利用气相色谱法分析不同萃取方法对鱼油中EPA、DHA含量的影响

本文利用气相色谱法(GC)对鱼油中的二十碳五烯酸(EPA)和二十二碳六烯酸(DHA)进行了定量分析,探究了快速检测EPA、DHA的分析条件,并以黄鲛鱼鱼胃为原料,利用建立的色谱分析方法分别测定了超声强化亚临界水萃取法、超声波辅助溶剂萃取法、酶解提取法和超临界CO₂萃取法获得的鱼油样品中的EPA和DHA的含量。结果显示:EPA的出峰时间是10.015 min,DHA的出峰时间是16.500 min。升温程序和分流比会显著影响目标峰(EPA、DHA)与其相邻峰的分离度R₁和R₂(p<0.01)。该法与国标GB5009.168-2016中的脂肪酸色谱分析方法相比,具有针对性强(可快速检测EPA、DHA)、准确性高、重现性好和快速高效的特点,样品分析时间由82 min缩短至18 min。在最佳分析条件下,上前述四种萃取方法获得鱼油中含有的EPA的检出量依次是54.67、35.23、40.13、33.40 mg/g,DHA的检出量依次是134.01、77.50、102.30、67.31 mg/g。     

一种提高EPA系统运行效率的机制与实现方法

为了提高EPA(Ethernet for Plant Automation)测控系统的运行效率和通信性能,在EPA确定性通信调度的基础上,提出了EPA-CS(EPA Cycle Synchronization,周期同步)机制.该机制通过使实现控制功能的用户层功能块与实现数据传输功能的EPA通信达成周期同步,解决了功能块无效执行和数据无效传输的问题.提出了机制的原理,给出了用巡回扫描和定时器中断实现机制的方法.实验表明:该机制能够有效降低EPA系统的运行负荷与通信负荷,提高系统的运行效率和通信性能;巡回扫描和定时器中断两种方法实现该机制的效果都比较明显,定时器中断实现的效果更好一些.     

Structured lipids from high-laurate canola oil and long-chain omega-3 fatty acids

The lipase-assisted acidolysis of high-laurate canola oil (HLCO; Laurical 25) with long-chain n−3 FA (DHA and EPA) was studied. Response surface methodology was used to obtain a maximal incorporation of DHA or EPA into HLCO. The studied process variables were the amount of enzyme (2–6%), reaction temperature (35–55°C), and incubation time (12–36 h). The amount of water added and the mole ratio of substrates (oil to DHA or EPA) were kept at 2% and 1∶3, respectively. All experiments were conducted according to a face-centered cube design. Under optimal conditions (4.79% of enzyme; 46.1°C; 30.1 h), the incorporation of DHA into HLCO was 37.3%. The corresponding maximal incorporation of EPA (61.6%) into Laurical 25 was obtained using 4.6% enzyme, a reaction temperature of 39.9°C, and a reaction period of 26.2 h. Examination of the positional distribution of FA on the glycerol backbone of modified HLCO with DHA showed that the DHA was primarily located in the sn-1,3 positions of the TAG molecules. However, lauric acid also remained mainly in the sn-1,3 positions of the modified oil. For EPA-modified Laurical 25, lauric acid was present mainly in the sn-1,3 positions, whereas EPA was randomly distributed over the three positions.     

Concentration of docosahexaenoic acid in glyceride by hydrolysis of fish oil withcandida cylindracea lipase

In an attempt to concentrate the content of DHA (docosahexaenoic acid) in a glyceride mixture containing triglyceride, diglyceride and monoglyceride, fish oil was hydrolyzed with six kinds of microbial lipase. After the hydrolysis, free fatty acid was removed and fatty acid components of the glyceride mixtures were analyzed. When the hydrolysis withCandida cylindracea lipase was 70% complete, the DHA content in the glyceride mixture was three times more than that in the original fish oil. The EPA (eicosapentaenoic acid) content became almost 70% of the original fish oil. Hydrolysis with other lipases did not result in an increase in the DHA content in the glyceride mixtures. Hydrolysis of DHA-rich tuna oil (DHA content is about 25%) withCandida cylindracea lipase resulted in 53% DHA in the glyceride mixture. The EPA content, however, remained close to that of the original tuna oil. In this report, the acyl chain specificity of lipases is evaluated in terms of hydrolysis resistant value (HRV). HRV is the ratio between the DHA contents in the glyceride mixture of hydrolyzed oil and original oil. HRV clearly indicates differences in hydrolysis between DHA and other fatty acids (e.g., saturated and monoenoic acids).     

EPA协议一致性测试方法

EPA是我国第一个拥有自主知识产权并被国际电工委员会（IEC）认可的工业自动化领域国际标准。本文在研究EPA协议一致性测试原理、静态测试与动态测试方法与实现技术的基础上，参照TFCN的结构框架对EPA抽象测试集进行形式化描述，提出了一种EPA协议一致性测试的方法，阐述了EPA协议实现一致性说明和协议实施附加信息的生成方法，并以变量写服务的测试为例，说明了EPA协议一致性测试流程。国家863／CIMS验收专家组委托的专家测试表明这种测试方法能够准确测试出被测协议实现与标准的一致程度。     

小型通用汽油机化油器的设计开发

根据厦门厦杏发动机的特点以及要求,开发通用机化油器MPZ09。通过对化油器结构特点、工作原理描述,最后在发动机上进行空载试验、负载试验及EPA法规工况试验。试验结果表明:湛江德利化油器有限公司开发该化油器一致性好且能满足发动机各项性能指标,符合EPA法规要求。     

鳗鱼肝脏和骨中脂肪酸测定及比较

利用有机溶剂法对鳗鱼肝脏和骨中所含油脂进行提取,比较研究提取鳗鱼肝油和骨油的感官表现、理化指标及其所含脂肪酸成分的差异。结果表明:提取鳗鱼骨油比肝油的感官评价好,但二者均达到鱼油标准SC/T350 2—20 00《鱼油》中精制鱼油一级标准。相比较而言,提取鳗鱼肝油较鳗鱼骨油饱和脂肪酸含量少(分别为24.3%和34.9%),二者单不饱和脂肪酸含量接近(分别为48.0%和49.6%),鳗鱼肝油较鳗鱼骨油多不饱和脂肪酸含量多(分别为12.1%和3.3%),特别是EPA含量(分别为1.90%和0.6%)和DHA的含量高得多(分别为9.0%和1.6%),未定性脂肪酸含量鳗鱼肝油也略高于鳗鱼骨油(分别为15.7%和12.1%)。因此,从脂肪酸种类和含量来看,鳗鱼肝油较鳗鱼骨油营养价值更高、品质更好。     

米曲霉脂肪酶催化鱼油酯酯交换制备高含量EPA/DHA甘油酯的研究

利用米曲霉脂肪酶催化甘油酯型鱼油和乙酯型鱼油的酯酯交换反应制备高含量EPA/DHA甘油酯,考察了底物摩尔比、反应温度、酶添加量和摇床转速对酶催化反应的影响,得到了最优酶催化反应条件:甘油酯型鱼油与乙酯型鱼油摩尔比1∶3,酶添加量14%,反应温度70℃,摇床转速150 r/min。在最优的酶催化反应条件下反应18 h,产物甘油酯型鱼油EPA和DHA含量可达到39.72%。在优化条件下对米曲霉WZ007菌丝体重复使用6次,甘油酯型鱼油产品中的EPA和DHA含量仍保持在34.51%。     

鱼油软胶囊中脂肪酸组成及比率分析

采用气相色谱法对海洋鱼油软胶囊中脂肪酸组成和比率进行分析,为合理补充DHA、EPA等多不饱和脂肪酸提供理论依据,并为鉴别海洋鱼油质量提供基础数据。结果表明:鱼油软胶囊中主要含有C14~C22脂肪酸,其中不饱和脂肪酸质量分数50.8%~85.1%,特别是具有重要生理作用的多不饱和脂肪酸,如C20:5(EPA,约占10.0%~35.1%)、C22:6(DHA,约占10.7%~20.5%);鱼油软胶囊中n-3不饱和脂肪酸质量分数约为22.5%~55.7%,n-6不饱和脂肪酸与n-3不饱和脂肪酸的比率约为0~0.7,EPA与DHA的比率约为0.8~1.9。