Development of a salmon protein hydrolysate that lowers blood pressure

A salmon protein hydrolysate (SPH) was developed containing several angiotensin I-converting enzyme (ACE) inhibitory tripeptides the most abundant of which were Val-Leu-Trp, Val-Phe-Tyr, and Leu-Ala-Phe. Simulated digestion experiments showed that active constituents of SPH would survive in the digestive tract and be available for absorption into the bloodstream. In fact, ACE inhibitory activity was improved following simulated digestion suggesting that there were larger peptides in SPH that might contribute to bioactivity in vivo. A single oral dose (1,500 mg/kg body mass) of SPH significantly lowered blood pressure in spontaneously hypertensive rats (SHR). The treatment of SHR with either SPH fraction (<3,000 Da) or SPH fraction (>3,000 Da) reduced blood pressure. We conclude that the ability of SPH to lower blood pressure is due to a combination of ACE inhibitory tripeptides as identified, as well as additional unknown, peptide species that are generated during digestion of SPH in the gastrointestinal tract.     

Characterization of ACE-inhibitory peptide associated with antioxidant and anticoagulation properties

A bioactive peptide Arg-Val-Pro-Ser-Leu (RVPSL) obtained from egg white protein was characterized by LC-MS and further chemically synthesized by the Fmoc solid phase method and investigated in terms of its angiotensin converting enzyme (ACE)-inhibitory activity, antioxidant property, and anticoagulation activity, as well as its stability in a simulated gastrointestinal digestion. The peptide exhibited an ACE-inhibitory activity with an IC(50) value of 20 μM. Also, the peptide could efficiently quench the (1,1)-diphenyl-2-picrylhydrazyl free radicals and exhibit high anticoagulation activity with a complete inhibition at 100 mM. Moreover, the peptide has a good stability against protease digestion. These results suggest that the peptide RVPSL may have potential to be used in nutraceuticals and functional food. Practical Application: The present research revealed a novel multifunctional peptide hydrolyzed from egg white protein. The peptide RVPSL was not only able to block the amplification of the coagulation cascade, but also able to inhibit ACE activity.     

猪皮胶原多肽的体外抗氧化特性研究

以猪皮胶原多肽为原料,研究其羟自由基清除能力、还原能力、对Fe2+诱导的脂质过氧化抑制能力以及对猪油氧化的抑制效果,考察其体外抗氧化特性.结果表明:在10mg/mL～50mg/mL浓度范围内,猪皮胶原多肽具有一定的羟自由基清除能力、还原能力和对Fe2+诱导的脂质过氧化抑制能力,且随着浓度的增加抗氧化作用也增强,当浓度为50mg/mL时,对羟自由基的清除率为56.38％,还原力为0.909,对Fe2+诱导的脂质过氧化抑制率为43.34％;不同添加量的猪皮胶原多肽对猪油氧化均有明显的抑制作用,当添加量为2％时,抗氧化效果优于0.02％的叔丁基羟基茴香醚(BHA).猪皮胶原多肽具有一定的体外抗氧化作用.     

猪皮明胶酶解工艺优化及其清除羟自由基能力评价

利用6种不同的蛋白酶水解猪皮明胶并检测所用酶的酶活,根据水解产物对·OH自由基的清除率,筛选最佳的水解蛋白酶为胰蛋白酶.通过单因素试验和L9(34)正交试验对胰蛋白酶解猪皮明胶的条件进行优化,单因素考察了酶料比、水解时间、水解温度、pH值对羟自由基清除率的影响.得到最佳酶解工艺条件为水解温度34℃,酶解时间3.0h,pH值7.0,酶料比6.0％.在此条件下,木瓜蛋白酶水解产物对·OH自由基的清除率为98.80％.     

粪肠球菌发酵生棉粕的工艺条件优化

为降低棉粕中游离棉酚含量,对粪肠球菌固态发酵生棉粕降解游离棉酚工艺条件进行了优化。首先对影响粪肠球菌固态发酵棉粕降解游离棉酚的料水比、初始pH、发酵时间、接种量、发酵温度进行单因素研究,确定对结果有较大影响的料水比、初始pH和发酵时间3个因素。然后利用Box-Behnken设计,对其进行优化。结果表明,料水比、初始pH和发酵时间的最佳条件分别是1∶0.53、6.57和3.06d。按照优化的条件发酵棉粕后游离棉酚含量降为231.68 mg/kg,降解率达67.85%。     

美拉德反应修饰的鲢鱼肽抗氧化活性初探

美拉德反应修饰是改善肽抗氧化活性的新途径。本实验采用鲢鱼肽与葡萄糖作为反应原料,以不同的浓度反应0,2,4,6,8,10h,并分别对棕色变化、还原糖、游离氨基、还原力和DPPH自由基清除活性进行了测定,结果表明美拉德反应产物均表现出很好的抗氧化活性,还原力在一定的范围内随时间的增加而增强,E组(10g鲢鱼肽和5g葡萄糖)最大,在10h时为A组的6.09倍。清除DPPH自由基的活性则在2h时达到较高的值,E组具有最高的的自由基清除率为64.45%。美拉德反应产物的还原力与DPPH自由基清除活性不一致,而且其抗氧化能力不完全依赖于产物的褐变程度。     

天然活性多肽及其应用前景

该文介绍近年来天然活性多肽研究概况,评价与总结活性多肽功能特性及其应用,展望其发展前景。     

甲鱼肽粉安全性的初步评价研究

目的 对甲鱼肽粉的安全性进行初步评价研究。方法 采用大、小鼠急性毒性试验、Ames 试验、小 鼠骨髓嗜多染红细胞微核试验、小鼠精子畸形试验和大鼠 30 d 喂养试验对甲鱼肽粉进行急性毒性、遗传毒性 和亚慢性毒性研究。结果 甲鱼肽粉对大、小鼠经口最大耐受量(MTD)均大于 20.0 g/(kg.bw); Ames 试验显示 在加与不加 S9 时各剂量组回变菌落数与自发回变对照组比较差异无统计学意义(P>0.05); 小鼠骨髓嗜多染红 细胞微核试验和精子畸形试验结果显示, 各剂量组的微核率和精子畸形率与阴性对照组比较差异均无统计学 意义(P>0.05); 30 d 喂养试验表明甲鱼肽粉未见明显毒性反应, 最大未观察到有害作用的剂量为 8.4 g/(kg.bw)。 结论 在本次实验条件下, 甲鱼肽粉经口 MTD>20.0 g/(kg.bw), 属实际无毒级, 并且未见遗传毒性, 30 d 喂养 试验未见其对受试动物有毒性损害作用。     

Interaction of MDpep9, a novel antimicrobial peptide from Chinese traditional edible larvae of housefly,with Escherichia coli genomic DNA

Antimicrobial peptides from edible insects may serve as a potentially significant group of food preservatives. In the present work, the mode of action of a novel antimicrobial peptide MDpep9 from Chinese traditional edible housefly larvae was investigated. MDpep9 was shown to bind to bacterial DNA from the results of gel retardation and fluorescence quenching experiments. Further investigations confirmed that MDpep9 could bind with the phosphate group of DNA and intercalate into the base pairs in a helix of DNA or locate in hydrophobic environment of DNA. The previous and present results demonstrated that MDpep9 has dual mechanisms of bactericidal activity: disrupting bacterial cell membranes and binding to bacterial genomic DNA to inhibit cellular functions, ultimately leading to cell death. The results of DNA-binding mode may be contributive in designing new and promising antimicrobial peptides for food preservatives.