乳酸菌发酵生产乳酸钙的条件优化

采用直接中和法,在乳酸菌发酵液中加入碳酸钙进行中和反应.通过对乳酸菌富集培养和发酵条件的优化提高发酵产酸量.单因素试验确定适宜培养条件为:接种量8％,装液量20％,温度36℃,初始pH值为6.0.用正交试验法对其发酵条件进行优化,最佳优化条件为:温度40℃,时间96h,接种量8％,碳源10％,初始pH值为7.0.再通过浓缩结晶法提取乳酸钙,最终乳酸钙收率可达72.10％.此工艺为后续乳酸菌发酵法回收利用含糖废液提供了实验基础和理论依据.     

乳酸菌发酵柿汁的制备工艺

介绍了以柿子汁为原料制备乳酸菌发酵饮料的工艺流程,并对原材料和发酵产品的一些营养指标进行了测量。实验表明,乳酸菌发酵的最佳条件是发酵温度30℃、接种量6%、菌种AS1.1482∶6038=2∶1。产品既保留了部分柿子汁的原有风味,又具有乳酸发酵形成的特殊风味,营养价值较高,有一定的保健作用。     

乳酸菌发酵混合蔬菜的初步研究

采用单因素试验和正交试验,研究并优化混合蔬菜乳酸菌发酵工艺,确定适宜的工艺参数,并对发酵液的感官、酶活、理化指标进行检测。结果表明,优化的乳酸菌发酵混合蔬菜的发酵条件为加糖量40%,嗜热链球菌∶保加利亚乳杆菌=1.5∶1.0,接种量3.00%,发酵时间20 d,发酵产品中淀粉酶活28.74 U/mL,超氧化物歧化酶活45.63 U/mL,蛋白酶活51.66 U/mL,总多酚4.52 mg/mL,总黄酮63.40 mg/mL,总糖344.38 g/L,还原糖291.25 g/L,总酸8.48 g/L,亚硝酸盐含量为0.16 mg/kg,感官评分为88分。该发酵产品具有一定的营养价值和保健功效。     

Selection and modification of yeasts and lactic acid bacteria for wine fermentation

Historically, the fermentation of grape juice to wine has been carried out by indigenous yeasts found on the berry. However, in newer wine regions, e.g. the USA, inoculation with selected wine yeast strains is employed. Grape juice is high in nutritional factors and difficulties in fermentation usually arise from the inhibitory effects of the high concentration of sugar initially present and the ethanol produced. A secondary fermentation, brought about by indigenous or added lactic acid bacteria, converts malic acid to lactic acid and carbon dioxide and often occurs. This ‘malolactic’ fermentation is usually slow. For both yeast and bacterial fermentations strain selection is based more on fermentation performance than on sensory characteristics of the wine, with increased tolerance of the yeast to ethanol and of the bacteria to low pH being emphasized. Attempts to increase the malolactic fermentation rate have been made by cloning and transferring the malolactic gene from Lactobacillus to wine yeast. In early attempts to produce wines with enhanced or novel sensory characteristics a leucine-less mutant of a homothallic wine yeast has been obtained which does not produce isoamyl alcohol.     

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.     

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。     

脱脂豆粉乳酸菌发酵的研究

脱脂豆粉是大豆经冷压榨提油后磨制得到的产物,粗蛋白含量高达40%,具有良好的食用加工性能。乳酸菌发酵能使其制品具有特有的保健作用和独特的风味。研究利用正交试验对影响脱脂豆粉乳酸发酵的各因素进行优化,结果表明,当豆粉与水比例为1∶5(g∶mL),添加1%葡萄糖,接种0.015%YC-381菌粉,在42℃发酵16h,产品的豆腥味较淡,酸味、口感最好。     

乳酸菌强化发酵生产辣椒酱的工艺研究

采用正交试验设计方法,对宝庆辣椒酱传统生产工艺的发酵和调配技术的工艺参数进行了优化.结果表明:乳酸菌强化发酵生产辣椒原酱的最佳条件为食盐量10%、接种量3%、发酵温度35℃、发酵时间13d;以一定重量的辣椒原酱为基准,辣椒酱调配的最佳条件为花生油20%、增稠剂(黄原胶)0.5%、鲜味剂(味精:酵母精=25:1)0.2%、护色剂(异抗坏血酸:月桂曲酸=l:1)0.2%.新工艺能提高辣椒酱的产品品质.     

豆腐乳中乳酸菌的分离鉴定与发酵特性研究

目的分离鉴定农家自制传统发酵豆腐乳中的乳酸菌,探讨其作为豆类乳酸菌发酵饮品菌株的可行性。方法利用MRS(man rogosa sharp)培养基分离豆腐乳中的乳酸菌,通过形态学观察、生理生化特性和16S rDNA基因序列分析进行鉴定,并将所分离到的乳酸菌与适合于豆类植物发酵的植物乳杆菌FJAT-7926(Lactobacillus plantarum FJAT-7926)和干酪乳杆菌FJAT-7928 (Lactobacillus casei FJAT-7928)进行发酵特性的对比研究。结果从豆腐乳中分离出1株乳酸菌,命名为FJAT-46777,该菌株菌体细胞为圆端直杆状或圆端弯曲杆状,无芽孢,革兰氏阳性,过氧化氢酶阴性,生理生化特征与发酵乳杆菌(Lactobacillus fermentum)一致,对菌株的16S rDNA基因进行扩增测序、分子系统发育树分析,也表明其为发酵乳杆菌。发酵乳杆菌FJAT-46777发酵的豆乳中乳酸菌增殖速度最快,最终活菌数最高,为9.42 lg(CFU/mL); pH值下降最快,最终pH值最低,为3.91;滴定酸度上升速度最快,最终滴定酸度最高,为62~ΟT。结论分离自豆类自然发酵食品中的发酵乳杆菌FJAT-46777,对豆类植物为主的基质具有更优良的发酵特性,发酵时间快,乳酸菌含量高,产酸能力强,适用于发酵豆乳的开发。     

不同乳酸菌在花生乳中的发酵特性

通过感官评定和酸度测定,分析7种乳酸菌在花生乳中发酵的特性,筛选出保加利亚乳杆菌和嗜热链球菌作为花生乳发酵的适宜菌株。进一步研究两种菌的混合配比、混合发酵适宜的温度和时间、接种量和蔗糖对混合发酵的影响及牛奶对混合菌发酵花生乳的促进作用,确立混合菌发酵的适宜参数:保加利亚乳杆菌和嗜热链球菌按1∶1混合,接种量为4%,蔗糖量4%,在42℃下对花生乳与牛奶体积比为7∶3的混合液发酵8h,可获得凝乳良好,酸味适口,具有花生独特香味的凝固型花生酸奶。     

自然发酵辣椒酱中乳酸菌的分离与鉴定

从自然发酵的辣椒酱中分离出产酸量高、生长良好的菌株,经过形态学鉴定、生理生化特性及发酵性能试验,最终选定Lact.1和Lact.2两株适用于发酵辣椒试验的乳酸菌。鉴定结果表明Lact.1为植物乳酸杆菌(Lactobacillusplanetarium),Lact.2为肠膜明串珠菌(Leuconostocmesenteroides)。试验结果表明两株乳酸菌产酸速度快,最适生长温度在30℃到40℃之间,最适生长pH 6.0,当食盐浓度在7%以下能生长。     

开菲尔(Kefir)酸牛乳酒中乳酸菌分离及发酵性能测定

对自制的开菲尔酸牛乳酒进行分离得到16株乳酸菌,通过显微镜观察及生理生化特性研究,结果为肠膜明串珠菌乳脂亚种两株,乳酸乳球菌乳酸亚种2株,乳酸乳球菌乳脂亚种2株,粪肠球菌1株,瑞士乳杆菌3株,德氏乳杆菌保加利亚亚种2株,嗜酸乳杆菌4株;经发酵性能测定,筛选出2株乳酸球菌LC2、LC6和3株乳酸杆菌LB3、LB4、LB8发酵活力较高、发酵乳组织状态及风味较好,可作为Kefir酸牛乳酒纯培养发酵剂乳酸菌的备选菌株.     

不同乳酸菌发酵对玉米粉性质的影响研究

研究了玉米粉经4种乳酸菌发酵后,玉米粉性质的变化.结果表明:4种乳酸菌发酵过程中,发酵液的pH值下降,乳酸含量增加;玉米粉的黏度增大、保水力增加,凝胶特性得到了很大的改善,其中植物乳杆菌和双菌种发酵对玉米粉的性质影响较大.     

全麦芽汁乳酸发酵饮料的研制

研究了麦汁制备和全麦芽汁乳酸发酵的工艺条件。结果表明：在pH5.6,料水比1︰4条件下,采用65℃糖化,可得到较高的浸出物收率和还原糖含量;选用5%接种量,在41℃下经过36hr的发酵,可得到口味纯正、酸度适宜的发酵液,经后熟和加蔗糖调配研制出酸甜可口、富含氨基酸、维生素等多种营养成分的全新麦芽汁乳酸饮料。     

发酵肉制品中乳酸菌的主要发酵特性

从发酵肉制品中分离、纯化乳酸菌132株,对它们的主要发酵特性如耐盐性、耐硝性、产黏液、产气等进行了测定,并比较了它们在不同培养基中的产酸情况。     

蜂蜜对酸奶生产中乳酸菌生长和产酸能力的影响

在脱脂乳粉制成的全乳固体含量为12%(w/v) 的复原乳中,分别添加5%(w/v)的蔗糖、果糖或蜂蜜,并以不添加甜味剂的复原乳作为对照,经过70℃、15min灭菌,冷却至室温,分别接种唾液链球菌嗜热亚种、德氏乳杆菌保加利亚亚种和嗜酸乳杆菌,接种量5%(v/v),培养温度37℃,分别在培养初始和经过24h培养时取样,测定其乳酸菌活性、pH值和乳酸含量。结果表明,添加量为5%(w/v)的蜂蜜对于3种乳酸菌均没有抑制作用,是酸奶生产的合适甜味剂。     

Exopolysaccharides production as affected by lactic acid bacteria and fermentation time

The aim of this work was to examine the ropiness of Lactobacillus helveticus BCRC14030, L. helveticus BCRC14076, and Streptococcus thermophilus BCRC14085, and evaluate the effect of fermentation time on exopolysaccharides (EPS) production by the ropy strain. Each of the three strains was inoculated in skim milk medium and incubated in a fermenter for 0–84 h at pH 5, 37 °C. The fermented samples, containing a net volume of 300 ml skim milk, were withdrawn at intervals of 0, 12, 16, 24, 32, 36, 48, 60, 72, and 84 h for determinations of ropy condition, EPS yield, and molecular mass. EPS with ropiness values of 11.3–21.0 mm, produced from L. helveticus BCRC14030 at 32–60 h demonstrated the ropy nature of the strain. Those EPS were composed of high molecular mass of 26,500 kDa. The highest EPS yield of 0.73 g l⁻¹ from this strain was observed (P < 0.05) at less favourable fermentation condition of 60 h. In addition, a relationship between the presence of high molecular mass and the ropiness of EPS from L. helveticus BCRC14030 was revealed.     

Pressure-resistant acclimation of lactic acid bacteria from a natural fermentation product using high pressure

Twenty colonies of Pediococcus acidilactici, Lactobacillus brevis, Lactiplantibacillus plantarum and Latilactobacillus curvatus were isolated from fermentation broth of pickled pepper by using MRS agar. The strains were acclimated using high pressure from 300 to 400 MPa for 1 to 5 min. For one generation of acclimation, the survived cells after first high pressure treatment were then activated by culturing on MRS agar for two days for the next high pressure treatment. After acclimation for 30 generations, the survival ratio of L. plantarum and L. curvatus was increased by 138 and 1222 times at 400 MPa for 1 and 3 min, respectively. Weibull model could appropriately fit the survival curves of L. plantarum and L. curvatus treated by high pressure. The time to the first decimal reduction of these two strains after acclimation was 3.5 and 1.8 times, respectively, longer than before acclimation at 300 MPa. From electron microscopy photographs, the acclimated L. curvatus was more curved, smaller and its cell wall was thicker than the unacclimated L. curvatus. After HPP treatment, L. plantarum and L. curvatus have higher cell integrity, smoother cell surface, more uniform protoplasm and smaller cavities in the cell protoplasm compared with unacclimated strains, suggesting that high pressure acclimation introduced some modification to bacteria intrinsic structures and increased their pressure resistance. Moreover, the fermentation performance including glucose utilization capacity and lactic acid production of the acclimated L. curvatus was respectively improved by 9.6% and 9.4% at 37 °C for 24 h in MRS medium.     

自然与乳酸菌强化发酵过程中红酸汤品质变化

利用红酸汤为原料,以总酸、亚硝酸盐、pH、还原糖、可溶性固形物、水分、抗坏血酸为检测指标,分析不同发酵时间自然与乳酸菌强化发酵的红酸汤品质变化规律。结果表明,在整个发酵过程中,自然与乳酸菌强化发酵的红酸汤中还原糖、抗坏血酸、可溶性固形物均呈逐渐下降的趋势;总酸含量和pH均在第6天达到峰值,分别为10.11 g/kg和3.04与10.26 g/kg和2.84;水分含量在第6天达到最低,分别为84.83%与84.18%;亚硝酸盐含量最高分别为0.052 2 mg/kg与0.030 4 mg/kg,未超标。因此,与自然发酵相比,乳酸菌强化发酵明显减少亚硝酸盐含量,缩短了红酸汤发酵周期,但自然发酵红酸汤品质更好。