum or Lactobacillus brevis. The study used the usual microbiological method for determining the number of microorganisms by seeding in an agarized culture medium, as well as processing experimental data. Results. As a result, we found that the introduction of a carbohydrate Supplement allows us to stabilize the dynamics of changes in the concentration of the studied starting systems at the same initial level throughout the main stage of fermentation.