鸡卵黄免疫球蛋白作为食品添加剂和抗体食品的应用

鸡卵黄免疫球蛋白IgY(Egg Yolk Immunoglobulin)是一种与哺乳动物IgG结构类似,具有较强免疫特性的功能蛋白.口服IgY可使机体获得被动免疫,抑制有害细菌或病毒对人体的侵害,增强机体的免疫力,因此IgY可作为食品添加剂或直接以具有免疫特性的卵黄制成抗体食品,达到防治疾病,保护健康的目的.     

一种新型的食品添加剂——鸡卵黄免疫球蛋白

当用某种抗原免疫产蛋母鸡时，鸡可产生相应的多克隆抗体─—免疫球蛋白，并被运送和储存于鸡卵的卵黄中，此种免疫球蛋白称为IgY（ImmumoglobulinofYolk）。一只母鸡一经免疫应答后，即可从其不断生产的鸡卵的卵黄中获得大量的、均一的、高效价的IgY，而且lgY有许多独到的优点，具有许多潜在的应用价值，可代替由免疫小鼠、兔等哺乳动物制备的抗体。因而近年来，国外对IgY的研究应用十分活跃，特别是将IgY作为食品的免疫型强化剂的应用研究正在不断开展，前景非常广阔。一、IgY的特点：1．IgY类似于哺乳动物的igY.分子量为180lH＞，…     

冰乙醇分级离心法分离纯化鸡卵黄免疫球蛋白(IgY)的研究

采用冰乙醇分级离心法提取鸡卵黄免疫球蛋白 (Immunoglobulin of egg yolk,IgY).通过低温乙醇沉淀、DEAE 葡萄糖凝胶 A-50 离子交换层析、Tris-HCl 缓冲液洗脱及 Sephadex G200 凝胶过滤等逐步纯化免疫球蛋白.研究卵黄稀释倍数、pH 值、乙醇添加量以及盐浓度对纯化效果的影响.分离纯化后所得的提取物经检测 IgY 纯度可达98%,且很好地保持了免疫球蛋白的活性.     

糖基化修饰对IgG/IgY结构和功能特性的影响

免疫球蛋白IgG与IgY在生物医药领域具有广阔的应用前景。糖基化在IgG结构与功能特性中发挥着重要作用,异常糖基化可能损伤IgG的功能,并引发自身免疫疾病。IgG-Fc的多糖链对保证IgG热稳定性,维持原有构象,抵抗蛋白酶水解,延长生物半衰期起着关键作用。与IgG相比,IgY具有制备优势并存在物种间进化差距,可作为抗生素替代物治疗人畜胃肠道感染病,应用前景广泛。目前,对IgY的糖基化研究相对不足,仅限于糖基化位点与糖链结构的测定,制约了对其开发利用。研究免疫球蛋白IgG/IgY的糖基化不但有助于阐明IgG/IgY生物学功能的作用机制,而且可为其制备、加工提供理论参照。本文主要针对IgG/IgY的糖基化研究进展做一综述。     

鸡卵黄抗体(IgY)的制备工艺研究

对鸡卵黄抗体(简称IgY)的制备工艺进行研究。通过低温乙醇沉淀、DEAE葡萄糖凝胶A-50离子交换层析、Tris-HCl缓冲液洗脱及Sephadex G200凝胶过滤等逐步纯化免疫球蛋白。研究卵黄稀释倍数、pH值、乙醇添加量以及盐浓度对纯化效果的影响。分离纯化后所得的提取物经检测IgY纯度可达98%。用大肠杆菌(E.coli)对其活性进行测定,效果良好,此方法能很好保持免疫球蛋白的活性。     

鸡蛋抗体的研究进展及其抗SARS病毒的可行性分析

鸡蛋抗体，即鸡卵黄中的免疫球蛋白，简称IgY。由于其具有不与人类补体结合，不与蛋白A结合以及不与类风湿因子结合等的免疫学特性，目前已被运用于疾病诊断检测和防治中。因此，利用IgY研制“非典”病毒特异性抗体，以用于预防“非典”病毒引起的呼吸道感染和治疗肺部感染及清除肠道中的病毒、防止排泄物引起的二次感染的设想有可能实现。本文就对鸡蛋抗体的研究进展及其抗SARS病毒的可行性作一分析、综述。     

抗变链球菌鸡卵黄免疫球蛋白(IgY)的制备及活性检测

以远缘链球菌(S.sorbrinus 6715血清型g)免疫产卵母鸡,应用酶联免疫吸附测定法(ELISA)测定鸡卵黄中免疫球蛋白(Immunoglobulin of Yolk,IgY)的活性,研究鸡免疫应答并制备出高免抗-S.sorbrinus IgY.结果显示以109 cfu/只剂量免疫的母鸡,第一次免疫后的第七天卵黄中出现特异性IgY,加强免设后抗体效价上升更快,经ELISA法检测,卵黄中的抗体效价到1384.而冷冻干燥后的IgY,其效价要超过12000.     

3种特异性IgY与IgG相对亲和力特性的比较研究

采用硫氰酸铵和尿素洗脱ELISA法两种方法,分别对牛β-酪蛋白、κ-酪蛋白和大肠杆菌O157:H7与对应抗原的卵黄抗体(IgY)与免疫球蛋白(IgG)抗体相对亲和力特性进行比较研究。结果表明：3种特异性IgY与抗原的相对亲和力比IgG要高,对蛋白抗原,两种抗体的相对亲和力相差不大,而对大肠杆菌O157:H7,两种抗体的差别明显加大,IgY的相对亲和力较IgG强。两类乳源蛋白抗体亲和力比较,发现κ-酪蛋白抗体与抗原的亲和力高于β-酪蛋白抗体,前者用于乳品免疫检测中,可提高方法灵敏度。     

低温乙醇除脂法纯化鸡卵黄中免疫球蛋白

采用低温乙醇除脂法提取鸡卵黄免疫球蛋白 (immunoglobulinyolk,IgY)。通过低温乙醇沉淀、透析和葡聚糖凝胶等不同方法逐步纯化免疫球蛋白。研究了卵黄稀释倍数、乙醇浓度、NaCl浓度以及离心转速对纯化效果的影响。分离纯化后所得的冷冻干燥制品 ,经SDS PAGE和抑菌试验检测可知 :可溶性蛋白质得率为每毫升蛋黄 1 2 6mg ,可溶性蛋白质含量占总蛋白质量的 97% ,且保持了免疫球蛋白的活性     

酪蛋白和乳球蛋白的抗体及酶标物制备研究

选用牛乳中的β-酪蛋白(β-CN)和β-乳球蛋白(β-Lg)为抗原对鸡体免疫,从鸡卵黄中用水稀释法及亲和色谱(HiTrapTM IgY Purification HP)纯化特异性鸡卵黄抗体(IgY)。PAGE电泳分析IgY纯度高达90%,ELISA效价为1:4096。用过碘酸钠氧化法进行抗原的过氧化物酶(HRP)标记,HRP与β-CN和β-Lg的分子个数比分别为1:1和1.5:1的标记效果最好,β-CN-HRP和β-Lg-HRP的效价高达1:640,其ELISA工作浓度分别为1:80和1:40。特异性IgY和酶标抗原为特异检测牛乳蛋白的酶联免疫吸附(ELISA)分析提供必要条件。     

Physicochemical properties of leftover egg yolk after livetins removal

Isolation of immunoglobulin Y (IgY) from egg yolk using water-dilution method generates large quantities of leftover pellet as the co-product. Although egg yolk is well known for its great emulsion property, there is a lack of understanding on how livetins removal would affect the emulsion and rheological properties of the pellet. Therefore, the objective of this study was to determine the effect of soluble protein removal on emulsifying and rheological characteristics of the leftover egg yolk. Egg yolk pellet exhibited distinct structural and physicochemical properties after soluble protein removal. Emulsions prepared from pellet were more vulnerable to coalescence instability than that of egg yolk, although both had a similar oil droplet size. Egg yolk displayed a Newtonian behaviour, compared to a shear-thinning behaviour of pellet. Pellet showed a higher apparent viscosity as well as higher viscoelastic moduli than those of egg yolk, probably due to increased hydrogen bond and hydrophobic interactions in the pellet. Therefore, the changes on the emulsion stability and the rheological properties of egg yolk after soluble proteins removal should be considered in food formulation and processing. Further study is needed to improve the emulsion property of pellet for uses in the food industry.     

卵黄高磷蛋白乳化性的研究进展

卵黄高磷蛋白是蛋黄中重要的活性功能成分之一,具有和酪蛋白相类似的组成与结构,表现出优异的乳化活性和乳化稳定性。文中分别从蛋白自身组成及结构、乳化作用环境、蛋白改性以及蛋白与其他添加剂协同作用等方面对卵黄高磷蛋白乳化特性的影响进行了阐述。     

绿色高效连续分离技术制备蛋黄中活性蛋白质和磷脂

为了实现蛋黄功能性成分的充分利用，采用绿色溶剂从新鲜蛋黄中高效连续分离具有生物活性的卵黄免疫球蛋白（immunoglobulin Y, IgY）、卵黄高磷蛋白（phosvitin, PV）和磷脂（phospholipids, PL）。首先采用水稀释法（稀释倍数为1:10）分离水溶性组分与脂蛋白，通过35%饱和(NH₄)₂SO₄和0.5% NaCl（w/v）对上清液进行盐析并用8% PEG 6000纯化IgY。脂质组分中的PV在pH5.0，90 ℃条件下的NaCl溶液（w/v）中进一步纯化。采用乙醇/乙酸乙酯比例为1:2（v/v）提取蛋黄中全部脂类，进一步采用乙酸乙酯在0 ℃下提纯蛋黄总脂中的PL。经脱盐、冷冻干燥后，IgY、PV和PL的纯度分别为97.38%、78.63%和85.94%。IgY和PV的得率分别为6.15、10.15 mg/mL。蛋黄总脂中PL的含量为35.18%。因其良好的多不饱和脂肪酸/饱和脂肪酸比率（0.70）和相对较低的n-6/n-3比率（5.37），该PL产品可应用于食品加工中。本方法简便、环保并且高效，可从蛋黄中依次分离出高纯度IgY、PV和PL，并为蛋黄的综合利用提供技术支持。     

酪氨酸酶特异性卵黄抗体Fab’片段的制备及其对酶活力的抑制性能

针对导致黑色素沉淀的酪氨酸酶,制备了特异性卵黄抗体Fab’片段,研究其对酶活力的抑制效果并从动力学角度进行分析。结果表明,胃蛋白酶法制备Fab’片段的最适条件为：pH?4.0、反应比（卵黄抗体-胃蛋白酶）1∶150（mg/U）、反应时间8?h。经免疫亲和柱纯化后可得理化性质稳定、纯度大于95%的Fab’片段;该片段通过非竞争性结合抑制酪氨酸酶活力,IC50为11.16?μmol/L,结合常数为5.79×105,抑制效果相比完整的卵黄抗体分子大大提高。本研究可为卵黄抗体Fab’片段作为潜在的酶活力抑制剂在食品、化妆品和医药等行业中应用提供理论参考。     

蛋黄免疫球蛋白的制备与应用

介绍蛋黄免疫球蛋白(IgY)的形成、特性、免疫程序、分离、提取、检测、应用等,重点为蛋黄免疫球蛋白的制备工艺。     

A new membrane based process to isolate immunoglobulin from chicken egg yolk

Although the importance of eggs as a source of specific antibodies has been well recognised, the generation of egg yolk immunoglobulins (IgY) is rarely chosen due to the peculiar composition of egg yolk and the lack of specific affinity ligands. In this work, we report a novel membrane based two-stage ultrafiltration process to isolate IgY from egg yolk. The effects of solution pH, ionic strength, stirring speed and permeate flux on the transmission of proteins were quantified using the pulsed sample injection technique and parameter scanning ultrafiltration. Under optimised conditions, the purity of immunoglobulin obtained was greater than 93% after the two-stage ultrafiltration process and the recovery of immunoglobulin from the feedstock was close to 87%. The resulting immunoglobulin product was then analysed by Isoelectric Focusing (IEF), SDS–PAGE and Circular Dichroism (CD), to confirm its isoelectric point, molecular weight and molecular secondary structure.     

Simple purification methods for an alphagalactose-specific antibody from chicken eggs

For many applications avian antibody from egg yolk (IgY) offers advantages over the well-known mammalian antibodies. Different experimental techniques for the purification of IgY from chickens immunized with an alphagalactose-containing antigen (alphaGal-trisaccharide) were compared. These included ammonium sulfate precipitation, filtration with diatomaceous earth, treatment with deoxycholate, and thiophilic and affinity chromatography. Samples were tested for overall purity, protein and lipid content, and specific activity. Evaluated on the basis of these results and the simplicity of the process, the favored purification method is ammonium sulfate precipitation of diluted egg yolk directly followed by affinity chromatography. The high lipid content of IgY preparations is greatly reduced by either thiophilic or affinity chromatography. Affinity purification of ammonium sulfate precipitated material resulted in anti-alphaGal-trisaccharide IgY preparations with approximately 1% of the original protein content but approximately 100-fold higher specific activity for the alphaGal-trisaccharide epitope.     

Physicochemical and functional properties of Chinese soft-shell turtle (Pelodiscus sinensis) egg

The physicochemical properties of Chinese soft-shell turtle egg were characterized for functional use in the food industry. The egg yolk of un-fertilized soft-shell turtle eggs was separated and fractionated into granules and plasma. Then, the egg yolk, albumen, granules, and plasma were freeze-dried for further analysis. Results showed that the Chinese soft-shell turtle egg typically comprised 50% egg yolk, 34% albumen, and 16% shell in average. The egg yolk composed of 61% granules and 39% plasma. The granules contained most of the protein, while the plasma contained most of the lipid in egg yolk. The albumen contained about 26% ash on a dry weight basis. Lysozyme was the major component in turtle egg albumen. The protein solubility of egg yolk, granules, and plasma was affected by the changes in pH, while that of albumen remains constant. The emulsifying and foaming properties increased when the concentration increased for all samples. Both the yolk and the albumen in turtle egg exhibited better functional properties than those in normal hen egg. These physicochemical and functional properties of Chinese soft-shell turtle egg are fundamental and essential for future study and food applications.     

Selective removal effect of subcritical fluid extraction on egg yolk lipids and characterization and enzymatic improvement of defatted egg yolk powder

This study investigated the effects of subcritical fluid extraction on lipid removal and the physicochemical properties of egg yolk powder. In addition, two-step enzymatic hydrolysis was used to improve the physicochemical properties. The content of total lipids and cholesterol decreased to 30.2% and 10.5 mg/g after subcritical propane-butane extraction, respectively, while phospholipids were retained. Protein solubility, surface hydrophobicity and total sulfhydryl results showed that this partial defatting avoided further quality deterioration of egg yolk powder. Scanning electron microscopy and confocal microscopy showed that the surface morphology and distribution of proteins and lipids changed with defatting degree. After two-step enzymatic hydrolysis, protein solubility of subcritical propane-butane extraction egg yolk powder significantly increased to 31.4% and soluble peptides with an average molecular weight lower than 1000 Da accounted for 70.0%. The improved defatted egg yolk powder is rich in protein, peptides and phospholipids and has great potential as a nutritional supplement.