离子交换法提取鸡蛋清溶菌酶

蛋清中用弱酸性阳离子交换树脂提取溶菌酶,将Na+型和H+型树脂混合用于吸附过程中,然后用硫酸铵溶液洗脱,盐析得到溶菌酶,每100mL蛋清可得0.4g,酶活0000U/mg左右。本方法减少了变性蛋白,其剩余蛋清所含杂质少,提高了蛋清的再利用价值,降低了成本。      

鸡蛋清中溶菌酶的提取工艺研究

应用阳离子交换树脂吸附法直接从鸡蛋清中提取溶菌酶,采用超滤方法将溶菌酶提取液浓缩及脱盐并进一步纯化。所得酶活力为15834U/mg,最终酶得率为56.57%。      

鸡蛋清中溶菌酶的提取工艺研究

应用阳离子交换树脂吸附法直接从鸡蛋清中提取溶菌酶,采用超滤方法将溶菌酶提取液浓缩及脱盐并进一步纯化。所得酶活力为15834U/mg,最终酶得率为56.57%。     

鸡蛋清中溶菌酶的提取

本文尝试了用新方法从鸡蛋清中提取溶菌酶，并采用了国外先进的随机质心映射优化程序，通过优化实验，确定了该方法的最佳工艺条件。在此基础上。本文还用差热扫描分析方法及溶菌酶的溶菌实验检测了产品。     

超滤法提取蛋清溶菌酶

对蛋清料液进行前处理:采用磷酸盐缓冲液稀释10倍,在24MPa压力下均质;对超滤工艺进行了研究,采用截留相对分子质量为30000的聚醚砜(PES)膜进行超滤;溶菌酶制品活力为14610U/mg.     

蛋清中溶菌酶的提取

研究了从新鲜蛋清中提取溶菌酶的方法。通过控制温度，调酸和加盐，可以使溶菌酶得到分离和纯化。采用超滤的方法将溶菌酶提取液浓缩及脱盐并进一步纯化。最后采用喷雾干燥的方法制成产品。产品活力可达１１０００ｕ／ｍｇ．     

鸡蛋清溶菌酶提取工艺的改进

创新改革了鸡蛋清溶菌酶的纯化、浓缩和干燥工艺。通过调整透析液的pH值,加入磷酸盐、再调整其pH值,然后离心去除杂质得到纯化液。将纯化液在(40±2)℃下真空旋转蒸发,变浊时倒出、冷冻,25℃以下真空干燥。产品呈淡黄色,活性范围13 539～15 741 U/mg、平均为 14 021U/mg,与超滤浓缩、冷冻干燥产品的活性(14 610 U/mg)基本一致。产率(0.724 8 g/kg蛋清)比报道的工艺高19.75倍。     

鸡蛋清中溶菌酶的提取与抑菌作用

研究从鸡蛋清中提取与精制溶菌酶的方法,观察溶菌酶对大肠杆菌与金黄色葡萄球菌的抑制作用.从鸡蛋清提取溶菌酶的方法:取出鸡蛋清,过滤,用蒸馏水溶解,加氯化钠,调节溶液pH至5.0,加入溶菌酶晶种,4℃下静置结晶,过滤,可以得到溶菌酶粗品.将粗品溶菌酶溶解,按上述步骤溶解后结晶,重复3次,可以精制溶菌酶.用滤纸片法观察溶菌酶对大肠杆菌与金黄色葡萄球菌的抑菌作用.结果表明,鸡蛋清溶菌酶提取的较优条件是:酶液pH 10.0、氯化钠加入量5%、蛋清液用2倍体积蒸馏水稀释.70℃下保温5min,鸡蛋清溶菌酶的精制率最高.鸡蛋清溶菌酶对大肠杆菌与金黄色葡萄球菌有明显抑制作用,80℃加热30min对鸡蛋清溶菌酶的抑菌作用影响很小.     

蛋清溶菌酶提取的研究进展

本文综述了溶菌酶的结构特点与作用机理,从生产工艺的角度介绍了当今蛋清溶菌酶提取的工艺过程中,不同的生物化学方法及其操作特点,以及溶菌酶活性与纯度测定的方法。     

蛋清溶菌酶的工业化提取技术

溶菌酶在医药和食品领域的广泛用途已引起大家的高度重视,然而适合工业化生产溶菌酶的方法仍不完善。本文探讨了阳离子交换树脂法从卵清蛋白中提取溶菌酶的工艺技术,从酶的得率、活性和纯度等几个方面进行了不同工艺条件的比较。      

蛋清溶菌酶提取工艺研究

采用盐析法从鸡蛋清中提取溶菌酶,探讨不同条件对溶菌酶收率等的影响,确定了最优操作参数。最佳提取条件为:蛋清浓度100%,氯化钠浓度5%,盐析pH10.5,盐析时间120h,提取收率在0.37%。采用比浊法对提取的溶菌酶进行酶活力的测定,酶活为13500U/mg。     

预处理蛋清料液溶菌酶的超滤工艺

采用超滤法从预处理的蛋清料液中提取蛋清溶菌酶。研究了卷式膜组件的膜孔径、膜材质、超滤时间、压力、温度等对渗透通量的影响。采用截留分子量为3万的PES膜进行超滤,膜透压为0.35MPa,温度为15℃,当超滤进行了150min后进行清洗,酶得率为63%,纯度为98.5%,酶活为14610U/mg或16831U/mg蛋白质。      

金属离子对鸡蛋清凝胶特性的影响

以鸡蛋清为材料,探讨了金属离子的种类和添加量对蛋清凝胶硬度、黏性、回复性以及持水性的影响。结果表明:添加NaCl和KCl对蛋清凝胶的硬度影响较小,均比对照略有升高,持水性无显著影响;而当MgCl2和CaCl2的添加浓度为0.05mol/L时,蛋清凝胶硬度和持水性与对照相比均下降了45%。大多数金属离子的添加会使得蛋清凝胶的黏性上升,回复性降低。     

Multifunctional peptides from egg white lysozyme

Hen’s egg white lysozyme (HEWL) is one of the major egg white proteins with well demonstrated antimicrobial activity. Bioactive peptides other than antimicrobial peptides from HEWL have not been reported; therefore, the purpose of the study was to explore new bioactivities of lysozyme-derived bioactive peptides. HEWL was hydrolysed with Alcalase and fractionated by cation-exchange chromatography. The Alcalase HEWL hydrolysate and its fractions were analyzed for inhibitory activities against calmodulin-dependent phosphodiesterase (CaMPDE) and antioxidant activities using oxygen radical absorbance capacity-fluorescein (ORAC-FL), 2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt radical cation (ABTS⁺) and 2,2-di(4-tert-octylphenyl)-1-picrylhydrazyl (DPPH) radical scavenging methods. The fractionated peptides had higher CaMPDE inhibition activity, ORAC-FL value and ABTS⁺ scavenging activity than those of the hydrolysate. Peptide sequences in the most overall active fractions were characterized by LC–MS/MS. Our results showed that HEWL hydrolysate and its peptide fractions may serve as useful ingredients in the formulation of functional foods and nutraceuticals.     

Rapid growth of Salmonella enteritidis in egg white reconstituted from industrial egg white powder.

The aim of this study was to evaluate the consequences of the egg white-drying process on egg white ability to limit Salmonella Enteritidis growth in addition to the elucidation of the factors involved. We observed rapid growth of Salmonella Enteritidis inoculated in egg white reconstituted from industrial powder in comparison with that observed in liquid egg white collected in the laboratory: Salmonella cell counts rose from 10(3) to 10(8) cells/ml of egg white from powder during 24 h incubation at 30 degrees C. This rapid growth was observed in powder from all egg-breaking factories investigated, and it was comparable to that observed in optimum medium (tryptone soy broth). In view of the mechanism of egg white resistance and the major role played by iron availability and by ovotransferrin, we investigated several hypotheses to explain this rapid growth: iron provided during the drying process and/or denaturation of protein (especially ovotransferrin). The rapid growth observed in egg white reconstituted from powder was in relation to egg white protein denaturation and especially ovotransferrin denaturation during powder pasteurization that enhanced the availability of iron necessary for Salmonella growth. The major role played by ovotransferrin and iron deficiency on Salmonella growth in egg white was illustrated in this study.     

卵清转铁蛋白的提取

利用离子交换层析方法,从鸡蛋清分离纯化了转铁蛋白,并用SDS-PAGE方法测得其分子量为7.7kDa,光谱分析在465nm处有特征吸收峰。      

Direct lysozyme separation from egg white by dye membrane affinity chromatography

An affinity membrane from hydrophylised polyethylene hollow fibre as the support matrix was prepared. Red HE‐3B was immobilised on the membrane and the adsorption behaviour of pure lysozyme solutions and homogenised egg white was investigated. Dye density (1.7 μmol ml⁻¹) and maximum binding capacity (26 mg lysozyme ml⁻¹) are comparable to those of commercial gel matrices. Dynamic binding capacity did not change when residence time was reduced from 3 to 1 min. A method for direct lysozyme separation from egg white was developed, with a productivity of 12 kg lysozyme m⁻³ h⁻¹. The purity of the eluted lysozyme, as determined by HPLC, was 88%, with a recovery of 92%. Dynamic capacity was kept constant at 70% of the maximum binding capacity for at least 10 cycles through membrane regeneration with 0.1 M NaOH and 1 M NaCl. Functional properties of egg white, as judged by viscosity and foaming capacity measurements, did not change after the chromatographic lysozyme depletion. © 1999 Society of Chemical Industry     

Antioxidant peptides obtained from goose egg white proteins by enzymatic hydrolysis

In this study, antioxidant peptides from goose egg white proteins produced using various enzymes were purified and characterised. Two peptides were named as p14 and p16, showing the highest scavenging activity of 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) radical and the highest metal ion chelating activity, respectively. The sequences of p14 and p16 were identified to be STMMEERRMKVY (1560.72 Da) and DVFRELRVQ (1161.62 Da), respectively. The sequence of p14 has a similarity of 75% to ovalbumin from Meleagris gallopavo and the sequence of p16 has a similarity of 67% to ovalbumin from Taeniopygia guttata. IC₅₀ values of p14 and p16 were determined, and results showed that DPPH radical scavenging activity was 81.6 and 205.5 μm , 2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulphonicacid)(ABTS) radical scavenging was 88.4 and 153.8 μm , hydroxyl radical scavenging was 85.5 and 116.3 μm and metal ion chelating was 170.6 and 117.9 μm , respectively. The two identified peptides from goose egg white hydrolysates act as potent natural antioxidant agents.