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On carrying out a screening, phage-resistant strains of Streptococcus thermophilus have been selected. As producers of exopolysaccharides, they can be used to form the texture of fermented milk and improve the rheological properties of fermented milk products in a natural, effective, and safe way. It has been suggested to use analysis of the capsule-formation of strains as an express method to evaluate the rheological properties. The technology of the bacterial concentrate Iprov it –Streptococcus thermophilus with phage-resistant producers of exopolysaccharides has been developed. The following technological modes were used: growing in a growth medium with the ratioof carbohydrates to soluble nitrogen C:N=3.5; biomass stabilisation (10% inulin protective medium, freezing at minus 60±1°C for 16±2 h, drying for 24±2 h to 32±1°C, moisture content in the preparation not more than 5%). These modes allowed obtaining 7.83±0.02 g of bacterial concentrate from 1 dm3 of the growth medium. Depending on the strain of Streptococcus thermophilus, the dry bacterial concentrate contained 4.4×1011–1.1×1011CFU/g of active microbiota.A technique has been developed that allows improving the rheological properties of fermented milk products by blending bacterial preparations to produce various products with concentrate of the Streptococcus thermophilusstrain. The optimal formulations of the mixtures have been selected. This has made it possible to modify the rheological characteristics of fermented products without using other thickeners. The effective viscosity of the products obtained has been increased by 13.3–54.3%, depending on the formulation of the mixture. The biotechnology of the bacterial concentrate Iprovit –Streptococcus thermophilus was implemented at the State Research Enterprise of the Institute of Food Resources, National Academy of Agricultural Sciences of Ukraine. Manufacture of the concentrate is regulated by the regulatory documents developed and approved: TU 15.5-00419880-100:2010 “Dry and liquid fermenting cultures. Specifications,” Technological Instructions for production of the fermented cultures IPROVIT for TU 15.5-00419880-100:2010 “Dry and liquid fermenting cultures. Specifications.” The novelty of the technological solutions was confirmed by Copyright Registration Certificate No. 51033. [ABSTRACT FROM AUTHOR]

Abstract: Nitrogen-fixing bacteria isolated from root nodules of Medicago plants growing in the 10 km zone around the Chernobyl nuclear power plant were screened for the production of new water-soluble acidic exopolysaccharides (EPSs). The different strains belonged to the Enteriobacteriaceae family (Enterobacter ludwigii, Raoultella terrigena, Klebsiella oxytoca), except for one which belonged to the Rhizobiaceae family (Sinorhizobium meliloti). All of the bacteria produced highly viscous EPS with an average molecular weight comprised between 1 × 106 and 3 × 106 Da. Five different compositions of EPS were characterized by physico-chemical analyses and 1H NMR spectroscopy: galactose/mannose (2/1), galactose/glucose (1/1), galactose/glucose/mannose (1/2/1), fucose/galactose/glucose (2/1/1) and fucose/galactose/glucose/mannose (2/2/1/1 or 1/1/2/4). Glucuronic acid, a charged monosaccharide, was also recovered in most of the different EPSs. [Copyright &y& Elsevier]