Study On The Determination Of Probiotic Bacteria And Its Functional Properties

One of the most promising areas for the development of functional foods lies inmodification of the activity of the gastrointestinal tract by use of probiotics. This experimentsystematically research the acid- and bile-tolerant, the transit tolerance, the ability to adhere tohuman intestinal cells and tl1e fLnctionaI properties of potential probiotic bacteria in order toselect the proper probiotic strains to survive, grow and perfOrm heaIth-promoting effects in theintestinal tract.Fourteen potential probiotic strail1s were tested in tl1is experiment. 7en of them wereisolated from commerciaI probiotics by usil1g TPY and HCl-acidified MRS agar andincubating anaerobically and aerobically at 37C, incIuding two Lactobacillus strains PB 1, A,two Bijidobacteria strains PBA, lNF two E}7le)vicoccus strains PB2, M1, and four Bacillusstrains PB3, M2, T2 and T3. Otl1ers were bougl1t from China General Microbiofogical CultureCo1lection Center (CGMCC), incIuding E1le)ncoccus faecalis A30, A3l, LactobacilliacidOPhilus A878 and A l l.All candidate probiotic strains were tested fOr the abiIity to adl1ere to higI1 differentiationaIcontinual cultured colorectal carcinoma cell line CCL-l87 cel1s. Low attachment to theCCL-l87 cells was observed with Bacillus strains. Moderate attachment was observed withLaclObacillus PB l, Bmpbaclerium INF, PBA and E)7le)ncoccus A31. High Attachment wasobserved with Enterococcus M1 and PB2.An in vbo methodology, which mimics iI1 vivo human upper gastrointestinal transit withHCl, pepsin, pancreatin and oxgaIl, was el11p1oyed to determine t11e effect of the undesirableconditions of the upper gastroinstestinal on potential probiotic strains. The result suggestedthat Lactobacillus A878, A, PB l, EnteIDcoccus M 1, A30, A3l, BytdObacterium PBA, lNFand Bacillus M2 were considered intrinsica]]y resistant. They can remain >95% viability whenincubated in silnuIated gastric and small intestinal juice for 3h and 4h respectiveIy, and theycan remain higher viability with the existence of milk protein. A1l strains tested have theability to grow in the presence of bile, and tI1e ability varied amOI1g t11e strains. LactobacillusPB1, A, Bytdobaclerium PBA, Enterococcus M l, A30 and A3 I showed high biIe toIerance.Others showed low bile tolerance.Cu1tures of pertential probiotic strains were anaerobically incubated at 37oC in brothsupplemented with sodium thiog1ycollate, oxgal] and choIesterol. The cholestero1 assimilated.,.ranged from 25% for Bifidobacterium PBA to 54% for Enterococcus A30. Enterococcus A30, A31, Lactobacillus A878, PBl and Bacillus M2, which assimilated more than 40% cholesterol from circumstances, can be good hypocholesterolemic candidate strains for functional food.It is concluded that Enterococcus Ml, A31, Lactobacillus PBl, Bifidobacterium PBA and INF have the ability to survive during gastric and small intestinal transit, and then colonize in the therminal ileum and colon; Enterococcus A31, A30, Lactobacillus A878, PBl and Bacillus M2 have strong ability to assimilate cholesterol.According to the Bergy's Manual of Systematic Bacteriology, Strains PBA, INF, Ml, PBl and M2 were identified as Bifidobacterium infantis, Bifidobacterium longum, Enterococcus faecium, Lactobacillus acidophilus and Bacillus subtilis respectively.