共查询到20条相似文献,搜索用时 15 毫秒
1.
Isolation and characterization of the microbial population of different South African kefir grains 总被引:2,自引:0,他引:2
R Corli Witthuhn Tersia Schoeman Trevor J Britz 《International Journal of Dairy Technology》2004,57(1):33-37
Kefir, a slightly acidic fermented milk, is produced by adding lactic acid bacteria and yeasts, in the form of grains, to milk. The bacteria and yeasts present in the kefir grains are known to vary widely. Selective growth media and morphological and biochemical characteristics were used for the isolation and identification of the microbes present in the grains from eight different sources in South Africa. The kefir grains were activated in milk for only 24 h to prevent any changes in the microbial population of the grains. The microbial numbers varied between 6.4 × 104 and 8.5 × 10 8 cfu/g on the media selective for the bacterial species and between 1.5 × 10 5 and 3.7 × 10 8 cfu/g on the media selective for the yeast species. The bacterial genera that were identified included Lactobacillus , Leuconostoc and Lactococcus and the yeast genera included Zygosaccharomyces , Candida and Saccharomyces . The distribution frequencies of the microbes in the different grains were determined and most of the grains were dominated by two microbial species. No pediococci, acetic acid bacteria or propionibacteria were detected. 相似文献
2.
Microbiological study of lactic acid bacteria in kefir grains by culture-dependent and culture-independent methods 总被引:4,自引:0,他引:4
Lactic acid bacteria (LAB) in different original kefir grains were first assessed using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) by a culture-dependent way, and were further confirmed by DNA sequencing techniques. Results indicated that a combined method of cultivation with PCR-DGGE and subsequent DNA sequencing could successfully identify four LAB strains from three kefir grains from Taiwan (named Hsinchu, Mongolia and Ilan). Lactobacillus kefiri accounted, in the three kefir grains, for at least half of the isolated colonies while Lb. kefiranofaciens was the second most frequently isolated species. Leuconostoc mesenteroides was less frequently found but still in the three kefir grains conversely to Lactococcus lactis which based on culture-dependent isolation was only found in two of the kefir grains. It was interesting to find that all three kefir grains contain similar LAB species. Furthermore, the DGGE as a culture-independent method was also applied to detect the LAB strains. Results indicated that Lb. kefiranofaciens was found in all three kefir grains, whereas Lb. kefiri was only observed in Hsinchu kefir grain and Lc. lactis was found in both Mongolia and Ilan samples. Two additional strains, Pseudomonas spp. and E. coli, were also detected in kefir grains. 相似文献
3.
Distribution of microorganisms with particular reference to encapsulated bacteria in kefir grains 总被引:4,自引:0,他引:4
Takahiro Toba Keizo Arihara Susumu Adachi 《International journal of food microbiology》1990,10(3-4):219-224
Propagable and non-propagable kefir grains in a form resembling cauliflower florets were observed by scanning electron microscopy (SEM) and light microscopy. In propagable grains short and long rod-shaped bacteria and yeasts formed separate colonies on the outside surface and inside. Internally, filaments which derived from capsules around the cells extended radially from a population of long rod-shaped bacteria. In non-propagable grains long rod-shaped bacteria with filamentous appendages were not observed, but only short rod-shaped bacteria and yeasts. Indian ink preparations showed presence of encapsulated bacteria in propagable grains and absence of these in non-propagable ones. The above results suggest that encapsulated bacteria are responsible for propagation of kefir grains. 相似文献
4.
TUĞBA KÖK TAŞ F YEŞIM EKINCI ZEYNEP B GUZEL‐SEYDIM 《International Journal of Dairy Technology》2012,65(1):126-131
Kefir grains might have different ratios and/or content of microflora according to their origin. The purpose of this study was to determine microbial flora of kefir grains produced in three regional universities in Turkey using polymerase chain reaction (PCR) and consensus sequence primers. According to the results of PCR products with the specific primers, the following were identified as the natural inhabitants of the kefir grains: Lactobacillus acidophilus, Lactobacillus helveticus, Streptococcus thermophilus, Bifidobacterium bifidum and Kluyveromyces marxianus kefir. The results of this study revealed that traditional kefir produced by using kefir grains as natural starter cultures contains lactic acid bacteria especially Lactobacillus spp. One of the sources also contained B. bifidum. This is the first record on the presence of B. bifidum in kefir grains. 相似文献
5.
ZEYNEP GUZEL‐SEYDIM JENNIFER T WYFFELS ATIF C SEYDIM ANNEL K GREENE 《International Journal of Dairy Technology》2005,58(1):25-29
Microbial populations in kefir and kefir grains were enumerated by plating. Total lactic acid bacteria, lactoccocci, lactobacilli and yeast populations increased during fermentation and increased slightly during cold storage. Kefir grains had a lactic acid bacteria : yeast ratio of 10 9 : 10 6 . In further studies, kefir grains were observed using scanning electron microscopy (SEM) methods, which indicated yeast colonization on the surface and middle part of the kefir grain. Three types of lactobacilli (short, long and curved) were noted throughout the grain. Lactococci were not observed under SEM; preparation of kefir grains for SEM may have caused removal of lactococci from the grains. 相似文献
6.
Kübra Purutolu Hümeyra spirli Mustafa Onur Yüzer Hüseyin Serencam Enes Dertli 《International Journal of Dairy Technology》2020,73(1):57-66
Traditional kefir grains were collected from distinct parts of Turkey, and their microbial profile was determined. A wide bacterial biota was observed formed by distinct lactic acid bacteria (LAB) in which Lactococcus lactis strains appeared to be dominant. Yeast species were also identified in kefir grains. Significant levels of antifungal and antibacterial activities were monitored in kefir isolates. All tested LAB produced an exopolysaccharide (EPS) containing glucose and galactose, and some strains formed a fructan‐type EPS. Importantly, low levels of antibiotic resistance were observed among the kefir isolates. 相似文献
7.
KATJA ZAJŠEK MITJA KOLAR ANDREJA GORŠEK 《International Journal of Dairy Technology》2011,64(4):544-548
The main goal of this work was to characterise and quantify the exopolysaccharide kefiran and to discover an effective procedure for its isolation from kefir grains, originating from the Caucasian Mountains. Capillary electrophoresis was used for the characterisation and quantification of the d ‐glucose and d ‐galactose in our samples at a mass ratio of 1:0.7. The effect of fermentation time on growth of kefir grains and the content of kefiran within the grains were determined. The pH profiles were monitored dynamically. In addition, the influence of fermentation temperature on kefir grains mass concentration (γKG) and the content of kefiran within the grains (wKEF/KG) were studied. The highest values for both were obtained at 30 °C. 相似文献
8.
Investigation on culturable microflora in tibetan kefir grains from different areas of china 总被引:1,自引:0,他引:1
Four samples of Tibetan kefir grains (TK-ZJUJ 01-04) from Tibet and surrounding areas were investigated via phenotypic and genotypic methods to compare and analyze the diversity of culturable microflora among different origins. As a result, 4 genera of microorganisms from TK-ZJUJ01: Bacillus subtilis (2.9 × 10(7) cfu/mL), Lactococcus lactis (8.2 × 10(7) cfu/mL), Kluyveromyces marxianus (3.0 × 10(6) cfu/mL), Saccharomyces cerevisiae (9.0 × 10(6) cfu/mL); 4 genera from TK-ZJUJ02: Lactobacillus kefiri (1.0 × 10(8) cfu/mL), Pichia kudriavzevii (5.0 × 10(6) cfu/mL), K. marxianus (1.9 × 10(7) cfu/mL), Kazachstania unispora (6.2 × 10(7) cfu/mL); 6 genera from TK-ZJUJ03: Leuconostoc lactis (4.6 × 10(7) cfu/mL), L. lactis (3.0 × 10(7) cfu/mL), Lactobacillus plantarum (3.0 × 10(7) cfu/mL), K. unispora (3.0 × 10(6) cfu/mL), K. marxianus (2.0 × 10(6) cfu/mL), (1.7 × 10(7) cfu/mL); and 4 genera from TK-ZJUJ04: L. plantarum (1.8 × 10(7) cfu/mL), Acetobacter fabarum (5.0 × 10(6) cfu/mL), K. unispora (6.2 × 10(7) cfu/mL), Pichia guilliermondii (6.2 × 10(7) cfu/mL) were identified. Yeasts like P. kudriavzevii and P. guilliermondii isolated in this study were the first time reported in Tibetan kefir grains. For TK-ZJUJ 01-03, lactic acid bacteria were the major microorganisms, which accounted for more than 50% of all the microbial population, while for TK-ZJUJ04, the largest microbial group was yeasts which accounted for more than 50%. In a word, study of diversity and composition of microflora provided us theoretical foundation for further investigation and application of Tibetan kefir grains. Practical Application: This is the basic research in order to develop and industrialize a new kind of yogurt starter which is naturally formed microbiota with both lactic acid bacteria and yeasts in it. 相似文献
9.
Gelling properties of kefiran, a food-grade polysaccharide obtained from kefir grain 总被引:1,自引:0,他引:1
Judith A. Piermaria Mariano L. de la Canal Analía G. Abraham 《Food Hydrocolloids》2008,22(8):1520-1527
The physicochemical and gelling properties of kefiran, a water-soluble glucogalactan with probed health-promoting properties, were investigated. Gel permeation chromatograms revealed a single distribution of molecular weight corresponding to 107 Da. Intrinsic viscosity of kefiran determined using Huggins extrapolations was 6.0 dl/g and using Kramer approximations was 5.95 dl/g.Kefiran has a Newtonian behaviour in diluted solutions, which becomes pseudoplastic at higher concentrations. Rheological behaviour of the solution before and after freeze drying was evaluated by small deformation oscillatory rheological measurements. The mechanical spectrum of solution corresponded to an entangled network behaviour. After freeze–thaw treatment of the solution, a rheological behaviour transition from a liquid-like system to a gel was observed. The storage modulus (G′) in cryogels was 35 times higher than the value obtained for the solution. Rheological characteristics of the cryogel were influenced by kefiran concentration. As the polymer concentration increased, higher number of interactions was evident for the increment in both moduli (G′ and G″). The behaviour of kefiran cryogels about 37 °C determines its ability to melt at mouth temperature. These results suggest that kefiran cryogels could be an interesting alternative for its application in food formulations. 相似文献
10.
Cheese whey fermented with kefir micro‐organisms: Antagonism against Salmonella and immunomodulatory capacity
下载免费PDF全文
![点击此处可从《International Journal of Dairy Technology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Alejandra Londero Carolina Iraporda Graciela L Garrote Analía G Abraham 《International Journal of Dairy Technology》2015,68(1):118-126
The antagonistic effect against Salmonella spp. and the immunomodulatory capacity of whey fermented with kefir grains and with three strains isolated from them – Lactobacillus plantarum CIDCA 8327, Lactobacillus kefiri CIDCA 8348 and Kluyveromyces marxianus var. marxianus CIDCA 8154 – were evaluated. Both fermented products interfered with the capacity of Salmonella spp. to associate and invade Caco‐2/TC7 cells and reduced up to the basal level the expression of the CCL20 in response to a pro‐inflammatory stimulus on Caco‐2 CCL20:luc cells. The products with potential application as probiotics obtained by fermentation of whey with kefir micro‐organisms represent an alternative to increase whey economic value. 相似文献
11.
12.
Kefir is a functional dairy product and the effects of kefir consumption on health have been well documented. Kefir grains have naturally high numbers of lactic acid bacteria and yeasts and are used in manufacturing kefir. The biomass of kefir grains slowly increases after successive fermentations. The effects of adding whey protein isolate, modified whey protein (MWP, fat replacer; Carbery Inc., Cork, Ireland), or inulin to milk and different atmospheric conditions (ambient or 6% CO2) during fermentation on the increase in biomass of kefir grains were investigated. Reconstituted milks (10% milk powder) enriched with whey protein isolate (2%), MWP (2%), and inulin (2%) were inoculated with kefir grains and fermented in ambient and 6% CO2 incubators at 25°C until a final pH of 4.6 was reached. Biomass increments of kefir grains were determined weekly over 30 d. Lactic acid bacteria and yeast contents of kefir grains were also determined. The highest biomass increase (392%) was found in kefir grains grown in milk supplemented with whey protein isolate under ambient atmospheric conditions. Application of CO2 did not provide a significant supporting effect on the biomass of kefir grains. Addition of MWP significantly accelerated the formation of kefir grain biomass (223%). The use of whey protein isolate, MWP, or inulin in milk did not cause any adverse effects on the microbial flora of kefir grains. 相似文献
13.
Films based on kefiran,an exopolysaccharide obtained from kefir grain: Development and characterization 总被引:2,自引:0,他引:2
Judith Araceli Piermaria Adriana Pinotti María Alejandra Garcia Analía Graciela Abraham 《Food Hydrocolloids》2009
Kefiran, an exopolysaccharide produced by microorganisms present in the kefir grains, is a glucogalactan that has several health promoting properties. In the present work, the ability of kefiran to form films and the effect of glycerol addition at different concentrations on film properties was evaluated. Kefiran was able to form films at concentrations ranging from 5 to 10 g/kg. The concentration 10 g/kg was selected because the films were easily removed from the plate. All film-forming solutions exhibited a pseudoplastic behavior; glycerol addition did not modify the solution rheological properties. 相似文献
14.
Assessment of the microbial diversity of Brazilian kefir grains by PCR-DGGE and pyrosequencing analysis 总被引:2,自引:0,他引:2
Leite AM Mayo B Rachid CT Peixoto RS Silva JT Paschoalin VM Delgado S 《Food microbiology》2012,31(2):215-221
The microbial diversity and community structure of three different kefir grains from different parts of Brazil were examined via the combination of two culture-independent methods: PCR-denaturing gradient gel electrophoresis (PCR-DGGE) and pyrosequencing. PCR-DGGE showed Lactobacillus kefiranofaciens and Lactobacillus kefiri to be the major bacterial populations in all three grains. The yeast community was dominated by Saccharomyces cerevisiae. Pyrosequencing produced a total of 14,314 partial 16S rDNA sequence reads from the three grains. Sequence analysis grouped the reads into three phyla, of which Firmicutes was dominant. Members of the genus Lactobacillus were the most abundant operational taxonomic units (OTUs) in all samples, accounting for up to 96% of the sequences. OTUs belonging to other lactic and acetic acid bacteria genera, such as Lactococcus, Leuconostoc, Streptococcus and Acetobacter, were also identified at low levels. Two of the grains showed identical DGGE profiles and a similar number of OTUs, while the third sample showed the highest diversity by both techniques. Pyrosequencing allowed the identification of bacteria that were present in small numbers and rarely associated with the microbial community of this complex ecosystem. 相似文献
15.
An easy-to-use method for quantitative analysis of bacterial exopolysaccharides (EPS) was developed. The acid treatment was resultant in removing proteins and lactose and allowed to avoid long-term operation as dialysis. It was shown that, as opposed to anthron and phenol–sulphuric acid methods, reducing sugars method after EPS hydrolysis with glucose as standard provided reliable results, no matter to the EPS monosaccharide composition. 相似文献
16.
17.
Feed destined for animal production as brewer's grains can be contaminated by Aspergillus section Flavi species. Lactic acid bacteria (LAB) play a defining role in the preservation and microbial safety of fermented foods. The objective of this study was to study the incidence of lactic acid bacteria, Aspergillus section Flavi and AFB1 in brewer's grains and the preliminary antifungal activity of native LAB in vitro. LAB and aflatoxigenic Aspergillus were found in high counts in brewer's grains used as raw material for pig feedstuff. However, AFB1 had low AFB1 natural incidence in samples. In vitro antifungal activity of LAB isolated showed that all bacteria tested inhibited two Aspergillus flavus strains assayed. The high incidence of LAB could be inhibiting the AFB1 production in by-products obtained from the beer industry. LAB strains with excellent antimicrobial activity were also found in this substrate. 相似文献
18.
Microbiological and chemical properties of kefir manufactured by entrapped microorganisms isolated from kefir grains 总被引:1,自引:0,他引:1
In this study, various yeasts (Kluyveromyces marxianus, Saccharomyces turicensis, Pichia fermentans) and lactic acid bacteria (Lactobacillus kefiranofaciens, Lactobacillus kefiri, Leuconostoc mesenteroides) were entrapped in 2 different microspheres using an entrapment ratio for the strains that was based on the distribution ratio of these organisms in kefir grains. The purpose of this study was to develop a new technique to produce kefir using immobilized starter cultures isolated from kefir grains. An increase in cell counts with fermentation cycles was observed for both the lactic acid bacteria (LAB) and yeasts, whereas the cell counts of kefir grains were very stable during cultivation. Scanning electron microscopy showed that the short-chain lactobacilli and lactococci occupied the surface of the LAB microspheres, whereas the long-chain lactobacilli were inside the microspheres. When the yeasts were analyzed, cells at a high density were entrapped in cracks on the surface and within the microspheres, where they were surrounded by the short-chain lactobacilli. The distribution of the LAB and yeast species in kefir produced from grains and microspheres showed that there was no significant difference between the kefirs produced by the 2 methods; moreover, Leu. mesenteroides and K. marxianus were the predominating microflora in both types of kefir. There was no significant difference in the ethanol and exopolysaccharide contents between the 2 kefirs, although the acidity was different. 相似文献
19.
L. Cossignani M. Gobbetti P. Damiani A. Corsetti M. S. Simonetti G. Manfredi 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1996,203(1):88-94
Freeze-dried mixed starters, freeze-dried wheat sourdough and mixed fresh-cell starters made withLactobacillus sanfrancisco CBI,L. plantarum DC400 andSaccharomyces cerevisiae 141 and/orS. exiguus M14 were used for leavening wheat doughs, and their microbiological, biochemical and breadmaking characteristics were compared with those of Italian traditional doughs produced by baker's yeast. All the doughs fermented with starters had more balanced microbiological and biochemical characteristics than dough started with baker's yeast in which alcoholic fermentation end-products largely predominated. By using starters, the greatest lactic acid bacteria cell number and acetic acid production, were achieved, along with more complete profiles of volatile compounds and greater structural stability of fermented doughs. Fresh-cell starters showed higher microbial functionality and represented the only way to enrich the doughs withS. exiguus M14, some of which survived the freeze-drying process. No differences were detected between the two different types of freeze-dried starters and the subsequent use (10 times) of doughs initially produced with freezedried starters eliminated initial differences in the microbial functionality with respect to fresh-cell starters. 相似文献
20.
Brewer's grains are the most important by-product of the brewery industry and it is mostly used as a protein and energy source in animal nutrition. Listeria monocytogenes is a food-borne pathogen can cause invasive diseases such as meningoencephalitis, sepsis, abortion, and gastroenteritis in humans and several animal species. The aim of this work was to study the antilisterial activity of lactic acid bacteria (LAB) isolated from brewer's grains. The incidence of Listeria spp. in brewer's grains was 3.12%. Twenty-one LAB inhibited the growth of the eight strains of L. monocytogenes. The mean inhibition halo of cell free supernatants of LAB ranged between 11.5 and 24.5 mm. The isolation of lactic acid bacteria with antilisterial activity from brewer's grains is promising based on their capacity to produce antimicrobial compounds. The production of antimicrobial metabolites by LAB in the substrate would generate an unfavorable environment for the growth of the pathogenic bacterium under study. 相似文献