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Probiotic Properties of Lactobacillus Strains Isolated from Tibetan Kefir Grains  [PDF]
Yongchen Zheng, Yingli Lu, Jinfeng Wang, Longfei Yang, Chenyu Pan, Ying Huang
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0069868
Abstract: The objective of this study was to evaluate the functional properties of lactic acid bacteria (LAB) isolated from Tibetan kefir grains. Three Lactobacillus isolates identified as Lactobacillus acidophilus LA15, Lactobacillus plantarum B23 and Lactobacillus kefiri D17 that showed resistance to acid and bile salts were selected for further evaluation of their probiotic properties. The 3 selected strains expressed high in vitro adherence to Caco-2 cells. They were sensitive to gentamicin, erythromycin and chloramphenicol and resistant to vancomycin with MIC values of 26 μg/ml. All 3 strains showed potential bile salt hydrolase (BSH) activity, cholesterol assimilation and cholesterol co-precipitation ability. Additionally, the potential effect of these strains on plasma cholesterol levels was evaluated in Sprague-Dawley (SD) rats. Rats in 4 treatment groups were fed the following experimental diets for 4 weeks: a high-cholesterol diet, a high-cholesterol diet plus LA15, a high-cholesterol diet plus B23 or a high-cholesterol diet plus D17. The total cholesterol, triglyceride and low-density lipoprotein cholesterol levels in the serum were significantly (P<0.05) decreased in the LAB-treated rats compared with rats fed a high-cholesterol diet without LAB supplementation. The high-density lipoprotein cholesterol levels in groups B23 and D17 were significantly (P<0.05) higher than those in the control and LA15 groups. Additionally, both fecal cholesterol and bile acid levels were significantly (P<0.05) increased after LAB administration. Fecal lactobacilli counts were significantly (P<0.05) higher in the LAB treatment groups than in the control groups. Furthermore, the 3 strains were detected in the rat small intestine, colon and feces during the feeding trial. The bacteria levels remained high even after the LAB administration had been stopped for 2 weeks. These results suggest that these strains may be used in the future as probiotic starter cultures for manufacturing novel fermented foods.
Microbiota of kefir grains  [cached]
Tomislav Poga?i?,Sanja ?inko,?imun Zamberlin,Dubravka Samar?ija
Mljekarstvo , 2013,
Abstract: Kefir grains represent the unique microbial community consisting of bacteria, yeasts, and sometimes filamentous moulds creating complex symbiotic community. The complexity of their physical and microbial structures is the reason that the kefir grains are still not unequivocally elucidated. Microbiota of kefir grains has been studied by many microbiological and molecular approaches. The development of metagenomics, based on the identification without cultivation, is opening new possibilities for identification of previously nonisolated and non-identified microbial species from the kefir grains. Considering recent studies, there are over 50 microbial species associated with kefir grains. The aim of this review is to summarise the microbiota composition of kefir grains. Moreover, because of technological and microbiological significance of the kefir grains, the paper provides an insight into the microbiological and molecular methods applied to study microbial biodiversity of kefir grains.
Kefir: A Probiotic Dairy-Composition, Nutritional and Therapeutic Aspects  [PDF]
Semih Otles,Ozlem Cagindi
Pakistan Journal of Nutrition , 2003,
Abstract: Kefir is fermented milk only made from kefir grains and kefir cultures as no other milk culture forms. Kefir grains are the mixture of beneficial bacteria and yeast with a polysaccharide matrix. During fermentation lactic acid, CO2, ethyl alcohol and aromatic compounds that make its unique organoleptic properties are occurred. Kefir is used for the treatment or control of several diseases for many years in Russia. It is begun to consume in some areas of the world, southwestern Asia, eastern and northern Europe, North America and Japan for its nutritional and therapeutic aspects. This paper attempts to review the consumption, process, chemical and nutritional composition and the health benefits of kefir.
Microbial profile of a kefir sample preparations: grains in natura and lyophilized and fermented suspension
Bergmann, Rafaela Strada de Oliveira;Pereira, Maria Aparecida;Veiga, Sandra Maria Oliveira Moraes;Schneedorf, José Maurício;Oliveira, Nelma de Mello Silva;Fiorini, Jo?o Evangelista;
Ciência e Tecnologia de Alimentos , 2010, DOI: 10.1590/S0101-20612010000400029
Abstract: probiotics are supplementary foods developed by microbial strains that improve animal health beyond basic nutrition. probiotics are consumed orally, regardless of being considered as normal inhabitants of the intestines, able to survive in enzimatic and biliary secretions. kefir is a probiotic originated from the old continent, fermented by several bacteria and yeasts, encapsulated in a polyssacharide matrix, and resembles jelly grains. kefir is also presented as its sourish product both in sugary or milky suspensions containing vitamins, aminoacids, peptides, carbohydrates, ethanol, and volatile compounds. kefir is known to have a diverse microbial content depending on the country and fermentative substrates, which cause distinct probiotic effects. in this sense, the purpose of this work was to isolate, identify, and quantify the microbial content of a native sugary kefir sample (fermented suspension and lyophilized natural grains). serial dilutions were plated on rogosa agar (ar) and de man, rogosa and sharpe (mrs), for lactobacillus; brain heart infusion (bhi), for total bacteria; sabouraud-dextrose-agar (sda), for yeasts and filamentous fungi; thioglycolate agar (ta), for streptococcus, acetobacteria and leuconostoc; and coconut water agar (cwa), and cwa supplemented with yeast extract (cway), for various genera. genera and species for all strains were identified through biochemical reactions and specific api systems. the microbial profile of kefir was different from other sources of grains despite the presence of similar microorganisms and others which have not been reported yet. the data obtained with the cwa and cwae media suggest that both substrates are alternative and salutary media for culture of kefir strains.
Application of Whey Permeate Fermented with Kefir Grains for the Shelf-Life Improvement of Food and Feed  [PDF]
Raúl Ricardo Gamba, Candela Moure, Gabriela Diosma, Leda Giannuzzi, Graciela Liliana De Antoni, ángela María León Peláez
Advances in Microbiology (AiM) , 2016, DOI: 10.4236/aim.2016.69064
Abstract: Fungal contamination by Aspergillus parasiticus and A. flavus causes negative effects on the production of food cereals. Kefir is an ancient fermented beverage obtained by the fermentation of different substrates with kefir grains. An important waste produced by the dairy cheese industry is the whey permeate, which nowadays is a strong ambient contaminant. The aim of this work was the standardization of the whey permeate fermenting conditions with kefir grains, the assessment of the antifungal activity of the cell-free-supernatants (CFS) from these fermentations and to compare it with that obtained with CFS of milk fermented with kefir grains. Finally, we studied if the addition of kefir fermented whey permeate to food (bread) and feed (poultry) could produce shelf life improvement. The optimal condition to obtain CFS with fungicidal effect was a fermentation with 10% w/v of kefir grains, at 30°C, for 24 hours until a pH 3.7. We found that CFS from whey permeate caused fungal inhibition, whereas CFS of kefir grains grown in milk showed lower antifungal activity. Additionally, the addition of kefir-fermented whey permeates in food (bread) and feed (poultry) improved their resistance to fungal contamination. This is the first report about the application of kefir-fermented whey permeate to improve the shelf life, suggesting its potential use as a biopreservative.
Sequencing-Based Analysis of the Bacterial and Fungal Composition of Kefir Grains and Milks from Multiple Sources  [PDF]
Alan J. Marsh, Orla O’Sullivan, Colin Hill, R. Paul Ross, Paul D. Cotter
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0069371
Abstract: Kefir is a fermented milk-based beverage to which a number of health-promoting properties have been attributed. The microbes responsible for the fermentation of milk to produce kefir consist of a complex association of bacteria and yeasts, bound within a polysaccharide matrix, known as the kefir grain. The consistency of this microbial population, and that present in the resultant beverage, has been the subject of a number of previous, almost exclusively culture-based, studies which have indicated differences depending on geographical location and culture conditions. However, culture-based identification studies are limited by virtue of only detecting species with the ability to grow on the specific medium used and thus culture-independent, molecular-based techniques offer the potential for a more comprehensive analysis of such communities. Here we describe a detailed investigation of the microbial population, both bacterial and fungal, of kefir, using high-throughput sequencing to analyse 25 kefir milks and associated grains sourced from 8 geographically distinct regions. This is the first occasion that this technology has been employed to investigate the fungal component of these populations or to reveal the microbial composition of such an extensive number of kefir grains or milks. As a result several genera and species not previously identified in kefir were revealed. Our analysis shows that the bacterial populations in kefir are dominated by 2 phyla, the Firmicutes and the Proteobacteria. It was also established that the fungal populations of kefir were dominated by the genera Kazachstania, Kluyveromyces and Naumovozyma, but that a variable sub-dominant population also exists.
Antifungal Activity against Aspergillus parasiticus of Supernatants from Whey Permeates Fermented with Kefir Grains  [PDF]
Raúl Ricardo Gamba, Carolina Ni Colo, Mariana Correa, Andrea Astoreca, Teresa Alconada, Graciela De Antoni, Angela León Peláez
Advances in Microbiology (AiM) , 2015, DOI: 10.4236/aim.2015.56049
Abstract: Aspergillus parasiticus, a common fungal contaminant in food, produces aflatoxin B1, which is classified as human carcinogen. Kefir is an ancient fermented beverage obtained by the fermentation of different substrates with kefir grains. A very important waste produced by the dairy cheese industry is the whey permeate, which nowadays is a strong ambient contaminant. The aim of this work was to assess the effect of whey permeates fermented with kefir grains against A. parasiticus growth, aflatoxin B1 biosynthesis, and the kefir microorganisms protection against the cell damage produced by aflatoxin B1. It was observed that kefir-cell-free-supernatants (CFS) produced fungal inhibition. A fungicidal effect was observed with 65% v/v of CFS in the culture medium (final pH 4.55 and total undissociated lactic and acetic acid concentration 34.08 mM). Under these conditions, aflatoxin production was not detected. Finally, it was found that non-viable kefir microorganisms protected HepG2 cells from the damage produced by aflatoxin B1.
Analysis of bacterial diversity of kefir grains by denaturing gradient gel electrophoresis and 16S rDNA sequencing
应用变性梯度凝胶电泳和16S rDNA序列分析对kefir粒中细菌多样性的研究

WANG Yin-yu,LI Hui-rong,JIA Shi-fang,WU Zheng-jun,GUO Ben-heng,
王荫榆
,李会荣,贾士芳,吴正钧,郭本恒

微生物学报 , 2006,
Abstract: Kefir is an acidic,mildly alcoholic dairy beverage produced by the fermentation of milk with a grain-like starter culture.These grains usually contain a relatively stable and specific balance of microbes that exist in a complex symbiotic relationship.Kefir grains can be considered a probiotic source as it presents anti-bacterial,anti-mycotic,anti-neoplasic and immunomodulatory properties.The microorganisms in Kefir grains are currently identified by traditional methods such as growth on selective media,morphological and biochemical characteristics.However,the microorganisms that isolate by these methods can not revert to Kefir grains which indicate that there are some other bacteria that are not isolate from it.In this study,PCR-based Denaturing gradient gel electrophoresis(DGGE) and sequence analysis of 16S ribosomal RNA gene((16S rDNA)) clone libraries was used for the rapid and accurate identification of microorganisms from Kefir grains.The PCR primers were designed from conserved nucleotide sequences on region V3 of(16S rDNA) with GC rich clamp at the 5'-end.PCR was performed using the primers and genomic DNAs of Kefir grains bacteria.The generated region V3 of(16S rDNA) fragments were separated by denaturing gel,and the dominant(16S rDNA) bands were cloned,sequenced and subjected to an online similarity search.Research has shown that regions V3 of(16S rDNA)s have eight evident bands on the DGGE gel.The sequence analysis of these eight bands has indicated that they belong to different four genera,among them three sequences are similar to Sphingobacterium sp.whose similarities with database sequences are over 98%,three sequences are similar to Lactobacillus sp.whose similarities with database sequences are over 96%,the other two sequence are similar to Enterobacter sp.,and Acinetobacter sp.whose similarities with database sequences are over 99% respectively.Although the DGGE method may have a lower sensitivity than the ordinary PCR methods,because when universal bacterial PCR primers are used, only the dominant microbiota of an ecosystem will be visualized on a DGGE gel,producing complex banding patterns.However,it could visualize the bacterial qualitative compositions and reveal the major species of the Kefir grains.Among them Sphingobacterium can be found in Kefir grains as the predominant flora which is reported for the first time.PCR-based DGGE and sequence analysis of(16S rDNA) proved to be a valuable culture-independent approach for the rapid and specific identification of the microbial species present in microecosystem and probiotic products.
Effects of Lactobacillus kefiranofaciens M1 Isolated from Kefir Grains on Germ-Free Mice  [PDF]
Yen-Po Chen, Ming-Ju Chen
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0078789
Abstract: Lactobacillus kefiranofaciens M1 is a novel probiotic strain that was isolated from kefir grains. Previously, we have demonstrated the immunoregulatory, anti-allergic, anti-asthmatic and anti-colitis abilities of L. kefiranofaciens M1 in a number of in-vitro and in-vivo experiments. However, whether the effects of L. kefiranofaciens M1 are elicited directly on the host or act by regulating the host's microbiota remains unknown. A number of studies have used germ-free or gnotobiotic animals to investigate the relationship between probiotics and colitis; therefore the aim of this study was to investigate the effects of L. kefiranofaciens M1 on germ-free mice. Such an approach should help in determining the direct effects of L. kefiranofaciens M1 on the host itself. Four-week-old female germ-free mice were inoculated intragastrically with 2×108 CFU/mouse L. kefiranofaciens M1 once or at 2-day intervals for 14 days. Bacterial colonization, the Th1/Th2 cytokine profile of the mice's splenocytes and the anti-colitis effect of L. kefiranofaciens M1 were investigated. The strongest response in terms of splenic Th1 cytokine IFN-γ and IL-12 production upon TLR activation was detected in the continuous treatment group when comparing to the single inoculation group and the germ-free control. In addition, continuous inoculation with L. kefiranofaciens M1 was found to ameliorate the symptoms of DSS-induced colitis in germ-free mice. However, L. kefiranofaciens M1 failed to colonize the host. Thus it would seem that L. kefiranofaciens M1 is likely to act directly on the host and not be involved in microbiota regulation.
Caracteriza??o físico-química e sensorial de kefir tradicional e derivados
Weschenfelder, S.;Pereira, G.M.;Carvalho, H.H.C.;Wiest, J.M.;
Arquivo Brasileiro de Medicina Veterinária e Zootecnia , 2011, DOI: 10.1590/S0102-09352011000200027
Abstract: it was evaluated different traditional kefir grain populations and their derivatives, kefir, kefir leban and kefir whey, regarding physicochemical and sensorial characteristics when inoculated into different standardized milk concentrations, with incubation time/temperature, maturation and filtration variables. the manipulation of the population of kefir grains was effective in obtaining products with similar physicochemical characteristics and the volume of milk used in the incubation significantly influenced the characteristics of derivatives. the sensory evaluation of kefir leban food formulations such as spiced hors d'oeuvre, showed good acceptability.
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