The dissertation is devoted to the study of the biological properties of active strains of bacteria capable of fermenting raw milk materials and determining the effectiveness of bacterial preparations created on their basis for fermented milk products. A screening of strains of lactic acid and bifido- and propionic acid bacteria from the collection of Institute of Food Resources of NAAS was carried out for traits valuable for the production of fermented dairy products (moderate energy of acid formation, productivity, high level of antagonistic activity to opportunistic microflora, production of exopolysaccharides, β-galactosidase activity), 7 strains
were selected as promising, namely S. thermophilus 2176, 2120, 2138, bifidobacteria - B. adolescentis 4400, B. bifidum 4101 and B. longum 4201 together with Propionibacterium freudenreichii ssp. schermanii 5104. Strains of various taxonomic groups, characterized by a high ability to synthesize the enzyme β-galactosidase, were identified and compositions based on them were created. The most β- galactosidase activity was distinguished by the composition BTP-F, amounting to 604 A / min. It has been established that, in order to ensure an effective reduction in the level of lactose, it is advisable to combine strains with a high and low level of β- galactosidase activity, since this makes it possible to shorten the fermentation period and reduce the level of lactose in the final product. New effective starter compositions for fermented baked milk and fermented milk product of mixed fermentation have been created. The first is based on S. thermophilus strains (2176, 2138, 2120) for the production of a fermented baked milk product. The second, by improving the biotechnology of fermentation compositions based on S. thermophilus by using bifidobacteria and propionic acid bacteria for the production of a fermented milk beverage of mixed fermentation. The resulting preparations allow manufacturing of dairy products in production with the highest microbiological purity. The regularities of the development of these strains were investigated separately and in compositions; the optimal conditions for the biomass
accumulation and the preservation of viability have been elaborated. The dose of inoculation and the regularities of functioning of the obtained fermentation compositions with direct inoculation of a milk base have been
established. For the production of fermented baked milk, it is proposed to introduce a solution of caramel sugar, which makes it possible to reduce the duration of the simmering of the milk mixture by 2.5-3 hours and to enhance the pronounced cream color. The technology of dairy products with the use of bacterial preparations of high biological activity, which are capable of providing the number of microorganisms during the entire storage period (at least 108 CFU / g), has been substantiated.
Using the method of rotatable central compositional planning for the cultivation of the bacterial preparation "BTP-F", the nutrient medium was optimized. The technological parameters for obtaining a bacterial preparation in semi-industrial conditions have been developed that make it possible to increase the yield of dry biomass by 30% and obtain from 1 dm3 of the nutrient medium (12.6 ± 0.3) g of dry concentrate with the number of lactic acid, bifido- and propionic acid bacteria, respectively, not less than 1.0 × 1010 CFU / g, and 2.0 × 1010 CFU / g and 3.0 × 109 CFU / g.
It has been shown that the fermented milk product obtained by fermenting milk with such a starter culture is characterized by high antagonistic activity against pathogenic and opportunistic microorganisms, the presence of vitamin B12 up to 180 μg / ml.
The technologies of new bacterial compositions and products have been introduced into production at the State Research Enterprise of Institute of Food Resources of NAAS and a number of enterprises in Ukraine.
On the basis of the research carried out, regulatory documents have been developed for bacterial concentrates of direct inoculation for fermented baked milk and BTP-F. Regulatory documentation has been developed for the production of the fermented milk product “Kozatskyi”, fermented baked milk product and the special purpose fermented milk product “Darynka”. Clinical trials have confirmed their therapeutic effect. The functional activity of the developed products: "Bacterial Concentrate BTP-F" and a fermented dairy product on its base, has been proven by clinical trials.
The novelty and originality of bacterial compositions and products created in the course of this work are covered by 2 patents for invention and 1 patent for utility model.
