Inflammation is the initial response of the immune system to potentially harmful stimuli (e.g., injury, stress, and infections). The process involves activation of macrophages and neutrophils, which produce mediators, such as nitric oxide (NO), prostaglandin E2 (PGE2), pro-inflammatory and anti-inflammatory cytokines. The pro-inflammatory cytokines interleukin-1β (IL-1β), interleukin 6 (IL-6), and tumor necrosis factor-α (TNF-α) are considered as biomarkers of inflammation. Even though it occurs as a physiological defense mechanism, its involvement in the pathogenesis of various diseases is reported. Rheumatoid arthritis, inflammatory bowel disease, Alzheimer’s disease, and cardiovascular diseases are only a part of the diseases, in which pathogenesis the chronic inflammation is involved. Fucoidans are complex polysaccharides from brown seaweeds and some marine invertebrates, composed mainly of L-fucose and sulfate ester groups and minor amounts of neutral monosaccharides and uronic acids. Algae-derived fucoidans are studied intensively during the last years regarding their multiple biological activities and possible therapeutic potential. However, the source, species, molecular weight, composition, and structure of the polysaccharides, as well as the route of administration of fucoidans, could be crucial for their effects. Fucoidan is reported to act on different stages of the inflammatory process: (i) blocking of lymphocyte adhesion and invasion, (ii) inhibition of multiple enzymes, and (iii) induction of apoptosis. In this review, we focused on the immunemodulating and anti-inflammatory effects of fucoidans derived from macroalgae and the models used for their evaluation. Additional insights on the molecular structure of the compound are included.

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Lactobacillus plantarum strains were isolated from fully ripened, white brined Bulgarian home-made cheeses. Strains were derived from phenotypically homogenous Lactobacillus group and were identified as L. plantarum based on both phenotypic and molecular identification (species-specific and multiplex PCR) methods. Heterogeneity of L. plantarum isolates was evaluated by Rep-PCR analysis. Further antimicrobial activity, antibiotic susceptibility and transit tolerance of the strains were evaluated. Most of them showed broad spectrum of activity against Gram-negative bacteria (including human pathogens) independent on the presence of organic acids or hydrogen peroxide. All strains were sensitive to amoxicillin and sulfamethoxazole/trimethoprim, resistant to clinically relevant beta -lactame antibiotics (penicillin and ampicillin) and to nalidixic acid, ciprofloxacin, streptomycin, and vancomycin. Significant variability in the sensitivity to tetracycline was noted. The tolerance to low pH, bile salts, pepsin and pancreatin at concentrations similar to those in the gastrointestinal tract was strain-dependent. The exposure to bile salts was less destructive than exposure to pH 2.0 for all tested strains. Based on their combined responses to the above selection criteria, four L. plantarum strains, RL29, RL34, RL36 and RL37, were selected as potential probiotics for in vivo studies.

The present work discusses the technological and new selection criteria that should be included for selecting lactic acid bacteria for production of fermented meat. Lactic acid bacteria isolated from Bulgarian traditional fermented “lulanka” salami was studied regarding some positive technological parameters (growth at different temperature, pH, and proteolytic activity). The presence of genes related to the virulence factors, production of biogenic amines, and vancomycin resistance were presented in low frequency in the studied lactic acid bacteria. On the other hand, production of antimicrobial peptides and high spread of bacteriocin genes were broadly presented. Very strong activity against L. monocytogenes was detected in some of the studied lactic acid bacteria. In addition, the studied strains did not present any antimicrobial activity against tested closely related bacteria such as Lactobacillus spp., Lactococcus spp., Enterococcus spp. or Pediococcus spp. To our knowledge this is the first study on the safety and antimicrobial properties of lactic acid bacteria isolated from Bulgarian lukanka obtained by spontaneous fermentation.

Twenty‐one Lactobacillus strains isolated from three types of Balkan homemade yogurts were grown on sodium caseinate, β‐casein or whey proteins, and the proteolysis was followed by electrophoresis and reversed‐phase high‐performance liquid chromatography. The best conditions allowing obtaining proteolysis without casein precipitation are 0.8% casein in 50‐mM phosphate buffer. The strains tested showed a relatively high proteolytic activity despite the limited conditions for bacterial growth. Within 72 and 96 h of incubation, 80–90% of β‐casein was consumed. They showed also a proteolytic activity toward α‐lactalbumin (ALA), being able to reduce its concentration between 5 and 55%, depending on the strains used. The capacity of the strains to hydrolyze β‐lactoglobulin was lower as compared with hydrolysis of ALA. Hydrolysis of casein by all strains produced peptides with an antibacterial effect against Escherichia coli. Consequently, to obtain a maximal hydrolysis of the dairy proteins seconded by appearance of antimicrobial peptides, a combination of strains with different beneficial properties to be used as starters was proposed. PRACTICAL APPLICATIONS Some of the 21 Lactobacillus strains isolated from three types of Balkan homemade yogurts may be used to proteolyze milk proteins in order to produce peptides with an antibacterial effect against Escherichia coli. To obtain a maximal hydrolysis of the dairy proteins seconded by appearance of antimicrobial peptides, a combination of strains with different beneficial properties to be used as starters should be determined. During fermentation process, milk proteins are acidified by the production of lactic acid and are hydrolyzed by proteases and peptidases from bacteria. This proteolysis is followed by a reduction of the number of epitopes and consequently by a decrease in allergenicity of hydrolyzed proteins. For these reasons, starters as Lactobacillus strains with beneficial properties able to reduce the allergenicity of fermented milk products are of great interest for the dairy industry.