共轭亚油酸的合成、分析与氧化稳定性

共轭亚油酸(CLA)具有抗癌、抗动脉硬化、减肥、提高免疫力等多种独特的生理功能,被誉为“21世纪的新型营养素”。本文就CLA的合成、分析、氧化稳定性及应用前景等方面,对国内外的研究进行了综述。CLA的合成包括化学法和生物法两大类,CLA的分析主要采用气相色谱法(GC)、银离子-高效液相色谱法(Ag^ -HPLC)和核磁共振法(NMR)。CLA不稳定,需进行保护以防止其氧化。     

Impact of Adding Polysaccharides on the Stability of Egg Yolk/Fish Oil Emulsions under Accelerated Shelf-Life Conditions

Polysaccharides can form interfacial complexes with proteins to form emulsions with enhanced stability. We assessed the effect of adding gum guar or gum arabic to egg yolk/fish oil emulsions. The emulsions were produced using simple or high-pressure homogenization, stored for up to 10 days at 45 °C, and characterized for their particle size and distribution, viscosity, encapsulation efficiency, oxidative stability, and cytotoxicity. Emulsions containing gum guar and/or triglycerides had the highest viscosity. There was no significant difference in the encapsulation efficiency of emulsions regardless of the polysaccharide used. However, emulsions containing gum arabic displayed a bridging flocculation effect, resulting in less stability over time compared to those using gum guar. Emulsions produced using high-pressure homogenization displayed a narrower size distribution and higher stability. The formation of peroxides and propanal was lower in emulsions containing gum guar and was attributed to the surface oil. No significant toxicity toward Caco-2 cells was found from the emulsions over time. On the other hand, after 10 days of storage, nonencapsulated fish oil reduced the cell viability to about 80%. The results showed that gum guar can increase the particle stability of egg yolk/fish oil emulsions and decrease the oxidation rate of omega-3 fatty acids.     

利用液相色谱–质谱联用技术研究二元表面活性剂体系–啶虫脒微乳剂热贮稳定性

应用液相色谱–质谱联用技术评价复配的阴/非离子二元表面活性剂复合体系–啶虫脒微乳剂的热贮稳定性。将二元表面活性剂复合体系–啶虫脒微乳剂于(54±2)℃下贮藏14天,取出后于室温下干燥24 h,用液相色谱–质谱联用仪测定啶虫脒含量。该法线性拟合方程为y=97 060.72x+542 587.4,线性范围为0.01~0.25 mg/L,相关系数为0.999 8。方法检出限为0.001 mg/L(S/N=3),色谱保留时间和色谱峰面积重复性分别为0.31%,1.44%(n=6),加标回收率为86.23%~107.20%。该法具有简单、准确和灵敏的特点。     

Connecting Rheological Properties and Molecular Dynamics of Egg-Tempera Paints based on Egg Yolk

Egg-tempera painting is a pictorial technique widely used in the Middle Ages, although poorly studied in its physico-chemical aspects until now. Here we show how NMR relaxometry and rheology can be combined to probe egg-tempera paints and shed new light on their structure and behavior. Based on recipes of the 15th century, model formulations with egg yolk and green earth have been reproduced to characterize the physicochemical properties of this paint at the mesoscopic and macroscopic scales. The rheological measurements highlight a synergetic effect between green earth and egg yolk, induced by the interactions between them and the structural organisation of the system. ¹H NMR relaxometry emphasizes the presence and the structure of a network formed by the yolk and the pigment.     

高效液相色谱法研究氨基酸测定中鸡蛋样品的微波水解

利用Pico-Tag高效液相色谱法（HPLC）研究了氨基酸分析中一种新的水解方法——微波水解法,鸡蛋样品以内含1％苯酚的6mol／L盐酸作为水解液水解,仅需7min即可求解完全,平均回收率为95％,相对标准偏差小于2％。方法简便、快速、准确、重现性好,适用于不同样品的水解处理。     

An Efficient Processing Strategy to Improve the Flavor Profile of Egg Yolk: Ozone-Mediated Oxidation

This study investigated the effect of ozone treatment on egg yolk volatiles and fatty acids. The composition and content of volatile substances and the fatty acid content of the egg yolk were changed significantly after ozonation. With proper ozone treatment (30 min), the aldehyde content in the egg yolk increased from 78.08% to 94.63%, and the relative content of dibutyl amine decreased from 1.50% to 0.00%. There were no significant differences among the types of fatty acids in the egg yolks after being treated with ozone, but there were differences in their relative contents. The results of SDS-PAGE showed no significant difference in yolk protein composition and contents among the groups. SEM results showed that moderate ozone treatment (20 min and 30 min) led to a regular and dense network structure of egg yolk. These results provided a theoretical basis for expanding the application of ozone technology in the egg yolk processing industry.     

测定鸡蛋胆固醇的高效液相色谱新方法

报道了测定鸡蛋蛋黄胆固醇含量的一种改进方法。蛋黄以水稀释后直接以乙醚和石油醚萃取,采用ＺｏｒｂａｘＯＤＳ反相色谱柱（０．４６ｃｍ×１５ｃｍ,５～６μｍ）,以乙腈－异丙醇（４∶１,Ｖ／Ｖ）为流动相,流速０．６ｍＬ／ｍｉｎ,检测波长２０８ｎｍ。在此色谱条件下,胆固醇含量与色谱峰高呈良好的线性关系,线性范围在０．０５～０．４０ｇ／Ｌ（ｒ＝０．９９９３）之间,最小检测量为０．０２ｇ／Ｌ。用于蛋黄胆固醇分析,样品无须皂化便可直接定量,简便、快速、重现性好。     

Development of an Enzyme Immunoassay for the Determination of the Herbicide Metsulfuron-Methyl Based on Chicken Egg Yolk Antibodies

Abstract

The development of an indirect competitive enzyme immunoassay for the sulfonylurea herbicide metsulfuron-methyl (MSM) is described. In contrast to traditional antibody generation in mammals, this extremely sensitive method is based on chicken egg yolk antibodies (IgY). They were raised in laying hens using an MSM-derivative-BSA hapten as immunogen. With a 1:10000 dilution of the antibody solution and a coating antigen (MSM-derivative-KLH) concentration of 10 μg L^?1 the IC₅₀ value achieved for the target analyte was 0.4 μg L^?1. The least detectable dose was established at 13 ng L^?1. Cross-reactivity was tested with 5 structurally related compounds, where only sulfometuron showed a significant binding. The ELISA was tested with spiked tap and surface water samples. This paper, for the first time, demonstrates the production of high-affinity IgY antibodies for a herbicide compound.     

纳米Pd粉的热稳定性研究

采用化学液相合成法制备了纳米Pd,热稳定性研究表明,温度在773～523K内,样品的平均粒径d与退火温度T之间服从Arrhenius关系,且平均粒径与退火时间t之间满足经验公式d=ktn。纳米Pd的热稳定范围T≤250℃。计算得到纳米Pd颗粒生长的表观激活能为0.15eV,远比纳米复合材料的生长激活能小（约为1eV）。故纳米Pd颗粒-极易长大,热稳定范围非常窄。     

高内相/自乳液聚合的共轭亚油酸低聚体的囊泡化及稳定性

采用自乳化法制备了高内相共轭亚油酸(CLA)的水包油(O/W)乳液, 并通过热引发乳液聚合反应得到共轭亚油酸低聚体(oligo-CLA); 将oligo-CLA用于自组装脂肪酸囊泡(FAV). 透射电子显微镜和动态激光光散射表征结果均表明, 在pH=8.6~13范围内得到了囊泡粒径为10~30 nm的FAV, 此结果对提高FAV的pH适应性具有理论意义. 自乳液聚合实验结果表明, 该高内相自乳化/热引发低聚反应策略可以使浓度高达75.3%(质量分数)的CLA完成无外加表面活性剂乳液聚合, 并使共轭双键总自交联率达到33%且控制oligo-CLA的平均聚合度约为6, 对规模化生产oligo-CLA及构筑FAV具有实用价值. 与CLA相比, oligo-CLA具有更好的低温溶解性, 由其自组装的FAV具有更好的环境适应性, 如耐酸性和抗钙皂能力, 而且显示出较好的钙响应囊泡体积膨胀率; 以极少量非离子表面活性剂Span 40或AEO₂辅助oligo-CLA形成的杂化囊泡具有更宽的pH适应性. 因此, 所制备的FAV在药物释放体系、 日用化学产品、 家用洗涤剂和个人护理产品中具有更广阔的应用前景.     

用尺寸排阻色谱法研究蛋白质的热稳定性

用尺寸排阻色谱ＺｏｒｂａｘＧＦ－２５０凝胶过滤柱研究了核糖核酸酶Ａ,马心肌红蛋白和溶菌酶的热稳定性。测定了蛋白质在尺寸排阻系统中的分配系数Ｋｄ并用荧光检测器分析了加热引起的蛋白质内源性荧光的改变,从而计算出了蛋白质的热变性转化点温度,测定了蛋白质天然态、热变性和盐酸胍诱导变性状态下的斯托期斯半径,实验结果进一步证帝了热变性后蛋白质不是呈真正的随机线状,而是保留了部分紧密的结构区域。用本方法研究了Ｐ     

Formulation of Conjugated Linoleic Acid Microemulsion Using Mixed Nonionic Surfactants

A novel class of conjugated linoleic acid (CLA)-in-water microemulsion based on Tween80, EL-35, ethanol, and n-octanol was investigated as potential food delivery systems. The influences of pH on the microemulsion region were considered. The microemulsion structural transition was divided into water-in-oil (W/O), bicontionuous, and oil-in-water (O/W) microemulsion by conductivity and viscosity method. The microemulsion size and polydispersity were determined by dynamic light scattering (DLS). The size of O/W microemulsion droplets depends strongly on the contents of surfactants and CLA, and the diameter ranges from 22.1 to 30.7 nm and from 18.3 to 32.8 nm, respectively. All samples keep a remarkable stability in the experiments of 30 days. The stability of CLA in microemulsion and ethanol solution was determined by ultraviolet-visible spectrophotometry, the results revealed that the stability of the CLA in the microemulsion was increased remarkably.     

硅烷接枝聚乙烯储存稳定性的研究

利用熔体流动速率测定仪进行了硅烷接枝聚乙烯的水解缩合交联反应的加速试验,发现该反应对水分浓度为一级反应,反应的表现活化能４２ｋＪ／ｍｏｌ,由此可推算Ａ组份的保存期。当催化剂存在时,水解缩合反应明显加快,这时的表观活化能降到２０ｋＪ／ｍｏｌ。     

十六烷基三甲基溴化铵对DNA热稳定性的影响

研究十六烷基三甲基溴化铵(CTAB)对DNA分子热稳定性的影响对于认识阳离子表面活性剂与DNA二者之间的相互作用具有重要的意义。用差示扫描量热法和变温紫外光谱法研究了CTAB对鲑鱼精DNA及降解的鲱鱼精DNA热稳定性的影响,发现CTAB使鲑鱼精DNA的热稳定性降低,但降低程度随CTAB浓度的增大而先增大后减小;CTAB使鲱鱼精DNA发生了两阶段熔解行为。     

Thermal Stability of Heteropoly Acids and Characterization of the Water Content in the Keggin Structure

The thermal stability of heteropoly acids of the Keggin type (H₄[SiMo₁₂O₄₀], H₃[PMo₁₂O₄₀], H₄[SiW₁₂O₄₀] and H₃[PW₁₂O₄₀]), being important new catalytic materials, was studied by DSC. Two groups of signals were observed: the low temperature endothermic peak group belongs to the water content, while the high temperature one is exothermic and indicates the thermal decomposition of the acids. The effect of microwave irradiation on the target compounds was also studied. The emphasis, however, was placed on the characterization of the water content of the acids. Several types of water can be classified and DSC curves provide additional information to explain the differences in the catalytic behavior. The study of the effect of heat treatment and the subsequent water absorption of the acids provided additional unique information concerning the pseudoliquid phase in the secondary structure of heteropoly acids. This revised version was published online in July 2006 with corrections to the Cover Date.     

苯乙烯/聚氯乙烯接枝膜的热稳定性研究

用自由基悬浮聚合法合成了苯乙烯 /聚氯乙烯接枝膜 ,并对产物热处理 ,然后进行紫外 -可见光谱 ,红外光谱 ,热失重分析。结果表明接枝苯乙烯后的聚氯乙烯膜热稳定性得到了提高。同时 ,讨论了热稳定性机理。     

卵磷脂有序体中碳酸钙超微颗粒的研究

近些年来，国内外对超微颗粒的研究正处方兴未艾，由于纳米级材料与大块物质的特性截然不同，引起了国内外科学工作者的关注，试图用各种方法制备各种超微颗粒．在有序体中制备铂、佬、金、银、锅等超微颗粒已有文献介绍山，在表面活性剂AOT与水形成的有序体中制各碳酸钙超细颗粒也有报导问，用脂质体合成某些超微颗粒的工作也有文章发表［3］．但是由卵磷脂（PC）与水组成人。膜体系制备碳酸钙超微颗粒尚未见到报导．我们根据分子有序组合体具有”隔室化”作用，形成纳米级空间的思路，采用PC－H。0有序体系作为生成碳酸钙的反应场所．…     

热分析法研究五倍子醛的热稳定性及其分解动力学

采用热重法,以氮气为保护气,分别在5、10、15、20℃/min的升温速率下,测得五倍子醛的热重-微分热重(TG-DTG)曲线,并在10℃/min的升温速率下测得样品的差示扫描量热(DSC)曲线。结合热失重数据和五倍子醛结构对其分解机理进行推断和验证,并运用双外推法对五倍子醛的热解动力学进行分析,求得原始状态和热平衡态下的动力学参数。研究结果表明,五倍子醛晶体在升温过程中先经历了非结合水和结合水的受热挥发阶段,然后在163℃之后发生热分解,分子中醛基断裂失去1分子的CO;随着升温速率的升高,五倍子醛的分解反应向高温区域移动,最大失重速率依次减小;热解活化能Eα为286.21 kJ/mol,指前因子lnA为70.21,热解机理函数g(α)=[-ln(1-α)]2/3,反应级数n=2/3;热解活化能随转化率的增加逐渐减小;经动力学参数推断,在室温(25℃)下,五倍子醛的贮存期为4～5年。     

合成方法对纳米Ce-Zr-Al高温稳定性及储氧性能的影响

采用柠檬酸溶胶凝胶、溶胶辅助共沉淀和溶胶共沉淀3种方法合成了不同Al掺杂的纳米CexZr1-xO2与Al2O3的复合体Ce-Zr-Al.用XRD、BET和H2-TPR表征了纳米Ce-Zr-Al复合体的抗烧结性与储氧性能,与未掺杂的铈锆固溶体相比,Al掺杂的纳米铈锆复合体的抗烧结性与储氧性能均有显著改善,柠檬酸溶胶凝胶法的最佳掺杂量为5倍Al(Al与CexZr1-xO2摩尔比),溶胶辅助共沉淀法最佳掺杂量为10倍Al,溶胶共沉淀法最佳掺杂量为5倍Al,其中,柠檬酸溶胶凝胶法合成的Ce-Zr-Al纳米复合物储氧量最高,为717.5 μmol/g-CeO2,占理论储氧量(即储氧效率)的49.3％.     

基于表面等离子体共振技术用鸡蛋黄抗体 IgY测定人血清中转铁蛋白

采用表面等离子体共振(SPR)方法, 用鸡蛋黄抗体(IgY)取代传统免疫检测中哺乳动物抗体IgG作为识别分子偶联于CM5传感芯片上, 对人血清中的转铁蛋白进行了检测. 考察了IgY在传感芯片上的偶联条件及芯片的再生条件. 结果表明, 在pH=4.0, IgY浓度为100 μg/mL, 流速为5 μL/min的最佳偶联条件下, SPR响应信号和转铁蛋白浓度在50~500 ng/mL范围内具有良好的线性关系, 检出限为39.56 ng/mL, 对人血清样品检测的日间变异系数<8%, 日内变异系数<5%, 平均回收率为86.22% ~94.51%.