Activity Of Fermented Milk Research Articles

Probiotic Properties of Lactobacillus brevis KU200019 and Synergistic Activity with Fructooligosaccharides in Antagonistic Activity against Foodborne Pathogens.

This study aims to evaluate the probiotic properties of Lactobacillus brevis (L. brevis) KU200019 and the synergistic activity with prebiotics on antimicrobial activity, and the potential application as an adjunct culture in fermented dairy products. The commercial strain, L. brevis ATCC 14869 was used as reference strain. L. brevis KU200019 was showed higher viability in simulated gastric (99.38±0.21%) and bile (115.10±0.13%) conditions compared to reference strain. L. brevis KU200019 exhibited antimicrobial activity against various foodborne pathogens. The supplementation of fructooligosaccharides (FOS) enhanced viability of lactic acid bacteria (>8 Log CFU/mL) and antioxidant activity [2,2-diphenyl-2-picrylhydrazyl radical assay (DPPH) assay, 31.23±1.14%; 2,2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS) assay, 38.82±1.46%] in fermented skim milk during refrigerated storage. L. brevis KU200019 was distinguished from the reference strain by its higher probiotic potential, antimicrobial activity, and higher antioxidant activity in fermented milk. Therefore, L. brevis KU200019 with FOS was demonstrated promising properties for further application in fermented dairy products with enhanced safety and quality.

Effect of incubation time, inoculum size, temperature, pasteurization time, goat milk powder and whey powder on ACE inhibitory activity in fermented milk by L. plantarum LP69 [pdf

Effect of incubation time, inoculum size, temperature, pasteurization time, goat milk powder and whey powder on ACE inhibitory activity in fermented milk by L. plantarum LP69 [pdf

Effect of incubation time, inoculum size, temperature, pasteurization time, goat milk powder and whey powder on ACE inhibitory activity in fermented milk by L. plantarum LP69

Effect of incubation time, inoculum size, temperature, pasteurization time, goat milk powder and whey powder on ACE inhibitory activity in fermented milk by L. plantarum LP69

Anti-Helicobacter pylori activity of fermented milk with lactic acid bacteria

Ten strains of lactic acid bacteria (LAB) were investigated for their anti-Helicobacter pylori effects. The bactericidal activity and organic acid content in spent culture supernatants (SCS) from fermented milk were measured. In addition, the exclusion effect of SCS against H. pylori infection of human gastric epithelial AGS cells was assayed. Three LAB strains, LY1, LY5 and IF22, showed better anti-Helicobacter effects than the other strains. There were no significant differences in the bactericidal activity of LAB strains between original SCS, artificial SCS and SCS treated by heating or protease digestion. However, neutralised SCS lost this activity. These results suggest that the anti-H. pylori activity of SCS may be related to the concentration of organic acids and the pH value but not to protein components. In the AGS cell culture test, both fermented LY5-SCS and artificial LY5-SCS significantly reduced H. pylori infection and urease activity (P < 0.05). In this study, in vitro methods were used to screen potential probiotics with anti-H. pylori activity. This may provide an excellent and rapid system for studying probiotics in the functional food and dairy industries.

Proteolytic activity of dairy lactic acid bacteria and probiotics as determinant of growth and in vitro angiotensin-converting enzyme inhibitory activity in fermented milk

L'activite proteolytique des bacteries lactiques et probiotiques laitiers determine la croissance et l'activite inhibitrice de l'enzyme de conversion de l'angiotensine (ACE) dans le lait fermente. Deux souches de Lactobacillus acidophilus (L10 et La 4962), de Bifidobacterium spp. (B. lactis B94 et B. longum Bl 536), et de Lactobacillus casei (L26 et Le 279), et une souche de Streptococcus thermophilus (St 1342) et de Lactobacillus delbrueckii ssp. bulgaricus (Lb 1466) ont ete etudiees pour leurs caracteristiques de croissance, activite proteolytique et liberation de peptides inhibant l'ACE in vitro dans du lait ecreme reconstitue. Les cultures pures croissaient bien a l'exception de Lactobacillus delbrueckii ssp. bulgaricus. Malgre une croissance lente, cette culture produisait des quantites substantielles d'acide lactique, venant en seconde position apres S. thermophilus. Toutes les souches presentaient des activites proteolytiques avec des peptidases intra- et extracellulaires dont une X-prolyl-dipeptidyl aminopeptidase. Cette enzyme coupait les sequences contenant une proline, ce qui ameliorait potentiellement la liberation de peptides varies et, en consequence, probablement la croissance cellulaire. L'importance de la proteolyse etait variable selon les souches, mais apparaissait dependante du temps. Toutes les cultures liberaient des peptides ayant une activite inhibitrice de l'ACE in vitro au cours de la croissance, avec pour B. longum et L. acidophilus L10 des valeurs d'IC 50 de 0,196 et de 0,151 mg.mL -1 respectivement.

Angiotensin I-converting enzyme inhibitory activity in milk fermented by wild-type and peptidase-deletion derivatives of Lactobacillus helveticus CNRZ32

Development of molecular methods has enabled detailed studies of the proteolytic system of Lactobacillus helveticus, which has a central role in the release of bioactive peptides during the fermentation of milk. The impact of general aminopeptidase (PepN) and X-prolyl dipeptidyl aminopeptidase (PepX) activity of L. helveticus on the level of angiotensin I-converting enzyme (ACE) inhibitory activity in fermented milk was elucidated by taking advantage of peptidase-negative derivatives of L. helveticus CNRZ32. According to the results, increased level of ACE-inhibitory activity was attained in milk fermented by the peptidase-deficient mutants. The ACE-inhibitory activity determined with the PepN-deficient strain decreased towards the end of fermentation, suggesting that PepN gives rise to a provisional accumulation of ACE-inhibitory peptides before their hydrolysis to shorter peptides or free amino acids. The ACE-inhibitory activity determined with the PepX-deficient strain increased throughout the fermentation, indicating specific blocking of the further hydrolysis of ACE-inhibitory peptides.