Probiotic spectra of lactic acid bacteria (LAB)

Lactic acid bacteria (LAB) and their probio-active cellular substances exert many beneficial effects in the gastrointestinal tract. LAB prevent adherence, establishment, and replication of several enteric mucosal pathogens through several antimicrobial mechanisms. LAB also release various enzymes into the intestinal lumen and exert potential synergistic effects on digestion and alleviate symptoms of intestinal malabsoption. Consumption of LAB fermented dairy products with LAB may elicit antitumor effects. These effects are attributed to the inhibition of mutagenic activity; decrease in several enzymes implicated in the generation of carcinogens, mutagens, or tumor-promoting agents; suppression of tumors; and the epidemiology correlating dietary regimes and cancer. Specific cellular components in LAB strains seem to induce strong adjuvant effects including modulation of cell-mediated immune responses, activation of reticuloendothelial system, augmentation of cytokine pathways and regulation of interleukins, and tumor necrosis factors. Oral administration of LAB is well tolerated and proven to be safe in 143 human clinical trials and no adverse effects were reported in any of the total 7,526 subjects studied during 1961-1998. In an effort to decrease the reliance on synthetic antimicrobials and control the emerging immunocompromised host population, the time has come to carefully explore the prophylactic and therapeutic applications of probiotic LAB.     

Probiotic potential of lactic acid bacteria from fermented Malaysian food or milk products

This study investigated the probiotic characteristics of lactic acid bacteria (LAB) isolated from 14 Malaysian fermented food or milk products. In total, 22.3% (121 of 542) of the LAB isolated from the local fermented products exhibited antibacterial activity against Micrococcus luteus. Twelve LAB that demonstrated better antibacterial activity against M. luteus as compared to a commercial strain Lactobacillus casei strain Shirota (LABPC) were selected for further characterisation. Based on 16S rRNA gene sequence, the LAB were identified as pediococci (seven) and lactobacilli (five). All 12 LAB showed bile tolerance, but only eight were acid tolerant at pH ≥ 3.0. The highest level of adhesion to HT‐29 cells was observed among the Lactobacillus sp. LAB 1 and 10. The LAB also showed antimicrobial activity against Escherichia coli and Staphylococcus aureus through the production of organic acids. LAB isolated from Malaysian fermented food and milk products, especially fermented tapioca, contains potential probiotic candidates.     

Probiotic lactic acid bacteria from Kung‐Som: isolation,screening, inhibition of pathogenic bacteria

Lactic acid bacteria (LAB) were isolated from Kung‐Som at various fermentation periods. Only ten strains, named D2SM22, D6SM3, D6SM24, D6SM26, D8SM21, D10SM5, D10SM11, D10SM16, D10SM20 and D16SM26 showed a survival rate of more than 50% under the simulated gastric juice. After being subjected to simulated gastric juice, four strains (D6SM3, D8SM21, D10SM16 and D10SM20) showed a survival rate of more than 50% in simulated small intestinal juices. Growth of strain D6SM3, D8SM21 and D10SM16 under micro‐aerobic and anaerobic conditions was not different. Tested pathogenic strains (Escherichia coli, Staphylococcus aureus, Bacillus cereus, Vibrio parahaemolyticus and Salmonella sp.) were inhibited by probiotic LAB. However, none of strains could produce bacteriocins. All strains were identified as Lactobacillus plantarum. No differences in pH, acidity, LAB count and liking scores between Kung‐Som produced with starter culture and conventional method were observed (P > 0.01).     

An analysis of the effectiveness of heat-killed lactic acid bacteria in alleviating allergic diseases

Allergic diseases are reported to be caused by a skew in the balance between T helper type 1 and 2 cells. Because some lactic acid bacteria have been shown to stimulate IL-12 (p70) production, which in turn shifts the balance between the T helper type 1 and 2 cell response from the latter to the former, they have the potential to either prevent or ameliorate disease conditions or both. They have therefore been extensively studied in the recent past for their probiotic activities. Nevertheless, much less information is available concerning the microbial factors that determine the strain-dependent ability to affect the production of cytokines. The objectives of our study were first to select potentially probiotic lactobacilli that strongly stimulate cytokine production in vitro, and then to determine whether the selected Lactobacillus strains could suppress antigen-specific IgE production in vivo by using allergic model animals. Finally, our investigation was extended to analyze which bacterial components were responsible for the observed biological activity. Twenty strains of heat-killed lactobacilli isolated from humans were screened for their stimulatory activity for the production of IL-12 (p70) by murine splenocytes in vitro. The results showed that some strains of Lactobacillus plantarum and Lactobacillus gasseri had a higher stimulatory activity for IL-12 (p70) production than the other lactobacilli tested; however, this effect was strain dependent rather than species dependent. Oral administration of the heat-killed strains that showed higher stimulatory activity for IL-12 (p70) production tended to reduce the serum antigen-specific IgE levels in ovalbumin-sensitized BALB/c mice compared with the controls. Among the lactobacilli tested, L. gasseri OLL2809 showed the highest activity in reducing the level of antigen-specific IgE. Furthermore, the stimulatory activity for IL-12 (p70) production was found to be reduced after treating the lactobacilli with N-acetyl-muramidase and to be positively correlated with the amount of peptidoglycan in the cells. The present data suggest that L. gasseri OLL2809 is a good candidate for potential probiotics in terms of either the prevention or amelioration of allergic diseases or both. In addition, the strain-dependent stimulatory activity for IL-12 (p70) production was found to be due, at least in part, to the amount of peptidoglycan present in the cells.     

益生菌干酪的工艺研究

将植物乳杆菌MA2及Kefir发酵剂应用于益生菌干酪生产中,并对干酪的理化指标、感官进行了测定、评价,结果显示:成熟45 d后,相比于普通干酪,添加了植物乳杆菌MA2及Kefir的新型益生菌干酪的可溶性氮及不饱和脂肪酸的含量显著升高;并且具有良好的风味和质地,其中MA2干酪具有明显的酸奶味,提高了干酪的适口性,更加符合国人的口味习惯,具有良好的生产开发前景;而Kefir干酪具有Kefir发酵乳的特有风味,带有适宜的酒香味,可以被开发成个性化干酪,丰富了干酪的品种。     

蔬菜汁的乳酸菌发酵

为制备不含任何动物性来源成分的纯植物性的乳酸菌发酵产品,采用双歧乳杆菌、植物乳杆菌、保加利亚乳杆菌、嗜酸乳杆菌4种乳酸菌,在豆角、香菇、番茄、青瓜、胡萝卜和包菜6和蔬菜培养液中进行发酵。实验结果证明,4种乳酸菌可以在不添加其他营养物质的纯蔬菜培养液正常生长,但是不同菌种适合的蔬菜培养液也不相同,且混合蔬菜培养液培养效果要好于单一蔬菜培养液。番茄和青瓜混合培养液适合双歧乳杆菌生长,包菜和青瓜混合培养液适合植物乳杆菌生长,包菜和番茄混合培养液适合保加利亚乳杆菌生长,豆角和青瓜混合培养液适合嗜酸乳杆菌生长。蔬菜的乳酸菌发酵产品,在4℃下冷藏2周后,4种菌体的存活率均在106CFU/mL以上。在不添加其他营养物质的条件下,蔬菜汁可以用来生产活性乳酸菌产品,满足素食主义者、乳糖不耐症者的消费需求。     

三种乳酸菌混合培养的研究

在5L罐中对保加利亚乳杆菌、嗜酸乳杆菌和嗜热链球菌进行了单独培养及混合培养研究。实验结果表明,嗜酸乳杆菌及嗜热链球菌会抑制保加利亚乳杆菌的生长,保加亚利乳杆菌与嗜酸乳杆菌可能对嗜热链球菌的生长具有促进作用,嗜热链球菌对嗜酸乳杆菌具有促进作用,保加利亚乳杆菌对嗜酸乳杆菌的生长没有促进作用。这种实验结果为混合培养益生菌提供的实验参考。     

风干香肠中乳酸菌的分离鉴定及益生特性研究

由风干香肠中分离纯化得到的3株乳酸菌ORC2、QM7和QM8,均能产乳酸、革兰氏染色阳性、接触酶阴性。经系统发育分析,结合菌落形态、细胞形态、生化反应试验,确定菌株ORC2和QM7为肠膜明串珠菌,QM8为柠檬明串珠菌。乳酸菌ORC2、QM7和QM8均能降低培养基中的胆固醇,且对·OH、DPPH·和O-2·有一定的清除能力,其清除率都与细胞浓度呈正相关。在细胞浓度为5×108CFU/mL时,菌株ORC2对·OH的清除率最高,为65.36%;菌株QM8对DPPH·的清除率最高,为61.21%;而对O-2·的清除率最高的菌株为QM7,达到75.70%。菌株QM7在培养96 h能清除最多的胆固醇,清除率为51.2%。     

黄瓜圣女果复合汁乳酸发酵饮料的研制

对保加利亚乳杆菌和嗜热链球菌进行驯化,使其适应复合菜浆的生长环境。通过正交试验确定黄瓜、圣女果复合汁乳酸发酵饮料的最佳发酵条件为:黄瓜汁:圣女果汁=1∶1(W/W),牛乳添加量为10%(V/V),接种量6%(V/V),发酵温度40℃,发酵时间18h。最佳调配方案为:白砂糖5%(W/W),柠檬酸0.15%(W/W),草莓香精0.02%(V/V)。     

利用Lactobacillus casei Zhang开发益生菌新鲜干酪

通过添加不同比例Lactobacillus casei Zhang发酵剂制作新鲜干酪,并对其在新鲜干酪中的活力和添加Lactobacillus后新鲜干酪的理化性质进行了研究。结果表明,Lb.casei Zhang在新鲜干酪中具有较高的活力,添加2%、1%、0.5% Lb.casei Zhang发酵剂的干酪中,4℃冷藏开始前,Lb.casei Zhang活菌数分别为2.24×10~8 cfu/g,1.38×10~8 cfu/g,5.55×10~7 cfu/g,4℃冷藏28d后,Lb.casei Zhang存活率分别为99.12%,98.31%,98.61%。在制作过程中和4℃冷藏过程中,与空白组相比,添加Lb.casei Zhang对新鲜干酪的pH值、滴定酸度、蛋白水解活性影响都不显著(P>0.05)。     

Antilisterial activity of lactic acid bacteria inoculated on cooked ham

This study was conducted to evaluate the ability of Lactobacillus sakei 1, a bacteriocin-producing (bac⁺) lactic acid bacterium (LAB), isolated from Brazilian fresh pork sausage to inhibit two Listeria monocytogenes strains (serotypes 4b and 1/2a) on cooked, sliced vacuum-packaged ham. L. sakei ATCC 15521 was used as a non-bacteriocin producer (bac⁻). L. monocytogenes (ca. 2 log CFU/mL) and LAB (ca. 6 log CFU/ml) were inoculated on the sterilized ham, vacuum-sealed and incubated at 8 °C for 10 days. A treatment with the bacteriocin Chrisin (UI/ml) was included. Both L. monocytogenes strains were significantly inhibited in the presence of either bac⁺ and bac⁻ LAB in comparison to the control (L. monocytogenes alone). Using a bacteriocinogenic strain of LAB did not offer an additional barrier to listerial growth in the studied meat system. The application of Chrisin did not affect at all the growth of L. monocytogenes.     

高效同化胆固醇乳酸菌菌株的筛选及在食品中的应用

从发酵食品中分离筛选能高效同化胆固醇的乳酸菌,以开发低胆固醇系列产品。从25个来源不同的样品中,分离筛选出8株乳酸菌,与活化出的8株已知乳酸菌共同在特殊培养基中培养,最后筛选出2株具有较高同化胆固醇能力的菌株。结果表明,嗜酸乳杆菌和植物乳杆菌应用于食品中,对食品风味影响较小,可大量应用。     

益生乳杆菌的筛选研究

以分离保存的15株乳杆菌为研究对象,从中筛选益生乳杆菌两株。通过检测乳杆菌的疏水性和自聚性,得到表面疏水性和自聚性均较高的菌株为Ind-3、CH10和M8。其中,乳杆菌CH10和M8在模拟胃肠环境下活菌数均达到106mL-1以上。通过灌胃乳杆菌CH10和M8,表明小鼠体重增加明显高与对照组,且实验组小鼠粪便中的β-半乳糖苷酶活性明显高于对照组。灌胃两株乳杆菌后,小鼠肠道内双歧杆菌与乳杆菌活菌数提高了,且肠杆菌、肠球菌和产气荚膜梭菌的生长繁殖受到不同程度的抑制,而对照组无明显变化。结果表明筛选出的两株乳杆菌可以促进小鼠对营养物质的吸收,提高肠道内有益菌的数量,抑制有害菌的生长繁殖,或许能够改善寄主肠道的微生态环境。     

Antifungal effect of organic acids from lactic acid bacteria on Penicillium nordicum

The control of fungal contamination is particularly important to avoid both spoilage of food and feed products and the occurrence of toxic compounds, known as mycotoxins. Some lactic acid bacteria (LAB) strains have shown the capacity to inhibit fungal growth and the production of mycotoxins. In this work, cell-free supernatants (CFS) of Lactobacillus plantarum UM55 and Lactobacillus buchneri UTAD104 were tested against Penicillium nordicum radial growth and OTA production. When CFS of these strains were used, the radial growth of the fungus was inhibited by less than 20%, but the production of OTA was reduced by approx. 60%. These antifungal effects resulted from organic acids produced by LAB. The CFS of L. plantarum UM55 contained lactic acid, phenyllactic acid (PLA), hydroxyphenyllactic acid (OH-PLA) and indole lactic acid (ILA), while L. buchneri UTAD104 CFS contained acetic acid, lactic acid and PLA. These organic acids were further tested individually for their inhibitory capacity. Calculation of the inhibitory concentrations (ICs) showed that acetic acid, ILA and PLA were the most effective in inhibiting P. nordicum growth and OTA production. When the inhibitory activity of LAB cells incorporated into the culture medium was tested, L. buchneri UTAD104 inhibited the production of OTA entirely in all conditions tested, but fungal growth was only inhibited completely by the highest concentrations of cells. Acetic acid production was primarily responsible for this effect. In conclusion, the ability of LAB to inhibit mycotoxigenic fungi depends on strain capability to produce specific organic acids, and those acids may differ from strain to strain. Also, the use of LAB cells, especially from L. buchneri, in food products prone to contamination with P. nordicum (e.g. dry-cured meats and cheeses) may be an alternative solution to control fungal growth and OTA production.     

Probiotic properties of lactic acid bacteria isolated from Mukeunji, a long-term ripened kimchi

Lactic acid bacteria (LAB) isolated from mukeunji was screened for characterization of beneficial properties required as probiotics. Among the isolates from mukeunji, 5 LAB strains were selected due to their high levels of tolerance to simulated gastric fluid. These strains were identified by using SDS-PAGE of whole cell protein pattern and 16S rDNA sequencing. Subsequently, it was found that 2 isolates, Lactobacillus brevis C1 and Lactobacillus plantarum G4 among the 5 isolates were highly resistant to bile cytotoxicity in terms of survival rate, 162.2 and 114.3%, respectively. According to the results of in vitro adhesion assay, Lb. brevis C1, Lb. plantarum G4, and Lactobacillus sakei N1 had higher numbers of adhesion to Caco-2 epithelium cells than that of Lactobacillus rhamnosus GG, a well known probiotic. None of the isolates produced a carcinogenic enzyme, β-glucuronidase. In addition, Lb. brevis C1 and Lb. plantarum G4 exhibited high levels of DPPH scavenging capacity. These results suggest that 2 isolates from mukeunji, Lb. brevis C1 and Lb. plantarum G4 may have potential for food products as probiotics because they showed high levels of bile acid tolerance and probiotic properties.     

Assessment of probiotic characteristics of lactic acid bacteria isolated from fermented yak milk products of Sikkim,India: Chhurpi,Shyow, and Khachu

The present study documents the probiotic attributes of indigenous lactic acid bacteria (LAB) isolated from local fermented Yak milk products namely Chhurpi, Shyow and Khachu prepared in the northern and eastern region of Sikkim in the Himalayas. Samples were collected aseptically and a total of 170 LAB was isolated and screened for putative probiotic properties like hypocholesteromic effect, acid tolerance, bile tolerance, bile salt hydrolase (BSH) activity and cell surface hydrophobicity. It was observed that 70 LAB isolates showed cholesterol lowering activity, out of which 35 isolates were selected that showed 50% and less cholesterol reducing effect in vitro. Acid tolerance test revealed good tolerance of 12 isolates at pH 2.5 and pH 2.0 for up to 2 hours. The tolerance to 0.5% and 1% of three bile salts acid revealed more growth in MRS broth containing taurocholic acid with the isolates revealing good BSH activity leading to bile acid deconjugation. The cell surface hydrophobicity ranged from 20–95%. Furthermore, 16S rRNA gene sequencing revealed Lactobacillus plantarum YD5S and YD9S, L. pentosus YD8S, L. paraplantarum YD11S, Enterococcus lactis YHC20 and E. faecium YY1 as the best isolates with technological properties. The isolates may serve as potential probiotic candidates with potential for hypocholesteromic benefits in the future.     

新疆喀什地区传统发酵酸乳中乳酸菌多样性的初步分析

为了对采自喀什地区的22个传统发酵酸乳样品的多样性进行研究,采用免培技术聚合酶链式反应-变性梯度凝胶电泳(Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis,PCR-DGGE)结合传统培养分离方法对22个酸乳样品进行研究。结果表明:用传统方法分离得到7种乳酸菌,其中德氏乳杆菌(L.delbrueckii subsp)为优势菌群。对采用PCR-DGGE方法得到的4条条带进行序列比对,结果表明瑞士乳杆菌(Lactobacillus.helveticus)的丰度最高,是酸乳样品中的优势菌群,次优势菌分别为德氏乳杆菌(Lactobacillus.delbrueckii subsp)、德氏乳杆菌保加利亚亚种(Lactobacillus delbrueckii subsp.bulgaricus)和嗜酸乳杆菌(Lactobacillus acidophilus)。传统分离法与PCR-DGGE技术结合能够更有效、更全面地分析传统乳制品中微生物的多样性及优势菌。     

Use of selected autochthonous lactic acid bacteria for Spanish-style table olive fermentation

The present work presents a successful attempt to achieve an enhanced and more predictable fermentation process in Spanish-style green olive technology by selection and use of autochthonous starter cultures. During the first phase of this work, two Spanish-like fermentations of green table olives of cultivar (cv) "Nocellara del Belice", coming from irrigated and not irrigated fields, were monitored, in order to highlight the best agricultural conditions for drupe production and to isolate lactic acid bacteria strains with relevant technological properties. Among 88 identified isolates, one Lactobacillus pentosus strain showed remarkable biochemical features and high acidification rate in synthetic brine. In the second phase, the selected strain was used as starter culture in three different trials to establish the best conditions for its use. Microbial counting, as well as starter tracking by M13 RAPD-PCR, reflected the optimal adaptation of the strain to the environment. Spontaneous fermentation needed a 14-day long lag phase to reach the same population as the inoculated trials. Moreover, sensory traits of table olives obtained with adjunct culture showed better characteristics compared to those processed in the other trials, in particular concerning the presence of off-odours.     

味全乳酸菌

乳品是消费者每天都需要摄入的东西,但因消费者自身原因会在摄入后产生不适的状况．加之最近频繁爆出乳品安全问题,让消费者对乳品的选择有了一些担忧．所以纯奶制品的销售额一直不太稳定,这给纯奶企业与经销商的投资带来了不利因素。但如果不是纯奶制品的乳品．例如果奶、花生奶等,却一直没有在销售业绩上出现下滑征兆。