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。     

发酵乳中酵母菌和乳酸菌生长的相互影响

探讨了乳酸菌和酵母菌之间的相互作用。在发酵过程中,酿酒酵母对乳酸菌的生长有抑制作用。乳酸菌能促进酿酒酵母和马克思克鲁维酵母的生长。酿酒酵母和乳酸菌共同接种有利于保持产品冷藏期间活菌数的稳定,菌株之间可能存在共生作用。      

鱼胶原蛋白酶解工艺及其活性肽抑制ACE酶的研究

本研究通过单因素实验和正交实验优化胃蛋白酶水解鱼胶原蛋白制备胶原多肽的工艺。采用高效液相色谱法测定海水鱼与淡水鱼胶原多肽血管紧张素转换酶（ACE）的抑制活性来表征其降血压功能。研究表明:胃蛋白酶制备鱼胶原多肽的最佳酶解工艺条件是水解温度为37℃,初始p H为2.5,酶与底物比例为1∶125（w/w）,底物质量分数为3%（w/v）,水解时间为12 h,此时鱼胶原蛋白溶液的水解度为19.17%。研究发现海洋鱼胶原蛋白和淡水鱼胶原蛋白的酶解上清液均具有较高的ACE抑制活性,半抑制浓度IC50分别为1.34 mg/m L和1.52 mg/m L。利用超滤离心管获得的不同分子量组分中,分子量小于3 ku的海洋胶原多肽CP-Ⅰ和淡水胶原多肽CP-Ⅲ的ACE抑制活性的半抑制浓度IC50分别为0.43 mg/m L和0.60 mg/m L,而相应分子量大于3 ku的海洋胶原多肽CP-Ⅱ和淡水胶原多肽CP-Ⅳ的半抑制浓度IC50分别为1.78 mg/m L和1.69 mg/m L。      

超高压微射流均质技术对铁棍山药汁营养成分的影响

为了探讨超高压微射流均质技术(HPM)对铁棍山药汁营养成分的影响,将山药汁分别在80、120、160 MPa压力下,依次进行2次处理和4次处理,分析铁棍山药汁中氨基酸、还原糖、总酸、总酚、黄酮以及抗氧化活性的变化。结果表明:随着微射流压力的增大,氨基酸增加;还原糖、总酸和黄酮呈较小幅度降低;总酚与抗氧化活性变化趋势一致,80 MPa有增加趋势,但120、160 MPa有降低趋势。结论:80 MPa压力4次的处理的效果最佳,超压微射流处理能较好的保持山药汁中的营养成分,可作为新型加工方法在铁棍山药产业中加以应用。      

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.     

乳酸菌发酵法检测牛乳中抗生素残留

目的建立一种简单、准确的检测牛乳中抗生素残留的方法-乳酸菌发酵法。方法以接种量和温度为变量,优化发酵条件;以青霉素为目标抗生素,建立检测方法;以发酵4 h未凝乳的样品中抗生素最低浓度为检测限,测定本方法对20种抗生素的检测限;对比本方法和GB/T 4789.27方法检测111个商品乳样品中抗生素残留检出率,验证本方法的准确性。结果建立了乳酸菌发酵法检测乳中抗生素残留的具体方法;确定了本方法对8类20种抗生素的检测限,其中4类12种抗生素的检测限低于其在牛乳中的最大残留限量(MRL);本方法和GB/T 4789.27方法检测111个商品乳样品抗生素残留检出率分别为9.0%和11.7%。结论本方法操作简单,结果准确,适合企业及基层检测单位作为初筛方法检测牛乳中的抗生素残留。     

奶啤生产中乳酸菌对酵母菌发酵作用的研究

利用乳酸菌和酵母菌的共生作用,对牛乳进行了混合菌种的发酵研究。分析了共生作用对产品pH值、滴定酸度、乙醇含量和α-氨基酸态氮的影响。研究结果表明,乳酸菌的加入不仅可以提高酵母菌的生长速度,而且可以提高产品的风味,奶啤的酒精含量相对啤酒较低,是酒精度较低的健康型饮料。     

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。     

Optimization of culture condition for ACEI and GABA production by lactic acid bacteria

Abstract: Gamma‐aminobutyric acid (GABA) and angiotensin‐converting enzyme inhibitor (ACEI) are compounds which can influence hypertension. The goal of this study is to optimize the culture condition for GABA and ACEI production by Lactobacillus plantarum NTU 102 fermented skim milk. In this study, we used 3‐factor‐3‐level Box–Behnken design combining with response surface methodology, where the 3 factors represent the concentration of skim milk, the concentration of monosodium glutamate, and culture temperature. Best conditions for GABA and ACEI production differed. The results indicated that L. plantarum NTU 102 produced the highest combined levels of GABA and ACEI at 37 °C, in milk having 8% to 12% nonfat solids supplemented with 0.6% to 1% MSG. Agitation of the medium during fermentation had no effect on GABA or ACEI production but extended incubation (up to 6 d) increases levels of the bioactive compounds. L. plantarum NTU 102 fermented products may be a potential functional food source for regulating hypertension.     

南丰蜜桔汁乳酸菌发酵过程中品质的变化

以南丰蜜桔汁为对象,采用乳酸菌发酵,检测发酵过程中菌落数、pH、总酸度、有机酸与糖的含量,测定发酵前后维生素C、总黄酮和多酚的含量。结果表明,乳酸菌能够较好地适应桔汁发酵环境,蜜桔发酵液总酸度随发酵时间的延长呈上升趋势,pH下降至3.2;蔗糖、果糖、葡萄糖含量均呈下降趋势;乳酸菌对柠檬酸、苹果酸、乙酸有一定的利用能力,使其呈下降趋势,而乳酸含量显著上升(p<0.05),由发酵前的0.44 mg/g升至13.05 mg/g;短链脂肪酸从5.23 mg/g增至13.05 mg/g;维生素C含量仍保持在80%以上;总黄酮和多酚类化合物含量显著上升,分别提高了12.9%和8%(p<0.05);发酵后氨基酸总量减少了13.9%,呈味氨基酸组成发生变化。乳酸菌可以作为发酵型南丰蜜桔汁的发酵剂,南丰蜜桔汁乳酸菌发酵可以改善风味,提高其营养保健价值。     

乳及乳制品中的抗高血压活性肽

论述了乳及乳制品中的抗高血压活性肽的分离纯化、构性关系、对血管紧张素转换酶的抑制活性和抗高血压机理，以及其在体内的吸收特性。展望了乳源抗高血压肽的应用前景。     

蔬菜乳酸菌腌渍发酵过程亚硝酸盐变化研究

研究了蔬菜腌渍发酵过程中添加乳酸菌纯培养液对亚硝酸盐含量变化的影响。实验结果表明,接种乳酸菌能降低蔬菜腌渍发酵过程中亚硝酸盐含量。4组乳酸菌腌渍发酵实验中,接种混合菌种(干酪乳杆菌∶鼠李糖乳杆菌∶植物乳杆菌=1∶1∶1)对蔬菜湿腌发酵时菜料和菜汤的亚硝酸盐含量降低效果最佳,接种植物乳杆菌对蔬菜干腌发酵时菜料亚硝酸盐含量降低作用最显著。     

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。     

Production of angiotensin I converting enzyme inhibitory (ACE-I) peptides during milk fermentation and their role in reducing hypertension

Fermented milk is a potential source of various biologically active peptides with specific health benefits. Angiotensin converting enzyme inhibitory (ACE-I) peptides are one of the most studied bioactive peptides produced during milk fermentation. The presence of these peptides is reported in various fermented milk products such as, yoghurt, cheese, sour milk, etc., which are also available as commercial products. Many of the ACE-I peptides formed during milk fermentation are resistant to gastrointestinal digestion and inhibit angiotensin converting enzyme (ACE) in the rennin angiotension system (RAS). There are various factors, which affect the formation ACE-I peptides and their ability to reach the target tissue in active form, which includes type of starters (lactic acid bacteria (LAB), yeast, etc.), substrate composition (casein type, whey protein, etc.), composition of ACE-I peptide, pre and post-fermentation treatments, and its stability during gastrointestinal digestion. The antihypertensive effect of fermented milk products has also been proved by various in vitro and in vivo (animal and human trials) experiments. This paper reviews the literature on fermented milk products as a source of ACE-I peptides and various factors affecting the production and activity of ACE-I peptides.     

Angiotensin I‐converting enzyme inhibitory peptides in skim milk fermented with Lactobacillus helveticus 130B4 from camel milk in Inner Mongolia,China

BACKGROUND: Angiotensin I‐converting enzyme (ACE) is a dipeptidyl carboxypeptidase associated with the regulation of blood pressure. ACE inhibition results in a lowering of blood pressure. Lactic acid bacteria are known to produce ACE inhibitors during fermentation. Fermented camel milk is the main traditionally fermented dairy food for desert nomads. The beneficial effects of fermented camel milk, which include the prevention of such diseases and conditions as gastroenteritis, tuberculosis and hypertension, have been demonstrated experimentally. RESULTS: ACE inhibitory activity was observed in fermented milk containing Lactobacillus helveticus 130B4, a strain isolated from traditionally fermented camel milk. The peptide that inhibited ACE was purified from the fermented milk by reverse‐phase high‐performance liquid chromatography. The amino acid sequence of the peptide was identified as Ala‐Ile‐Pro‐Pro‐Lys‐Lys‐Asn‐Gln‐Asp (IC₅₀ = 19.9 µmol L^?1). The same Ala‐Ile‐Pro‐Pro‐Lys‐Lys‐Asn‐Gln‐Asp sequence was found in κ‐casein (κ‐CN) f107–115 from milk. The inhibitory activity of this nonapeptide (κ‐CN f107–115) was almost preserved even after successive digestion with pepsin, trypsin and chymotrypsin. Furthermore, the inhibitory activity of the purified peptide was completely preserved after heat treatment at 100 °C for 20 min. CONCLUSION: The fermented milk prepared with Lactobacillus helveticus 130B4 contained an ACE inhibitory peptide, κ‐CN 107–115. This fermented milk was expected to have anti‐hypertensive effect after ingestion because the peptide was stable to digestive protease and heat treatment in vitro. Copyright © 2008 Society of Chemical Industry     

乳酸菌发酵在谷物产品中的应用及研究进展

谷物食品是人类能量摄入的主要来源之一,随着人们生活水平的提高,谷物食品的营养价值和食用品质受到了广泛关注。发酵是改善食品性质、功能及营养缺陷的重要方法,也是谷物加工的重要手段。乳酸菌能够利用碳水化合物进行生长代谢,在食品工业中被广泛应用于各种发酵制品,其发酵产生的代谢产物有许多重要的生理功能,包括调节肠道菌群平衡、提高免疫力、抗菌和抗肿瘤等。因此,乳酸菌发酵在谷物食品中的研究与应用,对提升食品品质具有重要意义。本文综述了乳酸菌发酵对谷物营养成分、生物功能和结构、理化性质的影响,总结了乳酸菌发酵谷物产品的优势以及乳酸菌发酵在多种谷物产品中的应用,分析了乳酸菌发酵谷物食品目前研究的不足及可能的发展方向, 拟为乳酸菌发酵在谷物中的研究与开发提供参考。     

甘肃藏区牦牛酸乳中优良乳酸菌及其组合发酵性能研究

通过对甘肃藏区牦牛酸乳中5株性状优良乳酸菌间进行组合发酵筛选,得出最佳发酵组合,并进一步对其发酵性能进行研究,结果表明:嗜热链球菌Q4和德氏乳杆菌保加利亚亚种G4为最佳组合,且其发酵性能优于单菌,即在冷藏期间,组合菌株Q4-G4所发酵的酸奶的抗后酸化能力增强,活菌数（大于109 CFU/m L）、黏度（7.4⁸.61 Pa·s）均大于单菌株且变化幅度小,产香能力增强、风味更佳,胞外多糖含量（129.28 mg/m L）显著高于单菌株Q4、G4（p<0.05）;与商业发酵剂YO-MIX300的发酵性能无显著性差异（p>0.05）。组合菌株Q4-G4可以作为混合发酵剂投入到酸奶的工业化生产中。      

Inhibition of spoilage lactic acid bacteria by lysozyme during wine alcoholic fermentation

The efficacy of lysozyme against indigenous lactic acid bacteria (LAB) and four inoculated spoilage LAB cultures was investigated in laboratory scale Chardonnay winemaking trials (at pH 3.8). These LAB cultures included Lactobacillus kunkeei, Lactobacillus brevis, Pediococcus parvulus , and Pediococcus damnosus . Three concentrations of lysozyme were used: 0, 125 and 250 mg/L. Alcoholic fermentation of the grape juice was carried out at 20±0.5°C using Saccharomyces cerevisiae . Lysozyme did not have any negative impact on yeast growth and sugar reduction. This enzyme was found to be very effective in inhibiting the growth of all four LAB cultures investigated. Under the given experimental conditions, as high as an 8 log cell reduction was obtained for some of the strains. The acetic acid production by L. brevis and L. kunkeei was significantly reduced in the treatments with 125 and 250 mg/L lysozyme added ( P < 0.01). The effect of lysozyme on the cells of the LAB cultures was examined under a scanning electron microscope. It is evident that lysozyme had a detrimental impact on the cells of these cultures. Based on these observations, it is concluded that lysozyme may be a useful tool for winemakers to control the growth of spoilage LAB and to reduce the production of volatile acids. The addition of lysozyme may also prevent the increase of volatile acidity during stuck/sluggish alcoholic fermentation. This tool is particularly useful in high pH wines where SO₂ is less effective.     

Application of pure and mixed probiotic lactic acid bacteria and yeast cultures for oat fermentation

Fermentation of a prebiotic containing oat substrate with probiotic lactic acid bacteria and yeast strains is an intriguing approach for the development of new synbiotic functional products. This approach was applied in the present work by using pure and mixed microbial cultures to ferment a heat‐treated oat mash. Results show that the strains studied were appropriate for oat fermentation and the process could be completed for 6–10 h depending on the strain. The viable cell counts achieved within this time were above the required levels of 10⁶–10⁷ cfu ml⁻¹ for probiotic products. Both single lactic acid bacteria strains and mixed cultures of the same strains with yeast were found suitable for oat fermentation. However, the pure LAB cultures attributed better flavour and shelf life of the oat drinks. The content of the prebiotic oat component beta‐glucan remained within 0.30–0.36% during fermentation and storage of the drinks obtained with each of the strains used. Thus, these products would contribute diet with the valuable functional properties of beta‐glucan. Also, the viability of pure and mixed cultures in the oat products was good: levels of cell counts remained above the required numbers for probiotic products throughout the estimated shelf‐life period. Copyright © 2005 Society of Chemical Industry     

红茶菌中醋酸菌和酵母菌的分离鉴定及其相互作用

采用涂布平板法分离红茶菌中的醋酸菌和酵母菌,然后将分离得到的醋酸菌和酵母菌按照一定比例分别进行共培养,比较细菌纤维素的产量差别。结果表明,从红茶菌中分离出1株醋酸菌,经鉴定为居间驹形杆菌（Komagataeibacter intermedius）;3株酵母菌,经鉴定分别为布鲁塞尔酒香酵母（Brettanomyces bruxellensis）、二孢接合酵母（Zygosaccharomyces bisporus）和核果梅奇酵母（Metschnikowia fructicola）,其中布鲁塞尔酒香酵母为优势酵母。当居间驹形杆菌与布鲁塞尔酒香酵母以1∶100的比例共培养时,产生的细菌纤维素最多达4.70 g/L;当二孢接合酵母和核果梅奇酵母以相同比例分别与居间驹形杆菌共培养时产生的细菌纤维素分别为3.59 g/L（高于对照组）和1.14 g/L（低于对照组）。由此可知,布鲁塞尔酒香酵母和Z. bisporus均能够促进居间驹形杆菌产细菌纤维素,而核果梅奇酵母对居间驹形杆菌没有明显的促进作用。