具有血管紧张素转换酶抑制活性的乳酸菌筛选及特性研究

血管紧张素转换酶（Angiotensin Converting Enzyme，ACE）是抗高血压药物的筛选靶位酶。以体外ACE抑制率为筛选指标，从传统发酵食品中筛选出12株具有ACE抑制活性的乳酸菌，研究了12株乳酸菌的ACE抑制活性和蛋白水解活性，以及模拟胃肠消化对乳酸菌发酵乳ACE抑制活性的影响和乳酸菌耐酸耐胆汁的特性。结果表明，CZ2112具有良好ACE抑制活性，经API鉴定系统鉴定为植物乳杆菌，ACE抑制类型为非竞争性抑制，24h发酵产物ACE抑制率可以达到83％，经模拟胃肠消化后抑制率为70％，邻苯二甲醛（OPA）法检测其蛋白水解活性为OPA指数0．43，对胃酸、胆汁具有较好的耐受性。     

干酪乳杆菌LC-15发酵乳血管紧张素转换酶体外抑制活性的研究

血管紧张素转换酶抑制剂筛选模型是一个用于抗高血压药物和功能性食品研究的有效模型。通过考察乳酸菌蛋白质水解能力与ACE抑制活性的关系，以一株具有较高ACE抑制活性的干酪乳杆菌LC-15为研究对象，研究了发酵时间、添加酪蛋白、酶水解处理和模拟胃肠消化对LC-15发酵乳的ACE抑制活性的影响。结果表明，乳酸菌对牛乳蛋白质的水解能力与ACE抑制活性呈现一定的正相关关系；干酪乳杆菌LC-15在复原脱脂乳中发酵至42h时，发酵乳的ACE抑制活性达到最高，此时ACE抑制率为66％；通过在复原脱脂乳中添加4％酪蛋白可以使LC-15发酵乳的ACE抑制活性提高到81％；控制复原脱脂乳水解度为10％，然后再利用LC-15进行发酵得到的发酵乳的ACE抑制活性达到85％；在模拟胃肠环境消化条件下LC-15发酵乳的ACE抑制活力从最初的85％下降到78％。     

具有ACE抑制活性乳酸菌菌株的筛选与鉴定

以ACE抑制活性和蛋白水解活性为检测指标,选择138株乳酸菌为出发菌株,筛选出具有强ACE抑制活性的乳酸菌菌株.结果表明,筛选出具有强ACE抑制活性的4株乳酸菌,其中3株菌为瑞士乳杆菌,1株菌为干酪乳杆菌.瑞士乳杆菌KLDS1.0485和干酪乳杆菌KLDS1.0486比例为1:1,制成的发酵乳ACE抑制活性可达到61.55%.因此,组合瑞士乳杆菌KLDS1.0485和干酪乳杆菌KLDS1.0486可作为制备乳源ACE抑制肽的优良菌株.     

用于低脂干酪开发的附属发酵剂的筛选

目的筛选出生产低脂干酪所需添加较为适宜的附属发酵剂。方法选择7株乳酸菌作为研究对象,测定其总肽酶活力、菌株生产能力、产酸能力、产粘能力、菌体自溶度、产胞外多糖数量、蛋白质水解能力等7种指标。结果 7株乳酸菌中嗜酸乳杆菌(Lactobacillus acidophilus,LA)总肽酶活力最高,为(256.46±11.88)μg/L,植物乳杆菌(Lactobacillus plantarum,LP)最低;菌株生长能力LA最好;菌株副干酪乳杆菌(Lactobacillus paracasei,LPC)在发酵10 h后的产酸能力最强且趋于稳定,pH在3.8左右;LP菌株产粘能力最优,为(168.10±14.72)mPa·s;瑞士乳杆菌(Lactobacillus helveticus,LH)菌株自溶度最好,达到35%;产胞外多糖数量最优菌株是LP,含量为(792.69±35.94)mg/L;LH的蛋白质水解能力最高,水解产生的游离氨基酸含量为(94.78±2.82)mg/L。结论 LH作为低脂干酪的附属发酵剂较好。     

纯种乳酸菌接种发酵辣椒综合品质特性研究

为了获得高产γ-氨基丁酸（GABA）且综合性能优良的乳酸菌,以10株乳酸菌作为出发菌株对发酵辣椒进行纯种接种发酵,采用逼近理想解排序（TOPSIS）法分别从发酵产酸、抑菌性、亚硝酸盐积累以及生成γ-氨基丁酸能力等方面进行多因素综合评价。结果表明,发酵乳杆菌与食果糖乳杆菌的产酸速度较好,最终产酸量分别为0.020 8 g/100 g、0.020 3 g/100 g;乳链球菌和戊糖乳杆菌对大肠杆菌和金黄色葡萄球菌的抑菌作用最明显,其抑菌圈直径d=11 mm;乳酸片球菌产亚硝酸盐能力最弱,最终含量为1.7 mg/kg;食果糖乳杆菌与乳酸片球菌产GABA能力强,分别为1.97 mmol/L、1.86 mmol/L。采用TOPSIS法对10株菌种进行多因素综合评价,最终得到发酵乳杆菌与食果糖乳杆菌为综合品质特性较好的发酵优良菌株。     

瑞士乳杆菌ND01(L.helveticus ND01)发酵乳中ACE抑制活性和γ-氨基丁酸的研究

从81株分离自新疆地区传统酸马奶中的乳杆菌中筛选到瑞士乳杆菌(L. helveticus)ND01.以该菌发酵1l%脱脂乳,测定其不同发酵时间的ACE抑制活性、游离氨基氮、γ-氨基丁酸(GABA)、pH值、OD值和滴定酸度.测定结果表明:37℃发酵24 h,发酵乳的ACE抑制活性最大值为67.18%;发酵至30h,γ-氨基丁酸的最大含量为165.11 mg/L;该菌株在pH 3.50条件下生长特性良好,具有较强的蛋白分解能力,为开发降血压乳制品提供可行性.     

微生物发酵法制备大豆ACE抑制肽菌种的筛选

以大豆分离蛋白为底物,以血管紧张素转化酶(ACE)抑制率和肽含量为检测指标,选择5株乳酸菌、3株霉菌和1株枯草芽孢杆菌为出发菌种,通过微生物发酵筛选出具有高ACE抑制活性的发酵菌株。结果表明:乳酸菌中具有强ACE抑制活性的菌株为保加利亚乳杆菌,ACE抑制率和肽含量分别为57.93%和3.27mg/mL;霉菌中具有强ACE抑制活性的菌株为米曲霉,ACE抑制率和肽含量分别为41.23%和2.17mg/mL;枯草芽孢杆菌ACE抑制率和肽含量分别为45.02%和2.25mg/mL。综合比较9种菌株的发酵特性,选用保加利亚乳杆菌作为制备大豆抗高血压活性肽优良菌株。     

酸驼乳发酵乳酸菌菌株的筛选及其发酵特性研究

对新疆自然发酵骆驼乳中乳酸菌菌群进行分离鉴定得到五株乳酸菌,其中乳杆菌3株分别为瑞士乳杆菌(Lactobacillus helveticus)、植物乳杆菌(Lactobacillus plantrum)和开菲尔乳杆菌(Lactobacillus kefiri),片球菌2株分别为乳酸片球菌(Pediococcus acidilactici)戊糖片球菌(Pediococcus pentosaceus)。分离鉴定出的五株乳酸菌在培养基中生长良好,其活菌数在培养16 h后能达到109 CFU/m L。将传统酸奶发酵剂接种于骆驼乳中并于42℃条件下培养,发现其在骆驼乳中能较好地产酸,其添加量在0.1%时最适。将筛选到的乳酸菌制备成生产发酵剂与传统酸奶发酵剂复配,得到瑞士乳杆菌组的复配效果最佳,具有最优的产酸效果,在经过6 h发酵后p H值降到4.5左右,酸度达到85oT,且制备的发酵骆驼乳具有最好的感官品质,其感官评分明显高于其他菌株复配进行发酵的骆驼乳产品。因此,可将0.1%传统酸奶发酵剂与筛选到的瑞士乳杆菌制备的生产发酵剂复配应用于酸驼乳发酵。     

不同瑞士乳杆菌发酵牛乳产肽的比较研究

为了从3 株瑞士乳杆菌(JCM1120、CICC6024 和实验室保存菌株L0906)中筛选出1 株产肽丰富的瑞士乳杆菌作为后续实验用菌株。采用水解度、pH 值、小肽含量3 个指标设计实验。结果表明：产酸能力最强的菌株CICC6024 在相同发酵过程中最大水解度明显高于其他菌株;菌株CICC6024 和菌株JCM1120 的小肽含量在发酵时间16h 处达到最大,菌株L0906 的发酵活性较为缓慢,在发酵时间28h 尚未达到顶峰;另外小肽的反相液相色谱峰图显示,菌株16h 时CICC6024 菌对应的20mAU 以上的小肽峰多达19 个。通过比较,最后选定CICC6024 菌株作为后续实验用菌株,发酵时间为16h。     

乳酸菌蛋白降解及产香能力分析

研究了分离自新疆酸奶疙瘩中6株乳酸菌在37℃下蛋白质降解和产香能力。结果表明,6株乳酸菌稳定期活菌数均在108CFU/mL以上,且凝乳细腻,具有良好的组织状态。各菌株发酵性能有差异,干酪乳杆菌、瑞士乳杆菌、乳脂乳球菌3株菌发酵性能较植物乳杆菌、嗜热链球菌、保加利亚乳杆菌发酵性能优,可用于不同风味和功能的发酵乳制品生产。其中,干酪乳杆菌具有良好的蛋白水解力,发酵15h,酪氨酸含量为594.33μg/mL;乳脂乳球菌产香性能好,发酵24h,丁二酮含量为12.32μg/mL、乙醛含量为59.27μg/mL,与其他菌株具有显著差异;瑞士乳杆菌具有强的产酸、产黏特性,发酵24h,酸度达159.76°T,黏度值1 389mPa·s。     

产ACE抑制肽乳酸菌的筛选、益生特性评定及应用

目的:筛选出富产血管紧张素转化酶(Angiotensin converting enzyme,ACE)抑制肽的乳酸菌并评定其益生特性.方法:依据蛋白水解度及ACE抑制率对乳酸菌进行初筛,然后依据模拟胃肠消化后的ACE抑制率最终筛出2株乳酸菌ZJUIDS09和ZJUIDS11,进一步评价其耐酸、耐胆盐、抗生素耐药性和抑菌...     

瑞士乳杆菌H11发酵乳饮料的ACE抑制活性及代谢组学研究

目的:研究瑞士乳杆菌H11与副干酪乳杆菌Lc-01两种发酵乳饮料在贮藏期间的代谢差异变化。方法:使用气相色谱-质谱（SPME-GC-MS）联用、高效液相色谱（HPLC）和超高效液相色谱串联四级杆飞行时间质谱（UPLC/Q-TOF MS）技术对4 ℃、贮藏28 d期间发酵乳饮料中的挥发性风味物质、代谢物以及ACE抑制活性之间的差异进行分析。结果:在4 ℃贮藏28 d后,瑞士乳杆菌H11发酵乳饮料的体外ACE抑制活性比副干酪乳杆菌Lc-01高60%以上,ACE抑制肽VPP和IPP含量也显著高于Lc-01（P<0.05）。采用SPME-GC-MS发现瑞士乳杆菌H11发酵乳饮料中香气成分丰富,特征风味物质2-庚酮和2-壬酮相对含量较高,分别为43.84%和12.39%。基于UPLC/Q-TOF MS的结果表明,贮藏期间两种发酵乳饮料的主要代谢差异物为肽、氨基酸和有机酸。结论:瑞士乳杆菌H11在制备发酵乳饮料方面存在巨大潜力。     

发酵乳中血管紧张素转换酶抑制剂的分离与鉴定

用瑞士乳杆菌生产具有抑制血管紧张素转换酶(ACE)活性的发酵乳并从其中分离血管紧张素转换酶抑制剂(ACEI)。脱脂乳经灭菌后,接种4%(V/V)的发酵剂,37℃培养24h,获得抑制ACE活性较高的发酵乳。对此发酵乳的乳清进行超滤、上海732阳离子树脂交换、SephadexG-15凝胶过滤和HPLC分步纯化,最终得到两种起主要作用的ACEI肽。经氨基酸分析和液相-质谱分析,这两种肽的氨基酸序列分别为:Phe-Pro(IC50:12.05μmol/L)和Ala-Glu-Glu(IC50:12.42μmol/L)。     

Characterization of the angiotensin-converting enzyme inhibitory activity of fermented milks produced with Lactobacillus casei

Our study assayed angiotensin-converting enzyme (ACE) inhibitory activity and fermentation characteristics of 41 food-originated Lactobacillus casei strains in fermented milk production. Twenty-two of the tested strains produced fermented milks with a high ACE inhibitory activity of over 60%. Two strains (IMAU10408 and IMAU20411) expressing the highest ACE inhibitory activity were selected for further characterization. The heat stability (pasteurization at 63°C for 30 min, 75°C for 25 s, and 85°C for 20 s) and resistance to gastrointestinal proteases (pepsin, trypsinase, and sequential pepsin/trypsinase treatments) of the ACE inhibitory activity in the fermented milks produced with IMAU10408 and IMAU20411 were determined. Interestingly, such activity increased significantly after the heat or protease treatment. Because of the shorter milk coagulation time of L. casei IMAU20411 (vs. IMAU10408), it was selected for optimization experiments for ACE inhibitory activity production. Our results show that fermentation temperature of 37°C, inoculum density of 1 × 10⁶ cfu/g, and fermentation time of 12 h were optimal for maximizing ACE inhibitory activity. Finally, the metabolite profiles of L. casei IMAU20411 after 2 and 42 h of milk fermentation were analyzed by ultra-HPLC electron spray ionization coupled with time-of-flight mass spectrometry. Nine differential abundant metabolites were identified, and 2 of them showed a strong and positive correlation with fermented milk ACE inhibitory activity. To conclude, we have identified a novel ACE inhibitory L. casei strain, which has potential for use as a probiotic in fermented milk production.     

抗ACE活性之瑞士乳杆菌的筛选

为了筛选能发酵牛乳产生较强抗高血压活性肽的乳酸菌,本研究通过发酵乳的抑制ACE活性试验,从二种干酪制品的混合样品中分离筛选出能发酵牛乳产生较强抗ACE活性的乳杆菌1002、1004和1006。经糖发酵、生长温度、精氨酸发酵产氨、产硫化氢试验及细胞壁中二氨基庚二酸(DAP)成分分析,确认它们均为瑞士乳杆菌。     

瑞士乳杆菌的益生功能及应用研究进展

瑞士乳杆菌具有强大的蛋白水解能力和诸多的益生活性,是当前益生菌研究的热点。本文对瑞士乳杆菌发酵牛乳产生的水解肽的益生活性及相关的蛋白水解系统,瑞士乳杆菌产生的胞外多糖益生活性和瑞士乳杆菌自身的益生活性进行了综述,并总结了瑞士乳杆菌在奶酪发酵中研究进展和新型应用的探索研究。诸多的研究表明,瑞士乳杆菌是一种具有广阔应用前景的益生菌。      

Proteolytic profiles and angiotensin-I converting enzyme and alpha-glucosidase inhibitory activities of selected lactic acid bacteria

ABSTRACT:  This study was conducted to examine the growth, proteolytic profiles as well as angiotensin-I converting enzyme (ACE) and α-glucosidase (α-glu) inhibitory potentials of selected strains of lactic acid bacteria (LAB). Two strains each of yogurt bacteria ( Streptococcus thermophilus —1275 and 285, and Lactobacillus delbrueckii ssp. bulgaricus —1092 and 1368), and probiotics ( L. acidophilus —4461 and 33200, and L. casei —2607 and 15286, and 1 strain of Bifidobacterium longum 5022), were cultivated in reconstituted skim milk (RSM) at 37 °C and their proteolytic profiles and ACE as well as α-glu inhibitory activities were determined. Among all the strains of lactic acid bacteria studied, yogurt bacteria grew very well, with the exception of L. delbrueckii ssp. bulgaricus 1368 which showed a slower growth during the initial 3 h of incubation. The growth pattern corresponded well with the decrease in pH for the organisms. All the organisms showed an increase in proteolysis with time. The variations in proteolytic capabilities translated into corresponding variations in ACE inhibitory potential of these organisms. Bifidobacterium longum 5022 showed the highest ACE inhibitory potential followed by L. delbrueckii ssp. bulgaricus 1368, L. casei 15286, S. thermophilus 1275, and L. acidophilus 4461. Organisms with high intracellular enzymatic activities grew well. Also, aminopeptidases of strains of L. acidophilus 4461 and S. thermophilus 1275 that could better utilize proline containing substrates showed enhanced ACE inhibitory potential. Lactic acid bacteria possessed the ability to inhibit α-glu activity, which endowed them an antidiabetic property as well.     

Effect of Flavourzyme® on Angiotensin‐Converting Enzyme Inhibitory Peptides Formed in Skim Milk and Whey Protein Concentrate during Fermentation by Lactobacillus helveticus

Angiotensin‐converting enzyme inhibitory (ACE‐I) activity as affected by Lactobacillus helveticus strains (881315, 881188, 880474, and 880953), and supplementation with a proteolytic enzyme was studied. Reconstituted skim milk (12% RSM) or whey protein concentrate (4% WPC), with and without Flavourzyme^® (0.14% w/w), were fermented with 4 different L. helveticus strains at 37 °C for 0, 4, 8, and 12 h. Proteolytic and in vitro ACE‐I activities, and growth were significantly affected (P < 0.05) by strains, media, and with enzyme supplementation. RSM supported higher growth and produced higher proteolysis and ACE‐I compared to WPC without enzyme supplementation. The strains L. helveticus 881315 and 881188 were able to increase ACE‐I to >80% after 8 h of fermentation when combined with Flavourzyme^® in RSM compared to the same strains without enzyme supplementation. Supplementation of media by Flavourzyme^® was beneficial in increasing ACE‐I peptides in both media. The best media to release more ACE‐I peptides was RSM with enzyme supplementation. The L. helveticus 881315 outperformed all strains as indicated by highest proteolytic and ACE‐I activities.