[The study of starter cultures compositions influence on the cholesterol level in fermented meat products].

The article considers the possibility of using starter cultures compositions to reduce cholesterol in meat fermented products. An analysis of own researches and other scientific data allowed to conclude that the ability to reduce cholesterol by starting cultures in vitro is the strain-specific property. In view of the technological properties and the ability to reduce cholesterol in vitro, six compositions of starter cultures from the MGUPP collection were suggested. The compositions consisted of microorganisms belonging to the three genuses: Lactobacillus, Pediococcus and Staphylococcus. The absence of antagonism between the strains within each composition was determined by perpendicular strokes. Strains of each composition were co-cultured in a medium containing cholesterol. The residual cholesterol amount in the medium was determined after 24 hours by the Zlatkis- Zakmethod. This method is based on the cholesterol reaction with FeCl3 in the presence of concentrated sulfuric acid and glacial acetic acid to form a yellow colored complex. It was found that the compositions showed stronger activity for cholesterol reduction than each strain separately. Synergistic effect of cholesterol reduction was detected in starter cultures strains included into compositions. Reduction of cholesterol observed at 25.0-45.7%of its initial concentration in the medium. In those compositions, which included strains with a high capacity to reduce cholesterol, total cholesterol degradation ability was also higher. It was found that starter cultures reduced cholesterol not only in vitro, but also in the process of meat raw material fermentation in production of dry-smoked sausage. Composition a (Lactobacillus sakei 105, Pediococcus pentosaceus 31, Staphylococcus xylosus 45 at a ratio of 1:1:1) was chosen for the manufacture of drysmoked sausage. Bacterial composition was introduced into the meat raw materials on the mince preparation step in an amount of 109 CFU/g mince. Cholesterol maintenance in minced meat and ready-made dry-smoked sausages was determined by HPLC. In minced meat it was 840±10 mg/kg. In the ready sausages the greatest amount of cholesterol was detected in the control sample and was 971±15 mg/kg. Increasing cholesterol levels apparently due to loss of product weight by drying. Cholesterol level decreased by 21.4% in the test sample with the addition of bacterial composition (763±12 mg/kg).

[Study of genetic control of pediocins synthesis].

Plasmid profiles of 2 strains of Pediococcus acidilactici and 3 strains of P. pentosaceus were studied. Synthesis of bacteriocins in 2 strains of P. acidilactici was coded on the plasmid which was confirmed by experiment with elimination of plasmids and subsequent electrophoregram, which demonstrated synchronous disappearance of bacteriocins synthesis characteristic in plasmid-lacking variants. In 3 strains of P. pentosaceus plasmids were not found which points to chromosomal localization of genes for bacteriocins production.

[Biotechnological conditions of the synthesis of bacteriocins].

In this review information on the cultivation of bacteriocin-producing microorganisms belonging to different taxonomic groups are presented. The data on the influence of the most important biotechnological parameters (nutrient medium, temperature, pH, phase of growth, etc.) on the synthesis of bacteriocins are given.