瑞士乳杆菌发酵乳制备ACE 抑制肽的条件优化

本研究以脱脂乳为主要原料,对瑞士乳杆菌发酵产生血管紧张素转化酶(angiotensin I-converting enzyme,ACE)抑制肽工艺条件进行研究。通过单因素试验和响应面试验设计,确定瑞士乳杆菌发酵脱脂乳生产ACE 抑制肽的最佳工艺条件为：脱脂乳浓度9.67%(m/V)、底物灭菌时间30min、接种量3%(V/V),温度38.82℃、发酵时间6.26h,测得ACE 抑制率为92.26%。研究结果证实利用发酵法生产乳源ACE 抑制活性肽对控制高血压具有重要意义。     

ACE抑制肽研究进展

该文对目前国内外有关ACE抑制肽研究进展进行综述,重点介绍制备ACE抑制肽原料、分离提取方法、结构与活性关系、活性测定方法和功能性评价方法,并简介其在食品中应用及发展前景,以期为对ACE抑制肽进一步研究提供参考。     

瑞士乳杆菌发酵乳清蛋白制备ACE抑制肽的条件优化

对瑞士乳杆菌发酵乳清蛋白产生血管紧张素转化酶(angiotensin converting enzyme,ACE)抑制肽的发酵条件进行探讨。通过单因素分析和响应面试验设计,确定发酵乳清蛋白制备ACE抑制肽的最佳工艺条件：发酵时间为17.52h,发酵温度为37.07℃,乳清质量浓度为114.1g/L,其ACE抑制率可达89.337%。     

发酵乳中ACE抑制肽的超滤工艺研究

本实验采用超滤法分离发酵乳中的ACE抑制肽,研究了超滤工艺的主要技术参数。结果表明:截留分子量为6000Da的超滤膜,在压力0.10MPa,温度25℃条件下,能得到具有较高ACE抑制活性的超滤液。     

发酵乳中ACE抑制肽生成的外部因素条件的研究

探讨了促进发酵乳中ACE抑制肽生成的外部因素条件。研究结果表明,菌株发酵凝乳(pH4.7～5.0)后,产生肽量迅速积累,ACE抑制活性大幅度增强,产生的肽量与ACE抑制活性具有正相关性。添加乳清蛋白和酪蛋白可提高发酵乳中的肽含量,添加酪蛋白组更为突出;添加乳清蛋白组肽粉ACE抑制活性减弱,而添加酪蛋白组肽粉ACE抑制活性增强。与发酵温度42℃相比,37℃发酵条件下有利于发酵乳ACE抑制肽生成;与4℃冷藏处理相比,37℃条件下保温培养对提高ACE抑制活性和肽含量更为显著(P<0.01),实验结果为发酵法生产ACE抑制肽提供了可靠的技术依据。     

苋籽ACE抑制肽降血压的体外评价

利用循证医学,依据血管紧张素转换酶(ACE)对血压的调节机理,以呋喃丙烯酰三肽(FAPGG)为血管紧张素Ⅰ模拟物,建立了胰蛋白酶模拟体外消化体系和大鼠肝脏混合功能氧化酶(MFO)模拟肝脏代谢体系,测得了未经处理的苋籽水解肽IC50值为1mg/mL,经过体外模拟消化和孵育处理后的苋籽水解肽IC50值为10mg/mL。      

苋籽ACE抑制肽降血压的体外评价

利用循证医学,依据血管紧张素转换酶(ACE)对血压的调节机理,以呋喃丙烯酰三肽(FAPGG)为血管紧张素Ⅰ模拟物,建立了胰蛋白酶模拟体外消化体系和大鼠肝脏混合功能氧化酶(MFO)模拟肝脏代谢体系,测得了未经处理的苋籽水解肽IC50值为1mg/mL,经过体外模拟消化和孵育处理后的苋籽水解肽IC50值为10mg/mL。     

米糠蛋白ACE抑制肽在大鼠体内降压效果的研究

采用灌胃和静脉注射的方法,观察了米糠蛋白ACE抑制肽对应激性高血压(SHR)大鼠的降压效果,并与卡托普利的降压效果进行了比较。分别以50、100、150 mg/kg·bw剂量的米糠蛋白ACE抑制肽一次性给药后,每2 h测量大鼠血压,连续测量8 h;实验持续4周,每天灌胃一次,每周测量血压及体重一次。SHR大鼠给予米糠蛋白ACE抑制肽后,血压均显著下降(p<0.05),并均在灌胃后2 h达到最低值,血压下降最大幅度为(31±6.8)mm Hg;而正常大鼠灌胃米糠蛋白ACE抑制肽后血压无显著变化,灌胃卡托普利则会明显降低其血压;长期灌胃米糠蛋白ACE抑制肽可使SHR大鼠血压下降明显(p<0.05),且降压效果稳定。      

德氏乳杆菌QS701产ACE抑制肽发酵条件的优化

通过单因素和正交实实验对德氏乳杆菌QS701产ACE抑制肽的发酵条件进行优化,以期提高ACE抑制肽的产量,并对该菌株的生长特征进行探讨。结果显示,影响ACE抑制活性的发酵条件的顺序为:发酵时间>发酵温度>接种量,在此实验中,德氏乳杆菌QS701的最佳发酵条件为:接种量3%、温度43℃、发酵时间72 h,在此条件下ACE抑制率可达到81.58%,所以将此发酵条件应用于ACE抑制肽的制备中。     

蚕蛹源ACE抑制肽的稳定性和抑制ACE动力学

研究了温度、pH、干燥方式和体外肠道酶消化对蚕蛹源ACE抑制肽稳定性的影响,并通过Lineweaver-Burk双倒数曲线作图和紫外光谱初步探讨了蚕蛹源ACE抑制肽对ACE的抑制机理。结果表明:蚕蛹源ACE抑制肽在高温、酸性和碱性条件下不稳定,易失活;冷冻干燥和喷雾干燥对蚕蛹源ACE抑制肽的活性影响较小;蚕蛹源ACE抑制肽对胃蛋白酶、胰蛋白酶和α-胰凝乳蛋白酶具有较强的抗消化能力,经胃蛋白酶、胰蛋白酶和α-胰凝乳蛋白酶共同消化后,蚕蛹源ACE抑制肽仍能保留初始活性的94.0%;蚕蛹源ACE抑制肽竞争性抑制ACE,其抑制常数(Ki)为0.06 mg/mL;ACE被蚕蛹源ACE抑制肽抑制后,ACE在240～280 nm附近的紫外吸光值明显增加,初步揭示了蚕蛹源ACE抑制肽抑制ACE活性时,ACE的分子结构发生了改变。     

Improved peptide generation from milk fermented by heat‐shocked Lactobacillus helveticus

High macromolecular protein content in bovine milk produces a firm and dense coagulum in the stomach. To increase the number of easily digested peptides, we were the first to introduce heat‐shocked Lactobacillus helveticus to fermented milk. The results showed that acid production was inhibited significantly (P < 0.01) over 14 h of fermentation; the content of small peptides and nonapeptide increased 28.03% and 27.78%, respectively, including three specific and fifteen common bioactivity peptides. The identified type of peptides from α‐casein, β‐casein and κ‐casein increased by 12.05%, 30.73% and 19.30%, respectively, and the distribution of peptides was similar to intestinal digestion. Therefore, this attenuated strain could improve the generation of small molecular peptides and bioactive peptides to promote the degradation of proteins and accelerate milk protein digestion and absorption. This approach might be used to develop functional dairy products.     

嗜酸乳杆菌混合发酵乳酒的研究

用嗜酸乳杆菌、酿酒酵母组合发酵生产牛乳酒。通过正交实验确定最佳工艺条件为:接种嗜酸乳杆菌1%,37℃发酵10h,后接入酿酒酵母1%,28℃发酵14h,加糖量6%(W/V)。成品指标:酒精度0.8%～1.2%,酸度70～80°T,糖度10%左右,无脂肪上清液析出,凝乳状态良好,乳白色不透明,酸度适中,醇香浓郁。      

Mucosal immunomodulation by the non-bacterial fraction of milk fermented by Lactobacillus helveticus R389

The health promoting effects ascribed to probiotic bacteria and fermented dairy products arise not only from bacteria themselves but also from metabolites derived from milk fermentation. Exopolysaccharides produced during milk fermentation and peptides derived from major milk proteins, when released during fermentation, are potential modulators of various regulatory processes in the body. The aim of this work was to increase the knowledge of the previously observed immunomodulating capacity of milk fermented by Lactobacillus helveticus R389 by the study of the mucosal immunomodulation exerted by the non-bacterial fraction of the milk fermented at a constant pH6 (NBFpH6). The effects on IL-6 production by small intestine epithelial cells, the profile of IgA+ and cytokine+ cells (IL-2, IL-6, IL-10, TNF-alpha and IFN-gamma) induced in the gut lamina propria, and the levels of total and specific secretory IgA in the lumen of BALB/c mice that received NBFpH6 for 2, 5 or 7 days were examined. There was an increase in the number of IgA+, IL-10+, IL-2+ and IL-6+ cells after all feeding periods. Total S-IgA in the small intestine lumen increased in mice that received NBFpH6 for 2 days. However, no specific antibodies against NBFpH6 were detected. Feeding of NBFpH6 for 7 days significantly (P<0.05) enhanced IL-6 secretion by small intestine epithelial cells. NBFpH6 induced a non-specific mucosal response that was down-regulated for protective immunity, enhancing IL-6 production by epithelial cells and IgA production in the small intestine. These events improve the immunological defenses at the intestinal level, increasing host protection against pathologies. Because mucosal immune responses induced by certain dietary antigens play a large part in the prevention of gastrointestinal diseases, the oral administration of a mucosal adjuvant such as NBFpH6 may positively affect the milieu of the intestinal lumen. The opportunity exists then to manipulate the constituents of the lumen of the intestine through dietary means, thereby enhancing the health condition of the host.     

瑞士乳杆菌发酵乳中多肽的分离对小鼠体外淋巴细胞增殖的影响

目的:分离瑞士乳杆菌发酵乳中多肽片段,并对分离片段的的免疫调节作用进行研究。方法:利用瑞士乳杆菌LH0906发酵牛乳获得多肽样品,采用离心、超滤的方法对所得多肽进行粗提,利用凝胶层析色谱和反相层析色谱进一步分离发酵乳中的多肽,使用Folin-Lowry法测定发酵后样品中多肽含量,采用3-(4,5-二甲基噻唑-2)-2,5-二苯基四氮唑溴盐(MTT)比色法检测发酵乳中的多肽对小鼠脾脏淋巴细胞体外增殖的影响。结果:牛乳发酵液其对小鼠脾脏淋巴细胞增殖效果显著高于未发酵牛乳,并经过凝胶层析色谱和反相层析色谱分离发酵乳得到的峰S12-A对小鼠脾脏淋巴细胞体外增殖效果十分显著(P<0.01),峰S12-C对小鼠脾脏淋巴细胞体外增殖效果显著(P<0.05)。结论:牛乳经瑞士乳杆菌LH0906发酵后,分离得到的多肽片段对小鼠脾脏淋巴细胞体外增殖具有显著的增强作用。     

乳酸菌发酵乳酶解液抗氧化作用的研究

利用比色法和化学发光法,研究了乳酸菌发酵乳酶解液(ELFM)抑制脑组织匀浆脂质过氧化的能力和清除自由基的作用.结果表明,ELFM抗脂质过氧化的能力随浓度的增大而增加,达到25%(体积分数)时,ELFM的脂质过氧化抑制率接近100%;ELFM对HO·具有极强的清除能力(IC50=1.35%),清除O2-的能力极弱.ELFM有很强的抗氧化作用,在功能性食品领域具有良好的应用前景.     

Lactobacillus helveticus fermented milk reduces arterial stiffness in hypertensive subjects

The present study evaluated the 10-week-treatment effect of Lactobacillus helveticus fermented milk containing the tripeptides isoleucyl-prolyl-proline (Ile-Pro-Pro) and valyl-prolyl-proline (Val-Pro-Pro) on ambulatory arterial stiffness index (AASI) by using the ambulatory 24-h blood pressure registration. The AASI improved significantly in the peptide milk group (p=0.043), but not in the placebo group (p=0.47), suggesting a mechanism for the antihypertensive effects of these peptides.     

瑞士乳杆菌发酵法研制牛肉香精的研究

以瑞士乳杆菌作为发酵剂菌种对牛肉酶解物进行发酵,利用瑞士乳杆菌分泌二肽酶、三肽酶等的特性,研究了其对牛肉酶解物口感及风味的影响,并在此基础上研制热反应牛肉香精。结果表明,发酵12h牛肉酶解物的苦味基本消失,肉香较浓郁,发酵18h其口感、风味均达到最佳;利用发酵牛肉汁制备热反应牛肉香精的工艺参数为:120℃、pH6.5、45min。     

Immunomodulating effects of peptidic fractions issued from milk fermented with Lactobacillus helveticus

The effect of peptides released during the fermentation of milk on the humoral immune system and on fibrosarcoma growth was studied. Lactobacillus helveticus was able to release peptidic compounds during milk fermentation due to its high proteolytic activity, as was shown by the degree of proteolysis and size-exclusion HPLC elution profiles. Three fractions of these compounds were separated and fed to mice during different periods (2, 5, and 7 d). The humoral immune response was assessed by following the number of IgA-secreting cells, and the antitumor activity was monitored by studying the regression of subcutaneously implanted fibrosarcomas. Feeding during 2 and 7 d with the medium-sized fraction (Fraction II) significantly increased the IgA-producing cells in the intestines, whereas feeding with the large compound fraction (Fraction I) during 5 d and the small compound fraction (Fraction III) during all three feeding periods provided similar increases. A double dose of Fraction II showed the highest IgA-producing cell count. The increase by Fraction III was shown to be caused by the presence of L-Tryptophan. Fraction II significantly decreased the size of fibrosarcoma when previously fed during 7 d, and feeding with Fraction I during 5 d decreased significantly its size after 35 d of growth. Although the mechanisms by which lactic acid bacteria enhance the immune system are not clear, this study clearly shows that bioactive compounds released in fermented milks contribute to the immunoenhancing and antitumor properties of these products. The release of bioactive peptides by lactic acid bacteria can have important implications on the modulation of the cellular immune response.     

复合乳酸菌发酵产双乙酰的研究

选用瑞士乳杆菌和乳酸乳球菌混合发酵产双乙酰。研究表明,当发酵时间、发酵温度、牛奶与奶油浓度之比、反应体系的pH、乳糖添加量和柠檬酸添加量分别为32h、37℃、3∶1、6.5、1.0%和2.0%时,双乙酰的产量达到了125mg/L。此外,添加乳糖和柠檬酸能大大促进产物双乙酰的积累。     

Effects of Lactobacillus helveticus TUST005 fermented milk on bone parameters in rats

The effects on bone parameters were investigated using ovariectomized rats and their control ones fed with water, skim milk, sour milk, Lactobacillus helveticus TUST005 fermented milk and whey filtrate of the L. helveticus TUST005 fermented milk for 10-week interventions, respectively. Our results indicated that the ovariectomized rats are considered a suitable model for osteoporosis. The L. helveticus TUST005 fermented milk significantly increased bone mineral density, bone mineral content, the maximal load of bone and decreased bone loss compared to sour milk, and whey filtrate of the L. helveticus TUST005 fermented milk has a higher influence on bone than the fermented milk.