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     

哺乳期干预甘油三酯型和磷脂型DHA对仔鼠体组织DHA水平的影响

研究哺乳期母鼠干预甘油三酯型DHA(DHA-TG)和磷脂型DHA(DHA-PL)对仔鼠体组织脂肪酸组成及二十二碳六烯酸(DHA)水平的影响。母鼠妊娠期给予n-3多不饱和脂肪酸(n-3PUFAs)缺乏饲料,产仔后分别给予n-3 PUFAs缺乏饲料(缺乏组)、含DHA-TG饲料(DHA-TG组)和含DHA-PL饲料(DHA-PL组),饲喂至仔鼠3周龄断乳。测定仔鼠脑皮质、肝脏、血清和红细胞总脂中脂肪酸组成和DHA含量。与缺乏组相比,哺乳期干预DHA-TG和DHA-PL后仔鼠各组织中DHA和n-3 PUFAs含量均显著升高,二十二碳五烯酸(DPA)、花生四烯酸(AA)、∑n-6 PUFAs与∑n-3 PUFAs比值均显著降低。其中DHA-PL组仔鼠脑皮质和红细胞总脂中DHA水平显著高于DHA-TG组,而肝脏和血清中DHA水平两组之间无显著性差异。总之,哺乳期母鼠补充DHA-TG和DHA-PL均可显著提高仔鼠各组织中DHA水平,其中DHA-PL对脑皮质和红细胞中DHA的补充效果更佳。     

化学添加剂对裂壶藻突变株发酵产DHA的影响

为了研究外源化学添加剂对裂壶藻（Schizochytrium limacinum）突变株发酵合成脂肪酸（SFAs、PUFAs和DHA）的影响,采用基于气相色谱-质谱（GC-MS）联用技术分析裂壶藻突变株产油脂肪酸的组成。通过单因素和正交实验设计,优化了乙醇胺（ETA）、萘氧乙酸（BNOA）和水杨酸（SA）三种化学添加剂的最佳添加条件。结果表明,添加150 mg/L的乙醇胺（ETA）、10 mg/L萘氧乙酸（BNOA）和1 mg/L水杨酸（SA）,裂壶藻突变株的DHA产量最高,达到6.18 g/L,比对照组提高了12.77%。综上所述,添加适量的化学添加剂可以提高裂壶藻突变株DHA的含量。      

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.     

Changes in lipids and their contribution to the taste of migaki-nishin (dried herring fillet) during drying

This study was conducted to investigate the changes in lipids and their effect on the taste of migaki-nishin during drying. Lipid was extracted from herring fillets following different drying stages to measure the degree of lipid oxidation and changes in lipid composition, and fatty acid profile. Peroxide value, carbonyl value and acid value of the lipids were significantly increased (P < 0.05) during the drying period. Marked increase in free fatty acids, with decreases in triglyceride and phospholipid content were observed in proportion to drying time and this result suggested that hydrolysis was induced by lipases and phospholipases. The decreases in polyunsaturated fatty acids (PUFAs), especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), were observed in the total lipids and phospholipid fraction. In addition, significant increase in PUFAs especially DHA was found in the free fatty acid fraction. Sensory evaluation showed that an addition of DHA to mentsuyu significantly (P < 0.05) enhances the intensities of thickness, mouthfulness and continuity. These results suggest that during drying period lipid oxidation was not only occurred but also lipolysis predominantly released DHA, which might have a contribution to kokumi enhancement of migaki-nishin.     

Healthy reduced-fat Bologna sausages enriched in ALA and DHA and stabilized with Melissa officinalis extract

Reduced-energy and reduced-fat Bologna products enriched with ω-3 polyunsaturated fatty acids were formulated by replacing the pork back-fat by an oil-in-water emulsion containing a mixture of linseed-algae oil stabilized with a lyophilized Melissa officinalis extract. Healthier composition and lipid profile was obtained: 85 kcal/100 g, 3.6% fat, 0.6 g ALA and 0.44 g DHA per 100 g of product and ω-6/ω-3 ratio of 0.4. Technological and sensory problems were not detected in the new formulations. Reformulation did not cause oxidation problems during 32 days of storage under refrigeration. The results suggest that it is possible to obtain reduced-fat Bologna-type sausages rich in ALA and DHA and stabilized with natural antioxidants, applying the appropriate technology without significant effects on the sensory quality, yielding interesting products from a nutritional point of view.     

婴儿配方奶粉中花生四烯酸含量的测定

本方法适用于婴儿配方乳粉中DHA含量的测定.本方法简便、快速、稳定,方法检出限为0.01 ppm.     

Mercury and Fatty Acids in Canned Tuna, Salmon, and Mackerel

ABSTRACT: Canned tuna ( n = 240), salmon ( n = 16), and mackerel ( n = 16) were analyzed for mercury and fatty acids. Average mercury levels were 188, 45, and 55 ppb, respectively, and below the FDA Action Level of 1000 ppb. "Light tuna in water" contained lower mercury (x = 54 ppb) compared with "white/albacore tuna in water," which contained higher eicosapentaenoic acid/docosahexaenoic acid (EPA/DHA) x= 711 mg/100 g wet tissue). Mercury residues in salmon (x = 45 ppb) and mackerel (x = 55 ppb) were lower than in tuna products, but the EPA/DHA levels were higher (salmon, ×= 1623 mg/100 g wet tissue; mackerel, ×= 851 mg/100 g wet tissue). Information from this study will help women of childbearing age to limit their intake of mercury while obtaining healthy fats from fish.     

鱼油制剂改善小鼠记忆作用的研究

目的:验证鱼油制剂具有改善小鼠记忆的作用。方法:按卫监发(1996)第38号《保健食品功能学评价程序和方法》中的改善记忆作用检验方法进行跳台试验和避暗试验。结果:鱼油制剂对动物记忆获得与巩固过程有一定的促进作用,能明显地提高小鼠跳台被动回避反应再现能力和提高避暗反应再现能力。结论:鱼油制剂具有明显改善记忆的作用。     

天然抗氧化剂对裂壶藻油氧化稳定性影响的研究

采用Schaal烘箱法,以过氧化值和DHA含量变化为油脂氧化稳定性的评价指标,研究5种天然抗氧化剂对裂壶藻油氧化稳定性的影响。从中选择3种较优的天然抗氧化剂按一定比例复配得到复配天然抗氧化剂,并研究其对裂壶藻油氧化稳定性的影响。结果表明:5种抗氧化剂均能提高裂壶藻油的氧化稳定性,其中维生素E、迷迭香酸、茶多酚对裂壶藻油的氧化稳定性的提升较大;3种天然抗氧化剂复配配方为维生素E与迷迭香酸、茶多酚复配比例为2∶1∶2时对裂壶藻油的氧化稳定性的提升最大,在此条件下15 d后裂壶藻油的过氧化值为(30.25±0.57)mmol/kg,且该配比下DHA含量为(3.32±0.12)g/100 g,油脂的过氧化值低,DHA含量高,品质较好。