鱼降压肽的大孔吸附树脂分离及其活性稳定性

采用大孔吸附树脂对碱性蛋白酶水解、水解度为34.52% 的鱼降压肽进行分离。结果表明,DA201-C 型大孔吸附树脂对鱼降压肽吸附性最好,乙醇体积分数为75% 时洗脱下来的组分具有最高的ACE 抑制活性,其IC50为1.52mg/ml。鱼降压肽中灰分由分离前的9.47% 减少到分离后的2.34%,肽和蛋白质含量分别由分离前的72.81%和81.26% 增加到分离后的80.24% 和92.42%。活性稳定性分析显示,胃蛋白酶和胰酶、中性和低酸性pH 值、55℃以下温度以及1000mmol/L 以内的NaCl 浓度对鱼降压肽的ACE 抑制活性影响较小。     

模拟胃肠消化对牡蛎低聚肽抗氧化活性的影响

以去壳牡蛎肉为原料通过酶解法制备牡蛎低聚肽,并通过体外模拟消化试验,对比消化前后牡蛎低聚肽分子量分布、DPPH自由基清除能力、羟自由基(·OH)清除能力、ABTS自由基清除能力、氧自由基吸收能力(ORAC)变化,探究牡蛎低聚肽经模拟胃、肠道消化后抗氧化活性的变化。试验结果显示,牡蛎低聚肽的相对分子量主要在1 000 Da以下,胃蛋白酶和胰蛋白酶消化后重均分子量下降不超过8.2%;胃蛋白酶和胰蛋白酶消化后,DPPH自由基清除率降低分别不超过7.9%,8.7%;胃蛋白酶和胰蛋白酶消化后,·OH清除率降低分别不超过9.3%,3.8%;胃蛋白酶消化后,ABTS自由基清除率降低9.2%,胰蛋白酶消化后,ABTS自由基清除率提高3.6%;胃蛋白酶和胰蛋白酶消化后,ORAC值分别提高11.5%,1.3%。胃肠消化对牡蛎低聚肽的抗氧化活性评价各指标均无显著性影响(P＞0.05)。说明牡蛎低聚肽具有较好的综合抗氧化活性和稳定性。     

蛋清肽的抗氧化稳定性与功能特性

选用胃蛋白酶水解冻干蛋清制得蛋清肽,测定蛋清肽的抗氧化稳定性及功能特性。研究温度和pH值对蛋清肽抗氧化稳定性的影响以及蛋清肽的乳化性、吸水能力和吸油能力。结果表明：随着蛋清肽质量浓度的增加其清除羟自由基( ·OH)、超氧阴离子自由基(O2－ ·)及DPPH自由基的能力均随之增加;温度与pH值对蛋清肽的抗氧化活性影响较大,在pH12.0条件下存放4h后其抗氧化活性消失;蛋清肽具有较好的乳化能力、乳化稳定性、吸油和吸水能力,这些均有利于其在食品和化妆品行业中的应用。     

大豆蛋白酶解肽的分子量分布及抑制ACE活性关系研究

研究不同蛋白酶作用的酶解肽表现在血管紧张素转化酶(ACE)活性抑制差异,酶解产物的水解度、分子量分布与ACE抑制率的相互关系。用胰蛋白酶、胃蛋白酶、中性蛋白酶、木瓜蛋白酶、碱性蛋白酶等五种蛋白酶对大豆分离蛋白酶解,进行了多肽增量、水解度、超滤膜分离及其ACE抑制率对比等实验。结果表明,碱性蛋白酶的多肽增量最大,胃蛋白酶次之,依次为木瓜蛋白酶和中性蛋白酶,胰蛋白酶则出现反常;水解度随着酶解的时间而增加,碱性蛋白酶的最大水解度可达到21%,依次为胃蛋白酶、木瓜蛋白酶和中性蛋白酶,最低为胰蛋白酶仅为9%左右;与此对应的碱性蛋白酶的酶解物的ACE活性抑制率为最高(44.9%),胃蛋白酶次之(43.5%)。分子量范围在1000Da以下组分对ACE的抑制效果最高,碱性蛋白酶作用获得的小分子肽组成为71.25%,胃蛋白酶的为69.35%,但其对应的ACE抑制率却为64.57%和78.49%。中性蛋白酶、木瓜蛋白酶和胰蛋白酶作用获得的小分子肽的ACE抑制率分别为45.7%、47.3%和29.6%。胃蛋白酶的降压肽制备效果为最好,其次为碱性蛋白酶、木瓜蛋白酶、中性蛋白酶和胰蛋白酶。     

基于RSM酶法提高蛋清ACE抑制活性

研究胰蛋白酶提高蛋清ACE抑制活性的最优条件。在单因素实验(加酶量、pH、温度、底物浓度)的基础上,通过Design-Expert软件结合4因子3水平的Box-Behnken模型响应面设计,建立胰蛋白酶酶解蛋清制备ACE抑制肽的三元二次回归正交模型。结果表明:胰蛋白酶酶法提高蛋清ACE抑制活性的最佳参数为:加酶量8%、底物浓度3%、温度39℃、pH8.0,水解3h,蛋清ACE抑制活性为54%,活性提高近10倍。     

酶解蛋清蛋白制备ACE抑制肽的工艺研究

为获取酶解蛋清蛋白制备血管紧张素转化酶(ACE)抑制肽的工艺参数,研究4种蛋白酶酶解蛋清蛋白所得产物对ACE的抑制活性,筛选出胰蛋白酶作为制备蛋清蛋白ACE抑制肽的适宜用酶。运用响应曲面法研究酶解时间、底物浓度([S])和酶与底物质量比([E]/[S])对制备ACE抑制肽工艺的影响,建立以上3因素与ACE抑制率关系的数学模型。结果确定胰蛋白酶酶解蛋清蛋白制备ACE抑制肽的适宜酶解条件为酶解时间4.87h、[S]3.06%、[E]/[S]2.91%、酶解温度45℃、pH7.4,此条件下制备的蛋清蛋白酶解产物ACE抑制率达到50.73%。     

酶法制备阿拉斯加鳕鱼降压肽的工艺优化及其产物的结构鉴定

以体外血管紧张素转化酶(ACE)抑制率为指标,筛选出制备阿拉斯加鳕鱼降压肽的最优酶。本研究通过正交实验以及单因素优化实验确定了阿拉斯加鳕鱼降压肽的最优酶解工艺,考察了最优工艺降压肽的氨基酸含量与分子量分布范围。结果表明:在菠萝蛋白酶、木瓜蛋白酶、胰蛋白酶、复合蛋白酶、碱性蛋白酶和酸性蛋白酶6种蛋白酶中,经胰蛋白酶酶解得到的降压肽ACE抑制率最高,为68.48%,其中影响胰蛋白酶活性大小的因素依次为温度、酶与底物质量比、料液比、pH和时间,最优酶解温度40℃,酶与底物质量比3%,料液比1:7,pH=7,酶解时间2 h。在此工艺条件下,降压肽ACE抑制率可达79.62%,氨基酸总含量为83%,分子量低于500 Da的降压肽可达到70.74%。优化的阿拉斯加鳕鱼降压肽的提取工艺可行、合理,降压肽也具有较高的体外ACE抑制活性。本研究结果为进一步考察食源性降压肽提供了参考。     

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。     

泥鳅ACE抑制肽的体外活性研究

以泥鳅蛋白为原料,酶解制备具有降血压活性的短肽,研究该肽的稳定性。在加热温度≤80℃条件下加热2h,泥鳅降血压肽(<2.5ku)的ACE抑制活性没有显著变化。当2.0≤pH≤8.0时,泥鳅降血压肽的ACE抑制活性变化不显著。冷冻干燥优于喷雾干燥。Mg2+对泥鳅降压肽的降压活性起到促进作用,而Zn2+和Mn2+抑制了肽的降压活性。葡萄糖对降压肽活性的影响程度明显大于蔗糖,随着浓度的升高,其ACE抑制活性逐渐降低,褐变程度加深;氯化钠对降压活性的影响不明显。在模拟胃肠道消化体系中,胃蛋白酶的消化显著提高了产物的降压活性;胰酶的消化降低了产物的降压活性。泥鳅多肽属于底物型ACE抑制肽。     

乌鸡低聚肽的制备及其稳定性研究

以乌鸡为原料,利用两步酶解法制备乌鸡低聚肽,以分子量分布为指标,研究了热处理、pH和体外胃肠道模拟消化对乌鸡低聚肽稳定性的影响。结果表明,乌鸡低聚肽分别于20、40、60、80、100℃下水浴2 h后,各个分子量区间的比例变化不超过2%;pH值分别为2、4、6、8、10,37℃水浴2 h后,各个分子量区间的比例变化不超过2%;分别经过胃蛋白酶单独消化、胰蛋白酶单独消化、先胃蛋白酶消化再胰蛋白酶消化,各个分子量区间的比例变化不超过4%。这表明乌鸡低聚肽具有较好的热稳定性、pH稳定性以及消化稳定性,为其在食品工业中的应用提供了一定的理论依据。     

Physiological,chemical and technological aspects of milk-protein-derived peptides with antihypertensive and ACE-inhibitory activity

Among the bioactive peptides derived from milk proteins, those with blood pressure-lowering effects are receiving special attention due to the prevalence and importance of hypertension in the Western population. A few antihypertensive products based on milk-protein-derived peptides with clinically proven health benefits already exist. This paper reviews the current literature on milk-derived peptides with antihypertensive effects. The structure-activity characteristics of angiotensin converting enzyme (ACE) inhibitory peptides are discussed, as well as their bioavailability, potential physiological affects and the existence of mechanisms of action other than ACE inhibition. The paper also focuses on the technological aspects of the production of bioactive dairy products with antihypertensive peptides, either by fermentation with selected microorganisms or by in vitro-hydrolysis and enrichment. Finally, the stability of the peptides during production and processing is addressed, including the potential interactions with other food components and their influence on peptide bioactivity and bioavailability.     

Activity and bioavailability of food protein-derived angiotensin-I-converting enzyme–inhibitory peptides

Angiotensin-I-converting enzyme (ACE) inhibitory peptides are able to inhibit the activity of ACE, which is the key enzymatic factor mediating systemic hypertension. ACE-inhibitory peptides can be obtained from edible proteins and have the function of antihypertension. The amino acid sequences and the secondary structures of ACE-inhibitory peptides determine the inhibitory activities and stability. The resistance of ACE-inhibitory peptides to digestive enzymes and peptidase affect their antihypertensive bioactivity in vivo. In this paper, the mechanism of ACE-inhibition, sources of the inhibitory peptides, structure–activity relationships, stability during digestion, absorption and transportation of ACE-inhibitory peptides, and consumption of ACE-inhibitory peptides are reviewed, which provide guidance to the development of new functional foods and production of antihypertensive nutraceuticals and pharmaceuticals.     

植物源性降压肽作用机制、制备与评价方式及相关研究进展

随着我国经济的发展,高血压患病率呈现高发趋势。药物治疗虽能有效降低血压,但长期服用存在明显副作用。饮食调控是缓解和辅助治疗高血压的重要手段,植物源性降压肽因功效明显且天然、无毒副作用,在世界范围内越来越引起科学家的关注。针对近年来植物源性降压肽在食品领域的研究进展,本文总结了植物源性降压肽的作用机理、制备方法和功效评价方法,进一步重点综述了植物源性食物如小麦、玉米、大豆、大米中降压肽的研究进展,为今后植物源性降压肽的进一步研究提供参考。     

Antihypertensive peptides of animal origin: A review

Many bioactive peptides trigger certain useful antihypertensive activities in the living body system and there is a mounting worldwide interest in the therapeutic potential of these bioactive peptides for exploitation in vivo against the hypertension. Studies suggest the antihypertensive properties for many bioactive peptides of animal origin with underlying mechanisms ranging from inhibition of angiotensin-converting enzyme to additional mechanisms to lower blood pressure such as opioid-like activities and mineral-binding and antithrombotic properties. Antihypertensive peptides are the most extensively studied of all the bioactivities induced by food protein hydrolysates, highlighting their importance in human health and disease prevention and treatment. There exist enormous opportunities for the production of novel peptide-based products in biopharmaceutical manufacturing industries for the treatment, prevention, and mitigation of hypertension. Numerous products have already struck on the global market and many more are in process. This article focuses on antihypertensive peptides identified in the meat, fish, blood, milk, dairy products, and egg and their probable application as novel ingredients in the development of functional food products as dietary treatment of hypertension.     

花生肽对原发性高血压大鼠的降压作用

研究花生肽对原发性高血压大鼠（SHR）的降压作用。采用鼠尾体外间接血压测量方法,观察花生肽单次给药和连续给药对SHR大鼠血压的影响。单次给药后,花生肽组可以降低SHR大鼠的血压;连续给药14d,花生肽组可以稳定降低SHR大鼠的血压并维持在较稳定的水平。单次或连续给药花生肽均对SHR大鼠具有降低血压的效果。     

酪蛋白磷酸肽副产物中ACEI肽的分离鉴定及稳定性研究

酪蛋白磷酸肽副产物中仍含有丰富的功能性多肽,从中回收具有降压活性的血管紧张素I转化酶抑制肽具有废物利用和环境保护的意义。本文在前期研究富集活性肽工艺的基础上,从粗富集产物中进一步分离纯化出具有降压活性的多肽单体,并对单体的分子量、一级序列及其稳定性进行了研究。研究结果表明,以粗富集产物为原料,仅通过阴离子交换树脂及液相制备两步就可获得活性较高的转化酶抑制肽单体P16和P18。P16分子量742.6,序列为GPFPIIV,属首次发现;P18分子量1385.8,序列为FFVAPFPE VFGK。二者均具有较高的耐酸碱性和热稳定性,经体外模拟胃肠消化过程后,发生不同程度的分解,但P16的活性在分解后反而升高12.8%,P18则降低37.5%。推测活性的升高或降低均与活性中心暴露或破坏有关。     

益生菌降压肽的研究现状及其国内外新产品开发趋势

本文阐述了降压肽的作用原理以及乳源性降压肽独特的降压优势,概述了由益生菌研究开发的降压肽产品的现状,同时介绍了国内外利用益生菌开发具降压肽产品的研究成果以及研发的趋势。根据国内外市场的需求,在国内开发具有降压肽活性酸奶制品以及相关的产品必将会产生显著的社会影响,带来可观的效益。     

Use of an electrodialytic reactor for the simultaneous β-lactoglobulin enzymatic hydrolysis and fractionation of generated bioactive peptides

The enzymatic hydrolysis of β-lactoglobulin and the fractionation of peptides were performed in one step in an electrodialysis cell with ultrafiltration membranes stacked. After 240 min of treatment, 15 anionic and 4 cationic peptides were detected in the anionic and cationic peptide recovery compartments. Amongst these 15 anionic peptides, 2 hypocholesterolemic, 3 antihypertensive and 1 antibacterial peptides were recovered and concentrated with migration rates ranging from 5.5% and 81.7%. Amongst the 4 cationic peptides, the peptide sequence ALPMHIR, identified as lactokinin and known to exert an important antihypertensive effect, was recovered with an estimated 66% migration rate. To our knowledge, it was the first attempt to perform hydrolysis under an electric field and to simultaneously separate anionic and cationic peptides produced.     

泥鳅蛋白酶解工艺条件的优化

以泥鳅蛋白为原料,酶解制备具有降血压活性的短肽。从9种蛋白酶中筛选出菠萝蛋白酶的酶解液具有较高降压活性,IC50值为0.65mg/mL。在单因素试验的基础上,采用和Box-Behnken和响应面法(RSM)优化了酶解泥鳅蛋白的工艺条件,以ACE抑制率为指标,探讨酶与底物的比值([E]/[S])、酶解温度和酶解时间对ACE抑制率的影响。结果表明：制备降血压肽的最佳酶解条件为[E]/[S]4.9‰、酶解时间5.9h、酶解温度54.4℃、pH6.5、底物质量分数30%,该条件下制备的泥鳅蛋白酶解产物的ACE抑制率为88.92%。