Development of Lactic acid Microorganisms during Fermentation of Substrate with an Increased Concentration of Carbohydrates

Introduction. Creating favorable conditions for the development of lactic acid microorganisms is one of the main factors in obtaining high-quality fermented products. The cycle of their life directly depends on the amount and composition of carbohydrates in plant tissue. Since a significant part of carbohydrates is consumed at the initial stage of fermentation process, additional fortification is needed. The research objective was to study the development rate of lactic acid microorganisms during the fermentation of plant substrate with a modified carbohydrate composition. Study objects and methods. The research featured model medium based on white cabbage of the Parus variety. The medium was fermented with different strains of lactic acid microorganisms: at the first stage of fermentation – Leuconostoc mesenteroides, at the second stage – Lactobacillus casei VKM 536, Lactobacillus plantarum VKM B-578, Lactobacillus brevis VKM B-1309, and their paired consortia. The initial plant material was subjected to grinding and removal of native microflora for the development of target lactic acid microorganisms, then inoculated with L. mesenteroides. The target lactic acid microorganisms were introduced after the first stage of fermentation with simultaneous adjustment of the carbohydrate composition. Results and discussion. The technology included modes of controlled two-stage microbial transformation of plant raw materials using modification of the carbohydrate composition of the substrate. A number of experiments made it possible to select the optimal composition of the consortium and establish the optimal fermentation time at the main stage of microbial processing. When the plant substrate was fermented by the consortium of L. casei + L. plantarum with an increased carbohydrate component, the decrease in the concentration was quite small: after 5–30 days, the decrease in the concentration of microorganisms did not exceed one order of magnitude, which was insignificant at an initial concentration of eight orders of magnitude. In other consortia, the decrease in the concentration of microorganisms was more pronounced. Conclusion. The fortification of the vegetable substrate with carbohydrates made it possible to maintain the concentration of lactic acid microorganisms at a level comparable to the concentration at the time of inoculation. The concentrations of microorganisms varied slightly in both monocultures and their paired consortia during the entire main fermentation stage of the model medium with a modified carbohydrate component. By the end of the main fermentation stage, the concentration of microorganisms did not fall below 107 CFU/g. Therefore, the resulting system “microflora – substrate” proved to have probiotic properties. The study can be used to develop new technological modes of controlled step-by-step fermentation of plant raw materials in order to improve the quality indicators of the final product.

Properties of Microfibers of Various Compositions as a Component of Cellular Composites

The paper presents studies on the properties of various types of micro-reinforcing fibers to assess their role and effectiveness in the structure formation of the cellular composite. Based on the data on the weight loss after exposure in a model medium of cement, analysis of the alkali resistance of fibers of five different types – basalt fiber, heat-treated basalt fiber, polymer fiber and glass fibers from two different manufacturers – was carried out. It is shown that the fibers have a sufficiently high durability in the medium of hardening cement, which is expressed by a relatively insignificant weight loss of the original fiber after exposure in a model medium for 28 days in ambient conditions. The weight loss for some fibers sharply increases when hardening conditions are changed to hydrothermal ones. The images of fibers exposed in a model medium of cement, obtained using scanning microscopy, were also analyzed, and the character of distribution of acidic and basic adsorption sites on the surface of fibers depending on the type was assessed. Based on the analysis of the obtained data, we can talk about a high number of active sites on the surface of basalt and glass fibers, which ensures the formation of crystalline new formations on them and makes it possible to predict their high adhesion to the cement matrix.

Challenges in the primary prevention of sudden cardiac death in hypertrophic cardiomyopathy in the young

A case of hypertrophic cardiomyopathy in the transition from childhood to adulthood, which was low risk by the conventional risk assessment model, medium risk by the adult risk prediction model, and high risk by the paediatric risk prediction model, was inserted an implantable cardioverter-defibrillator. Three years post-implantation, the patient was resuscitated with an appropriate discharge of cardioverter-defibrillator.

Preparation and characteristics of W/O microemulsion stabilized with polyglycerylpolyricinoleate as a potential system for oral insulin delivery

Aim. The aim of the present work was to develop the composition and study the characteristics of water-in-oil microemulsion stabilized with polyglycerylpolyricinoleate — Tween 80 — ethanol mixture as a potential system for oral insulin delivery. Materials and methods. To determine the boundaries of the regions of existence of water-in-oil microemulsion in the pseudo-three component systems water — polyglycerylpolyricinoleate (PG-3-PR, Gobiotics BV, Netherlands)/ Tween 80/ethanol — paraffin oil, mixtures of paraffin oil and surfactants with oil — surfactant ratios from 9.5:0.5 to 0.5: 9.5 (wt.) were thoroughly mixed and titrated with an aqueous phase (distilled water).Compositions with the value of hydrophilic-lipophilic balance of the PG-3-PR — Tween 80 mixture equal to 6.15 were studied. Among several types of formed systems, a single-phase region corresponding to a homogeneous, optically transparent, liquid water-in-oil microemulsion was determined. The kinetic and thermodynamic stability of a number of compositions, including those containing insulin (Actrapid HM, Novo Nordisk А/С, Denmark), was studied. The values of the effective viscosity of microemulsions at different ratios of surfactant — oil and surfactant — co-surfactant were determined using a vibration viscometer. Based on the results obtained, a composition was selected to study the kinetics of insulin release into a model environment that simulated the environment of the small intestine. Insulin solution (the control sample) and the insulin-containing microemulsion were placed in the dialysis bags and immersed in 50 mL of PBS (pH 7.4) in a shaking incubator at 180 rpm and 37 ° С. At predetermined intervals, the aliquots of dissolution media were withdrawn, and the concentration of the released peptide was determined by the Bradford assay using a UV spectrophotometer at 595 nm. Results. The composition with 9:1 surfactant — co-surfactant ratio, containing 10 % of the aqueous phase (an insulin solution with a concentration of 100 IU / ml), which remained stable both during three cycles of freezing/thawing and heating/cooling, and after long-term storage at room temperature, was selected to study the kinetics of in vitro release of the peptide into the model medium. The effective viscosity of the sample was 2.4±0.04 Pa.s. The microemulsion sample demonstrated a prolonged release of insulin within 48 hours of the experiment (43 %). Conclusions. As a result, the boundaries of the existence of microemulsion regions in pseudo-three — component systems water — polyglycerylpolyricinoleate / Tween 80 / ethanol — paraffin oil were established, as well as the values of the effective viscosity of a number of compositions were determined. The study of the kinetic and thermodynamic stability of the obtained systems, including those containing insulin, as well as the study of the kinetics of the release of biologically active substance from the microemulsion into the model medium, allowed us to determine the optimal composition for further development of nanoscale dosage forms intended for prolonged delivery of insulin to the gastrointestinal tract.