米糠蛋白源ACE抑制肽的酶解制备及活性研究

目的：开发米糠新产品。方法：以ACE抑制率为指标,通过单因素和响应面试验对米糠蛋白进行酶解工艺优化研究,并对最优酶解物活性肽进行超滤分离、活性评价和氨基酸组成分析。结果：米糠蛋白最优酶解工艺条件为：pH 7.2,底物质量浓度8.2 g/100 mL,酶解温度46 ℃,酶解时间3 h,酶添加量0.3 g/100 g米糠蛋白,在此条件下所得酶解物ACE抑制率为(73.15±0.64)%,而且酶解物含有丰富的疏水性氨基酸(23.09 g/100 g);活性分析表明,分子量＜3 kDa活性肽组分在同质量浓度(1.0 mg/mL)下ACE抑制活性[(81.68±1.08)%]优于分子量＞3 kDa活性肽组分[(58.65±2.21)%]和酶解物[(72.64±1.61)%]。结论：米糠蛋白酶解物具有显著的ACE抑制活性,活性肽组分的分子量对ACE抑制活性具有显著影响。     

米糠蛋白酶解物类阿片拮抗活性的研究

采用水解度(DH)对酶解米糠蛋白进行了研究，比较六种蛋白酶对米糠可溶性蛋白的水解作用，结果发现胰蛋白酶对米糠可溶性蛋白的水解作用最强，它的最适作用条件为：pH8．0，温度为37℃，[E]／[S]为12．5usp-u／kg。采用离体豚鼠回肠(GPI)检定法测定上述酶解物的类阿片拮抗活性，结果发现胰蛋白酶水解产物具有明显的类阿片拮抗活性，DH为11．9％时，其水解产物(样品A)的类阿片拮抗活性最高。体积排阻高效液相色谱测定它的相对分子质量分布范围在125-24233Da之间。     

米糠蛋白及其活性肽的研究与利用进展

综述了米糠蛋白提取工艺,功能特性及其活性肤在降血压(ACE抑制肽),阿片样拮抗活性,抗氧化,免疫调节等方面的作用,并且概括了米糠蛋白及肽在食品行业的应用.     

预分离米糠蛋白类阿片拮抗肽的离子交换工艺

研究离子交换层析法对米糠蛋白酶解物超滤透过液中类阿片拮抗肽的初步分离提取。采用强酸性阳离子交换树脂,上样流速:SV0.8,上样pH值:5.0;洗脱液氨水浓度:1mol/mL,洗脱速度:SV1.2。离体豚鼠回肠(GPI)检定法鉴定表明,在此条件下制备的米糠蛋白类阿片拮抗肽活性得到提高。     

酶解法制备核桃谷蛋白-1 ACE抑制肽的工艺优化

为获得优质的核桃蛋白血管紧张素转化酶(ACE)抑制肽的制备原料及优化其制备工艺,采用连续提取法从脱脂核桃粕中依次分离出清蛋白、球蛋白、醇溶蛋白、谷蛋白-1和谷蛋白-2 5种组分蛋白,测定5种组分蛋白的占比及ACE抑制率,以ACE抑制率最大的组分蛋白作为原料采用酶解法制备ACE抑制肽,在筛选出最适酶解用酶基础上,采用单因素试验与响应面试验优化酶解制备核桃蛋白ACE抑制肽的工艺。结果表明：5种组分蛋白中谷蛋白-1占比仅次于谷蛋白-2,且其ACE抑制率最高,以核桃谷蛋白-1为原料,在筛选出胃蛋白酶作为酶解用酶基础上,经工艺优化得到最优的酶解法制备核桃谷蛋白-1 ACE抑制肽的工艺条件为酶解温度46℃、酶解时间6 h、酶用量4.2%(以底物质量计)、酶解pH 1.6,在该条件下所得核桃谷蛋白-1酶解液的ACE抑制率为(50.08±2.34)%。因此,核桃谷蛋白-1经胃蛋白酶酶解可生产ACE抑制活性较高的核桃多肽。     

米糠蛋白类阿片拮抗肽的分离纯化

采用体积排阻色谱和反相高效液相(RP-HPLC)对米糠蛋白酶解物进行分离纯化,得到一种具有较高活性的类阿片拮抗肽,体积排阻高效液相色谱(SE-HPLC)测定它的相对分子质量为546Da。     

鱿鱼肝脏蛋白水解液及ACE 抑制肽的制备

为高效利用鱿鱼及其下脚料肝脏蛋白水解物,采用酶解技术和凝胶过滤分离等技术对鱿鱼肝脏蛋白水解液中抑制肽进行研究。结果表明：胃蛋白酶为鱿鱼肝脏蛋白水解的最佳酶类,同时以水解度和ACE 抑制活性为指标,得出胃蛋白酶水解的最佳条件：在36℃条件下酶解22h,酶与底物的质量比2%,底物质量分数2.5%。经过上述条件处理的水解液再经超滤处理(截留分子质量为20kD)后,用Sephadex G-50 进行分离,洗脱得到5 个峰,其中组分B 的ACE 抑制活性最高,其半抑制浓度(IC50)达到1.80mg/mL。     

利用对虾消化腺丝氨酸蛋白酶制备鲍鱼外套膜ACE抑制肽

利用鲍鱼加工副产物外套膜制备具有抑制血管紧张素转移酶(angiotensin converting enzyme,ACE)活性的生物活性肽,为鲍鱼加工副产物的高值化利用提供新思路.采用从凡纳滨对虾消化腺中制备的丝氨酸蛋白酶,酶解皱纹盘鲍外套膜蛋白,以酶解物ACE抑制活性为评价指标优化条件.酶解液通过3 kDa超滤膜后,...     

鱿鱼下脚料水解物的制备及降血压抑制肽研究

通过对鱿鱼肝脏蛋白水解液中抑制肽的研究,为鱿鱼及其下脚料水解物的高效利用奠定了理论基础。采用酶解技术和凝胶过滤分离等技术进行研究。实验得出:胃蛋白酶为鱿鱼肝脏蛋白水解的最佳酶类,同时以水解度和ACE抑制活性为指标,得出胃蛋白酶水解的最佳条件:在36℃条件下酶解22h,酶与底物的质量比2%,底物浓度2.5%。经过上述条件处理后的水解液经超滤处理(分子量为20ku)后,用Sephadex G-50进行分离,洗脱得到等5个峰值,其中组分B的ACE抑制活性最高,其半抑制浓度(IC50)达到1.80mg/mL。     

从麦胚蛋白质中制备降血压肽的研究

用超临界CO2对小麦胚芽脱脂，碱溶酸沉淀法提取麦胚蛋白，用8种蛋白酶分别进行单一酶和复合酶水解麦胚蛋白生产降血压肽，用高效毛细管电泳(HPCE)测定其活性。碱性蛋白酶生产水解物的活性最大，其对麦胚蛋白作用的最适pH为9，温度为50～55℃，加酶量为24AU／kg，水解度为16．5％时所得水解物对ACE有强烈抑制用。     

鹰嘴豆肽、大豆肽功能性质的研究

研究对比了鹰嘴豆肽和大豆肽的水解度、抗氧化性、吸油性、吸湿及保湿性等功能特性的差异,以及蛋白酶种类对肽产物功能性质的影响。结果表明,①酶Ⅱ(Protease from Bacillus sp.)制备的蛋白肽抗氧化性和吸油能力最好,且在低湿度下的吸湿性和高湿度下的保湿性也最好;酶Ⅲ(Papain from papaya latex)制备的蛋白肽水解度最高;酶Ⅰ(Protease fromAspergillus melleus)制备的蛋白肽在不同湿度条件下都有较好的吸湿性能。②大豆肽的水解度和抗氧化能力比鹰嘴豆肽好。③Desi肽吸油能力最强,在抗氧化性上仅次于大豆肽,高低湿度环境下都有很好的保湿能力,其中Desi肽Ⅱ这些特征最为明显。④Kabuli肽在不同湿度条件下的吸湿和保湿能力都较好。     

Preparation of casein phosphorylated peptides and casein non-phosphorylated peptides using alcalase

Casein was digested with a cheaper enzyme, alcalase, to produce casein phosphorylated peptides and casein non-phosphorylated peptides concurrently. The casein hydrolyzates were separated to the two kinds of peptides by using combined treatment of CaCl₂ and ethanol. Casein phosphorylated peptides and non-phosphorylated peptides constitute some peptides with molecular weight lower than 2509 Da and 2254 Da respectively as determined using size exclusion HPLC, particularly when a degree of hydrolysis of 20% for the casein hydrolyzates was achieved. At the end, the recovery of casein phosphorylated peptides reached 24%. Phosphorus component of casein phosphorylated peptides was found to be 3.08%. The nitrogen recovery of casein non-phosphorylated peptides was about 76%.     

Bioactive peptides derived from bovine whey proteins: opioid and ace-inhibitory peptides

Regulatory peptides can be released by enzymatic proteolysis of food proteins and may act as potential physiological modulators of metabolism during the intestinal digestion of the diet. The possible regulatory effects of peptides relate to nutrient uptake, immune defence, opioid and antihypertensive activities. Milk proteins, especially caseins, are an important source of these bioactive peptides. During recent years, major whey protein components, α-lactalbumin and β-lactoglobulin, were also shown to contain bioactive sequences. Peptides showing opioid and angiotensin I-converting enzyme (ACE) inhibitory activity were found in α-lactalbumin and β-lactoglobulin. Opioid peptides, α-lactorphin and β-lactorphin, were liberated during in vitro proteolysis of bovine whey proteins, and pharmacological activity was observed at micromolar concentrations. Whey hydrolysates showed ACE-inhibitory activity after proteolysis with different digestive enzymes, and several active peptides were identified. The results demonstrated the existence of several biologically active whey-derived peptides and hydrolysates. The findings of the study can be exploited in the development of foods with special health claims (e.g. treatment of hypertension) as well as in identifying new applications in food.     

Antimicrobial peptides and pregnancy

Antimicrobial peptides (AMPs) are small proteins produced by epithelial surfaces and inflammatory cells, which have broad-spectrum antimicrobial and immunomodulatory activities. They are known to be important in a number of infectious and inflammatory conditions and have been shown to be present in a number of sites throughout the female reproductive tract. Inflammation and infection are associated with a number of complications of pregnancy including preterm labor, and AMPs may play a key role in maintaining and protecting pregnancy. The aim of this review is to describe the expression and function of AMPs in the pregnant female reproductive tract and their relation to preterm labor.     

Analyses of peptides in sake mash: forming a profile of bitter-tasting peptides

Some oligopeptides and amino acids have a strong influence on the sensory qualities of sake, but the formation process of such compounds in sake mash has not been well elucidated. In this study, we investigated the formation process of bitter-tasting peptides derived from rice proteins in sake mash, because knowledge about their formation may contribute to the quality control of sake. We analyzed rice protein hydrolysates in sake mash, as well as in the enzymatic digest of steamed rice grains digested by either sake-koji or by crude enzyme extracted from sake-koji. SDS–PAGE showed that a smaller amount of polypeptides (> M.W. 10,000) accumulated in the supernatant of sake mash than in either enzymatic digest. The concentration of peptides in the supernatant of sake mash increased gradually from the early stages of fermentation. Five bitter-tasting peptides (No. 9, < QLFNPS; No. 13, < QLFNPSTNP; No. 17, < QLFNPSTNPWH; No. 18, < QLFNPSTNPWHSP; No. 20, < QLFGPNVNPWHNP), which were previously found in sake mash, were not found in significant amounts in sake-koji. On the other hand, these peptides accumulated at the early stages of both sake mash fermentation and the enzymatic digests, although the levels in sake mash were higher than those in the digests. The present study demonstrated that the 5 bitter-tasting peptides formed in high concentrations when steamed rice grains were digested under conditions of sake mash fermentation with yeast.     

紫苏肽制备工艺研究

以脱脂紫苏粕为原料,在预先采用酸性乙醇-水溶剂法脱除植酸、单宁等物质后,采用Alcalase碱性蛋白酶进行酶解,制备紫苏肽.以水解度为指标,分别探讨水解时间、水解温度、pH、底物质量浓度、酶用量等因素对水解反应的影响.通过正交实验,确定最佳水解工艺条件为:底物质量浓度30 g/L,pH 9.5,水解温度60℃,酶用量7％,水解时间4.0h.该条件下,水解度可达38.75％,氮回收率为87.62％.对粗产品进行脱色,确定较佳脱色工艺条件为:活性炭用量5％,pH 3,脱色温度60℃,脱色时间40 min.脱色液经冷冻干燥后得产品,其蛋白质含量为67.1％,相对分子质量小于1 000的组分占总量的85.3％.     

Bioactive peptides and lactic fermentations

Milk proteins contain regions within their primary structures that encrypt for many latent biological activities. The beneficial health effects associated with some fermented dairy products may, in part, be attributed to the release of bioactive peptide sequences during the fermentation process. Peptides displaying opioid, mineral binding, cytomodulatory and hypotensive activities, for example, have been identified in cheese and yogurt. Much effort has to date concentrated on the release of angiotensin-converting enzyme (ACE) inhibitory peptides due to their potential to act as hypotensive agents. Peptide fractions obtained by hydrophobic interaction chromatography of different cheese varieties (Blue, Camembert, Edam, Emmental, Gouda and Havarti) were reported to give systolic blood pressure (SBP) decreases in spontaneously hypertensive rats (SHR) ranging from 7.1 to 29.3 mm mercury (Hg). Skim milks fermented with various strains of Lactobacillus helveticus , and in one case also with Saccharomyces cerevisiae , have been reported to display SBP decreases in mildly hypertensive human volunteers ranging from 4.6 to 14.1 mmHg. These human hypotensive effects have, in part, been attributed to the release of potent casein-derived tripeptide inhibitors of ACE during fermentation. In general, the likelihood of any bioactive peptide released during fermentation mediating a physiological response is dependent on the ability of that peptide to reach an appropriate target site. Therefore, peptides may need to be resistant to further degradation by gastrointestinal and serum proteinases/peptidases following oral ingestion in order to display a functional food effect.     

抗氧化肽的研究现状

抗氧化肽在食品、保健品、医药以及化妆品等领域展现出巨大的应用潜力。该文综述了抗氧化肽的制备、分离纯化、结构鉴定、分子修饰、抗氧化活性评价及作用机理,分析总结了生物信息学工具在抗氧化肽研究中的应用,指出了抗氧化肽研究与开发中存在的问题,展望了抗氧化肽的发展前景,旨在为其深度开发利用提供参考。     

肽类抑菌物质效价的测定

采用琼脂扩散法以Nisin为标准样品,对副干酪乳杆菌(LactobacillusparacaseiHD1.7)产生的肽类抑菌物质效价测定条件进行了研究,结果表明在2号检测培养基中添加0.75%琼脂、以浓度为106cfu/mL枯草芽孢杆菌为指示菌是最佳检测效价的条件,在此条件下测得的肽类抑菌物质的效价为1.6×104IU/g。     

Bioactive peptides in dairy products

Bioactive peptides are hydrolysates with specific amino acid sequences that exert a positive physiological influence on the body. They are inert within the native protein, but once cleaved from the native protein by microbial or added enzymes and/or gastrointestinal enzymes during the digestive process, they apply their beneficial traits. Dairy products, particularly fermented products, are potential sources of bioactive peptides: several of them possess extra‐nutritional physiological functions that qualify them to be classified under the ‘Functional Foods’ label. Biological peptides in milk, the methods of their generation and their prevalence in dairy products are reviewed along with the reported health benefits and safety aspects.