益生菌Lactobacillus casei Zhang和Bifidobacterium lactis V9在活性乳酸菌饮料中的应用

以L.casei Zhang和B.lactis V9为发酵菌株制备活性乳酸菌饮料,评价2株益生菌对活性乳酸菌饮料感官品质的影响及在货架期内的存活稳定性,为L.casei Zhang和B.lactis V9在产品中的应用提供基础数据。研究结果显示,利用L.casei Zhang单独发酵制备活性乳酸菌饮料的最适添加量为1.0×107CFU/g,4℃28 d贮藏期内保持高于3.0×108CFU/g水平;最佳复配发酵组合为L.casei Zhang+B.animalis V9(1∶1,2.0×107CFU/g),4℃28 d贮藏期内样品中总的益生菌活菌数保持5.0×108CFU/g以上,且在口感和滋气味方面感官评价分值最高;B.animalis V9与L.casei Zhang共同发酵发生协同效应,B.animalis V9的添加可促进L.casei Zhang的增殖,且有利于改善L.casei Zhang单株发酵样品的感官品质。     

哈萨克斯坦传统发酵乳制品中乳酸菌的多样性

为了阐明哈萨克斯坦传统发酵乳制品中乳酸菌生物多样性,采用传统纯培养方法对采集的5份传统发酵乳制品中的乳酸菌进行分离纯化,运用16S rRNA基因序列分析方法和系统发育树研究进行属种鉴定。结果表明,从5份传统乳制品中分离鉴定了49株乳酸菌分属于4个属8个种或亚种,乳杆菌属(Lactobacillus)44株,片球菌属(Pediococcus)1株、肠球菌属(Enterococcus)3株,链球菌属(Streptococcus)1株。其中乳杆菌属、片球菌属、肠球菌属、链球菌属是哈萨克斯坦地区传统发酵乳制品中的主要乳酸菌,其中Pediococcus pentosaceus为优势菌种,占总分离株的22%。     

内蒙古腌制沙葱中乳酸菌分离鉴定

以采集自内蒙古腌制沙葱为研究对象,通过微生物纯培养方法分离培养其中乳酸菌。应用16S r RNA基因序列分析和系统发育关系研究手段,对分离菌株进行鉴定,并与其他地区不同种类发酵蔬菜中分离得到的乳酸菌进行比较。结果表明:共分离得到6株乳酸菌,包括2株干酪乳杆菌(Lactobacillus casei),2株乳酸乳球菌乳酸亚种(Lactococcus lactis subsp lactis)、1株肠膜明串珠肠膜亚种(Leuconostoc mesenteroides subsp.mesenteroides)和1株Lactobacillus diolivorans。相比于其他地区发酵蔬菜中分离所得的乳酸菌,内蒙古腌制沙葱样品分离得到的乳酸菌数量虽少,但也具有特有菌种。     

益生菌L.casei Zhang和B.lactis V9在发酵乳中发酵特性的评价

以L.casei Zhang和B.lactis V9为研究对象,评价其发酵特性及对发酵乳品质的影响。研究结果显示,4℃下贮藏21 d,L.casei Zhang和B.lactis V9的添加对发酵乳的p H值、滴定酸度(TA)、黏度和持水性基本无影响;L.casei Zhang和B.lactis V9在发酵乳中存活稳定;B.lactis V9的添加可促进L.casei Zhang的增殖,同时可进一步改善L.casei Zhang发酵乳的气味和风味。     

内蒙古赤峰地区传统发酵乳制品中乳酸菌的分离与鉴定

通过探索内蒙古赤峰地区传统发酵乳制品中乳酸菌的多样性,为当地人们制作传统发酵乳制品提供理论依据与菌种资源是具有重要意义的。通过采用传统纯培养方法对15份采集来自内蒙古赤峰地区的传统发酵乳制品(6份酸奶油样品、5份酸牛奶样品、4份奶豆腐样品)进行乳酸菌的分离纯化,运用16S rRNA序列分析和系统发育进化关系对其种属进行鉴定。结果表明:经16S rRNA基因序列分析,将分离到的116株乳酸菌鉴定为7个属,13个种。其中Lactococcus lactis占总分离株的56%,是内蒙古赤峰地区发酵乳制品中的优势菌种。     

Lactobacillus casei Zhang与Saccharomy cescerevisiae QH2-2混合培养工艺的研究

对Lactobacillus casei Zhang和Saccharomyces cerevisiae QH2-2的混合发酵工艺进行了研究。通过对氮源、发酵温度和接菌工艺的优化证实以大豆蛋白粉为氮源,30℃同时接菌的发酵工艺能获得更高的L.casei Zhang vv和S.cerevisiae QH2-2活菌数,对高密度发酵的发酵温度和接菌工艺进行优化证实,30℃同时接菌条件下,两株菌均获得最高活菌数。其中L.casei Zhang活菌数达到2.25×10~(10)m L~(-1),S.cerevisiae QH2-2活菌数达到6.21×10~8m L~(-1)。冻干菌粉中L.casei Zhang的活菌数达到2.67×10~(11)g~(-1),S.cerevisiae QH2-2的活菌数达到1.23×10~9g~(-1)。上述菌种的混合发酵为益生菌发酵剂和微生态制剂的制备提供了参考。     

发酵香肠菌种的筛选及初步鉴定

以发酵香肠发酵剂的选择标准为原则,对分离自发酵香肠的20株乳酸菌进行了筛选。对筛选出的适合于发酵香肠生产的5株乳酸菌进行生化鉴定,初步鉴定结果为:FG-1、ML-2为植物乳杆菌(L.plantarum),GL-2、GX-2为干酪乳杆菌(L.casei),F2-2为鼠李糖乳杆菌(L.rhamnosus)。     

西藏地区发酵牛乳中产细菌素乳酸菌的筛选及鉴定

从西藏地区藏族传统发酵乳中分离乳酸菌,采用生理生化特性和16S基因序列同源性分析对其进行鉴定,通过双层琼脂平板扩散法筛选具有抑菌活性的菌株。结果表明,共分离37株乳酸菌,其中,乳杆菌属(Lactobacillus)35株、明串珠菌属(Leuconostoc)2株;35株乳酸杆菌为Lactobacillus casei 16株、Lactobacillus paracasei 7株、Lactobacillus plantarum 4株、Lactobacillus fermentum 2株、L.delbrueckii subsp.bulgaricus 2株、Lactobacillus helveti-cus 1株、Lactobacillus diolivorans 3株;7株L.casei和L.paracasei的发酵上清液对3株细菌指示菌表现出明显抑制作用,所有菌株对真菌无抑菌活性;在排除有机酸、H2O2等的干扰和经蛋白酶K处理后,初步确定7株乳酸菌发酵上清液中的抑菌物质为细菌素。     

分离自内蒙古传统发酵酸马奶中L.casei Zhng潜在益生特性的研究

从内蒙古地区蒙古族家庭制作的16份酸马奶样品中分离得到的50株乳杆菌中，经耐酸性实验和人工胃肠消化液耐受性实验，筛选出1株对酸耐受性强的乳杆菌，为L.casei Zhang。将L.casei Zhang制成发酵乳后，其对人工胃肠消化液的耐受性要高于纯菌体，这是由于乳蛋白对消化液的缓冲作用和对菌体的保护作用所致。L.casei Zhang对介质中胆盐的最大耐受浓度为1．6g／100mL。L．casei Zhang具有一定的胆盐水解酶活性，可以分解培养介质中的牛磺胆酸钠释放出游离胆酸；L.casei Zhang在37℃培养24h可脱除培养介质中49．61％的胆固醇。这一结果表明，L.casei Zhang可以作为潜在的益生菌。     

内蒙古鄂尔多斯地区酸粥发酵液中乳酸菌的分离鉴定

对采集自内蒙古鄂尔多斯地区的6份酸粥发酵液中的乳酸菌进行了分离、鉴定和生物学特性研究。采用15,30,45℃3个分离温度共分离出18株乳酸菌。通过16S rRNA序列分析等研究将这些菌株鉴定为Lactobacillus(L.)casei8株,L.plantarum2株,L.brevis3株,L.fermen-tum1株,L.helveticus4株。分析认为L.casei是鄂尔多斯地区酸粥发酵液中的优势菌群。对30℃分离株进行传统生化鉴定,结果与16S rRNA序列分析结果一致。     

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.     

奶酒中乳酸菌的分离与筛选

从内蒙古锡林郭勒牧区自然富集菌种发酵的新鲜奶酒发酵醪中分离到乳酸菌20株，以生产性能为指标，经过8次筛得到两株试验菌株。通过乳酸发酵试验，蛋白质凝固能力明显提高，产酸能力达到二次发酵要求，蛋白质与乳清分离效果良好，乳清的风味及口感均优；中试生产结果表明，奶酒质量得到明显的提高，菌种的性能达到了预期效果。（孙悟）     

阿尤恩地区自然发酵牛乳中乳酸菌分离鉴定及多样性研究

为了分离、保藏自然发酵乳中乳酸菌菌种,丰富自然发酵乳中乳酸菌多样性信息.本文采用传统的纯培养分离方法和宏基因组16S rRNA基因测序技术对阿尤恩地区自然发酵牛乳的乳酸菌多样性进行研究.纯培养结果表明:5份自然发酵牛乳中共分离出111株乳酸菌,鉴定为5个属10个种,其中Lactococcus lactis,占总分离株的...     

Isolation and identification of microorganisms in Kazakhstan koumiss and their application in preparing cow-milk koumiss

Koumiss is a type of famous fermented mare milk and considered an important nutritious beverage in central Asian countries. However, the production of koumiss cannot meet public demand in the market due to availability of mare milk. In the present study, 52 lactic acid bacteria and 20 yeast strains from traditional homemade Kazakhstan koumiss were isolated and identified. The isolates were used in a trial that included fermented cow milk, and the flavor profiles, color, and taste to determine their contribution in the co-fermentation of cow milk. Based on the sensory evaluation, KZLAB13 and KZY10 strains were selected as the best cofermentation combinations. The optimal fermentation conditions were confirmed as the ratio of the starter culture 2.4:1.6 % (vol/vol) KZLAB13 strain to KZY10 strain and a temperature of 36°C for 16 h using response surface methodology. After evaluating the quality of the optimized cow-milk koumiss compared with the Kazakhstan koumiss, results suggested that cow milk fermented by these 2 strains possessed a promising taste, flavor, and physicochemical and rheological properties. Altogether, our results showed that cow milk fermented with a combination of KZLAB13 and KZY10 strains can simulate the taste, flavor, and quality of traditional koumiss. Our study provided a novel alternative to mare-milk koumiss and could be used in dairy programs to fulfill the needs of people.     

西部传统发酵乳品中乳酸菌筛分及其亚硝酸盐降解能力

为探究西部牧区传统发酵乳品中乳酸菌多样性及其优势菌种的亚硝酸盐降解能力,为工业化利用提供参考,应用16S rDNA技术鉴定分离菌株,并对分离菌株亚硝酸盐降解能力采用比色法进行分析,比较不同地区、不同发酵乳品中不同种类乳酸菌亚硝酸盐降解能力的差异。结果表明：1）104?份样品中共分离得到275?株乳酸菌,鉴定出6?个属23?个种,其中瑞士乳杆菌（Lactobacillus helveticus）为青海、甘肃、新疆、内蒙古、西藏传统发酵乳品中共有菌株,L. helveticus和植物乳杆菌（L. plantarum）为酸牦牛奶、酸马奶、酸驼奶、奶渣发酵乳品中共有菌株。2）275?株乳酸菌亚硝酸盐降解率在4.8%～99.9%之间波动,其中50%的菌株表现出较好的亚硝酸盐降解能力,平均在91.3%以上。3）降解能力因菌株来源和乳酸菌种类不同存在差异性,来源于西藏的菌株显著高于青海、甘肃、新疆的菌株（P＜0.05）;来源于奶渣中的菌株显著高于酸牦牛奶和酸马奶中的菌株（P＜0.05）;在分离出的8?种优势菌株中L. plantarum、副干酪乳杆菌（L. paracasei）、短乳杆菌（L. breris）显示了稳定高效的亚硝酸盐降解能力,其中L. plantarum降解能力最强,且部分菌种间降解能力存在显著性差异（P＜0.05）。     

利用16S rDNA序列及tuf-RFLP鉴定蒙古国发酵乳中的乳酸菌

运用16S rDNA序列分析和tuf-RFLP技术对采于蒙古国扎布汗省的25份发酵乳样中分离出的110株乳酸菌进行鉴定。首先将分离的110株乳酸菌的16S rRNA基因进行扩增,测序并构建系统发育树,初步鉴定为41株嗜热链球菌,40株瑞士乳杆菌,11株德氏乳杆菌保加利亚亚种,2株发酵乳杆菌,1株乳明串珠菌,2株肠膜明串肠膜亚种,1株乳酸乳球乳酸亚种和12株属于干酪族的菌株。由于干酪乳杆菌族的16S rDNA序列差异很小,故采用tuf-RFLP技术对这12株进行了进一步的验证,通过分离菌株与模式菌株tuf-RFLP图谱的比较分析,结果表明这12株菌均为干酪乳杆菌。     

Identification of Lactobacillus from koumiss by conventional and molecular methods

Lactobacilli are considered to be one of the most important potential probiotics in the dairy industry. Twelve strains of Lactobacillus were isolated from home-made koumiss samples, a traditionally fermented mare milk in China. The isolates were identified based on physiological and biochemical characteristics and analysis of 16S RNA sequences. They were proven to be Lactobacillus helveticus, Lactobacillus fermentum, Lactobacillus casei and Lactobacillus plantarum. The results demonstrated that both methods were essential to identify an isolate accurately.     

类开菲尔粒中乳酸菌和酵母菌的分离鉴定及生物学特性

从采自内蒙古锡林高勒河流域牧区的类Kefir粒中分离出8株乳酸球菌和6株酵母菌，通过对其形态、培养特性、生物学特性的研究，鉴定乳酸球菌中，2株属于明串珠菌属，3株属于片球茵属，3株属于肠球菌；酵母菌中4株属于克鲁维酵母属，2株属于酒香酵母属。     

基于16S rDNA高通量测序方法比较新疆西北部地区乳品中微生物的多样性

为更加全面地了解新疆特色乳品中微生物多样性,比较不同动物来源的原奶和酸奶的细菌群落结构,运用高通量测序技术,对乳品中细菌16S r DNA V4-V5区测序,进而对新疆克州和塔城地区牛奶、驼奶、马奶、羊奶、酸牛奶、酸驼奶和酸马奶7种乳品中细菌群落组成和多样性进行分析。研究共获得539 557条有效序列,379个OTU。多样性分析表明,原奶样品中细菌Shannon-Wiener指数明显高于酸奶样品。微生物群落组成分析发现,不同乳品之间菌群组成差异较大。7种乳品中的菌群均以厚壁菌门和变形菌门为主,但原奶样品主要以变形菌门为主,而酸奶样品主要以厚壁菌门为主。在属水平上,牛奶主要以假单胞菌属(Pseudomonas)为主,驼奶主要以埃希菌属-志贺菌属(Escherichia-Shigella),马奶主要以明串珠菌属(Leuconostoc)为主,羊奶中的优势菌属为乳球菌属(Lactococcus),而酸牛奶、酸驼奶和酸马奶都是以乳杆菌属(Lactobacillus)为优势菌属。不同动物来源的原奶和酸奶样品中的微生物多样性存在显著差异,并且原奶中检测到的环境污染菌和致病菌(或条件致病菌)的丰度也相对较高。本研究结果将为准确评估乳品中的微生物群落对新疆地区少数民族健康的影响提供一定的数据基础。     

The role of interaction between yeasts and lactic acid bacteria in African fermented milks: a review

Yeasts are present in indigenous African fermented milks in numbers up to log 8 cfu g(-1), together with a varied lactic acid bacteria (LAB) flora, and therefore potentially contribute to product characteristics. However, interaction between yeasts and LAB in these products has received little notice. In studies of indigenous fermented milk in Zimbabwe and Uganda, many samples contained more than one species of yeast, but Saccharomyces cerevisiae was most commonly isolated. Other frequent isolates were other species of Saccharomyces and several species of Candida. Most yeast isolates were lactose-negative but usually galactose-positive. Some strains assimilated lactate and citrate. The growth in milk of strains of yeasts and LAB, isolated from naturally soured milk in Zimbabwe, and their interaction when selected pairs of strains were grown together has been studied. Interactions were shown by the significantly different amounts of certain metabolites produced, such as acetaldehyde and malty aldehydes, when co-cultures were compared to pure cultures. Preliminary sensory acceptance tests did not show, however, that milks made from a co-culture with Candida kefyr and LAB were preferable to the pure LAB culture. Further work is still needed to elucidate the reactions that may be taking place in fermented milk between varying LAB and yeast populations. The potential for use as starter cultures depends on various aspects, including the final product being prepared. The role of other microorganisms in naturally fermented milk also needs to be studied.