不同乳酸菌发酵酸面团对面包品质及风味的影响

以酸面团典型菌株植物乳杆菌(Lactobacillus plantarum,Lp)、类食品乳杆菌(Lactobacillus paralimentarius,Lpa)和发酵乳杆菌(Lactobacillus fermentum,Lf)为发酵菌,探讨自然发酵酸面团(对照),3种单一乳酸菌和4种复合乳酸菌Lpa+Lp (1...     

发酵馕面团中优势菌群的分离及其在馒头发酵中的应用研究

对新疆地区3份发酵馕面团样品中微生物进行分离、纯化,通过形态观察及分子生物学技术对分离菌株进行鉴定,并通过测定乳酸菌的产酸和酵母菌的产气能力,筛选优良菌株用于发酵馒头的制备,分析其对馒头感官品质及风味物质的影响。结果表明,分离纯化得到36株乳酸菌和51株酵母菌,乳酸菌包括旧金山乳杆菌（Lactobacillus sanfranciscensis）、植物乳杆菌（Lactobacillus plantarum）、发酵乳杆菌（Lactobacillus fermentum）和粪肠球菌（Enterococcus faecalis）4种;酵母菌包括发酵毕赤酵母（Pichia fermentans）、酿酒酵母（Saccharomyces cerevisiae）和膜毕赤酵母（Pichia membranifaciens）3种。植物乳杆菌产酸量最大,为113.55～127.8 g/L;酿酒酵母和发酵毕赤酵母产气较快。发酵毕赤酵母与安琪酵母单独发酵馒头时,在醇类和酯类物质的种类和相对含量上差异较大,风味差异明显;植物乳杆菌与发酵毕赤酵母菌混菌发酵馒头时,随着发酵毕赤酵母添加量增加,可降低馒头中醇类、醛类...     

不同乳酸菌在毛酸浆发酵中的特性研究

为比较嗜热链球菌（Lactobacillus plantarum）（L1）、保加利亚乳杆菌（Lactobacillus bulgaricus）（L2）、瑞士乳杆菌（Lactobacillus helveticus）（L3）、植物乳杆菌（Lactobacillus plantarum）（L4）、短乳杆菌（Lactobacillus brevis）（L5）和干酪乳杆菌（Lacbobacillus casei）（L6）在毛酸浆发酵中的特性,研究发酵过程中总酸含量、活菌数和色泽的变化。结果表明,发酵过程中,6种乳酸菌活菌数均能维持在8.0 lg（CFU/mL）以上,生长良好,其中乳酸菌L4、L5和L6在毛酸浆中产酸能力较好,最高总酸含量分别为11.85 g/L、10.95 g/L、10.45 g/L,并均能很好地保持发酵液本身的颜色,色差值均＜54.51;当乳酸菌L4、L5和L6按不同接种比例复合发酵毛酸浆果汁时,各处理间活菌数和发酵液颜色变化基本一致,当乳酸菌L4∶L6为3∶2（V/V）进行复合发酵时,最终所得毛酸浆发酵液的总酸含量（17.91 g/L）最高。     

甘南牧区犏牛酸奶中优良乳酸菌的分离与鉴定

从甘南牧区采集的犏牛酸奶中分离得到76 株乳酸菌。筛选得到3 株凝乳快速、产酸力强、凝乳质地优良的乳酸菌菌株,包括1 株球菌和2 株杆菌。采用16S rRNA基因序列比对分析,鉴定3 株乳酸菌分别是屎肠球菌（Enterococcus faecium）、德氏乳杆菌（Lactobacillus delbrueckii）和发酵乳杆菌（Lactobacillus fermentum）。通过球杆菌混合发酵实验,结果表明混合菌株发酵的产酸速率比单菌株发酵明显加快,且后酸化程度较弱,其感官质量也明显优于单菌发酵。     

广西地区青年人肠道乳酸菌的分离及其发酵酸奶品质的评价

采用传统的可培养方法对广西青年人肠道乳酸菌进行了分离与纯化,通过16S rRNA序列分析对菌株进行了鉴定,并将筛选菌株作为酸奶发酵剂应用。结果表明,分离到的23株乳酸菌中被鉴定为发酵乳杆菌（Lactobacillus fermentum）11株,唾液乳杆菌（Lactobacillus salivarius）6株,格氏乳杆菌（Lactobacillus gasseri）2株,副干酪乳杆菌（Lactobacillus paracasei）1株,融合魏斯氏菌（Weissella confuse）2株和口乳杆菌（Lactobacillus oris）1株。筛选乳酸菌制作的酸奶之间芳香类物质差异并不显著（P＞0.05）,而酸奶样品间酸味、后味A和丰度差异较大。进一步分析表明,副干酪乳杆菌HBUAS54287、唾液乳杆菌HBUAS54223与HBUAS54248、格氏乳杆菌HBUAS54233、发酵乳杆菌HBUAS54238与HBUAS54318乳酸产生能力较强,可进一步筛选用于酸奶复合发酵剂的开发。     

东北酸菜优良乳酸菌筛选及其抑菌特性研究

该实验从东北酸菜中分离纯化并鉴定出40种乳酸菌,主要为植物乳杆菌（Lactobacillus plantarum）、融合魏斯氏菌（Weissella confuse）、副干酪乳杆菌（Lactobacillus paracasei）、干酪乳杆菌（Lactobacillus casei）、食窦魏斯氏菌（Weissella cibaria）。通过测定乳酸菌乳酸产量及其抑制大肠杆菌（Escherichia coli）的能力,探究乳酸菌的产酸量与其抑菌作用之间相互关系。结果表明,菌株C1、E8、A5产酸能力较强,发酵12 h后发酵上清液中乳酸质量浓度＞12 g/L,抑菌圈直径＞12 mm,对大肠杆菌抑制能力强。表明东北酸菜中乳酸菌的产酸量与抑菌作用存在紧密的联系。     

植物乳杆菌发酵对燕麦蛋白溶解度和营养特性的影响

利用植物乳杆菌(Lactobacillus plantarum)发酵燕麦酸面团,测定发酵过程中面团酸度和菌落总数的变化以显示菌体在体系中的生长情况,并着重研究乳酸菌发酵对燕麦蛋白的溶解度和体外消化率、氨基酸组成和营养指标的影响。结果表明：植物乳杆菌在燕麦基质中生长良好,具有较强的产酸能力;植物乳杆菌发酵可以显著(P＜0.05)提高燕麦蛋白的溶解度,发酵24h和48h的样品与未发酵样品相比,分别提高了19.50%和54.06%。采用胃蛋白酶和胰蛋白酶两步法分析发酵过程中燕麦蛋白体外消化率的变化,发现植物乳杆菌发酵可以显著(P＜0.05)提高燕麦蛋白的体外消化率。植物乳杆菌发酵对燕麦蛋白的总氨基酸含量及组成无显著影响,但其氨基酸评分(AAS)由原来的71.53提高到76.60,蛋白质功效比值(PER)也有所增加。     

酸面团发酵过程中蛋白质分解及多肽形成的变化规律

本文以小麦粉,酵母菌和植物乳酸菌M616(Lactobacillus plantarum M616)为原料制备酸面团,酵母发酵面团以及乳酸菌发酵面团,研究酸面团发酵过程中蛋白的分解及肽的形成规律,采用SDS-PAGE分析酸面团发酵过程中蛋白质的组成变化,利用Bradford法分析蛋白质含量的变化,并通过HPLC研究蛋白组分降解形成多肽的含量变化。结果表明,酵母菌对面团中蛋白质几乎没有降解作用,植物乳酸菌M616在面团发酵过程中对面团蛋白具有较强的降解作用,表现为各蛋白含量随发酵时间的进行逐步减少,且在4~10 h之间变化最为显著。其中可溶性蛋白和中分子量麦谷蛋白的降解最为明显,醇溶蛋白含量在0~10 h之间逐渐增加后逐渐减少。对发酵前后多肽含量变化分析发现植物乳酸菌可以明显促进面团中多肽的形成和含量的增加。     

江西酸芋荷中乳酸菌的分离鉴定及在泡菜发酵中的应用

以江西省赣州客家常见传统发酵食品酸芋荷为样品,采用MRS-碳酸钙培养基筛选出具有明显溶钙圈、产酸量较大的15株细菌。通过生理生化特征分析及16S rRNA基因序列比对、构建系统发育树,鉴定为8株植物乳杆菌（Lactobacillus plantarum）,5株短乳杆菌（Lactobacillus brevis）,2株干酪乳杆菌（Lactobacillus casei）。对15株乳酸菌进行耐酸、耐胆盐、耐盐能力测定,筛选得到性能优良的乳酸菌菌株A03c4、A03d1。人工接种乳酸菌A03c4、A03d1发酵泡菜,缩短了发酵时间,改善了传统发酵泡菜的品质。本研究为乳酸菌泡菜发酵剂开发的菌种选育提供了依据。     

麦胚乳酸菌发酵饮品的工艺优化及品质分析

以麦胚为原料,利用复合乳酸菌发酵研制麦胚乳酸菌发酵饮品。以离心沉淀率为评价指标,优化稳定剂含量;采用单因素试验及正交试验,优化麦胚乳酸菌发酵饮品工艺条件,并测定其理化指标。结果表明,最佳稳定剂为羟丙基二淀粉磷酸酯0.5%、琼脂0.2%;最佳发酵工艺条件为嗜热链球菌（Streptococcus thermophiles）、保加利亚乳杆菌（Lactobacillus bulgaricus）、乳双歧杆菌（Bifidobacterium lactis）、鼠李糖乳杆菌（Lactobacillus rhamnosus）、植物乳杆菌（Lactobacillus plantarum）、嗜酸乳杆菌（Lactobacillus acidophilus）、干酪乳杆菌（Lactobacillus casei）按照配比1∶1∶1∶1∶1∶1∶1制备发酵剂,接种量0.03%,发酵时间24 h,发酵温度 42 ℃。在此最佳条件下,麦胚乳酸菌发酵饮品为乳酪色,质地黏稠,口感细腻,总蛋白3.53 g/100 g,总膳食纤维2.12 g/100 g,维生素E 1.28 mg/100 g,亚油酸669 mg/100 g,α-亚麻酸75.8 mg/100 g,乳酸活菌数2.1×109 CFU/mL。     

Effects of several starter cultures on the anti-mold activity and sensory attributes of a traditional flat bread (Sangak) from Iran

Effects of 8 different sourdoughs and their replacement levels at 10, 20, and 30%(w/w) on the volume (of dough), crust hardness, organoleptic, and anti-mold properties of Iranian sangak bread were investigated. Saccharomyces cerevisiae, Lactobacillus plantarum, Lactobacillus acidophilus, and Leuconostoc mesenteroides were selected for the preparation of sourdough samples. The highest dough volume was achieved when sourdough (those having S. cerevisiae) was used at 30%. The highest taste scores were found with the bread sample using the above-mentioned starters at 30% sourdough replacement level. Considering the chewing, appearance, and overall quality of the new products, most of the samples maintained the favorite sensory aspects of sangak bread. Use of lactic acid bacteria and yeast strains as part of the sourdough formulation (followed by the use of sourdough in the dough formulation) resulted in improved crust properties and greater anti-mold activities.     

植物乳杆菌ST-III发酵苦荞面团中蛋白质降解规律的研究

苦荞蛋白作为苦荞中最主要的生物活性物质以及重要的营养成分之一,具有生物价高与氨基酸比例均衡等优点。但由于苦荞蛋白的组成中面筋蛋白含量较少且本身难以被吸收等方面的问题,其加工利用一直受到较大的限制。面团发酵技术作为一种能够提升面团加工品质以及最终产品营养价值的微生物发酵技术,能够提高谷物中蛋白质的利用率。本文选用植物乳杆菌ST-III(Lactobacillus plantarum ST-III)应用于苦荞面团发酵,通过比较苦荞发酵面团(Buckwheat Sourdough,简称BS)、小麦发酵面团(Wheat Sourdough,简称WS)和混合发酵面团(Wheat-Buckwheat Sourdough,简称WBS)发酵过程中变化发现：植物乳杆菌ST-III在BS发酵过程中菌落密度始终较大且显著高于WS和WBS中植物乳杆菌ST-III的菌落密度(p＜0.05),发酵24 h后可达到13.62 logCFU/g酸面团,同时,BS的pH为6.58,接近植物乳杆菌ST-III的最适pH,总酸含量最高达到24.39 mL,其中,乳酸以及乙酸含量分别是WS 与WBS的1.61-1.75倍以及1.06-1.15倍。此外,通过对三种面团发酵过程中总蛋白、清蛋白、醇溶蛋白、谷蛋白以及游离氨基酸含量的测定,并利用SDS-PAGE凝胶电泳发现,植物乳杆菌ST-III在发酵过程中对三种酸面团中总蛋白及其各组分的降解作用有显著差异(p＜0.05),其中,植物乳杆菌ST-III发酵对BS中苦荞蛋白的降解效果最为明显,且游离氨基酸含量随着发酵的进行呈上升趋势。综上可知,利用植物乳杆菌ST-III发酵苦荞酸面团不仅能够改善苦荞中面筋蛋白含量不足导致的加工品质较差的问题,而且提升了苦荞中蛋白质的利用率。     

植物乳酸菌M616对发酵酸面团发酵特性的影响

本文研究了在酸面团发酵过程中,植物乳酸菌M616(Lactobacillus plantarum M616)对面团p H、TTA以及糖类含量变化的影响,并利用F3流变式发酵仪和吹泡仪对面团发酵力及流变特性的变化进行了研究。结果表明植物乳酸菌M616不仅对酵母菌的生长具有一定抑制作用,而且在面团p H和TTA的变化过程中起主导作用;另外,乳酸菌对淀粉的降解作用大于对还原糖的吸收,从而使面团中还原糖的含量增加,增加面团的甜味。在发酵后期,面团p H降低至3.73,这在一定程度上抑制了体系中霉菌和其它杂菌的生长。植物乳酸菌的生长代谢不仅显著提高了面团黏度、筋力,而且减缓了面团在发酵过程中韧性的降低。其中发酵酸面团对面团黏度和筋力影响最大,发酵过程中酸面团的最大黏度和筋力可以达到酵母发酵面团的2倍。     

Microbial re-inoculation reveals differences in the leavening power of sourdough yeast strains

A method based on microbial re-inoculation, or the so-called backslopping and subsequent proofing of rye bread dough simulating commercial one-stage sourdough process, was used for the screening of the leavening capacity of sourdough yeast strains. Two yeast strains were initially tested with seven Lactobacillus strains. Thereafter, 17 yeast strains, mostly of sourdough origin, were tested with a backslopping procedure with heterofermentative Lactobacillus brevis as an acidifying lactic acid bacteria (LAB). The highest leavening capacity was found in sourdoughs containing Candida milleri, in particular when it was accompanied by obligately homofermentative Lactobacillus acidophilus or facultatively heterofermentative Lactobacillus plantarum when it acted homofermentatively. The leavening capacity of the reference strain Saccharomyces cerevisiae was about half that of C. milleri in all sourdoughs tested. The re-inoculation procedure increased the differences found in the leavening capacity of the tested yeast strains during final proofing of rye bread dough. The backslopped sourdoughs containing a heterofermentative Lactobacillus strain were more suppressive than those containing a homofermentative strain. The highest leavening capacity was found in C. milleri strains. The use of one backslopping cycle before assaying the leavening capacity of a laboratory sourdough is recommended since it helps to differentiate between yeast strains to be tested for their leavening power in the final bread dough.     

Parameters of rye,wheat, barley,and oat sourdoughs fermented with Lactobacillus plantarum LUHS135 that influence the quality of mixed rye–wheat bread,including acrylamide formation

A Lactobacillus plantarum strain was used for the production of rye, wheat, barley, and oat sourdoughs, and the influence of different sourdoughs on mixed rye–wheat bread quality parameters and acrylamide formation was evaluated. L. plantarum LUHS135 demonstrated versatile carbohydrate metabolism, good growth and acidification rates, and the ability to excrete amylolytic and proteolytic enzymes in various cereal sourdoughs. The same starter and different cereal substrates allow to produce sourdoughs showing different characteristics. The type of sourdough and its quantity had significant influence on acrylamide content in bread (P ≤ 0.0001), and using 5% or 10% of wheat sourdough, 5%, 15%, or 20% of barley sourdough, and 5% or 15% of oat sourdough, it is possible to reduce acrylamide content in bread. Thus, manufacturers need to take into account application of apparent technological approaches for acrylamide in bread reducing.     

The bacteriocin producer Lactobacillus amylovorus DCE 471 is a competitive starter culture for type II sourdough fermentations

Type II sourdoughs were prepared using Lactobacillus amylovorus DCE 471, a producer of the bacteriocin amylovorin L. The strain was used as a starter culture for rye and wheat sourdoughs on laboratory scale (10 L), and in rye sourdough on pilot scale (100 L). The sourdoughs were acidified to a pH of around 3.5 within 15 h (laboratory dough) to 25 h (pilot‐scale dough). Final amylovorin L titres of 0.3–0.4 (laboratory scale) and 0.2 (pilot scale) MAU kg^?1 of sourdough were detected. After baking of wheat dough that was supplemented with the pilot‐scale sourdough, no amylovorin L activity was recovered from the breadcrumbs. On laboratory scale, aeration or the addition of complex carbohydrates hardly affected growth or amylovorin L production. Rye and wheat sourdough fermentation were rather similar despite differences in sugar concentrations. The persistence of L. amylovorus DCE 471 during rye sourdough fermentation, both on laboratory and pilot scale, was confirmed by repetitive sequence‐based polymerase chain reaction (rep‐PCR) and by testing isolates towards an amylovorin L‐sensitive organism. Further, rep‐PCR indicated that the background microbiota of the flour—probably responsible for the production of low amounts of acetic acid—grew poorly and were overgrown by L. amylovorus DCE 471 during the pilot‐scale fermentation. Copyright © 2007 Society of Chemical Industry     

不同发酵基质的酸面团对酵母面团体系面包烘焙及老化特性的影响

应用分离自我国传统酸面团的区域特色乳酸菌--旧金山乳杆菌分别发酵小麦粉和小麦麸皮基质制成（小麦/麦麸）酸面团,研究了两种不同发酵基质的酸面团及其添加量对酵母面团体系面包烘焙及老化特性的影响。结果表明：与小麦粉制作的空白组面包相比,小麦酸面团可以明显改善面包的比容和感官品质;添加未发酵麦麸制作的非酸面团麦麸面包品质低于空白组,但引入麦麸酸面团（10%、20%、30%）后面包比容和感官评定得分均高于相对应的非酸面团麦麸面包。小麦酸面团和麦麸酸面团以及小麦麸皮均可以改善面包的老化特性,在相同贮藏期内,酸面团面包和麦麸面包的硬度增加量、水分迁移量和老化焓值都低于空白组,并且添加麦麸酸面团的面包其硬度和老化焓值都低于相对应的非酸面团麦麸面包。     

Prevalence,Genetic Diversity,and Technological Functions of the Lactobacillus sanfranciscensis in Sourdough: A Review

The use of sourdough as a leavening agent in bread making is a very old method that can be traced back to ancient times. Sourdoughs harbor a complex microbiota that is affected by multiple factors including factors related to cereal plants, grains, and sourdough processing techniques. Lactobacillus sanfranciscensis is the key autochthonous bacterium of the traditional sourdough microbiota and it is said to be “sourdough adapted” species. Despite the great dominance of this bacterium in sourdoughs, the origin of this species still remains unclear. Lactobacillus sanfranciscensis positively influences all aspects of sourdough and fermented foods. However, the positive influence of this species on sourdough is a strain‐dependent characteristic. The first purpose of this review was to discuss factors affecting the microbiota of sourdoughs with particular emphasis on reasons behind the remarkable prevalence of L. sanfranciscensis in this ecological niche. The second objective was to discuss the genotypic and phenotypic classification of L. sanfranciscensis strains and the influence of this species on technological and functional characteristics of sourdough including its influence on rheological properties of dough and bread characteristics, texture, aroma, and shelf‐life through the inhibition of fungal growth.     

Flavour of sourdough wheat bread crumb

This study investigates the effect of adding sourdough to wheat bread dough on the production of flavour compounds in wheat bread crumb. The sourdoughs were fermented with starter cultures of lactic acid bacteria alone and in combination with sourdough yeasts. The volatile compounds in the bread crumb were isolated by a dynamic headspace technique and extraction analysis, analysed by gas chromatography (GC), and identified on the basis of GC retention times for reference compounds and mass spectrometry (MS). The chemical analyses were combined with sensory evaluation. The volume of the loaves increased significantly when the doughs had 5–20% sourdough added compared with the control bread (bread without sourdough). In the sourdough bread, the content of acetic acid, 2-methylpropanoic acid, and 3-methylbutanoic acid was generally higher, and loaves made with the addition of sourdoughs fermented withLactobacillus plantarum, L. delbrueckii, orL. sanfrancisco had a higher content of 2- or 3-methyl-1-butanol than control bread. Interactions were seen between the starter cultures and the sourdough yeasts, and the production of the following compounds was increased depending on the starter culture used and on the sourdough yeast: ethanol, 2-methylpropanol, 2/3-methyl-1-butanol, 2-phenylethanol, benzyl alcohol, acetic acid, 2-methylpropanoic acid, and 3-methylpropanoic acid. Bread made with an addition of 5% to 15% sourdough fermented withL. sanfrancisco had a pleasant, mild and sour odour and taste.L. plantarum bread had a strong, sour and unpleasant odour and a metallic sour taste with a sour aftertaste, but when the sourdough was also supplemented with the sourdough yeastSaccharomyces cerevisiae, the bread attained a more aromatic wheat bread flavour, which may be caused, in part, by a higher content of 2/3-methyl-1-butanol, 2-methylpropanoic acid, 3-methylbutanoic acid and 2-phenylethanol.     

Potential of Lactic Acid Bacteria to Inhibit Rope Spoilage in Wheat Sourdough Bread

The ability of selected lactic acid bacteria to inhibit the growth of rope-forming Bacillus strains in laboratory experiments and in wheat bread was investigated. Growth of Bacillus subtilis and Bacillus licheniformis was inhibited by Lactobacillus plantarum VTT E-78076 and Pediococcus pentosaceus VTT E-90390 in an automated turbidometry assay and in test bakings. Rope spoilage of wheat bread was inhibited by adding 20-30 g of sourdough/100 g of wheat dough if the sourdough was fermented with Lactobacillus plantarum VTT E-78076,Pediococcus pentosaceus VTT E-90390 or Lactobacillus brevis (commercial starter culture) and the pH values of sourdoughs were adjusted below 4.0 and the amount of total titratable acidity value was >12. Addition of lactic acid alone in concentrations comparable with those formed in sourdoughs did not prevent rope spoilage.