Fermentation Characteristics of Heterolactic Acid Bacteria in Green Bean Juice

Green bean juice was fermented with 10 species (14 strains) of heterofermentative and two homofermentative lactic acid bacteria to select organisms which might be used to carry out a complete fermentation. Lactobacillus cellobiosus was the only organism to remove all fermentable sugars from bean juice with or without 2.5% NaCI. Nine other cultures used from 75–95% of the sugars. Lactobacillus cellobiosus also produced the lowest final pH among the 14 strains. A complete analysis of the major fermentation substrates and products was done for each of the organisms. Fermentation balance calculations showed a range from 74–132% carbon recovery. These bacteria showed considerable variation in the ability to degrade malic acid and to form mannitol and acetic acid.     

Stability of Mannitol to Lactobacillus plantarum Degradation in Green Beans Fermented with Lactobacillus cellobiosus

Mannitol, in fermented green bean juice, was converted to lactic acid by Lactobacillus plantarum when the initial pH was raised to 3.9. However, at pH 3.5, mannitol was stable to anaerobic degradation by a 10⁶ CFU/ml inoculum of 19 strains of L. plantarum and four isolated homofermentative lactobacilli. Several strains were capable of limited mannitol degradation at an initial pH 3.7. Completely fermented beans were microbiologically stable for at least 6 months under anaerobic conditions at 27°C. It is possible that heterolactic acid-fermented vegetables are microbiologically stable provided fermentable sugars are removed and the pH is lowered below pH 3.7.     

Ascorbic Acid Retention in Retort Pouched Green Beans

The L-ascorbic acid (AA) retention in and sensory quality of green beans processed under home-canning conditions in retort pouches and metal cans were compared. Green beans processed in cans retained slightly more AA than that processed in the pouches, possibly due to overprocessing of the pouched product. Metal cans offered better AA retention in the green beans than the retort pouches during 11 wk of storage at 21°C, due mainly to a higher rate of AA degradation occurring in the pouched product during the first week of storage. Sensory evaluation showed that the retort pouched beans were significantly better (p < 0.05) than the canned green beans in flavor, texture, and overall acceptance, but not in color.     

鼠李糖乳杆菌乳酸发酵动力学的研究

鼠李糖乳杆菌是一类重要的L-乳酸生产菌,研究其发酵条件及其动力学对发酵工艺及其过程控制具有重要意义.本文针对鼠李糖乳杆菌1.549,通过摇瓶悬浮试验确定其最佳培养条件及发酵培养基组成.在此基础上,研究初始葡萄糖浓度和产物乳酸的积累对发酵过程的影响,建立发酵动力学模型.结果表明,鼠李糖乳杆菌1.549摇瓶发酵最佳培养条件:温度34℃,种龄8 h,接种量5%.由正交试验确定的摇瓶最佳发酵培养基组成:酪蛋白胨15 g/L,酵母膏4 g/L,葡萄糖50 g/L,柠檬酸二铵1 g/L,K2HPO4 2 g,L,乙酸钠2 g/L,MgSO4 0.3g/L,MnSO4·H2O 0.03 g/L,FeSO4·7H2O 0.03 g/L.鼠李糖乳杆菌利用葡萄糖L-乳酸发酵动力学模型结果与本试验结果吻合较好,其乳酸发酵机制属部分生长耦联型.动力学参数揭示,高浓度的初始葡萄糖底物和乳酸的积累对发酵的影响在于其对细胞生长的抑制.     

一株发酵乳杆菌(Lactobacillus fermentium)对柠檬酸的发酵特性研究

本文讨论了一株能高效转化利用高酸性水果(如青梅)中柠檬酸的发酵乳杆菌菌株的发酵特性。结果表明,该菌株能在以柠檬酸为主要碳源和能源的基础培养液中进行发酵生长,在转化利用柠檬酸的过程中仅仅产生少量的乙酸和乳酸,因此能将培养液中可滴定酸含量降低50%以上。菌株对乙醇具有较高的耐受性,当培养液中乙醇浓度达到9%(V/V)以上时,菌株的生长和柠檬酸代谢也就受到明显的抑制;菌株对亚硫酸盐非常敏感,培养液中仅仅添加0.5 m M的亚硫酸钠后,菌株的生长和柠檬酸代谢将会被完全抑制。培养液中蔗糖的添加能促进菌株的生长和柠檬酸代谢,但在柠檬酸存在的情况下,该菌株对蔗糖的转化利用较弱,因此,发酵期间培养液中糖的总含量并没有出现明显的下降。     

基因组改组鼠李糖乳杆菌生产L-乳酸发酵培养基的优化

通过单因素试验确定了耐酸性强、高产L- 乳酸的改组菌株Lc-F34 的发酵最适碳源为葡萄糖、初始葡萄糖浓度为90～110g/L,淀粉葡萄糖水解物可以作为乳酸发酵的碳源;最适氮源为酵母抽提物,玉米浆次之,玉米浆可以部分或全部代替酵母抽提物作为乳酸发酵的氮源;适量的MgSO4 和MnSO4 对该菌株的发酵有刺激作用,MgSO4 最适浓度为0.3%,MnSO4 最适浓度为0.05%。     

Lactobacillus paracasei W2产苯乳酸的发酵动力学研究

研究Lactobacillus paracasei W2分批发酵过程中细胞生长、苯乳酸(PLA)的积累、葡萄糖消耗的变化规律。基于Logistic方程和Luedeking-Piret方程,建立了PLA分批发酵过程中细胞生长、产物合成及基质消耗随时间变化的数学模型。通过Matlab 7.0 软件进行最优参数估计和非线性拟合,拟合模型R2均大于0.955,显示了模型与实验数据能较好地吻合,反映了Lactobacillus paracasei W2分批发酵合成PLA过程的动力学特征。     

Lactobacillus acidophilus Group Lactic Acid Bacteria Applied to Meat Fermentation

Lactobacillus acidophilus group bacteria (L. acidophilus, L crispatus, L. amylovorus, L. gallinarum, L. gasseri, L. johnsonii) , probiotic lactic acid bacteria, were applied to meat fermentation. Of six strains, L. gasseri (predominant lacto-bacilli in human intestinal tracts) JCM1131^T exhibited greatest fermentation performance in meats. This strain resisted gastric acid and bile, and would thus have no detrimental effects in the intestinal tract. Inoculation of the strain depressed the propagation of S. aureus cells and their enterotoxin production during meat fermentation. Results suggest probiotic lactic acid bacteria could be effectively utilized for meat fermentation to produce healthy meat products.     

Sensory Evaluation of Tempeh Produced by Fermentation of Common Beans

A tempeh fermented product was prepared from fresh and hard-to-cook (HTC) common beans with the mold Rhizopus oligosporus. Fresh samples fermented for 0, 24 and 48 hr were used to prepare fried tempeh, atoles and cookies at various substitution levels. Atoles were also prepared with fermented hardened beans. A panel evaluated samples for the sensory variables: appearance, odor, color, flavor, texture, and acceptability. For fried tempeh, flavor and acceptability were the sensory variables most affected by fermentation. Atoles, supplemented with fermented fresh and HTC seeds, had significantly lower (P<0.05) flavor and color than controls, respectively. Interestingly, acceptability of atoles, from both fresh and HTC samples, and of cookies was not significantly different (P>0.05) from the controls.     

Lactobacillus kefiranofaciens发酵生产Kefiran多糖的初步研究

研究了发酵条件(温度、起始pH、接种量等)对乳酸菌Lactobacillus kefiranofaciens发酵产Kefiran多糖的影响,并对菌体的形态及发酵特性进行了研究。研究结果表明,菌体形态在生长期间会发生改变,为短杆状-链杆状-短杆状;胞外多糖是从菌体生长期开始合成的;接种量为10%、起始pH为5.3、培养温度为25℃时有利于多糖的合成;CaCO3、Tween80和NaCl的添加量分别为1.2%、4%和0.25%时,胞外多糖的产量可达1.50g/L。     

Fermentation of Lye-treated Carrots by Lactobacillus plantarum

Sodium hydroxide treatment of peeled and trimmed carrots was investigated to rid them of natural epiphytic microflora that interferes with fermentation. It also formed a buffered brine by subsequent neutralization with acetic acid. Two lye concentrations (1% and 2% NaOH) and three treatment times (1,15 and 30 min) were evaluated. Inoculation of Lactobacillus pluntarum into NaOH-treated carrot brines resulted in a controlled fermentation yielding lactic acid almost exclusively. Percent carbon recovery varied from 83.7 to 148.3. More than 92% of available glucose and >85% fructose, but <13% sucrose, were utilised after 7 days fermentation. Texture and surface color (L*) of fermented NaOH-treated carrots were affected (p < 0.05) by NaOH concentration and treatment time. The product flavor was not adversely affected by alkaline treatment.     

乳酸菌发酵辣椒泡菜工艺的研究

研究了辣椒泡菜在不同的蔗糖添加量、接种量及食盐添加量的条件下对辣椒泡菜发酵时总酸的影响,并在此基础之上,通过正交试验确定发酵辣椒泡菜最优工艺条件为蔗糖添加量为3％ (w/v),接种量为8％ (v/v),食盐添加量为4％ (w/v),在20℃～25℃发酵7d～15d.通过质构及有机酸分析,结果显示用此方法发酵的辣椒,质地优良、产酸率高.此外,辣椒中的亚硝酸盐含量远低于国家标准.因此,本发酵工艺具有应用于工业化生产的前景.     

干酪乳杆菌纯种发酵大豆乳培养基的优化调配

从益生菌乳制品中自行分离选育出的生长繁殖力强、发酵活力高的干酪乳杆菌(05-20)为试验菌株,研究了牛乳和蔗糖在大豆乳中的添加量对干酪乳杆菌在大豆乳中发酵的凝乳时间、凝乳时活菌数、pH值、滴定酸度及产品感官风味的影响,通过方差分析确定了发酵培养基中牛乳和蔗糖的最适添加量分别为20%和7%,完成了以大豆乳作为干酪乳杆菌最佳载体的初步探索,为进一步研制开发益生菌发酵大豆乳制品奠定了基础.     

影响嗜酸豆乳质量的因素探讨

研究了嗜酸乳杆菌在豆乳中生长繁殖与发酵产酸的变化规律，探讨了发酵剂、豆乳加工主要工艺和发酵工艺条件对酸豆乳质量的影响。发现嗜酸乳杆菌嗜热链球菌混合发酵豆乳，有利于提高产酸率，改善制品风味和发挥嗜酸乳杆菌的营养保健作用；添加乳糖等可发酵糖、鼐粉等营养成分可促进乳酸功物生长与产酸；控制豆乳固形物浓度（５－６％）、接种量（４％）和添加物量（全脂乳粉５％、蔗糖５％）在３７℃下发酵５小时可获得质量的较邹的冀     

中心组合设计优化基因组改组干酪乳杆菌Lc-F34生产L-乳酸发酵条件研究

随着L- 乳酸在可降解塑料中的应用逐渐增加,乳酸发酵生产受到广泛重视。为了获得较高的生产效率,对于用于工业生产的菌株--基因组改组菌株Lc-F34,优化其发酵工艺是十分必要的。本实验采用中心组合试验设计对干酪乳杆菌基因组改组菌株Lc-F34 发酵工艺进行优化研究,获得该菌株的发酵工艺为：最适pH5.5,度40.2℃。     

乳酸菌发酵桃脯制备工艺

以桃为原料进行乳酸菌发酵,然后利用发酵后的桃块经糖液煮制,常温浸糖,适温烘制做成乳酸菌发酵桃脯。通过试验,确定乳酸菌发酵桃脯制备方法:45%糖液煮至桃没有生心,糖煮时间10 min,常温浸糖时间24h,将浸糖后成型的桃块放入烘箱中,60℃烘制20 h。按照此方法制得的桃脯酸甜可口,不仅桃味浓郁,而且还具有乳酸菌发酵产品特有的风味。     

干酪乳杆菌纯种发酵大豆乳工艺研究

以从益生茵乳制品中自行分离选育出的生长繁殖力强、发酵活力高的干酪乳杆菌(05-20)为试验菌株.通过正交试验研究了干酪乳杆菌纯种发酵大豆乳的工艺条件.结果表明:干酪乳杆菌发酵含有20%牛乳和7%蔗糖的大豆乳(豆与水的比例为1:10)培养基的最适工艺条件为:总接种量7%(活菌数约为7×107 cfu/mL),基质起始pH 7.0,发酵温度37℃,有氧条件发酵;采用最适工艺条件进行干酪乳杆菌发酵大豆乳,凝乳时间为5 h,发酵产品的总活菌数为2.3×109 cfu/mL,pH 4.5,滴定酸度80.2°T;发酵产品呈乳白色,凝乳良好,质地细腻,酸甜适口,具有浓郁的豆香和发酵香气.本研究为工业化生产干酪乳杆菌发酵大豆酸乳产品及其推广应用提供了科学依据,同时也为研制和开发其他多功能益生菌豆乳制品提供了新的思路和方法.     

干酪乳杆菌发酵废弃烟梗制备L-乳酸操作参数的优化

采用单因子试验研究了6个操作参数(发酵方式、发酵时间、装载量、接种量、发酵温度及初始p H)对干酪乳杆菌(Lactobacillus casei)XJL发酵废弃烟梗制备L-乳酸的影响。根据单因素试验结果,选取接种量、装载量、初始p H及发酵温度进行四因素三水平正交试验。结果表明:1初始p H、接种量和装载量对L-乳酸的产率影响显著。2最优操作参数组合为初始p H 7.0、装载量120/250m L(250 m L的锥形瓶装载120 m L的废弃烟梗提取液)、接种量(种子液的移入体积与接种后培养液体积的比例)7.5%、37℃静置培养48 h;此条件下,废弃烟梗发酵产L-乳酸可达157.50 g/kg。      

青豆油脱胶工艺研究

对青豆毛油水化脱胶工艺路线中所添加酸的种类进行了研究,探讨了柠檬酸、磷酸、柠檬酸与磷酸1∶1的混合液等3种酸溶液对青豆油脱胶率的影响效果,并对影响水化脱胶工艺的主要因素进行了单因素试验,以水化时间、水化温度、酸的添加量、加水量等4个因素为研究对象进行进行二次回归旋转正交试验,得出了该工艺的主要影响因素在该工艺中的最佳操作条件,添加的酸为磷酸:柠檬酸为1∶1的混合溶液、脱胶时间55 min、脱胶温度64℃、酸添加量0.4％、加水量6.9％.该条件下得到的青豆油最大脱胶率为11.08％.