芥菜半干腌制发酵过程中乳酸菌的分离及特性研究

本文主要对芥菜半干腌制发酵过程中不同时期的乳酸菌进行分离鉴定及特性研究,从中分离出6种菌。经形态特征、培养特性和生化试验等鉴定,结果表明,这6种菌分别为:肠膜状明串珠菌、发酵乳杆菌、植物乳杆菌、乳酸片球菌、酵母菌和短乳杆菌。并观察了发酵过程中各个时期的主导菌相,最后得出保证腌制芥菜腌制成功的因素及其最终发酵pH。     

酸泡菜发酵过程中乳酸菌区系的研究

在几种酸泡菜的发酵过程中,分离、鉴定出肠膜明串珠菌,葡聚糖明串珠菌、小片球菌、植物乳杆菌、短乳杆菌、发酵乳杆菌、棒状乳杆菌等乳酸菌种类。明串珠菌、片球菌一般在发酵前期出现.乳杆菌则在发酵的中后期占优势,其中以植物乳杆菌最常见。     

市售臭豆腐中菌种的分离及生化鉴定

本实验通过对市售臭豆腐发酵卤水中细菌多样性分析,分离纯化其中的各种菌株,后对其进行生化鉴定和食用安全性验证试验,从中筛选出适合安全食用的臭豆腐发酵的菌株。结果发现,市售臭豆腐卤水存在多种微生物,它们是乳酸菌(其中包括短乳杆菌、棒状乳杆菌扭曲亚种和植物乳杆菌)、芽孢杆菌(其中有巨大芽孢杆菌、环状芽孢杆菌)、假单胞菌、弧菌未知种。通过安全性试验的菌种有4种,分别为植物乳杆菌、假单胞菌、环状芽孢杆菌以及棒状乳杆菌扭曲亚种。     

泡菜中乳酸菌优良菌株的分离鉴定及发酵性能的研究

从多种酸、泡菜中分离出86株菌,对其在最适温度和低温下产酸速率及硝酸盐降解能力进行测定,筛选出5株产酸速率快,硝酸盐降解能力强的菌株,经形态学鉴定及生理生化反应试验,初步鉴定其为:植物乳杆菌2株,短乳杆菌1株,戊糖乳杆菌1株,肠膜明串珠菌葡聚糖亚种1株.并对5株菌的发酵性能进行测定.     

自然发酵酸菜汁中乳酸菌的分离筛选与鉴定研究

从自然发酵的酸菜汁中分离出3株高产酸菌株,利用现代分析技术与经典分类法对上述三株高产酸菌株进行了系统的细菌学鉴定。鉴定结果表明,三株高产酸菌株分别为肠膜明串珠菌(Leuconostocmesenteroides)、短乳杆菌(Lactobacillusbrevis)和植物乳酸杆菌(Lactobacillusplanetarium)。     

泡菜中产气乳酸菌分离鉴定研究

为了解泡菜中主要乳酸菌种类及其产气特性,从泡菜中分离14株乳酸菌,对菌落、菌体形态特征观察,进行接触酶、产H2S、明胶液化、pH值为4.5条件下生长、需氧、石蕊牛奶实验、碳水化合物发酵产酸测试、产气测试。结果发现7菌株属乳酸杆菌属,分别为嗜酸乳杆菌、植物乳杆菌、短乳杆菌、食品乳杆菌(消化乳杆菌)、弯曲乳杆菌、米酒乳杆菌、坏发酵乳杆菌。1菌株是假肠膜明串珠菌。短乳杆菌、假肠膜明串珠菌、坏发酵乳杆菌都产气。     

腌制蕌头发酵过程中乳酸菌的鉴定及生物学特性比较研究

从传统自然腌制的藠头发酵液中,分离得到七个乳酸菌株,进行了形态学、生理、生化鉴定及生物学特性分析.结果表明:短乳杆菌具有较强的产酸能力和良好的生长特性,在30℃下培养16h,发酵液的pH从7.0降至4.22,活菌数达到2.2 X109cfu/mL;短乳杆菌具有较强的耐盐性,且无蛋白分解活性,具有较强的亚硝酸盐降解能力,发酵36h后,能使含量为125mg/L的亚硝酸盐全部转化,说明短乳杆菌具备作为腌制藠头用发酵剂的优良特性.     

新疆特色食品中优良乳酸菌的筛选及分离鉴定

该研究利用传统培养法从自然发酵的新疆特色食品中分离筛选出3株菌,通过菌株形态观察、生理生化试验及16S rDNA序列分析对菌株进行鉴定。结果表明,菌株L-6、L-7和L-8分别被鉴定为肠膜明串珠菌（Leuconostoc mesenteroides）、植物乳杆菌（Lactobacillus plantarum）及短乳杆菌（Lactobacillus brevis）。产酸试验结果表明,这3株菌均具有较强的产酸能力,发酵12 h后发酵液pH值可达4.0以下,其中菌株L-7产酸能力最强,在15 h后其发酵液pH值在3.5以下,可用于辣椒酱或其他发酵食品发酵剂的研制。     

玉米酸汤面自然发酵过程中乳酸菌的分离鉴定及特性研究

对玉米酸汤面自然发酵过程中不同时期的乳酸菌进行分离鉴定及特性研究,从中分离出5株乳酸细菌,利用现代分析技术与经典分类法对其进行了系统的细菌学鉴定.鉴定结果表明,这5株乳酸菌分别为:戊糖片球菌、乳酸乳球菌、植物乳球菌、肠膜明串珠菌、德氏乳杆菌.并测定了发酵过程中乳酸菌的数量变化及各发酵阶段的主导菌相,最后得出适宜的发酵条件.     

发酵白菜中乳酸菌的分离及鉴定

利用钙溶圈等方法从5种发酵白菜中分离筛选出了13株菌，确认其中9株为乳酸菌，经过形态学测试及生理生化反应试验，最后确定9株菌中有8株属于乳杆菌属，分别是：植物乳杆菌3株、短乳杆菌2株、微小乳杆菌2株、发酵乳杆菌1株。     

蔬菜发酵菌种的筛选及发酵特性

为了选择适合蔬菜发酵的发酵菌种,本研究从四川泡菜老汤中分离的6 种乳酸菌Lactobacillus plantarum、Lactobacillus fermentum、Lactobacillus brevi、Lactobacillus pentosus、Leuconostoc mesenteroides、Lactobacillus lactics筛选发酵菌种。6 种乳酸菌接入亚硝酸盐的MRS培养液中,6 种乳酸菌还原亚硝酸盐的大小顺序为Lactobacilluspentosus＞Lactobacillus plantarum＞Leuconostoc mesenteroides＞Lactobacillus fermentum＞Lactobacillus lactics＞Lactobacillus brevis。以pH值降低的速率为发酵速率,Lactobacillus plantarum、Lactobacillus pentosus、Leuconostocmesenteroides这3 种发酵剂的发酵速率较其他3 种快,并且通过乳酸菌的全细胞蛋白电泳实验得出此3 种乳酸菌在甘蓝发酵过程中能够成为优势菌。从乳酸菌还原亚硝酸盐的能力、发酵速率、发酵菌种的生存能力（是否能成为优势菌）的实验结果表明Lactobacillus plantarum、Lactobacillus pentosus、Leuconostoc mesenteroides这3 种乳酸菌作为蔬菜发酵的发酵剂。通过对3 种发酵菌种发酵特性的研究可知,Leuconostoc mesenteroides较另两种生长周期短,稳定期维持时间短,很快进入衰退期。Lactobacillus plantarum菌较Lactobacillus pentosus、Leuconostoc mesenteroides耐酸,Leuconostoc mesenteroides对酸敏感。Leuconostoc mesenteroides最适生长温度为30 ℃,Lactobacillus plantarum、Lactobacillus plantarum两种菌的最适生长温度是37 ℃。15 ℃条件下Leuconostoc mesenteroides的光密度（OD600 nm）值很低,说明Leuconostoc mesenteroides较Lactobacillus plantarum、Lactobacillus pentosus对低温敏感。     

Biochemical characterization of lactic acid bacteria isolated from spontaneous fermentation of 'Almagro' eggplants

A total of 149 strains of lactic acid bacteria isolated from the spontaneous fermentation of 'Almagro' eggplants were characterized and identified. Of the isolates, 148 were determined as belonging to the genus Lactobacillus. A coccoid, gram-positive database-negative isolate was obtained in the early stages of fermentation. The Lactobacillus strains were divided into six groups based on sugar fermentation patterns and other physiological and morphological characteristics, and were identified as Lactobacillus plantarum biotype 1 (54.4%), Lactobacillus brevis biotype 2 (19.5%), Lactobacillus fermentum (9.4%), Lactobacillus brevis biotype 3 (5.4%), Lactobacillus pentosus (4.7%) and nine strains, which were not included in the previous species, were grouped as Lactobacillus spp. (6.0%). Fermentation was initiated by Lactobacillus brevis biotype 2 and Lactobacillus fermentum. During the fermentation Lactobacillus plantarum became the predominant species.     

恩施市泡萝卜中乳酸菌的分离鉴定及其对品质的影响

对5份恩施地区泡萝卜中的乳酸菌进行了分离鉴定,同时对其分离株在以萝卜为原料的泡菜中的发酵特性进行了评价。结果表明:分离出18株乳酸菌菌株,分别为隶属于片球菌属(Pediococcus)的戊糖片球菌(P.pentosaceus)和隶属于乳酸杆菌属(Lactobacillus)的食品乳杆菌(L.alimentarius)、短乳杆菌(L.brevis)、副干酪乳杆菌(L.paracasei)、发酵乳杆菌(L.fermentum)和植物乳杆菌(L.plantarum),其中8株分离株为L.plantarum。通过质构分析发现,乳酸菌纯种发酵制备的多数泡萝卜样品硬度和脆性均明显高于自然发酵样品。通过电子鼻分析发现,W1C、W3C和W5C对多数乳酸菌纯种发酵泡萝卜水的响应值明显偏高。通过主成分分析发现,菌株L.paracasei HBUAS51063和L.plantarum HBUAS51053具有相对较佳的发酵特性。由此可见,恩施市泡萝卜中乳酸菌以L.plantarum为主,乳酸菌纯种发酵可提升多数泡萝卜的品质。     

韩国泡菜加工过程中微生物区系的研究

为了解韩国泡菜在制作过程中微生物的区系,分离鉴定其在腌制、发酵过程中的优势微生物。结果表明：韩国泡菜腌制过程中优势乳酸菌经鉴定为短乳杆菌（Lactobacillus brevis）、植物乳杆菌（Lactobacillusplantarum）;优势酵母菌为近平滑假丝酵母（Candida parapsilosis）、粗状假丝酵母（Candida valida）;韩国泡菜在发酵过程中的优势乳酸菌为植物乳杆菌（Lactobacillus plantarum）、弯曲乳杆菌（Lactobacillus curvatus）、短乳杆菌（Lactobacillus brevis）、肠膜明串珠菌肠膜亚种（Leuconostoc mesenteroides subsp. mesenteroides）;优势酵母菌为近平滑假丝酵母（Candida parapsilosis）、粗状假丝酵母（Candida valida）、酿酒酵母（Saccharomyces cerevisiae）。     

Use of starter cultures of lactic acid bacteria and yeasts in the preparation of togwa,a Tanzanian fermented food

Starter cultures of lactic acid bacteria (Lactobacillus brevis, Lactobacillus cellobiosus, Lactobacillus fermentum, Lactobacillus plantarum and Pediococcus pentosaceus) and yeasts (Candida pelliculosa, Candida tropicalis, Issatchenkia orientalis and Saccharomyes cerevisiae) isolated from native togwa were tested singly or in combination for their ability to ferment maize-sorghum gruel to produce togwa. All species of bacteria showed an ability to ferment the gruel as judged by lowering the pH from 5.87 to 3.24-3.49 and increasing the titratable acidity from 0.08% to 0.30-0.44% (w/w, lactic acid) in 24 h. Yeasts used singly showed little activity within 12 h, but lowered the pH to 3.57-4.81 and increased the acidity to 0.11-0.21% in 24 h. Yeasts in co-culture with lactic acid bacteria (LAB) had a modest effect on the final acidity (P<0.05). The number of lactic acid bacteria and yeasts increased while the Enterobacteriaceae decreased with fermentation time. The pH was lowered and lactic acid produced significantly (P<0.05) fastest in natural togwa fermentation and in samples fermented by L. plantarum or L. plantarum in co-culture with I. orientalis. The content of fermentable sugars was reduced during fermentation. Most volatile flavour compounds were produced in samples from fermentation by P. pentosaceus and I. orientalis in co-culture with either L. plantarum or L. brevis.     

浙东腌冬瓜优势乳酸菌的分离及产酶特性分析

通过微生物分离和鉴定从浙东传统腌冬瓜中得到4株优势菌,分别为植物乳杆菌(Lz151)、发酵乳杆菌(Lz152)、棒状乳杆菌(Lz153)和戊糖乳杆菌(Lz154),通过酶学分析方法对4株乳酸菌的产生乳酸脱氢酶、亚硝酸盐还原酶、酯酶和转氨酶的特性进行研究。实验表明,4株乳酸菌都有乳酸脱氢酶、亚硝酸盐还原酶、酯酶和转氨酶活性,植物乳杆菌和发酵乳杆菌有较高的乳酸脱氢酶活力,分别达到122.34 U/m L和113.56 U/m L;发酵乳杆菌和戊糖乳杆菌有较高的亚硝酸盐还原酶活性,分别为17.62 U/m L和13.42 U/m L,而棒状乳杆菌具有最低的亚硝酸盐还原酶活力,为4.74 U/m L;植物乳杆菌和棒状乳杆菌比其他两种乳酸菌有较高的酯酶活性,达到11.53 U/m L和13.78 U/m L。此外,植物乳杆菌和戊糖乳杆菌有较高的转氨酶活性,分别为25.37 U/m L和23.19 U/m L。4株乳酸菌产酶的最适温度和p H存在菌种间差异,而且同一株菌产生各种酶的最适条件也不同,分离乳酸菌分别在30℃、35℃、40℃产各种酶的能力最高,而发酵乳杆菌、植物乳杆菌的最适产酶p H分别为6.0、7.0。     

Identification of lactic acid bacteria from spontaneous fermentation of 'Almagro' eggplants by SDS-PAGE whole cell protein fingerprinting

In order to complete the previously performed phenotypic identification [Sánchez et al., 2000. Int. J. Food Microbiol. 59 (2000) 9], whole cell protein patterns obtained using Sodium Dodecyl Sulphate Polyacrylamide Gel Electrophoresis (SDS-PAGE) of 149 lactic acid bacteria (LAB) strains, isolated from 'Almagro' eggplants spontaneous fermentation, were analysed. Phenotypic identification of those strains had revealed the presence of the species Lactobacillus (Lb) plantarum, Lb. pentosus, Lb. brevis biotype 2, Lb. brevis biotype 3, Lb. fermentum, Lactobacillus spp. and Aerococcus viridans. The SDS-PAGE technique generated complex and stable patterns that were easy to interpret and compare with those of the 17 reference strains used in this study. After numerical analysis of the resulting electrophoretic protein patterns, six well-delineated clusters were discriminated that, with some exceptions, correlated well with the different groups phenotypically found. Only two strains showed unique protein patterns without meaningful homology to any of the reference strains used for this study and remained unidentified.     

四川泡菜中两株优良乳酸菌的鉴定及不同发酵条件下对泡菜品质的影响

研究四川自然发酵泡菜中的优势乳酸菌及其不同发酵条件下对泡菜品质的影响,以从四川家庭制作的泡菜中筛选出的两株具有良好的产酸能力和独特风味的乳酸菌作为研究对象,通过16S rRNA序列分析对其进行鉴定,鉴定结果表明Pickle-1为Lactobacillus fermentum,Pickle-2为Lactobacillus plantarum。通过人工接种两株乳酸菌发酵萝卜实验,分析两株菌的接种比例、接种量、发酵温度、加盐量4个因素的不同水平对泡菜感官品质、产酸速率、乳酸菌含量、亚硝酸盐含量的影响。结果表明：不同因素对不同指标的影响有差异,其中发酵温度对感官评分、乳酸菌活菌数以及产酸速率影响都最大,菌液比例对亚硝酸盐含量影响最大。     

Microbiological and fermentation characteristics of togwa,a Tanzanian fermented food

Selected microbiological and metabolic characteristics of sorghum, maize, millet and maize-sorghum togwa were investigated during natural fermentation for 24 h. The process was predominated by lactic acid bacteria (LAB) and yeasts. The mesophiles, lactic acid bacteria, and yeasts increased and the Enterobacteriaceae decreased to undetectable levels within 24 h. The isolated microorganisms were tentatively identified as Lactobacillus plantarum, Lactobacillus brevis, Lactobacillus fermentum, Lactobacillus cellobiosus, Pediococcus pentosaceus, Weissella confusa, Issatchenkia orientalis, Saccharomyces cerevisiae, Candida pelliculosa and Candida tropicalis. The pH decreased from 5.24-5.52 to 3.10-3.34. Maltose increased initially and then decreased, fructose decreased and glucose levels increased during the first 12 h of fermentation. The organic acids detected during fermentation included DL-lactic, succinic, formic, pyruvic, citric, pyroglutamic and uric acid. Lactate was the predominant acid and increased significantly with time. The volatile organic compounds (VOC) detected included acetaldehyde, 2-methyl-propanal, 2-methyl-butanal, 3-methyl-butanal, ethanol, 2-methyl-1-propanol, 2-methyl-1-butanol, 3-methyl-1-butanol, diacetyl and acetoin. Ethanol was the predominant VOC and it increased significantly with time.     

Use of Lactobacillus strains to start cassava fermentations for Gari production

Two Lactobacillus strains, Lactobacillus plantarum BFE 6710 and Lactobacillus fermentum BFE 6620, were used to start cassava fermentations in a pilot study under field production conditions in Kenya, to determine their potential to establish themselves as predominant lactobacilli during the fermentation. Predominant strains from three fermentations were isolated throughout the 48 h fermentation period. The use of these strains in high numbers clearly resulted in 1 to 2 log higher lactic acid bacteria (LAB) counts over the course of the fermentation when compared to the uninoculated control. 178 predominant LAB isolates were grouped based on their phenotypic characteristics, and were characterised to strain level by RAPD-PCR, followed by PFGE strain typing. Overall, L. plantarum strains represented the majority of the isolates, followed by Weissella confusa and Lactococcus garvieae strains. The results of RAPD-PCR and PFGE strain typing techniques indicated that L. plantarum BFE 6710 was successful in asserting itself as a predominant strain. In contrast, L. fermentum BFE 6620 failed to establish itself as a predominant organism in the fermentation. The success of the L. plantarum strains to predominate in the cassava fermentation demonstrates the potential for development of Lactobacillus starter cultures to industrialise the Gari production process.