Background. The probiotics immobilization technology is one of the most effective ways for controlled and continuous delivery of viable cells into the intestine. It is well known that multifaceted physiological roles of bifidobacteria are to normalize and stabilize the microbiocenosis, to form intestine colonization resistance, to synthesis amino acids, proteins and vitamins, to maintain non-specific resistance of the organism and so all. Such a wide range of positive effects on the macroorganism allows us to consider bifidobacteria as a basis for functional immobilized healthcare products development.
Objective. Taxonomic position determination of the Bifidobacterium longum strain selected for immobilization, study of the viability of this bifidobacteria strain in a complex probionic product based on highly dispersed silica in simulated gastrointestinal tract's conditions and after freeze-drying.
Methods. The production strain Bifidobacterium longum IMV B-7165 from the Institute of Food Resources of the National Academy of Agrarian Sciences of Ukraine collection of industrial strains has been used in the study. It was isolated from the healthy human infant's gastrointestinal tract.
Commonly used bioinformatics, microbiological, biotechnological and statistical methods have been applied.
Results. The best alignments for the sequence of bifidobacteria isolate "4202" 16S rRNA (it was previously deposited as Bifidobacterium longum IMV B-7165) and classic dendrograms based on these results were performed. According to the results of microscopic studies of samples of microorganisms with highly dispersed silica products ("Enterosgel", "Sillard P" and "Toxin.Net") it was found that the immobilization of the Streptococcus thermophilus and bifidobacteria cultures did not differ fundamentally. To study the immobilization effect on the bifidobacteria preservation and properties the following carriers were used: "Enterosgel", "Toxin.NET" and "Sillard P". The survival of immobilized bifidobacteria was further studied in simulated gastrointestinal conditions: immobilized cells are better protected from acid and bile, although with increasing acidity, survival decreases in both control and immobilized cells.
Conclusions. The taxonomic position of a bifidobacterial isolate from the healthy human infants used in immobilization studies was clarificated (Bifidobacterium animalis subsp lactis). Under the simulated conditions of the upper gastrointestinal tract in the case of acid and bile impact, the best survival was demonstrated by immobilized cultures of bifidobacteria together with the Enterosgel sorbent (a content of 10% by weight of the culture). The survival of immobilized preparations after freeze-drying was slightly reduced in the case of immobilization on the "Enterosgel" and "Toxin.NET" samples of enterosorbents (a content from 15% to 25% by weight of the culture). The best results were observed in the case of immobilization of bifidobacteria with 5% content of the "Toxin.NET" enterosorbent (enterosgel + inulin).
