Omega-3 Fatty Acids and Total Polychlorinated Biphenyls in 26 Dietary Supplements

ABSTRACT: A limited sampling and analysis of commercial supplements found 51% to 124% eicosapentaenoic acid (EPA) and 61% to 153% docosahexaenoic acid (DHA) as provided on product labels. Daily intakes of EPA plus DHA from label recommendations would provide 123% to 1087% of the adequate intake (AI) for pregnant and lactating women (that is, 0.13 to 0.14 g/day) and up to 43% of the daily reference dose (RfD) for polychlorinated biphenyls (PCB) for a 60-kg person. However, if a smaller dose of the supplements were taken to meet the AI, only 0.9% to 11.5% of the RfD for PCB would be obtained. Algal oil supplements did not have detectable PCB residues, but those products only provided DHA and not EPA.     

海水鱼与淡水鱼omega-3多不饱和脂肪酸含量的比较研究

研究杭州市场常见野生和饲养淡水鱼以及海水鱼omega-3多不饱和脂肪酸（PUFA）的成分及含量。将购买的四个品种淡水鱼（野生和饲养）和六种海水鱼鱼肉去骨切碎,用有机溶剂提取总脂肪,甲酯化后的脂肪酸用气相色谱分离分析。结果表明：总PUFA的含量为从海水刺鲳的37．2mg／100g到淡水野生桂鱼的1821．8mg／100g,其中omeg-3PUFA有C18：3n-3,C18：4n-3,C20：5n-3,C22：5n-3,C22：6n-3,总omega-3PUFA含量为从海水刺鲳的32．3mg／100g到淡水饲养黑鱼的1104．3mg／100g。不同品种鱼脂肪酸含量存在显著性差异（p〈0．001）。结论：野生和饲养淡水鱼以及海水鱼中omega-3PUFA的含量及成分均因品种不同而异,淡水鱼的摄入完全能满足人体日常所需的omega3多不饱和脂肪酸。     

Factors Affecting Separation of Low Fat Flesh from Fatty Fish by Cryo-shattering

Our previous report on separating low fat flesh from fatty fish by cryo-shattering indicated that at appropriate temperatures, fat content in particles increased with particle size. The effect was temperature dependent; that effect of low temperature on fracture stress and elastic modulus of model fish flesh was further examined at - 60°C to - 196°C. The fish flesh showed abrupt changes in compression and tensile fracture stress at about - 90°C and - 150°C; such changes strongly affected fat content-particle size relations (FCPSR). Using measured fracture stress and elastic modulus values, FCPSR was successfully simulated when Bond's equation was linked with an empirical equation to estimate work index values.     

Omega-3 Fatty Acids in Lake Superior Fish

Proximate analysis and fatty acid composition of eight commercially important species of Lake Superior fish were determined. Palmitic acid (C16:0) was the predominant saturated fatty acid, accounting for 68–79% of total saturated acids. Oleic acid (C18:1) was the most abundant monounsaturated fatty acid. Linoleic acid (C18:2), linolenic acid (C18:3), eicosapentaenoic acid (C20:5) and docosahexaenoic acid (C22:6) were the predominant polyunsaturated fatty acids. Brining, smoking and refrigerated storage caused a reduction in total lipid, but only a small loss in n-3 fatty acids. The data revealed that most Lake Superior fish examined were excellent sources of polyunsaturated fatty acids with very high levels of omega-3 (n-3) fatty acids, especially eicosapentaenoic and docosahexaenoic acids.     

Cholesterol Content and Fatty Acids Composition of Mangalitsa Pork Meat

The aim of this study was to examine variability in cholesterol content and fatty acid composition in musculuslongissimus (MLLT) of various genotypes of pigs. Out of 30 male castrated animals used in the trial, 20 were Mangalitsa pigs (Swallow Belly - SBM and White - WM) while 10 were of the Swedish Landrace breed – SL. The representative of pig meat breeds, SL had significantly less cholesterol in MLLT compared to SBM and WM pigs. The total monounsaturated fatty acids (MUFA) and unsaturated fatty acids (USFA) content was higher in SBM and WM than in SL pigs (p< 0.001).     

鹅肥肝中脂肪酸沉积规律研究

以朗德鹅肥肝在填饲过程中脂肪酸沉积规律为对象,研究不同填饲周期饱和脂肪酸、单不饱和脂肪酸和多不饱和脂肪酸沉积的规律性。结果表明：鹅肥肝在填饲前、填饲1 周、填饲2 周、填饲3 周、填饲4 周的总脂肪含量分别为4.70%、15.42%、24.19%、50.35%、81.40%,除填饲1、2 两周之间差异不显著外其他组间差异显著(P ＜ 0.05);饱和脂肪酸占总脂的比例分别为1.96%、2.08%、3.82%、8.20%、14.78%,饲喂1～4 周间差异显著(P ＜ 0.05);不饱和脂肪酸占总脂的比例分别为20.17%、33.47%、34.29%、45.33%、75.63%,除第1周与第2 周间无显著性差异外,其他组间差异显著(P ＜ 0.05),说明填饲后期不饱和脂肪酸水平显著增加。     

Fatty Acid and Cholesterol Changes in Pork Longissimus Muscle and Fat due to Ractopamine

Fatty acid (FA) composition and cholesterol (CHL) content from control and Ractopamine (Rac) treated pigs were evaluated. Lipids were extracted from the longissimus (LD) and subcutaneous fat (SC) and methyl esters of the FA were formed for gas chromatography. CHL content of the LD was determined using direct saponification. Pigs were fed 0, 5, 10 or 20 ppm Rac for about 40 kg of grain prior to slaughter. Rac had no consistent effect on the FA composition of SC or muscle (neutral or polar) lipids. CHL content in the LD of treated animals was about 9% lower (P < 0.01) than controls. Rac reduced the CHL content of the LD and had limited effect on the FA profile of muscle or SC fat.     

Adsorption and Desorption of Cholesterol in Continuous Supercritical Fluid Processing of Anhydrous Milk Fat

The adsorption breakthrough volume of adsorbent for cholesterol reduction of anhydrous milk fat (AMF) was determined by passing supercritical carbon dioxide (SC-CO₂) phase through an adsorption column with magnesium silicate at 40°C/241 bar. The breakthrough quantity for 76% cholesterol reduction was 2.0g fat/g adsorbent. With in-line adsorption on magnesium silicate, the cholesterol reduction in the extracts was 80 to 86%. Magnesium silicates saturated with cholesterol were regenerated with 10% ethanol in CO₂ at 40°C and 64°C/241 bar. The adsorption capacity of the magnesium silicate regenerated with 10% ethanol in SC-CO₂ at 40°C/241 bar was close to its original value. Its behavior was described by the Langmuir isotherm.     

Fortification of Foods with Omega-3 Polyunsaturated Fatty Acids

A $600 million nutritional supplements market growing at 30% every year attests to consumer awareness of, and interests in, health benefits attributed to these supplements. For over 80 years the importance of polyunsaturated fatty acid (PUFA) consumption for human health has been established. The FDA recently approved the use of ω-3 PUFAs in supplements. Additionally, the market for ω-3 PUFA ingredients grew by 24.3% last year, which affirms their popularity and public awareness of their benefits. PUFAs are essential for normal human growth; however, only minor quantities of the beneficial ω-3 PUFAs eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are synthesized by human metabolism. Rather PUFAs are obtained via dietary or nutritional supplementation and modified into other beneficial metabolites. A vast literature base is available on the health benefits and biological roles of ω-3 PUFAs and their metabolism; however, information on their dietary sources and palatability of foods incorporated with ω-3 PUFAs is limited. DHA and EPA are added to many foods that are commercially available, such as infant and pet formulae, and they are also supplemented in animal feed to incorporate them in consumer dairy, meat, and poultry products. The chief sources of EPA and DHA are fish oils or purified preparations from microalgae, which when added to foods, impart a fishy flavor that is considered unacceptable. This fishy flavor is completely eliminated by extensively purifying preparations of n-3 PUFA sources. While n-3 PUFA lipid autoxidation is considered the main cause of fishy flavor, the individual oxidation products identified thus far, such as unsaturated carbonyls, do not appear to contribute to fishy flavor or odor. Alternatively, various compound classes such as free fatty acids and volatile sulfur compounds are known to impart fishy flavor to foods. Identification of the causative compounds to reduce and eventually eliminate fishy flavor is important for consumer acceptance of PUFA-fortified foods.

[Supplementary materials are available for this article. Go to the publisher's online edition of Critical Reviews in Food Science and Nutrition for the following free supplemental files: Additional text, tables, and figures.]     

人乳脂脂肪酸组成及其制备方法研究进展

该文介绍人乳脂的脂肪酸组成及吸收特点最新研究进展,并介绍目前几种人乳脂替代品的人 工构造方法。     

Cholesterol Oxidation in Fish and Fish Products

Fish and fish products are important from a nutritional point of view due to the presence of high biological value proteins and the high content of polyunsaturated fatty acids, especially those of the n‐3 series, and above all eicosapentaenoic acid and docosahexaenoic acid. However, these important food products also contain significant amounts of cholesterol. Although cholesterol participates in essential functions in the human body, it is unstable, especially in the presence of light, oxygen, radiation, and high temperatures that can cause the formation of cholesterol oxidation products or cholesterol oxides, which are prejudicial to human health. Fish processing involves high and low temperatures, as well as other methods for microbiological control, which increases shelf life and consequently added value; however, such processes favor the formation of cholesterol oxidation products. This review brings together data on the formation of cholesterol oxides during the preparation and processing of fish into food products which are recognized and recommended for their nutritional properties.     

家庭烹调对鲟鱼中脂肪酸和胆固醇的影响

对杂交鲟鱼（Acipenser baerii×A. schrenckii）进行了清蒸、油煎、微波、微波烤、烤箱烤和压力锅煎6 种家庭烹调处理,测定其脂肪和胆固醇含量、脂肪氧化指标和各脂肪酸含量的变化。结果表明,所有烹调方法均降低了n-3/n-6多不饱和脂肪酸含量的比值,其中压力烹调比值最高（0.85）,清蒸次之（0.83）,而烤箱烤最低（0.73）。胆固醇保存率以清蒸和压力锅煎最高,两种处理间无显著差异。烹调后样品酸价和硫代巴比妥酸值上升而过氧化值下降,并与样品的胆固醇含量相关。清蒸和压力烹调中脂肪酸和胆固醇变化相对较少,可能与其密闭烹调条件造成氧化程度较低有关。     

不同饱和度的三酰甘油酯的共存对胆固醇氧化的影响

为了评价三酰甘油酯的不同饱和程度对胆固醇氧化的影响,将精制的沙丁鱼油三酰甘油酯(碘价IV=182.6)、部分氢化沙丁鱼油三酰甘油酯(IV=174.5)、全氢化沙丁鱼油三酰甘油酯(IV=92.0)分别与胆固醇混合,制成CST、CTPH和CTFH三组试样,在25℃避光处诱导其氧化。研究结果表明:试样的氧化稳定性随着上述各试样的不饱和程度的增加而降低。CST的过氧化物诱导期比CTPH的短,并且在较短的诱导期内CST中组成沙丁鱼油三酰甘油酯的高度不饱和脂肪酸(PUFA)比CTPH的明显减少。各试样中生成的主要胆固醇氧化物有7-β-羟基胆固醇、7-酮基胆固醇、β-环氧化胆固醇和胆甾烷三醇。胆固醇氧化物的生成量随着过氧化物价(POV)的变化和PUFA的减少而增加。胆固醇的氧化与共存的鱼油三酰甘油酯的自动氧化有关。尽管在胆固醇氧化物生成阶段,降低鱼油三酰甘油酯的不饱和度可有效地延缓胆固醇的氧化,但是在诱导期以后胆固醇的氧化速率与CST和CTPH中PUFA的比例无关。     

Physical and Oxidative Stabilization of Omega-3 Fatty Acids in Surimi Gels

ABSTRACT: The objective of the study was to compare the dispersion and oxidative stability of omega-3 fatty acid oil in high- and low-quality surimi gels during 4-mo refrigerated and frozen storage. Low-quality surimi was prepared by subjecting Alaska pollock surimi to 7 freeze–thaw cycles. Surimi gels were prepared with 4% modified starch, 2% salt, and 0.5% or 1% algal DHA or concentrated fish EPA-DHA oil, and stored at −18 or 3 °C for 4 mo after being vacuumed packed and pasteurized. The effect of surimi gel properties on oil dispersion was examined using light microscopy equipped with image process software. The extent of lipid oxidation was monitored by thiobarbituric acid reactive substances (TBARS), peroxide value (PV), and fatty acid methly esters (DHA and EPA). Very fine and uniform oil dispersion was observed in the high-quality surimi gel with the average droplet size of 12.37 μm² and dispersion of 1.73 × 10⁻³ droplets/μm² compared to 84.32 μm² and 0.57 × 10⁻³ droplets/μm² in the low-quality gel. Throughout the 4 mo storage, TBARS and PV of high-quality surimi gel were significantly (P < 0.05) lower than those of low-quality surimi gel. The decreases in omega-3 fatty acids in the high-quality surimi gels were lower than those in the low-quality surimi gels under both storage conditions. Results confirm that a highly cohesive gel matrix is required to have a fine dispersion and oxidative stability of omega-3 fatty acids in the surimi gel system. Practical Application: Uniform dispersion and oxidative stability of omega-3 fatty acid oil can be achieved in the highly cohesive surimi gel system without use of antioxidants. This suggests that surimi can be used as a protein-based carrier in developing high omega-3 fatty acids-containing seafood products.     

Dietary Fat Reduces Odd-Numbered and Branched-Chain Fatty Acids in Depot Lipids of Rabbits

Forty eight Californian×New Zealand White rabbits were randomly distributed in three groups of 16 animals each. A control (with no added fat) and two diets enriched at a rate of 30 g fat kg^-1 were used. Olive oil and sunflower oil were used as sources of fat for the fat-supplemented diets. Branched chain (BCFA) and n-odd-numbered carbon fatty acids (ONFA) in the perirenal fat depots of control animals were respectively 5 and 22 mg g^-1 of total fatty acids, while in fat-enriched diets they were around 3 and 16 mg g^-1, respectively. The ratio of unsaturated: saturated fatty acid in perirenal fat was 1·25:1 when the control diet was administered and around 1·80–1·95:1 in fat-enriched diet groups, which represents approximately a 50% increase (P<0·01). However the melting points of the fats showed little difference (NS) between the control group and the group with olive oil addition whilst the sunflower oil-supplemented group showed only a 5·7% lower value (P<0·01). In a second experiment in which diets with equal digestible energy and protein were used, reductions in total amounts of ONFA (P<0·01) and BCFA (P<0·05) were observed in the perirenal fat of animals receiving the fat-enriched diets. The addition of fat depressed the concentrations of ONFA and BCFA, which may act to maintain the consistency of fat in a narrow range, avoiding to some extent the production of undesirable soft and floppy carcasses. © 1997 SCI.     

15种淡水鱼肌肉脂肪含量及脂肪酸组成分析

为比较淡水鱼肌肉脂肪酸在鱼类科、目以及种属间的差异,本文采用氯仿-甲醇(体积比=2:1)法提取15种淡水鱼背部肌肉的粗脂肪,运用气相色谱-质谱联用方法,分析了15种淡水鱼脂肪酸的组成。结果表明,15种淡水鱼肌肉粗脂肪含量在3.76%~14.74%,15种淡水鱼共检出24种脂肪酸,其中8种饱和脂肪酸(SFA),5种单不饱和脂肪酸(MUFA)和11种多不饱和脂肪酸(PUFA)。不同淡水鱼脂肪酸除个别有差异外,其他组成基本相同,但其含量因淡水鱼所在目、科和种属不同存在显著性差异,多不饱和脂肪酸含量最高,均在35%以上。不同鱼种的粗脂肪中EPA和DHA总含量有所差异,鲈鱼粗脂肪中DHA和EPA最高,总含量达到30%,而泥鳅粗脂肪中的EPA和DHA总含量仅为8.51%。部分鱼种可以作为EPA和DHA的良好膳食来源,具有较高的利用和开发价值。     

Enhancement of Release of Short-Chain Fatty Acids from Milk Fat with Immobilized Microbial Lipase

Candida cylindracea or Rhizopus arrhizus lipase was entrapped in polymer gels prepared from photo-cross-linkable resin prepolymers. The immobilized enzyme was used in milk fat hydrolysis and effective in enhancing the release of short-chain fatty acids compared with free enzyme. The molar percentage of short-chain fatty acids (butyric acid to capric acid) released in the reaction increased significantly after enzyme immobilization. The gel composed of hydrophobic long-chain prepolymer gave the highest increase, with 5.9-fold and 4.5-fold increases for C. cylindracea and R. arrhizus lipase, respectively. Difference in substrate diffusion rate between milk fat triglycerides may be responsible for this behavior.     

Validation of a Single-Extraction Procedure for Sequential Analysis of Vitamin E, Cholesterol, Fatty Acids, and Total Fat in Seafood

Food lipid major components are usually analyzed by individual methodologies using diverse extractive procedures for each class. A simple and fast extractive procedure was devised for the sequential analysis of vitamin E, cholesterol, fatty acids, and total fat estimation in seafood, reducing analyses time and organic solvent consumption. Several liquid/liquid-based extractive methodologies using chlorinated and non-chlorinated organic solvents were tested. The extract obtained is used for vitamin E quantification (normal-phase HPLC with fluorescence detection), total cholesterol (normal-phase HPLC with UV detection), fatty acid profile, and total fat estimation (GC-FID), all accomplished in <40 min. The final methodology presents an adequate linearity range and sensitivity for tocopherol and cholesterol, with intra- and inter-day precisions (RSD) from 3 to 11 % for all the components. The developed methodology was applied to diverse seafood samples with positive outcomes, making it a very attractive technique for routine analyses in standard equipped laboratories in the food quality control field.