Evaluating nutritional quality of pacific fish species from fatty acid signatures

Eight fish species common to the Pacific Northwest coastal waters were categorised according to total lipids in a ranking from lean fish (e.g. walleye pollock) to oily fish (e.g. herring) species. Comprehensive fatty acid signatures were compared on both the relative proportion of total fatty acids and the proportion of total carcass lipid content. Generally, fish species from the Pacific coast had a relatively high proportion of n-3 highly polyunsaturated fatty acids (n-3 HUFAs), of which more than 80% was accounted for by C20:5n-3 (EPA) and C22:6n-3 (DHA), with species-specific and lower proportions of oleic acid (C18:1n-9) and palmitic acid (C16:0) also dominating. The MUFA contents of fish were lower (P < 0.05) in the lipids of lean and low-fat fish compared to those of fattier species. In contrast, higher (P < 0.05) proportions of polyunsaturated fatty acids (PUFAs) existed in the low-fat species with DHA contents ranging from 18% to 29% in the low-fat fish and from 8% to 10% in the fattier fish, such as herring and capelin. Expressing the same fatty acid content data in terms of absolute amount of fatty acids (e.g. gFA/100 g wet tissue) showed that both EPA and DHA contents in the flesh of pollock and hake were indeed many fold lower than those found in fatty fish, such as herring. The findings confirm that it is important that both the total lipid content and the fatty acid composition of these Pacific fish food sources be considered when making evaluations on the nutritional quality.     

Fatty acid profiles of commercially important fish species from the Mediterranean, Aegean and Black Seas

The fat content and fatty acid compositions in the flesh of eight commercially important fish species from the seas of Turkey were evaluated. The fatty acid compositions of wild fish species ranged from 25.5% to 38.7% saturated (SFA), 13.2–27.0% monounsaturated (MUFAs) and 24.8–46.4% polyunsaturated acids (PUFAs). Among them, those occurring in the highest proportions were myristic acid (C14:0, 1.70–10.9%), palmitic acid (C16:0, 15.5–20.5%), palmitoleic acid (C16:1, 2.86–17.0%), stearic acid (C18:0, 3.32–8.18%), oleic acid (C18:1n9 cis, 6.11–20.8%), linoleic acid (C18:2n6, 0.93–4.03%), octadecatetraenoic acid (C18:4n3, 0.02–4.55%), cis-5, 8, 11, 14, 17-eicosapentaenoic acid (EPA, C20:5n3, 4.74–11.7%) and cis-4, 7, 10, 13, 16, 19-docosahexaenoic acid (DHA, C22:6n3, 7.69–36.2%). The proportions of PUFAs-n3 (ranging from 21.7 for mullet to 43.7 for scad) were higher than those of PUFAs-n6 (ranging from 1.24 for bogue to 4.34 for red scorpion fish). EPA and DHA were high in all fish species, increasing the value of these fish species.     

Fatty acid composition and cholesterol content of selected marine fish in Malaysian waters

A consumer survey identified 10 species of most-preferred marine fish for daily consumption in Malaysia. Total lipids extracted from 10 species of the selected fish were analyzed for their total fat, fatty acids composition and cholesterol content. Most of the fish contained less than 6% lipid by weight and total cholesterol content was 37.1–49.1 mg/100g. The composition of fatty acids showed that total ω-3 poly unsaturated fatty acids (ω-3 PUFA; 29.7–48.4%) were the highest, followed by other PUFA (27.7–40.0), ω-6 PUFA (11.0–20.0%), saturated fatty acid (3.63–11.4%), and finally, mono unsaturated fatty acid (MUFA; 1.37–9.12%). All samples showed a much higher content of ω-3 PUFA when compared to standard menhaden oil. Most of the fish had a higher ω-3/ω-6 ratio (2.16 –4.14) than the standard menhaden oil (2.03) except for Four Finger Threadfin (1.50), Indian Mackerel (1.67) and Striped Sea Catfish (1.78). The ratio of PUFA/saturated of the samples ranged from 5.49 to 25.2.     

Fatty acid profiles and fat contents of commercially important seawater and freshwater fish species of Turkey: A comparative study

The fat content and fatty acid compositions of edible muscle of commercially important seawater and freshwater fish species were investigated. The fatty acid compositions of seawater fish species were found to be 25.5–39.4% saturated (SFA), 13.2–29.0% monounsaturated (MUFAs) and 25.2–48.2% polyunsaturated acids (PUFAs), whereas the fatty acid compositions of freshwater fish from Lake Seyhan consisted of 28.0–34.6% saturated (SFA), 10.7–22.7% monounsaturated (MUFAs) and 23.2–43.7% polyunsaturated acids (PUFAs). The proportions of n3 PUFAs of seawater fish (ranging from 22.6 for waker to 44.2% for blue fish) were higher than those of n3 PUFAs of freshwater fish (ranging from 11.5% for North African catfish to 28.4% for zander). However, the levels of n6 PUFAs of seawater fish (ranging from 0.43% for blue fish to 14.4% for sea bass) were lower than those of n6 PUFAs of freshwater fish (ranging from 5.27% for kutum to 16.8% for tench). The results showed that fatty acid profiles of most freshwater fish are basically comparable to those of seawater fish as sources of PUFAs.     

鱼粉加工副产物中鱼油的精炼及其脂肪酸组成分析

对鱼粉加工副产物中鱼油的精制进行研究,得到鱼粉加工副产物中鱼油精炼的最佳工艺：添加1%磷酸（体积分数60%）脱胶,3% NaOH（质量分数12%）溶液脱酸以及15%活性炭脱色,在85 ℃条件下减压蒸馏脱臭10 min。在精炼过程中,鱼油中饱和脂肪酸含量下降,其他脂肪酸含量变化较小。所制备鱼油的理化指标均达到精制鱼油一级要求,其中多不饱和脂肪酸总含量达到0.69 g/mL,二十二碳六烯酸和二十碳五烯酸含量分别为0.229 g/mL和0.121 g/mL。     

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。     

磷浓度对粉核油球藻Pinguiococcus pyrenoidosus CCMP2078生长和脂肪酸组成的影响

以粉核油球藻(Pinguiococcus pyrenoidosus CCMP2078)为实验材料,探讨了不同磷浓度对其生长、脂肪酸组成、EPA和PUFAs含量的影响。结果表明:在18~144μmol/L磷浓度范围内,P.pyrenoidosus CCMP2078的生长较好,当磷浓度为144μmol/L时,藻生长最快,细胞干重为0.11g/L;磷浓度为3.6μmol/L时,藻的生长受到明显抑制,细胞干重仅为磷浓度为36μmol/L时的一半,此时藻体的EPA和PUFAs含量均达最低值。在18~144μmol/L的磷浓度范围内,EPA和PUFAs含量随着磷浓度的升高呈下降趋势,当磷浓度为18μmol/L时,EPA和PUFAs含量均最高,分别占总脂肪酸的18.4%和33.57%。     

Manipulation of fatty acid composition of Nile tilapia (Oreochromis niloticus) fillets with flaxseed oil

Nile tilapia (Oreochromis niloticus) is one of the most consumed species among freshwater fish reared in Brazil. However, studies show low levels of n‐3 fatty acids in freshwater fish reared in captivity in comparison with those reared in their natural habitats. The Nile tilapia used in this study were raised in captivity for a period of 5 months and fed varying amounts (0, 1.25, 2.5, 3.75 and 5%) of flaxseed oil as a substitute for sunflower oil (control). No significant differences (P > 0.05) in total lipid (TL) content were found between fillets of tilapia fed the different diets. TL analysis of fatty acid methyl esters by capillary gas chromatography revealed a total of 50 components common to all treatments studied. The major fatty acids present were linoleic acid (18:2n‐6), oleic acid (18:1n‐9) and palmitic acid (16:0). All treatments led to significant % increases in α‐linolenic acid (18:3n‐3), eicosapentaenoic acid (20:5n‐3) and docosahexaenoic acid (22:6n‐3). Increases in both total n‐3 fatty acids and total polyunsaturated fatty acids were observed concomitantly with decreases in total n‐6 fatty acids, resulting in increases in n‐3/n‐6 ratio, with increasing level of flaxseed oil in the feed. Thus feed supplementation with flaxseed oil contributed greatly to raising the nutritional lipid value of Nile tilapia fillets. Copyright © 2007 Society of Chemical Industry     

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.]     

Fatty acid composition and volatile compounds of selected marine oils and meals

BACKGROUND: Although volatile compounds characterising seafood have been studied extensively, no similar data are available regarding the volatiles of raw materials used in fish feed. Therefore the aim of this study was to make an initial screening of the volatiles of various common marine raw materials used in the aquaculture feed industry. Nine commercial marine oils (German (GFO1, GFO2 and GFO3) and Norwegian (NFO) fish oils and salmon (SO1 and SO2), tuna (TO), sardine (SRDO) and shrimp (SHO) oils) and eight commercial marine meals (Peruvian (PFM1 and PFM2), Danish (DFM1 and DFM2) and prime quality (PQFM1 and PQFM2) fish meals and Antarctic krill meals (KM1 and KM2)) were analysed for their fatty acid profiles and volatile flavour compounds. The relation between fatty acids and volatiles was examined. RESULTS: The highest polyunsaturated fatty acid and eicosapentaenoic acid (20:5ω3) contents and ω3/ω6 ratio were found in NFO. The fatty acid composition of all marine meals except krill meals was found to be more variable among batches than that of marine oils. Regarding volatiles, all marine raw materials were characterised by the complete absence or negligible levels of eight‐ and nine‐carbon alcohols and carbonyls. All marine oils were found to have high 2‐ethyl furan, 2‐methylenebutyl cyclopropane, hexanal, 2,4‐octadiene and 3,5‐octadiene contents. Marine meals, unlike marine oils, were characterised by the almost complete absence of unsaturated and cyclic hydrocarbons and terpenes and very low levels of furans. CONCLUSION: Volatiles of marine meals differ from those of marine oils. Unlike fatty acids which give useful traceability information, volatiles seem to fail in this role owing to their strong variability. Copyright © 2008 Society of Chemical Industry     

Fatty acid composition of total lipids,neutral lipids and phospholipids in wild and farmed matrinxã (Brycon cephalus) in the Brazilian Amazon area

BACKGROUND: The chemical composition of Amazonian fish is extremely variable, being influenced by the season and the type and amount of food. A special interest in the fish oil composition has been developed owing to the presence of essential fatty acids, since this is directly related to human health. This study aimed to investigate the fatty acid composition (FAC) of the total lipid (TL), neutral lipid (NL) and phospholipid (PL) fractions of the dorsal muscle and orbital cavity of farmed and wild matrinxã in the Amazon area captured in different seasons. RESULTS: Fatty acids (FA) were analysed by high‐resolution gas chromatography/mass spectrometry. Sixty‐five FA were detected in the TL, 66 in the NL and 55 in the PL. The main FA found in farmed and wild fish were oleic, palmitic, stearic and linoleic acids. No distinctions in the quality or quantity of these fractions between dorsal muscle and orbital cavity were found. CONCLUSION: The season had a significant influence on the TL and FAC. Fish captured during the dry season showed lower levels of lipid and a higher percentage of long‐chain polyunsaturated fatty acids. Matrinxã farmed in a semi‐intensive system showed a nutritional quality comparable to that of wild matrinxã captured in the wet season. Copyright © 2007 Society of Chemical Industry     

Fatty acid and triacylglycerol composition and thermal behaviour of fats from seeds of Brazilian Amazonian Theobroma species

Raw materials for cocoa butter substitutes, replacements or equivalents depend mostly on the unsteady supply from wild stands of plants, while there is no current supply of Neotropical origin. Seed fats from Theobroma species (T cacao, T bicolor, T grandiflorum, T obovatum, T subincanum, T speciosum, T sylvestre and T microcarpum, plus the closely related species Herrania mariae) were analysed for fatty acid and triacylglycerol composition by gas and liquid chromatography respectively, for iodine value, for melting point by open capillary tube and for solid fat content (SFC) by nuclear magnetic resonance. All Theobroma species had significantly lower palmitate levels than T cacao, except for T sylvestre and T speciosum, T microcarpum presented highly unsaturated fat (C18:2), while H mariae had high levels of arachidate. Fats from T sylvestre and T speciosum had a similar iodine value to T cacao and a higher melting point. No fat from the other species presented a similar melting profile to cocoa butter. T sylvestre and T bicolor were the most similar to T cacao but had a higher SFC at human body temperature. T sylvestre and T speciosum seed fats had more POP than cocoa butter. Fats from seeds of T speciosum, T sylvestre and T bicolor could be recommended as cocoa butter substitutes, while fats from species of the section Glossopetalum could be employed in products requiring fats with a lower melting point. © 2002 Society of Chemical Industry     

Fatty acid composition of herring (Clupea harengus L.): influence of time and place of catch on n‐3 PUFA content

The fatty acid composition (FAC) was determined in muscle samples from 963 herring (Clupea harengus L.) caught during 2001–2003 in waters around Denmark. The overall variation in FAC was mainly related to seasonal (summer or winter) and annual (2001, 2002 or 2003) variation. No clear variation due to place of catch (Baltic Sea, Skagerrak, Kattegat or the northern, western or eastern part of the North Sea) was found. Of the nutritionally important n‐3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), EPA seemed to show a seasonal variation, with the highest amount during summer, whereas no periodic variation was observed for DHA. Herring from one catch, however, were found to have an extraordinarily high amount of EPA (11%) compared with all other catches (amounts of EPA ranging from 4 to 8%). This high EPA content found only in herring caught in May 2003 in the northern North Sea (NSN) was in large contrast to the herring caught in the same place 3 months earlier, which had the lowest EPA content overall. The abrupt increase in EPA level from February to May was not correlated with biological parameters such as spawning type, maturity status, age, sex and size, but it might be related to variation in the FAC of the calanoid copepods on which the herring feed. Considering the nutritional aspects, the high‐EPA herring from the NSN catch in May 2003 had a relatively low lipid content (7%), making them highly suitable for human consumption. Copyright © 2007 Society of Chemical Industry     

6种常见食用蜻蜓稚虫含油率与脂肪酸组成分析

为评价6种云南和贵州地区常见食用蜻蜓稚虫油脂的营养价值,采用索氏提取法和GC-MS分析和比较了闪蓝丽大蜻、碧伟蜓、小团扇春蜓、黄蜻、大团扇春蜓、赤褐灰蜻6种蜻蜓稚虫的含油率和油脂脂肪酸组成。结果表明:6种蜻蜓稚虫含油率为5.72%~11.90%,其中大团扇春蜓的含油率最高,赤褐灰蜻的最低。6种蜻蜓稚虫油脂分别鉴定出18~29种脂肪酸,其中包括奇数碳脂肪酸、二十碳五烯酸(EPA)和二十二碳六烯酸(DHA)等具有特殊功能的脂肪酸;不饱和脂肪酸(UFA)占脂肪酸总量的61.50%~65.22%,多不饱和脂肪酸(PUFA)占UFA总量的29.57%~50.00%,棕榈酸相对含量最高,为17.57%~24.61%;n-6 PUFA与n-3 PUFA比值为0.68~1.30,接近淡水鱼类,黄蜻和赤褐灰蜻的饱和脂肪酸(SFA)、单不饱和脂肪酸(MUFA)和PUFA的含量之比分别为1.17∶1.2∶1和1.3∶1.18∶1,接近北大西洋公约组织和美国心脏协会推荐的人体摄入比(1∶1.5∶1和(0.8~1)∶1.5∶1)。     

海洋鱼油的生产与应用

全面回顾了国内外海洋鱼油生产与应用的历史与现状,指出海洋鱼油作为二十碳五烯酸(EPA)、二十二碳六烯酸(DHA)等ω-3多不饱和脂肪酸的重要来源,正在饲料、食品以及药品等领域展示其良好的应用前景.     

深海粗鱼油的精炼工艺研究

对深海杂鱼粗鱼油精炼工艺进行优化,考察了磷酸体积分数、超量碱和活性白土添加量对鱼油酸值、回收率和感官品质的影响,并对精炼鱼油的理化指标及脂肪酸组成进行分析。结果表明:适宜的精炼条件为采用占鱼油质量1%、体积分数80%的磷酸脱胶,脱胶油中加入占鱼油质量1.5%的超量碱和理论碱量的Na OH(4 mol/L)脱酸,脱色选用添加占鱼油质量20%的活性白土;精炼鱼油的理化指标均达到我国水产行业精制鱼油的一级标准(SC/T 3502—2000),酸值(KOH)由(5.52±0.12)mg/g下降到(0.29±0.11)mg/g;精炼工艺对鱼油脂肪酸组成的影响较小,其中二十碳五烯酸和二十二碳六烯酸的总量约占总脂肪酸含量的38%,且分别占多不饱和脂肪酸含量的35.99%和51.59%,品质较优。     

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。     

Phospholipids of marine origin. The lantern fish (Lampanyctodes hectoris)

Lantern fish of the species Lampanyctodes hectoris were shown to contain phospholipids (10 g kg^?1) and non-phosphorylated lipids (140 g kg^?1). The phospholipid fraction consisted of phosphatidyl choline (47% of total phospholipids), phosphatidyl ethanolamine (42%), phosphatidyl serine (3%), phosphatidyl inositol (1%), sphingomyelin (4%), lyso-phosphatidyl choline (1%) and cardiolipins (2%). Lantern fish (L hectoris) meals normally contain unacceptably high lipid contents (150 g kg^?1 and over); this characteristic was found not to be due to a high phospholipid level in the lantern fish. The major fatty acid of the phospholipids was C22:6n-3 (25% total fatty acids) followed by C16:0 (18%), C18:ln-9 (16%) and C20:5n-3 (8%). This distribution was different from that of the non-phosphorylated lipids where the major fatty acid was C16:0 (21%) followed by C18:ln-9 (19%), C20:5n-3 (11%), C20:l (7%) and C22:6n-3 (7%). The lantern fish press oil and residual meal lipids had fatty acid distributions similar to those of the non-phosphorylated lipids.