大豆多肽生理活性、应用与前景分析

大豆多肽作为一种生物活性肽,具有防辐射、抗疲劳、降血脂、降血压和减肥等生理功能,在食品、化工、医疗等领域有巨大的开发价值。以近年来各种实验证据为依托,简要综述了大豆多肽的生理活性,揭示其广泛的应用前景。     

大豆发酵食品中的活性肽及其生理功能研究进展

来源于大豆发酵食品的活性肽,被证实具有抗氧化、抗高血压、抗糖尿病、抗肿瘤等生理活性功效,而其功能与大豆发酵时所用微生物菌株及发酵工艺密切相关。然而,我国针对来源于大豆发酵的功能食品及活性肽的生产与应用的研究仍处于起步阶段。针对这一现状,对国内外的大豆发酵食品加工现状及其来源的大豆活性肽在预防治疗新陈代谢疾病中的应用潜力进行了概述,并对这一领域后续的研究方向进行了展望,以期为我国大豆发酵食品及其活性肽的研究与开发提供参考。     

大豆低聚肽的研究进展

大豆低聚肽是大豆蛋白经过分离和纯化等处理后得到的小肽混合物。本文概述了大豆低聚肽的制备和分离纯化方法、大豆低聚肽的理化特性和功能特性及大豆低聚肽的应用。     

大豆小肽螯合铁的制备工艺及光谱分析研究

通过铁源筛选比较得知,氯化亚铁比较适合与大豆小肽进行螯合反应制备大豆小肽螯合铁,利用响应面法优化了大豆小肽螯合铁的制备工艺,优化结果为:小肽与亚铁盐质量比4∶1,反应pH5.0,反应温度40℃,得到离子螯合率平均值为56.81%,经中试车间生产试制得到大豆小肽螯合铁的得率是78.3%,螯合率为82.39%,检测大豆小肽螯合铁的主要成分中的蛋白含量为78.94%,铁的含量为10.87%。红外和紫外光谱分析检测结果显示:大豆小肽和大豆小肽螯合铁(Fe~(2+))红外吸收峰的强度在不同波长位置上有明显的变化,大豆小肽螯合铁(Fe~(2+))在紫外波长上发生了明显的位移且宽化,表明大豆小肽螯合铁(Fe~(2+))形成了络合物。同时对大豆小肽螯合铁的结构进行了预测。     

pH值和热处理对大豆肽稳定性的影响

分别采用Folin-酚法、SE-HPLC、火焰原子吸收分光光度法研究了pH值和加热处理对大豆肽的稳定性(包括溶解性、分子量分布、可溶性钙结合量)的影响.结果表明:在pH值3～11时对大豆肽的溶解性和分子量分布均无显著影响,pH值9时大豆肽的钙结合能力最大;高温热处理(温度为80℃、100℃)对大豆肽的溶解度无显著影响,但都不同程度的增加了大分子(>20 KDa)的相对含量,100℃时肽的聚合速度更快;80℃加热10 min提高了大豆肽的钙结合能力,热处理温度升高或加热时间延长均会导致钙结合能力的下降.     

大豆蛋白活性肽保健功能性的研究

大豆蛋白活性肽具有多种生物功效和保健功能,如:降血压、降血脂、促进钙磷吸收、调节免疫、延缓衰老等等。本文就调节免疫、延缓衰老作了深入的研究,并且对大豆蛋白肽潜在的应用价值及其应用前景作一综述     

大豆肽对高脂血症大鼠的降脂作用

研究大豆肽对高脂血症大鼠的降血脂、抗氧化作用以及对血液流变学指标的影响.采用高脂饲料喂养SD大鼠造成高脂血症模型,然后随机分组:正常组、高脂模型组、血脂康组(100 mg kg-1d-1)、大豆肽灌胃组(400 mg kg-1 d-1)、大豆肽灌胃组(800 mg kg-1 d-1)、大豆肽腹腔注射组(100 mg kg-1 d-1)、大豆肽腹腔注射组(400 mg kg-1 d-1),正常组给予普通饲料喂养,其余组给予高脂饲料.持续给药大豆肽30 d,期间每两周眼静脉取血一次,分离血清,检测TC、TG和HDL-C指标;实验结束当天腹主动脉取血,分离血清,检测SOD、MDA和NO指标.结果显示大豆肽能显著降低高脂血症大鼠的TC、TG和LDL-C,但对HDL-C没有显著影响;大豆肽给药组的SOD指标明显高于模型对照组,而MDA和NO指标则显著降低.表明大豆肽液对高脂血症大鼠具有一定的降脂作用,能降低血浆黏度,同时提高机体抗氧化能力.     

大豆肽免疫调节作用的研究进展

通过体内和体外实验发现,大豆肽是一类具有免疫调节作用的生物活性肽,可以改善机体的免疫功能,在功能性食品领域将大有所为。文章就大豆肽对免疫系统中非特异性免疫、细胞免疫和体液免疫等方面的调节作用进行综述,并对目前研究过程中存在的问题进行了讨论。     

大豆肽奶的研制及加工技术研究

本文在大豆肽制取和提纯工艺基础上研制大豆肽奶饮料。其奶粉为主要原料，大豆肽为主要辅料，选择配方与技术条件，确定加工大豆肽奶饮料的生产工艺、操作要点和产品质量标准。     

大豆肽的制备及其在养殖业中的应用

大豆肽是大豆蛋白经水解得到的低分子肽混合物,具有比大豆蛋白更优越的理化特性和生理功能,存很多领域引起广泛关注.综述大豆肽的制备方法及其在养殖业中的应用现状,为大豆肽应用于饲料添加剂提供参考.     

花生蛋白碱性蛋白酶水解物对血管紧张素转化酶抑制作用的初步研究

分别以碱性蛋白酶Alcalase和中性蛋白酶Neutrase对花生分离蛋白进行水解．制备花生分离蛋白水解物．并测定不同水解时间所得产物对血管紧张素转化酶(ACE)的抑制活性。未水解的花生分离蛋白没有ACE抑制活性．用中性蛋白酶Neutrase水解所得的水解物显示弱ACE抑制活性。然而，碱性蛋白酶Alcalasc水解物具有很强的ACE抑制活性．水解0．5h时水解物活性最高，其半抑制浓度为(IC50)0．56mg／mL。本研究表明，当用碱性蛋白酶Alcalase水解时，花生分离蛋白是生产ACE抑制肽的良好蛋白质来源，花生分离蛋白碱性蛋白酶Alcalase水解物可作为具有降压功能的功能食品添料。     

Seaweed Protein Hydrolysates and Bioactive Peptides: Extraction,Purification, and Applications

Seaweeds are industrially exploited for obtaining pigments, polysaccharides, or phenolic compounds with application in diverse fields. Nevertheless, their rich composition in fiber, minerals, and proteins, has pointed them as a useful source of these components. Seaweed proteins are nutritionally valuable and include several specific enzymes, glycoproteins, cell wall-attached proteins, phycobiliproteins, lectins, or peptides. Extraction of seaweed proteins requires the application of disruptive methods due to the heterogeneous cell wall composition of each macroalgae group. Hence, non-protein molecules like phenolics or polysaccharides may also be co-extracted, affecting the extraction yield. Therefore, depending on the macroalgae and target protein characteristics, the sample pretreatment, extraction and purification techniques must be carefully chosen. Traditional methods like solid–liquid or enzyme-assisted extraction (SLE or EAE) have proven successful. However, alternative techniques as ultrasound- or microwave-assisted extraction (UAE or MAE) can be more efficient. To obtain protein hydrolysates, these proteins are subjected to hydrolyzation reactions, whether with proteases or physical or chemical treatments that disrupt the proteins native folding. These hydrolysates and derived peptides are accounted for bioactive properties, like antioxidant, anti-inflammatory, antimicrobial, or antihypertensive activities, which can be applied to different sectors. In this work, current methods and challenges for protein extraction and purification from seaweeds are addressed, focusing on their potential industrial applications in the food, cosmetic, and pharmaceutical industries.     

Antithrombotic Activity of Brewers’ Spent Grain Peptides and their Effects on Blood Coagulation Pathways

Antithrombotic activity of brewers’ spent grain peptides before and after simulated gastrointestinal digestion and their effects on blood coagulation pathways were evaluated. Two hydrolysates were produced using sequential enzymatic systems: alkaline protease + Flavourzyme (AF) and neutral protease + Flavourzyme (PF). Simulation of gastrointestinal digestion of AF and PF hydrolysates was made using porcine pepsin and pancreatin enzymes, obtaining the corresponding digested samples: AFD and PFD, respectively. Peptides were fractionated by ultrafiltration using a 1 kDa cut-off membrane. Hydrolysates had peptides with medium and low molecular weights (2100 and 500 Da, respectively), and Glu, Asp, Leu, Ala, and Phe were the most abundant amino acids. Gastrointestinal digested hydrolysates presented high proportion of small peptides (~500 Da), and higher amount of Val, Tyr, and Phe than hydrolysates. Mass spectrum (HDMS Q-TOF) of AFD-ultrafiltered fraction <1 kDa exhibited peptides from 500 to 1000 Da, which are not present in AF. PFD showed the generation of new peptides from 430 to 1070 Da. All samples showed thrombin inhibitory activity. However, no effect was observed on prothrombin time. Peptides <1 kDa from hydrolysates and digested samples delayed thrombin and thromboplastin time respect to the control (~63%). Also the samples showed thrombin inhibitory activity at common pathway level. Thus, brewers’ spent grain peptides exerted their antithrombotic activity by inhibiting the intrinsic and common pathways of blood coagulation. This is the first report to demonstrate that brewers’ spent grain peptides are able to delay clotting time after simulated gastrointestinal digestion.     

Amino Acid Profiles and Biopotentiality of Hydrolysates Obtained from Comb Penshell (Atrina pectinata) Viscera Using Subcritical Water Hydrolysis

The recovery of amino acids and other important bioactive compounds from the comb penshell (Atrina pectinata) using subcritical water hydrolysis was performed. A wide range of extraction temperatures from 140 to 290 °C was used to evaluate the release of proteins and amino acids. The amount of crude protein was the highest (36.14 ± 1.39 mg bovine serum albumin/g) at 200 °C, whereas a further increase in temperature showed the degradation of the crude protein content. The highest amount of amino acids (74.80 mg/g) was at 230 °C, indicating that the temperature range of 170–230 °C is suitable for the extraction of protein-rich compounds using subcritical water hydrolysis. Molecular weights of the peptides obtained from comb penshell viscera decreased with the increasing temperature. SDS-PAGE revealed that the molecular weight of peptides present in the hydrolysates above the 200 °C extraction temperature was ≤ 1000 Da. Radical scavenging activities were analyzed to evaluate the antioxidant activities of the hydrolysates. A. pectinata hydrolysates also showed a particularly good antihypertensive activity, proving that this raw material can be an effective source of amino acids and marine bioactive peptides.     

Sunflower Protein Hydrolysates Reduce Cholesterol Micellar Solubility

Plant protein hydrolysates are a source of bioactive peptides. There are peptides that decrease the micellar cholesterol solubility from bile acids and therefore may reduce in vivo cholesterol absorption. The presence of these peptides in sunflower protein hydrolysates has been studied. Sunflower protein hydrolysates produced with alcalase plus flavourzyme or with pepsin plus pancreatin inhibited in some degree the cholesterol incorporation to micelles. Protein hydrolysates generated after 30 min of hydrolysis with alcalase, and after 30 min of hydrolysis with pepsin, were the inhibitoriest of the cholesterol incorporation to micelles. The average amino acid hydrophobicity of inhibitory peptides in cholesterol micelles was higher than the observed in the corresponding protein hydrolysates. This high hydrophobicity probably favours their inclusion in the lipid micelles. In vivo, this inhibition may translate in a decrease of cholesterol absorption. Reported results show that a combination of different characteristics such as peptide size or hydrophobicity may be responsible of the inhibitory activity of generated peptides.     

Valorization of rice by-products: Protein-phenolic based fractions with bioactive potential

Rice bran (RB) is an important by-product from the rice production with a high valorization potential. The aim of the present work was to explore this potential by considering combined protein and phenolic fractions and enzymatic hydrolysis. The influence of different protocols in the recovery/fractioning of protein were evaluated, including defatting procedures, in rice brans from two very different locations: Portugal and Colombia. The different protein fractions achieved were characterized. Proteins were further hydrolyzed using trypsin and their hydrolysates were characterized in terms of degree of hydrolysis and peptide size. Moreover, the total phenolic content (TPC) and phenolic compounds’ profile on extracted fractions and hydrolysates of RB from Portugal and Colombia were determined. The functional potential was assessed in terms of antioxidant and antihypertensive activities. Though the protein concentrates had already significant potential bioactivities, protein hydrolysates showed that the TPC, antioxidant and antihypertensive activities significantly increased with the digestion by trypsin. Hydrolysates of RB from Portugal presented a higher antioxidant and hypertensive activities in comparison with hydrolysates of RB from Colombia, moreover it presented a higher content of TPC. This study indicated that the exploitation potential of rice bran can be increased with simple fractioning procedures, that combined protein/phenolic fractions are important to deliver functionality and that hydrolysis can be a relevant tool to release that functionality. Furthermore, regional differences in rice bran composition are also important factors to consider. Overall, this knowledge can be used to increase the industrial potential of valorization for this by-product.     

Fractionation of tryptic gliadin hydrolysates based on proline levels

The central domain (CD) and terminal domains (TDs) of wheat gliadins contain high and low levels of the amino acid proline (Pro), respectively. The CD is rather hydrophilic while the TDs are rather hydrophobic and contain most of the ionisable amino acids, although present only in low levels. Therefore, peptides derived from the CD or TDs may strongly differ in their physico–chemical properties. Trypsin cleaves peptide bonds at lysine and arginine residues which are mainly present in the TDs and was used in the present study. Several fractionation methods were examined to isolate CD and TD related peptides from tryptic hydrolysates. Pro was used as a marker for CD and TD related peptides. Both semi-preparative reversed-phase HPLC separation and fractionation of the water-soluble peptides of the tryptic gliadin hydrolysates by graded ethanol precipitation resulted in peptide fractions with different Pro levels. Whereas the fractions precipitating up to 90% ethanol were Pro rich, a Pro poor fraction consisting of small peptides was soluble in 90% ethanol solution. The water insoluble peptides of the tryptic hydrolysates also showed a low Pro level. Ultrafiltration of the water-soluble peptides using a 5-k membrane resulted in small Pro poor peptides and larger Pro rich peptides.     

Fish Sidestream-Derived Protein Hydrolysates Suppress DSS-Induced Colitis by Modulating Intestinal Inflammation in Mice

Inflammatory bowel disease is characterized by extensive intestinal inflammation, and therapies against the disease target suppression of the inflammatory cascade. Nutrition has been closely linked to the development and suppression of inflammatory bowel disease, which to a large extent is attributed to the complex immunomodulatory properties of nutrients. Diets containing fish have been suggested to promote health and suppress inflammatory diseases. Even though most of the health-promoting properties of fish-derived nutrients are attributed to fish oil, the potential health-promoting properties of fish protein have not been investigated. Fish sidestreams contain large amounts of proteins, currently unexploited, with potential anti-inflammatory properties, and may possess additional benefits through bioactive peptides and free amino acids. In this project, we utilized fish protein hydrolysates, based on mackerel and salmon heads and backbones, as well as flounder skin collagen. Mice fed with a diet supplemented with different fish sidestream-derived protein hydrolysates (5% w/w) were exposed to the model of DSS-induced colitis. The results show that dietary supplements containing protein hydrolysates from salmon heads suppressed chemically-induced colitis development as determined by colon length and pro-inflammatory cytokine production. To evaluate colitis severity, we measured the expression of different pro-inflammatory cytokines and chemokines and found that the same supplement suppressed the pro-inflammatory cytokines IL-6 and TNFα and the chemokines Cxcl1 and Ccl3. We also assessed the levels of the anti-inflammatory cytokines IL-10 and Tgfb and found that selected protein hydrolysates induced their expression. Our findings demonstrate that protein hydrolysates derived from fish sidestreams possess anti-inflammatory properties in the model of DSS-induced colitis, providing a novel underexplored source of health-promoting dietary supplements.     

大豆蛋白酶解物的抗消化性及离子强度对其聚集的影响

分别采用体积排阻色谱和Folin-酚法测定了经酸性蛋白酶(蛋白酶M、胃蛋白酶)、中性蛋白酶(蛋白酶A、蛋白酶N)、枯草杆菌碱性蛋白酶Alcalase酶解后制得的大豆肽经过模拟体内消化之后分子量的变化,以及离子强度对酶解物聚合的影响.大豆肽的高效液相色谱体积排阻色谱图显示,50％左右的大豆肽的分子量集中在10～30 kD...     

Biofunctionality of Enzymatically Derived Peptides from Codfish (Gadus morhua) Frame: Bulk In Vitro Properties,Quantitative Proteomics,and Bioinformatic Prediction

Protein hydrolysates show great promise as bioactive food and feed ingredients and for valorization of side-streams from e.g., the fish processing industry. We present a novel approach for hydrolysate characterization that utilizes proteomics data for calculation of weighted mean peptide properties (length, molecular weight, and charge) and peptide-level abundance estimation. Using a novel bioinformatic approach for subsequent prediction of biofunctional properties of identified peptides, we are able to provide an unprecedented, in-depth characterization. The study further characterizes bulk emulsifying, foaming, and in vitro antioxidative properties of enzymatic hydrolysates derived from cod frame by application of Alcalase and Neutrase, individually and sequentially, as well as the influence of heat pre-treatment. All hydrolysates displayed comparable or higher emulsifying activity and stability than sodium caseinate. Heat-treatment significantly increased stability but showed a negative effect on the activity and degree of hydrolysis. Lower degrees of hydrolysis resulted in significantly higher chelating activity, while the opposite was observed for radical scavenging activity. Combining peptide abundance with bioinformatic prediction, we identified several peptides that are likely linked to the observed differences in bulk emulsifying properties. The study highlights the prospects of applying proteomics and bioinformatics for hydrolysate characterization and in food protein science.