乳酸菌冷冻干燥保护剂的筛选及加速储存稳定性试验

通过正交试验设计,确定适合嗜热链球菌最佳冻干保护剂配方为脱脂乳粉12%,海藻糖1%,甘油3%,谷氨酸钠1%(均为质量分数)。通过加速储存实验,同批冻干样品在不同温度(30,42,60℃)条件下储存,分别采样,测定活菌数,建立储存稳定性方程,由方程外推出得到4℃降解速率常数为1.656×10-4。     

保护剂对冷冻干燥过程中乳酸菌特性影响的研究

采用在酸豆奶中添加蔗糖、异麦芽低聚糖、脱脂奶粉、乳糖等不同保护剂进行冷冻干燥，探讨不同保护剂对乳酸菌特性的影响。结果表明：添加异麦芽低聚糖、蔗糖、脱脂奶粉的酸豆奶，其活菌存活率较高，接种后能迅速复活，产酸迅速，与冷冻干燥前无差异。其中以异麦芽低聚糖对乳酸菌的保护效果最佳。     

真空冷冻干燥过程中保护剂对乳酸菌的保护机理

通过综述乳酸菌发酵剂生产过程中真空冷冻干燥前期不同保护剂的添加对其保护机理,提出合理的保护措施,为工业化生产较高稳定性的乳酸菌发酵剂提供理论依据.     

真空冷冻干燥乳酸菌的研究进展

乳酸菌的存活率在真空冷冻干燥过程中容易受到多种因素的影响,合理的冻干工艺以及保护剂的合理使用是有效提高乳酸菌真空冷冻干燥后存活率和储藏期的有效手段。本文介绍了真空冷冻干燥的原理、影响乳酸菌冻干存活率的因素,并对如何提高乳酸菌冻干存活率和储藏期进行了探讨,以期为制备高活性和耐储藏的乳酸菌发酵剂提供参考。     

泡菜乳酸菌冻干保护剂的研究

为了提高泡菜用直投式乳酸菌发酵剂的生物活性,考察了11种保护剂对乳酸菌真空冷冻干燥的保护效果,选择其中效果较好的四种保护剂进行正交试验,结果表明,以10%脱脂乳、5%海藻糖、7%谷氨酸钠、3%山梨醇和3%VC作为复合保护剂,乳酸菌的冻干存活率较高,可达89.5%。将活菌体悬浮于不同pH值的保护剂中进行冻干,结果显示,介质pH值对冻干存活率有影响,当pH值为6.8时,存活率可达到90.5%。     

保护剂对真空冷冻干燥酸马乳粉中乳酸菌的影响

以真空冷冻干燥酸马乳粉中乳酸菌为考察对象,采用二水平部分析因设计和最陡爬坡实验筛选了3种乳酸菌冻干保护剂,并确定了中心组合实验的中心实验点。通过响应面实验优化得到3种冻干保护剂的最优添加量为麦芽糊精2.30%(W/V)、海藻糖3.50%(W/V)、α-环状糊精3.10%(W/V)。在此条件下,酸马乳粉中乳酸菌活菌数为(8.78±0.10)×108CFU/g。真空冷冻干燥酸马乳粉具有较高的乳酸菌活菌数与较佳的风味和品质,可为新疆地区马乳及其制品的加工提供一定的理论依据。     

保护剂对真空冷冻干燥酸马乳粉中乳酸菌的影响

以真空冷冻干燥酸马乳粉中乳酸菌为考察对象,采用二水平部分析因设计和最陡爬坡实验筛选了3种乳酸菌冻干保护剂,并确定了中心组合实验的中心实验点。通过响应面实验优化得到3种冻干保护剂的最优添加量为麦芽糊精2.30%（W/V）、海藻糖3.50%（W/V）、α-环状糊精3.10%（W/V）。在此条件下,酸马乳粉中乳酸菌活菌数为（8.78±0.10）×108CFU/g。真空冷冻干燥酸马乳粉具有较高的乳酸菌活菌数与较佳的风味和品质,可为新疆地区马乳及其制品的加工提供一定的理论依据。      

冷冻干燥对乳酸菌代谢活力的影响

以保加利亚乳杆菌和植物乳杆菌ST-Ⅲ为研究对象,用15%蔗糖、10%海藻糖、15%蔗糖＋2%谷氨酸钠及10%脱脂乳为冷冻保护剂,与不加冷冻保护剂的样品进行冻干后菌种活力的对比,测定冷冻干燥后菌体中己糖激酶、丙酮酸激酶、乳酸脱氢酶的活力,胞外蛋白及胞内Ca2＋的浓度变化。结果表明：冷冻干燥对菌体的己糖激酶和丙酮酸激酶影响不显著,对乳酸脱氢酶具有显著性的影响。同时,不加保护剂菌体的胞外蛋白含量明显高于添加保护剂的,而胞内Ca2＋却远低于其他组。这一结果说明,冷冻干燥使代谢关键酶如乳酸脱氢酶失活,同时对细胞膜造成了损伤,从而引起细胞代谢活力的下降。     

冷冻干燥对乳酸菌代谢活力的影响

以保加利亚乳杆菌和植物乳杆菌ST-Ⅲ为研究对象,用15%蔗糖、10%海藻糖、15%蔗糖+2%谷氨酸钠及10%脱脂乳为冷冻保护剂,与不加冷冻保护剂的样品进行冻干后菌种活力的对比,测定冷冻干燥后菌体中己糖激酶、丙酮酸激酶、乳酸脱氢酶的活力,胞外蛋白及胞内Ca2+的浓度变化。结果表明:冷冻干燥对菌体的己糖激酶和丙酮酸激酶影响不显著,对乳酸脱氢酶具有显著性的影响。同时,不加保护剂菌体的胞外蛋白含量明显高于添加保护剂的,而胞内Ca2+却远低于其他组。这一结果说明,冷冻干燥使代谢关键酶如乳酸脱氢酶失活,同时对细胞膜造成了损伤,从而引起细胞代谢活力的下降。      

保加利亚乳杆菌冷冻干燥保护剂的筛选

采用响应面分析法筛选并优化了保加利亚乳杆菌冻干保护剂,研究发现在众多物质中脱脂乳、海藻糖、菊粉、麦芽糊精对菌种保护作用突出,以冻干后细胞存活率为响应值,当脱脂乳5.94%,海藻糖7.75%,菊粉8.39%,麦芽糊精9.04%作为混合保护剂使用时,细胞存活率达到90.46%。使用液氮进行预处理并且保护剂的体积为菌体两倍时可以使菌体存活率达到91.93%.     

乳酸菌直投发酵剂培养与冷干条件的优化

采用响应面法对保加利亚乳杆菌(Lactobacillusbulgaricus)和嗜热链球菌的增菌(Streptococcusther-mophilus)培养基进行了优化,并且对其冻干保护剂进行了筛选,结果表明通过流加碱控制保加利亚乳杆菌的pH值为5.8,嗜热链球菌的pH值为6.4,培养15h,菌体的浓度分别达到1.24×109cfu/mL和8.05×108cfu/mL。离心收集到的菌体,在-70℃的冰箱先预冻3h,然后在冷阱温度-51℃、真空度9Pa冻24h,最终可以得到含活菌数为1.43×1010cfu/g的高活力酸乳发酵剂。     

制备冷冻干燥乳酸菌的相关影响因素的研究进展

从技术和经济角度出发,让乳酸菌在干燥及其后续的贮藏过程中,尽可能多的存活是非常重要的。这篇文章主要综述与冷冻干燥乳酸菌制备的几个相关因素。     

Genetic screening of lactic acid bacteria of oenological origin for bacteriocin-encoding genes

A total of 330 lactic acid bacteria isolated from South African red wines during alcoholic and malolactic fermentations and 9 commercial malolactic bacteria starter cultures were screened for antimicrobial activity. Of the entire screened isolates, 26 strains, belonging to the species Lactobacillus plantarum, Lactobacillus paracasei, Lactobacillus hilgardii and Oenococcus oeni, showed activity towards various wine-related and non-wine-related indicator strains. A PCR-based screening revealed the presence of the plantaricin encoding genes plnA, plnEF, plnJ and plnK in five selected Lb. plantarum strains. Furthermore, a co-culture experiment with Lb. plantarum and Enterococcus faecalis was performed. A complete inhibition of cell growth of Ent. faecalis was observed within 72 h. Four putative bacteriocin-encoding genes in the genome of O. oeni were identified and sequenced.     

乳酸菌液态发酵兔肉的研究

采用乳酸菌液态发酵法泡制免肉，研制出一种具有泡菜风味的兔肉食品。     

乳酸菌发酵代谢合成叶酸的影响因素

对嗜酸乳杆菌以及乳酸乳球菌发酵合成叶酸的影响因素进行了研究。结果表明,乳酸菌代谢合成叶酸的产率为17~100μg/L,菌种、培养时间、pH值、对氨基苯甲酸(PABA)质量浓度会影响乳酸菌合成叶酸的产量。与乳酸乳球菌乳酸亚种相比,嗜酸乳杆菌CH-2生成的叶酸产量要高。不同菌株生成叶酸的能力与pH值有关,嗜酸乳杆菌在pH值为4.2叶酸产率明显下降,乳酸乳球菌乳酸亚种产叶酸的能力则不受pH值影响。添加PABA可以显著提高乳酸菌的叶酸产率。选择适宜的乳酸菌菌株,优化发酵工艺参数可以提高乳及相关食品中叶酸的质量浓度,达到生物方式强化叶酸的效果。     

大豆蛋白水解物促进乳酸发酵的作用

通过研究添加大豆蛋白水解物对保加利亚乳杆菌培养过程中体系的酸度、粘度、细菌生长量的影响，验证了大豆蛋白水解产物对保加利亚乳杆菌增殖的促进作用。     

Selection of potential probiotic lactic acid bacteria from fermented olives by in vitro tests

The present study aims to evaluate the probiotic potential of lactic acid bacteria (LAB) isolated from naturally fermented olives and select candidates to be used as probiotic starters for the improvement of the traditional fermentation process and the production of newly added value functional foods. Seventy one (71) lactic acid bacterial strains (17 Leuconostoc mesenteroides, 1 Ln. pseudomesenteroides, 13 Lactobacillus plantarum, 37 Lb. pentosus, 1 Lb. paraplantarum, and 2 Lb. paracasei subsp. paracasei) isolated from table olives were screened for their probiotic potential. Lb. rhamnosus GG and Lb. casei Shirota were used as reference strains. The in vitro tests included survival in simulated gastrointestinal tract conditions, antimicrobial activity (against Listeria monocytogenes, Salmonella Enteritidis, Escherichia coli O157:H7), Caco-2 surface adhesion, resistance to 9 antibiotics and haemolytic activity. Three (3) Lb. pentosus, 4 Lb. plantarum and 2 Lb. paracasei subsp. paracasei strains demonstrated the highest final population (>8 log cfu/ml) after 3 h of exposure at low pH. The majority of the tested strains were resistant to bile salts even after 4 h of exposure, while 5 Lb. plantarum and 7 Lb. pentosus strains exhibited partial bile salt hydrolase activity. None of the strains inhibited the growth of the pathogens tested. Variable efficiency to adhere to Caco-2 cells was observed. This was the same regarding strains' susceptibility towards different antibiotics. None of the strains exhibited β-haemolytic activity. As a whole, 4 strains of Lb. pentosus, 3 strains of Lb. plantarum and 2 strains of Lb. paracasei subsp. paracasei were found to possess desirable in vitro probiotic properties similar to or even better than the reference probiotic strains Lb. casei Shirota and Lb. rhamnosus GG. These strains are good candidates for further investigation both with in vivo studies to elucidate their potential health benefits and in olive fermentation processes to assess their technological performance as novel probiotic starters.     

乳酸菌产胞外多糖的研究

综述了乳酸菌产胞外多糖的研究进展，包括产胞外多糖的菌株、影响生物合成的因素等，并介绍了乳酸菌产胞外多糖的开发及应用。     

乳酸菌发酵剂高密度培养的研究

研究了乳酸菌生长繁殖的环境条件(温度、接种量、起始pH等)和培养基组成(氮源、碳源、缓冲盐等),优化确定了乳酸菌发酵剂的适宜培养条件为:起始pH值为6.5,培养温度为37℃,培养基配比为麦芽糖∶乳糖(1∶1)2%、牛肉膏1.0%、缓冲盐A0.5%、NaCl0.25%、MgSO40.1%,接种量4%,进一步探索了半连续法进行高密度培养,结合优化的培养条件,可使乳酸菌的液体发酵活菌密度至1.1×1012CFU/mL。