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.     

Atlantic salmon (Salmo salar) muscle structure integrity and lysosomal cathepsins B and L influenced by dietary n-6 and n-3 fatty acids

This study had two main objectives: first, to evaluate the impact of different types and levels of dietary n-6 and n-3 fatty acids (FAs) on Atlantic salmon muscle structure integrity; second, to highlight a possible role of lysosomes and lysosomal degrading enzymes, cathepsins, in fish muscle structure integrity, in relation to dietary fatty acids. Four groups of Atlantic salmon (90 g starting weight) in fresh water tanks were fed one of four diets containing 23% crude lipids, with 100% of the added oils as either fish oil (FO), rapeseed oil (RO), eicosapentaenoic acid (EPA) enriched-oil or docosahexaenoic acid (DHA) enriched-oil. The RO diet was characterised by low levels of EPA + DHA (10% of total FAs), whereas the EPA and DHA diets were characterised by very high levels of EPA + DHA (>50% of total FAs). Fatty acid composition of the muscle crude lysosomal fraction (CLF) generally reflected the diets. Salmon fed the RO diet presented a muscle CLF FA composition close to the one of the FO group, showing moderate PUFA levels, and comparable cathepsin B and cathepsin L activities, relative gene expression of cathepsin B and cathepsin L in the muscle and rate of myofibre–myofibre detachments post-mortem. Salmon fed the EPA and DHA-enriched-oil diets presented a fairly similar muscle CLF FA composition, but different from the FO and RO groups. In the EPA and DHA groups, the percentage of PUFAs in the muscle CLF, the rate of myofibre–myofibre detachments and the relative gene expression of cathepsin B were higher than in the FO and RO groups. Cathepsin B and cathepsin L total activities in the muscle were however lower in the EPA and DHA groups 0 h post-mortem. Dietary lipids influenced the level of lysosomal degrading enzyme activity cathepsin B and cathepsin L as well as the relative gene expression of cathepsin B. Feeding Atlantic salmon with rapeseed oil and extreme levels of EPA + DHA highlighted the impact of fatty acid composition of the diet on salmon muscle integrity and the complexity of the process involving muscle lysosomes and cathepsins in relation to these dietary fatty acids.     

鱼油海藻糖酯的合成与表面性质研究

分别以EPA乙酯、DHA乙酯和海藻糖为原料,在非水相酶反应体系中合成了EPA和DHA的海藻糖酯,采用硅胶柱层析和半制备高效液相色谱对反应液进行分离纯化,得到各自的单酯,并利用电喷雾质谱、核磁共振方法确定了两种单酯的结构.EPA海藻糖单酯和DHA海藻糖单酯的HLB值分别为10.39、9.97,因此可作为O/W型表面活性剂.利用Douy环法分别测定了30、40、50、60%时EPA海藻糖单酯、DHA海藻单酯的表面张力,发现二者的表面张力随温度的升高而降低.对其临界胶束浓度(CMC)进行计算表明,CMC随温度升高略有下降,并且DHA海藻糖单酯的CMC比EPA海藻糖单酯的CMC大约低1个数量级.     

酶法富集小黄鱼内脏鱼油中EPA和DHA甘油酯

目的：以小黄鱼内脏精炼鱼油为原料,通过脂肪酶选择性水解法富集二十碳五烯酸（eicosapentaenoic acid,EPA）甘油酯和二十二碳六烯酸（docosahexaenoic acid,DHA）甘油酯。方法：采用气相色谱峰面积外标法定量测定EPA和DHA甘油酯总含量。通过单因素和响应面试验,考察反应时间、pH值、反应温度、加酶量等因素对富集效果的影响。结果：确定最佳工艺条件为反应时间4 h、pH 8.0、反应温度30 ℃、加酶量1.0%,在此条件下,EPA和DHA甘油酯总含量为21.65%,且4 个因素对EPA和DHA甘油酯富集的影响依次增强。结论：富集后鱼油理化指标和感官评价均优于精炼鱼油,EPA和DHA甘油酯总含量是富集前的1.74 倍,获得了天然的EPA和DHA甘油酯。     

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。     

The labile lipid fraction of meat: from perceived disease and waste to health and opportunity

The fatty acid composition of beef and pork has been stigmatized due to their relationships with several diseases from cardiovascular disease to cancer. Meat lipids are, however, one of the few components of meat that can be modified in content and composition, and can present opportunities for value added production and health promotion. Until regulations and policies are in place to define requirements for fatty acid enrichment, however, the process remains relatively academic. Once practical goals are in place for fatty acid enrichment in meat, both theory and practice need to converge for successful production of fatty acid enriched meat. The present review covers aspects of policy in Canada, and requirements for research networks to respond to theoretical and practical challenges associated with production of fatty acid enriched meat. Finally, needs for education and marketing are outlined which must be in place to truly realize a transition of meat lipids from perceived disease and waste to health and opportunity.     

Fatty acid composition in some selected marine fish species living in Turkish waters

The muscle fatty acid (FA) composition of 12 selected marine fish species living in Turkish waters was determined. FA profiles of muscle were compared in terms of total and individual saturated (SFAs) and unsaturated fatty acids. Total SFA, monounsaturated fatty acid (MUFA), n‐3 polyunsaturated fatty acid (n‐3 PUFA) and n‐6 polyunsaturated fatty acid (n‐6 PUFA) contents as well as n‐3/n‐6 FA and eicosapentaenoic acid (EPA)/docosahexaenoic acid (DHA) ratios differed (P < 0.01) in all fish species. Palmitic acid (16:0) among total SFAs, oleic acid (18:1n‐9) among MUFAs, DHA (22:6n‐3) among n‐3 PUFAs and 18:2n‐6 and 20:4n‐6 among n‐6 PUFAs were the most abundant FAs. The ratio of n‐3/n‐6 PUFA contents, indicating the availability of n‐3 PUFAs that are beneficial for human health, ranged from 2.67 to 12.61. The EPA/DHA ratio was between 0.17 and 0.83 in the marine fish species studied. Copyright © 2005 Society of Chemical Industry     

丹参提取物与几种抗氧化剂在浓缩EPA和DHA中的抗氧化作用比较

本文比较了丹参提取物（ＳＭＥＣ）、茶多酚、ＴＢＨＱ、ＢＨＴ等几种抗氧化剂在浓缩ＥＰＡ和ＤＨＡ中的抗氧化作用的强弱，表明，在相同浓度下，丹参提取物的抗氧化作用不如茶多酚、ＢＨＴ及ＴＢＨＱ，丹参提取物及茶多酚的抗氧化作用均随浓度的升高而加强，丹参提取物与ＢＨＴ或ＴＢＨＱ有阶同作用，共同使用可大大增强抗氧化作用。     

浅议DHA、EPA及其应用

DHA(二十二碳六烯酸)和EPA(二十碳五烯酸)属ω-3系多不饱和脂肪酸,对人体有着重要的生理作用,成为当今科研领域研究的热点之一。文章阐述了DHA、EPA的分子结构、代谢途径以及它们的生理作用。此外,介绍了其生物来源、应用和当前的研究热点。