传统发酵辣椒中产香乳酸菌的分离鉴定

该研究旨在筛选出产香优异的乳酸菌改善发酵辣椒风味品质。从86份传统发酵辣椒中分离纯化得到486株菌株,以接种发酵辣椒的香气感官评分值和各菌株发酵液的乙偶姻测定值为评价指标,筛选出了3株产香优异菌种。根据菌株的形态学特征、16S rDNA测序分析以及API试纸条鉴定,确定H3D为植物乳杆菌(Lactobacillus plantarum),6d-16为戊糖乳杆菌(Lactobacillus pentosus),6-12为戊糖片球菌(Pediococcus pentosaceus)。3株菌种的发酵辣椒感官评分值均在93分以上,发酵液的乙偶姻测定值分别为37.737、53.160、26.716 mg/L,同时3株菌对酸、NaCl、胆盐均具备一定的耐受性,可作为辣椒发酵的优异菌株。     

传统发酵食品中耐胃肠道环境乳酸菌的筛选及其在酸乳发酵中的应用

在前期从民族传统发酵食品中分离得到的乳酸菌中,通过检测在人工胃肠道溶液中存活率筛选胃肠道环境耐受性强的菌株,再通过感官评价、质构测定等对耐受性强的菌株应用于酸乳发酵潜力进行综合性评价。结果显示,58株从民族地区传统食品中分离的乳酸菌中有7株菌于4种人工胃肠道溶液中存活率均在50%以上,其中5株菌的发酵酸乳感官评价得分较高;而菌株"新E6"发酵的酸乳在质构破裂力、最大黏附力、硬度、内聚力、弹性、胶黏性、咀嚼性以及黏度、持水力等指标都较优,分子生物学鉴定结果"新E6"为坚强肠球菌(Enterococcus durans),为后续益生菌的开发奠定基础。     

Production of exopolysaccharides by lactic acid bacteria isolated from traditional fermented foods in Nigeria

Lactic acid bacteria isolated from traditional fermented foods in Nigeria were investigated for their ability to produce exopolysaccharides (EPS). The test organisms were chosen after screening in a modified exopolysaccharide selection medium (mESM). The ability of the test organisms to produce EPS in whey medium (WM) and supplemented whey media (SWM I, SWM II) with combinations of lactose, KH₂PO₄, NH₄Cl, casamino acids, mineral salts and yeast extract was determined. Amongst the test isolates, only Leuconostoc mesenteroides (from sorghum ogi) and Lactobacillus plantarum (from maize ogi) demonstrated the highest form of EPS production. Adjustment of the pH of SWM II to 6.2 increased the viscosity relative to that of SWM I (5.7) that was not adjusted. The effect of incubation temperature showed that at 25 °C, the viscosity was higher for L. mesenteroides and L. plantarum than at 30 and 40 °C. However, the biomass yield was lower, the least lactose was utilized and less lactic acid was produced at this temperature. More galactose and glucose were liberated at 30 °C that at 25 and 40 °C. This paper suggested that the viscous nature of some traditional foods in sub-Saharan Africa may be partly due to excretion of polysaccharides during the fermentation processes.     

Isolation of halophilic lactic acid bacteria from traditional Chinese fermented soybean paste and assessment of the isolates for industrial potential

Lactic acid bacteria (LAB) from traditional Chinese fermented soybean paste were isolated and identified. A total of 61 LAB were selectively obtained from 32 homemade Chinese soybean pastes. The isolated LAB were divided into two groups by their salt tolerance, 28 halophilic LAB and 33 non-halophilic LAB. Phenotypic analysis showed that these LAB belonged to four genera and 13 species. Tetragenococcus halophilus was the predominant species in the identified strains. Four species of LAB were firstly isolated from fermented soybean food product, Lactobacillus panis, Lactobacillus pentosus, Lactobacillus vaccinostercus and Lactobacillus collinoides. T. halophilus T5 showed vigorous growth and fast acidification in high salt concentration. The volatile compounds of mixed microorganism soybean paste with T. halophilus T5, Zygosaccharomyces and Torulopsis candida, during the different fermentation stage were higher in number than those of normal soybean paste at same processing procedure.     

传统发酵豆酱中产脂肪酶菌株的筛选

脂肪酶属于羧基酯水解酶类,能将甘油三酯逐步地水解成甘油和脂肪酸。该研究从东北三省传统的家庭自制豆酱上获得纯培养真菌389株,通过三丁酸甘油酯平板法初筛获得具有脂肪酶活性的菌株41株,其中青霉属的真菌27株、曲霉5株、毛霉3株、犁头霉2株、酵母菌1株、镰孢菌2株、帚霉菌1株。结果表明,青霉属的真菌无论从数量还是酶活都高于其他属的真菌,其中橘灰青霉（Penicillium aurantiogriseum）数量最多。在分离到的菌株中,毛霉属的卷枝毛霉（Mucor circinelloides）酶活最高,是具有生物催化潜力的功能菌株。     

传统发酵豆酱中产蛋白酶菌株的筛选

该研究从东三省各地采集家庭自制豆酱254份,通过分离培养,获得纯培养真菌菌株389株。采用脱脂牛奶平板初筛获得具有蛋白酶活性的菌株31株,其中曲霉属真菌12株、青霉5株、毛霉4株、镰孢菌3株、帚霉1株、芽枝孢3株、犁头霉1株、红曲2株。通过发酵复筛提取其粗酶液,用福林酚法测定粗酶液的蛋白酶活性,筛选出了两株具有较高蛋白酶活性的米曲霉。     

Fibrinolytic enzymes in Asian traditional fermented foods

Cardiovascular diseases, such as heart attack and stroke, are the leading causes of death in North America. According to data provided by the World Health Organization in 2000, heart diseases are responsible for 29% of the total mortality rate in the world. Since cardiovascular diseases have a major impact on an individual’s quality of life, a tremendous amount of research has been done in the area of prevention and the treatment of the diseases. Fibrinolytic enzymes are agents that dissolve fibrin clots. Recently many food derived fibrinolytic enzymes have been found in various traditional Asian foods. Fibrinolytic enzymes can be found in a variety of foods, such as Japanese Natto, Tofuyo, Korean Chungkook-Jang soy sauce, and edible honey mushroom. Enzymes have been purified from these foods, and their physiochemical properties have been characterized. Fermented shrimp paste, a popular Asian seasoning, was shown to have strong fibrinolytic activity. These novel fibrinolytic enzymes derived from traditional Asian foods are useful for thrombolytic therapy. They will provide an adjunct to the costly fibrinolytic enzymes that are currently used in managing heart disease, since large quantities of enzyme can be conveniently and efficiently produced. In addition, these enzymes have significant potential for food fortification and nutraceutical applications, such that their use could effectively prevent cardiovascular diseases.     

赤峰地区酸菜中乳酸菌的筛选与初步鉴定

从传统发酵的酸菜汁中分离筛选到10株产酸能力较高的乳酸菌.通过形态特征、菌落特征和生理生化特征进行分析可知,其中3株为肠膜明串珠菌葡聚糖亚种,3株为植物乳杆菌,3株为短乳杆菌,l株为乳酸片球菌.并对其中4株代表菌株做了生长曲线和产酸量分析.     

Diversity of lactic acid bacteria associated with traditional fermented dairy products in Mongolia

Spontaneous milk fermentation has a long history in Mongolia, and beneficial microorganisms have been handed down from one generation to the next for use in fermented dairy products. The objective of this study was to investigate the diversity of lactic acid bacteria (LAB) communities in fermented yak, mare, goat, and cow milk products by analyzing 189 samples collected from 13 different regions in Mongolia. The LAB counts in these samples varied from 3.41 to 9.03 log cfu/mL. Fermented yak and mare milks had almost identical mean numbers of LAB, which were significantly higher than those in fermented goat milk but slightly lower than those in fermented cow milk. In total, 668 isolates were obtained from these samples using de Man, Rogosa, and Sharpe agar and M17 agar. Each isolate was considered to be presumptive LAB based on gram-positive and catalase-negative properties, and was identified at the species level by 16S rRNA gene sequencing, multiplex PCR assay, and restriction fragment length polymorphism analysis. All isolates from Mongolian dairy products were accurately identified as Enterococcus faecalis (1 strain), Enterococcus durans (3 strains), Lactobacillus brevis (3 strains), Lactobacillus buchneri (2 strains), Lactobacillus casei (16 strains), Lactobacillus delbrueckii ssp. bulgaricus (142 strains), Lactobacillus diolivorans (17 strains), Lactobacillus fermentum (42 strains), Lactobacillus helveticus (183 strains), Lactobacillus kefiri (6 strains), Lactobacillus plantarum ssp. plantarum (7 strains), Lactococcus lactis ssp. lactis (7 strains), Leuconostoc lactis (22 strains), Leuconostoc mesenteroides (21 strains), Streptococcus thermophilus (195 strains), and Weissella cibaria (1 strain). The predominant LAB were Strep. thermophilus and Lb. helveticus, which were isolated from all sampling sites. The results demonstrate that traditional fermented dairy products from different regions of Mongolia have complex compositions of LAB species. Such diversity of LAB provides useful information for further studies of probiotic strain selection and starter culture design, with regard to the industrial production of traditional fermented milk.     

传统发酵牦牛酸乳中高产胞外多糖乳酸菌的筛选与鉴定

目的:以四川红原、西藏羊八井地区传统牦牛酸乳中分离出的57株乳酸菌作为实验菌种,筛选出高产胞外多糖乳酸菌。方法:通过菌落拉丝法、硫酸-苯酚法的测定。结果:实验菌株胞外多糖产量在19.95⁹1.08μg/m L之间,其中菌株代号为32-2、67-1、41-1和27的胞外多糖产量较高,分别为91.08、89.76、87.22、87.40μg/m L。通过16S r DNA序列同源性鉴定表明代号32-2菌株鉴定为屎肠球菌（Enterococcus faecium）、代号67-1菌株为肠膜明串株菌肠膜亚种（Leuconostoc mesenteroides subsp.mesenteroides）、代号41-1菌株为干酪乳杆菌（Lactobacillus casei）、代号27菌株为肠膜明串珠菌（Leuconostoc mesenteroides）。结论:为研究具有提高酸乳品质能力的发酵菌株提供依据。      

传统发酵蔬菜中拮抗温和气单胞菌的乳酸菌的筛选与鉴定

目的:从传统发酵蔬菜中筛选对温和气单胞菌具有拮抗作用的乳酸菌。方法:采用双层琼脂扩散法筛选,通过生理生化反应和16S rRNA序列分析进行鉴定,研究蛋白酶、p H和温度等因素对乳酸菌无细胞上清液（CFS）抑菌活性的影响,采用扫描电镜分析乳酸菌无细胞上清液对温和气单胞菌细胞结构完整性的影响。结果:从腌渍酸黄瓜中筛选出对温和气单胞菌（10⁶CFU/m L）具有较强抑制活性的菌株LZH2-5,经鉴定为植物乳杆菌（Lactobacillus plantarum）。LZH2-5无细胞上清液经胰蛋白酶、木瓜蛋白酶、中性蛋白酶、碱性蛋白酶和胃蛋白酶处理后其抑菌活性分别丧失29.38%、23.93%、22.30%、19.47%和14.59%;经40、60、80℃处理30 min后其拮抗活性基本不变,在100℃和121℃处理30 min后活性分别下降了16.66%和25.40%,在p H3.0⁴.0范围内保持其抑菌活性,粗提物的最小抑菌浓度12.0 mg/m L。扫描电镜表明经LZH2-5 CFS处理使温和气单胞菌的细胞结构破坏并溶解。结论:从腌渍酸黄瓜中筛选的植物乳杆菌LZH2-5对温和气单胞菌具有较强抑制作用,初步分析抑菌活性物质为细菌素类,可作为水产品养殖过程中控制温和气单胞菌的拮抗制剂出发菌株。      

Exopolysaccharide-producing lactic acid bacteria strains from traditional Thai fermented foods: isolation, identification and exopolysaccharide characterization

Lactic Acid Bacteria (LAB) isolated from various traditional Thai fermented foods were screened for exopolysaccharides (EPS) production. From 104 isolates, two rod-shaped and five coccal-shaped LAB were able to produce EPS from sucrose on solid media. However, only the cocci were capable of producing EPS in liquid media and these were identified as Pediococcus pentosaceus. Pediococcus pentosaceus strains AP-1 and AP-3 produced EPS in high yield. In liquid media containing sucrose as carbon source, the amount of EPS produced by AP-1 and AP-3 strains was 6.0 and 2.5 g/L, respectively. The isolated and purified EPSs were chemically characterized. On the basis of sugar composition, methylation analysis and nuclear magnetic resonance spectroscopy, both the EPSs were shown to belong to the same dextran class. In particular, both EPSs differed from linear dextran by branching through 3,6-di-Osubstituted alpha-D-glucopyranosyl residues. The EPS from P. pentosaceus AP-3 was characterized by a relatively higher degree of branching and by a higher molecular weight than that from P. pentosaceus AP-1.     

Identification and antimicrobial susceptibility of lactic acid bacteria from retail fermented foods

One important safety criterion of using lactic acid bacteria (LAB) in food applications is to ensure that they do not carry transferable antimicrobial resistance (AR) determinants. In this study, 63 LAB belonging to six genera, Streptococcus, Lactobacillus, Lactococcus, Enterococcus, Leuconostoc, and Pediococcus, were recovered from 28 retail fermented food products in Maryland, identified to species with 16S-23S rRNA spacer PCRs, and characterized for antimicrobial susceptibility against eight antimicrobials. Besides intrinsic resistance to ciprofloxacin or vancomycin in some lactobacilli, tetracycline resistance was observed in two Streptococcus thermophilus isolates from one cheese and one sour cream sample and was associated with the presence of a nonconjugative tet(S) gene. The results indicated a low level of AR among naturally occurring and starter LAB cultures in fermented dairy and meat products in the United States; therefore, the probability for foodborne LAB to serve as reservoirs of AR is low. Further studies involving a larger sample size are needed to assess the potential risk of AR gene transfer from LAB in fermented food products.     

辽西传统发酵食品中抗单增李斯特菌乳酸菌的筛选与鉴定

目的:从传统辽西发酵食品中筛选对单增李斯特菌具有良好拮抗作用的乳酸菌菌株。方法:采用双层琼脂扩散法筛选乳酸菌优良菌株。采用酸性实验、热处理实验、蛋白酶敏感性实验分析拮抗特性,利用生长曲线分析拮抗物质形成过程,扫描电镜分析细胞结构完整性。通过生理生化实验和16S rRNA序列进行菌株鉴定。结果:从13株乳酸菌中筛选出1株抗单增李斯特菌活性较强的菌株DL3,抗菌物质存在于无细胞上清液中。经胃蛋白酶处理后抑菌活性丧失了27.50%,胰蛋白酶和木瓜蛋白酶可使抑菌活性完全丧失,经121℃处理15 min后,抑菌活性仍保留96.88%,在p H2.5~6.5时具有抑菌活性,表明菌株DL3产生的抑菌物质可能为细菌素。添加菌株DL3无细胞上清液可使单增李斯特菌的生长曲线延迟期和稳定期延长4 h,显著地缩短了其生长期。扫描电镜结果表明经菌株DL3无细胞上清液处理的单增李斯特菌菌体变小且边缘模糊不清,其中一端细胞原生质发生泄漏。经鉴定菌株DL3为植物乳杆菌。结论:获得1株对单增李斯特菌有较强拮抗活性的植物乳杆菌DL3,该菌的拮抗活性物质可能为细菌素,可作为食品防腐剂潜在的应用菌株。      

Lactic acid bacteria in traditional fermented Chinese foods

Food fermentation is a widely practiced and ancient technology in China. Lactic acid bacteria (LAB) are involved in many fermentation processes of Chinese traditional foods, demonstrating their profound effects on improving food quality and food safety. This review article outlines the main types of LAB fermentation as well as their typical fermented foods such as koumiss, suan-tsai, stinky tofu and Chinese sausage. The roles of LAB and the reasons for their common presence are also discussed.     

Screening of lactic acid bacteria isolated from fermented table olives with probiotic potential

The aim of this work was to study the potential probiotic properties of lactobacilli associated with table olives. From a total of 111 isolates from spontaneously fermented green olive brines, 109 were identified at species level by multiplex PCR amplifications of the recA gene. One hundred and seven of these were identified as Lactobacillus pentosus, one as Lactobacillus plantarum, and another as Lactobacillus paraplantarum. Repetitive bacterial DNA element fingerprinting (rep-PCR) with GTG₅ primer revealed a higher variability within the L. pentosus isolates and nine different clusters were obtained. Most of them showed high autoaggregation ability, low hydrophobicity properties, and lower survival to gastric than to pancreatic digestion; however, no isolate showed bacteriocin, haemolytic or bile salt hydrolase activities. A multivariate analysis based on results from phenotypic tests led to the segregation of some L. pentosus isolates with promising potential probiotic characteristics, which are even better than probiotic reference strains. Due to the autochthonous origin of the strains, their use as starter cultures may contribute to improving natural fermentation and the nutritional characteristics of table olives.     

Advantages and disadvantages of non-starter lactic acid bacteria from traditional fermented foods: Potential use as starters or probiotics

Traditional fermented foods are a significant source of starter and/or non-starter lactic acid bacteria (nsLAB). Moreover, these microorganisms are also known for their role as probiotics. The potential of nsLAB is huge; however, there are still challenges to be overcome with respect to characterization and application. In the present review, the most important steps that autochthonous lactic acid bacteria isolated from fermented foods need to overcome, to qualify as novel starter cultures, or as probiotics, in food technology and biotechnology, are considered. These different characterization steps include precise identification, detection of health-promoting properties, and safety evaluation. Each of these features is strain specific and needs to be accurately determined. This review highlights the advantages and disadvantages of nsLAB, isolated from traditional fermented foods, discussing safety aspects and sensory impact.     

Distribution and genetic diversity of lactic acid bacteria from traditional fermented sausage

This study was conducted to investigate the distribution and genetic diversity of the native lactic acid bacteria (LAB) population in nem chua, a popular traditional Vietnamese uncooked fermented sausage. A total of 74 LAB isolates were identified and their molecular fingerprints were obtained using repetitive-PCR (rep-PCR) and pulse-field gel electrophoresis (PFGE). The results revealed that the majority of LAB isolates were Lactobacillus plantarum (67.6%), followed by Pediococcus pentosaceus (21.6%). A minority of LAB (9.5%) were Lactobacillus brevis and Lactobacillus farciminis (1.4%). A large genetic plasticity within the same species was also observed. Both rep-PCR and PFGE methods were found to be acceptable regarding reproducibility and reliability. However, this study demonstrated the higher discriminatory power of PFGE compared to rep-PCR, as observed by the higher number of clusters generated (17 and 12 clusters of L. plantarum respectively, seven and six clusters of P. pentosaceus respectively and four and two clusters of L. brevis respectively), and lower percentage of similarity among clusters in PFGE data analysis. These results also revealed that there was not a single LAB strain that was found to predominate in the product. To our knowledge, this is the first detailed analysis of the native LAB population in nem chua. As this traditional sausage is fermented naturally or only with back-slop, knowledge about the native LAB population in the product is very important to understand the microflora that has been active in fermenting the nem chua and to ensure the safety of this uncooked sausage.     

传统发酵酸牛奶中乳酸菌多态性分析

以从内蒙古呼伦贝尔市牧区采集的1份传统发酵酸牛奶样品为研究对象,对其进行乳酸菌的分离鉴定。通过传统纯培养法分离出17株菌,并对17株菌进行16SrDNA序列分析、多位点pheS序列分析和生理生化鉴定,鉴定的结果为11株乳酸乳球菌乳酸亚种、1株格式乳球菌、1株粪肠球菌、2株植物乳杆菌植物亚种及2株弯曲乳杆菌。乳酸乳球菌乳酸亚种为优势菌(占总分离菌株的64.7%)。     

传统腌腊肉制品中乳酸菌的筛选与鉴定

从12个传统腌腊肉制品中分离得到52株乳酸菌,通过形态学初步鉴定,选出具有代表性的12株乳酸菌进行生化鉴定,初步确定L31、L94、LS76、LS81、LS101为戊糖乳杆菌(Lactobacillus pentosus),LS51为食品乳杆菌(L.alimentari-us),LS14为干酪乳杆菌(L.casei),LS21、LS33为弯曲乳杆菌(L.curvatus),LS41为清酒乳杆菌(L.sake),L22、LS92为乳酸球菌,未能鉴定其种类。