Fatty Acid Profiles and Lipid Oxidation Status of Sun Dried,Deep Fried,and Smoked Sardine (Rastrineobola argentea) from Lake Victoria,Tanzania

Freshwater fishes contain long chain omega-3 and omega-6 polyunsaturated fatty acids (PUFAs) of highest nutritional value. PUFAs in fish are susceptible to oxidative damage during processing and subsequent storage. Sardines (Rastrineobola argentea) are an important fish species of Lake Victoria, constituting 72.3% of the total landings by weight on the Tanzanian side of the lake. Fatty acid profiles and lipid oxidation status of sun-dried, deep-fried, and smoked sardines were investigated. Lipid oxidation was assessed by peroxide value, thiobarbituric acid reactive substances (TBARS), and free fatty acids. Fatty acids were analyzed by gas chromatography with flame ionization detector. The three omega-3 PUFAs: docosahexaenoic acid (C22:6n-3), docosapentaenoic acid (C22:5n-3), and eicosapentaenoic acid (C20: 5n-3) contributed 57–60, 63, and 38% of PUFAs in sun-dried, smoked, and deep-fried sardines, respectively. Lipid oxidation reactions were more pronounced in sardines dried on sand and rocks, with TBARS values 97.87 and 84.18 µmolMDA/kg, respectively. The polyene index was significantly lower (p < 0.05) in deep-fried sardines, indicating lower retention of PUFAs in the product. Lake Victoria sardines are a rich source of omega-3 PUFAs. PUFAs in sun-dried sardines are prone to oxidative damage. Smoking resulted in relatively higher retention of omega-3 fatty acids in products.     

不同规格野生黄鳍金枪鱼肌肉营养分析与评价

探究不同规格黄鳍金枪鱼(Thunnus albacares)肌肉营养成分及品质差异,实验以野捕的 3种规格黄鳍金枪鱼J1 (4.2±1.2) kg、J2 (22.5±2.5) kg和J3 (50.8±3.9) kg为研究对象,通过常规生化分析方法对金枪鱼肌肉的常规营养成分、氨基酸、脂肪酸及矿物质元素进行比较分析。结果显示,(1) J1组水分含量显著高于J2、J3组;J2、J3组粗蛋白含量显著高于J1组(P<0.05);J3组粗脂肪含量显著高于J1、J2组(P<0.05)。(2)检出19种常见氨基酸,氨基酸含量最高的为谷氨酸(3.04~ 3.25 g/100 g),必需氨基酸中含量最高的为赖氨酸(2.02~2.15 g/100 g),最低的为色氨酸(0.31~ 0.45 g/100 g)。非必需氨基酸含量J3>J2>J1 (P<0.05);必需氨基酸、呈味氨基酸含量J1组显著低于J3组(P<0.05)。依据氨基酸评分(AAS),缬氨酸为第一限制性氨基酸;以化学评分(CS)为评分标准,J1、J2组第一限制性氨基酸为色氨酸,J3组为苯丙氨酸+酪氨酸。(3)各组共检出25种脂肪酸,以多不饱和脂肪酸(PUFA)为主,含量最高的为二十二碳六烯酸(DHA),占总脂肪酸含量的37.46%~39.18%。DHA含量J3组显著高于J1、J2组;二十碳五烯酸(EPA)含量J2、J3组显著高于J1组;DHA∶EPA比值J1组显著高于J2、J3组(P<0.05)。单不饱和脂肪酸(MUFA)含量J3>J2>J1;PUFA含量J3组显著高于J1、J2组(P<0.05)。PUFA/饱和脂肪酸(SFA)、n-3系多不饱和脂肪酸/n-6系多不饱和脂肪酸(n-3/n-6)比值J2、J3组显著高于J1组(P<0.05)。h/H比值J3组显著高于J1、J2组(P<0.05)。(4) J2、J3组Na、Ca含量显著高于J1组,J1组K含量最高且显著高于J2、J3组(P<0.05)。4种重金属元素均低于食品中建议的最大允许限量,其中Fe含量最大的为J3组,且J3>J2>J1 (P<0.05);Cu含量最大的为J3组,且显著高于J1组(P<0.05)。综合分析,大规格黄鳍金枪鱼具有更好的营养质量,本研究为居民膳食的选择及黄鳍金枪鱼人工配合饲料的配制提供了科学依据。     

Fatty acid and proximate composition of bluefin tuna (Thunnus thynnus) muscle with regard to plasma lipids

The composition of tail muscle fatty acids from wild and cultured bluefin tuna reared on a diet based on herring and sardine, along with the plasma lipid profile of the farmed individuals, was determined. The total lipid content of farmed bluefin in this study was 0.922 g/100 g or 3.49 g of saturated fatty acids (SAFA), 4.48 g of monounsaturated fatty acids (MUFA), 2.58 g polyunsaturated fatty acids (PUFA) n‐3 and 0.37 g of PUFA n‐6 fatty acids; for wild specimens, it was 0.920 g/100 g, or 2.85 g of SAFA, 4.82 g of MUFA, 2.78 g PUFA n‐3 and 0.27 g of PUFA n‐6 fatty acids. The major fatty acids in this study were 16:0; 16:1, n‐7; 18:1, n‐9 and DHA 22:6, n‐3 acids. The sum of these major components accounted for more than 57% and 80% of the total fatty acids in all the samples of farmed and wild tuna respectively. No significant differences in the proximate composition were demonstrated between farmed and wild samples, except for the energy value, in favour of the farmed tuna. Statistically, glucose tends to increase together with cholesterol (CHOL) and plasma triglyceride, as for these pairs, it showed positive correlation coefficients and P>0.05. Some measured tuna metabolites demonstrated strong mutual correlations, especially GLU, CHOL and TRIG, which are crucial factors in the lipid profile of animals.     

Preservation Methods for Retaining N-3 Polyunsaturated Fatty Acids in Alaska Coho Salmon (Oncorhynchus kisutch) Products

Abstract

Coho salmon (Oncorhynchus kisutch) fillets were processed using five different methods (smoking, canning, freezing, acidifying, and salting) to evaluate the effect of preservation choice on the quality of polyunsaturated fatty acids (PUFA). Salmon preserved by smoking, canning, or freezing retained higher values of total fatty acids, including n-3 PUFAs such as eicosapentaenoic acid and docosahexaenoic acid. Salting and acidifying (pickling) treatments resulted in a significant decrease in PUFAs. The results of this study are intended to provide direction for handling and storage of salmon to retain the maximum levels of high-value n-3 PUFAs.     

Comparison of fatty acid and amino acid profiles of steamed Chinese mitten crab

The fatty acid and amino acid compositions of different grades of steamed Chinese mitten crab were analyzed. In total, 37 types of fatty acid were identified and quantified, with monounsaturated fatty acids and polyunsaturated fatty acids (PUFAs) constituting approximately 70 % of all fatty acids. Oleic acid, palmitic acid, and linoleic acid were dominant with approximately 30, 20, and 10 % of overall contents, respectively. The highest levels of fatty acids were found in special-grade animals, followed by first-grade and second-grade samples. The ratio of n-3/n-6 PUFAs ranged from 0.54 to 2.64, showing Eriocheir sinensis to be rich in n-3 PUFAs. In addition, claw and body meat were rich in amino acids and essential amino acids (EAA), while leg meat had higher content of flavor amino acids (FAA). Among almost all amino acids, the highest levels were found in Eriocheir sinensis of special grade, then first and second grade. On the whole, our results indicate that special-grade Eriocheir sinensis is highly nutritious due to its high levels of fatty acids and amino acids.     

Effect of Seasonality,Location, and Size on Lipid Content in North Pacific Troll-Caught Albacore Tuna (Thunnus alalunga)

ABSTRACT

Two hundred and thirty-nine albacore tuna (Thunnus alalunga) were troll-caught in the mid-Pacific Ocean and off the US Pacific Coast from June to November 2003. Catch location, harvest date, and sea surface temperature were recorded for individual fish, and lipid and moisture content in the white muscle were determined. The average weight of the alba-core was 6.07 kg and lipid content was highly variable (0.67–18.74%). There was an inverse correlation between the lipid and moisture content of albacore (R² = 0.93), and percent lipid increased slightly in fish caught later on in the season (R² = 0.24). Geographical Information Systems (GIS) software was used to determine correlations between lipid content and geographic location. Lipid content varied considerably among tuna caught at similar latitudes; however, most fish caught below 40°N had a lipid content of less than 10%, while the fish with the highest lipid content (13–19% lipid) were all harvested above 40°N.     

Fatty acid composition of New Zealand green-lipped mussels, Perna canaliculus: Implications for harvesting for n-3 extracts

Marine bivalves offer a potentially important source of long-chained polyunsaturated fatty acids (PUFA) for human health supplements. Lipid extracts from individual New Zealand green-lipped mussels (NZGLM) were analyzed as fatty acid methyl esters (FAME) by gas chromatography to assess geographical and seasonal differences between large (86 ± 1 mm) male and female and small (44 ± 1 mm) mussels. PUFAs dominated in spring and summer, comprising ∼ 50% of total fatty acids. Moreover, the commercially important n-3 fatty acids, 20:5n-3 (eicosapentaenoic acid, EPA) and 22:6n-3 (docosahexaenoic acid, DHA) together accounted for 70-79% of total PUFAs in spring and summer. During winter there was a marked decrease in condition and total n-3 PUFAs and a concomitant increase in saturated fatty acids in mussels, suggesting they had already spawned, had increased metabolic demands and limited PUFA-rich phytoplankton as food. While total n-3 content was not significantly different, there were geographical differences in individual n-3 fatty acids. Mussels collected from the cooler waters of Stewart Island had greater levels of 20:5n-3 (EPA), while those collected in Marlborough had greater concentrations of 22:6n-3 (DHA), which was attributed mainly to differences in phytoplankton composition. Total n-3 content and the condition index varied seasonally with greater concentrations of n-3 PUFAs, especially EPA, recorded in large mussels in spring, coincident with spring diatom blooms. Total PUFA levels and condition indices remained high in summer. There was no significant difference in condition indices, total n-3 content, DHA or EPA levels between large male and female mussels. Conversely, large mussels had significantly greater amounts of n-3 PUFAs than small mussels at Marlborough Sounds, while small mussels had marginally greater total n-3 concentrations than large mussels at Stewart Island. Taken together, these results suggest that the NZGLM offers a potentially important source of n-3 PUFAs for human health supplements. Our findings suggest that optimal harvesting conditions occur in spring when mussel condition and n-3 content peak for large mussels. Although DHA and EPA levels varied geographically, total n-3 content was not significantly different between sites, which implies that harvesting mussels for n-3 extracts would be driven more by logistical considerations.     

Proximate Composition,Cholesterol, and Fatty Acid Content of Brown Shrimp (Crangon crangon L. 1758) from Sinop Region,Black Sea

Proximate composition, cholesterol, and fatty acid content of brown shrimp (Crangon crangon L. 1758) harvested from the Sinop region of the Black Sea in Turkey was determined. Crude protein, lipid, moisture, and ash contents were 18.47 ± 0.09 g/100 g, 0.95 ± 0.05 g/100 g, 79.21 ± 0.01 g/100 g, and 1.39 ± 0.01 g/100 g, respectively. Cholesterol content was 173.56 ± 0.24 mg/100 g. Fatty acid composition was 33.04% saturated (SFAs), 22.17% monounsaturated (MUFAs), and 29% polyunsaturated (PUFAs). Among the SFAs, palmitic acid (C16:0) was predominant at 20.69% of the total fatty acid composition. Oleic acid (C18:1) was the predominant MUFA (14.25%), and the highest PUFAs were eicosapentaenoic acid (EPA, C20:5n-3) and docosahexaenoic acid (DHA, C22:6n-3), contributing 41% and 32% to the total PUFA content of the lipids, respectively. Thrombogenicity (TI) and atherogenicity (AI) index values were 0.31 and 1.34, respectively. The highest essential amino acids were leucine, lysine, valine, and isoleucine; while the highest levels of non-essential amino acids were aspartic acid, glutamic acid, glycine, and alanine, respectively.     

Fatty acid content and composition in tissues of Baikal grayling (Thymallus baicalensis), with a special focus on DHA synthesis

Long-chain polyunsaturated fatty acids of n-3 family (n-3 LC PUFAs) are physiologically essential compounds required for normal growth and development of animals, including humans. The ability of fish species to synthesize n-3 LC PUFAs varies significantly across different trophic levels. We have studied fatty acid (FA) content (mg/g of wet weight) and level (% of total FAs) in the brain, liver, heart, intestine, female and male gonads, muscle, and adipose tissues of commercially important wild freshwater Baikal grayling. Additionally, FA content and level of Baikal grayling juveniles have been studied. In all tissues of Baikal grayling, some LC PUFAs, namely, 24:5n-3 and 24:6n-3 (C24 PUFAs), have been found. These FAs are the intermediate products in the synthesis of docosahexaenoic acid (DHA, 22:6n-3) by the Sprecher pathway. The levels of C24 PUFAs in tissues differed significantly: the highest levels of C24 PUFAs were found in adipose tissue and the lowest values in the gonads of females, liver, brain, and head of juveniles. According to the dynamics of DHA and C24 PUFAs, the maximum rate of DHA synthesis is achieved in brain of Baikal grayling, while the lowest rate of DHA synthesis probably occurs in adipose tissue. Although all studied tissues had differences in the number of FAs and their levels, 16:0, 18:1n-9, 16:1n-7, 20:5n-3, and DHA dominated. Male gonads contained an extremely high level of furan FAs — presumably beneficial substances for human health. Additionally, the nutritional value of the tissues of Baikal grayling as a source of n-3 LC PUFAs for humans has been estimated.

     

Physicochemical and Microbiological Assessment of Ready-to-Eat Tuna Döner Kebab During Marination,Cooking, and Different Storage Conditions

ABSTRACT

The aim of this work was to investigate the use of bluefin tuna (Thunnus thynnus) in ready-to-eat döner kebab production and determine the effects of marination, cooking, and storage conditions (4 and ?18°C) on physicochemical and microbiological properties of döner kebab. The raw tuna meat and raw, cooked, and stored döner kebab samples were subjected to moisture, protein, fat, ash, pH, cholesterol, biogenic amines, lipid oxidation, fatty acids profile, microbiological, and sensory analysis. The major fatty acids in tuna döner kebab were palmitic, stearic, oleic, omega-3, and omega-6 fatty acids; unsaturated fatty acids were higher than saturated fatty acids (p < 0.05). Low biogenic amine and cholesterol contents were determined in döner kebab. While cooking affected the proximate composition, microbial load, and the levels of histamine and tyramine (p < 0.05), marination did not have any significant effect. The study results indicated that using tuna meat in döner kebab production could be an alternative approach to provide new seafood products without posing any acceptability problems in terms of quality factors.     

A quantitative comparison between diet and body fatty acid composition in wild northern pike (Esox lucius L.)

The fatty acid compositions of wild female northern pike (Esox lucius L.) and their principle prey species were compared to assess the extent to which pike modify the relative abundance of dietary fatty acids during assimilation and to indicate the optimum dietary content of essential fatty acids (EFAs) for pike. Only minor differences existed between the estimated whole body fatty acid composition of pike and diet fatty acid composition as calculated from the contribution of each prey species to the pike's diet. Saturated fatty acids comprised a slightly higher percentage of diet lipids (25% wt) than of pike lipids (21% wt) whereas monounsaturated fatty acids were less abundant in diet lipids (26% wt) than in pike (29% wt). Percentages of total polyunsaturated fatty acids (PUFAs), n - 3 fatty acids, and n - 6 fatty acids were approximately 43, 30, and 13% wt respectively and differed by less than 1% wt between pike and diet lipids. Among individual PUFAs, the largest differences occurred in 20:5 (n-3) and 22:6(n-3) which comprised, on average, 9.6 and 14.7% wt respectively of diet lipids and 5.9 and 18.3% wt respectively of pike lipids. The close similarity in fatty acid composition between pike and their diet suggests that pike may have limited abilities to elongate and desaturate 18 carbon PUFAs and may require specific long chain PUFAs in the diet. The n-3 PUFA content of the pike's natural diet may exceed the minimum EFA requirements of better studied species such as rainbow trout and turbot.     

北太平洋长鳍金枪鱼年龄与生长初步研究

北太平洋长鳍金枪鱼(Thunnus alalunga)是金枪鱼渔业的主要捕捞对象之一,其资源的养护和管理日益受到各方关注,鱼类年龄鉴定是渔业资源研究的重要内容之一。根据2013~2014年北太平洋长鳍金枪鱼探捕所采集的227个脊椎骨样本,用不同的染色方法分成4组进行年龄的鉴定,选用线性模型、指数模型和幂指数模型对叉长和脊椎骨半径进行拟合,最后选出结果最好的鉴定组和拟合模型,通过年龄鉴定估算长鳍金枪鱼的Von Bertalanffy生长方程。研究结果表明,北太平洋长鳍金枪鱼的叉长范围为52~104 cm,优势叉长组为81~90 cm,占总数的83.1%;年龄组成以5、6龄较多,占样本总数的80.86%。最终得到北太平洋长鳍金枪鱼生长方程为:Lt=109.180 2[1-e~(-0.258 783(t-1.991 28))],t_(tp)=2.25。     

Effects of Frying-Chilling-Reheating on the Lipid Content and Fatty Acid Composition of Cultured Sturgeon (Huso huso,Beluga) Fillets

Slices of Huso huso were fried, chilled, and then reheated to evaluate for the changes in lipid characteristics. The total lipid content of raw sample was 3.09 g/100 g which consists of 29.1 g/100 g saturated fatty acids (SFAs), 42.554 g/100 g monounsaturated fatty acids (MUFAs), and 28.126 g/100 g polyunsaturated fatty acids (PUFAs). In fried samples, levels of C18 fatty acid groups, MUFAs, PUFAs, and n6/n3 ratio increased while SFAs, EPA, and DHA content decreased. Upon chill storage, C18:2 fatty acid and n6/n3 ratio decreased while n3 fatty acids increased slightly. Free fatty acid (FFA) decreased after frying, but peroxide value (PV) increased with subsequent decrease at chilled condition.     

冬夏两季五种经济鱼类组织脂肪酸含量及组成分析

为了解不同季节不同鱼类不同组织中的不同脂肪酸含量,科学地指导鱼类膳食消费,本实验研究了冬夏两季,采集自上海市场常见的5种经济鱼类:大黄鱼(海洋肉食性),银鲳(海洋杂食性),日本鳗鲡(淡水肉食性),莫桑比克罗非鱼(淡水杂食性),草鱼(淡水草食性),分别检测鱼背部肌肉、腹部肌肉、尾部肌肉、肝脏和腹腔脂肪组织的脂肪含量和脂肪酸绝对含量。结果显示,5种鱼肌肉脂肪酸谱存在显著差异,并与各自的生活环境及食性均有关系;在鱼的腹腔脂肪或肝脏中,饱和脂肪酸(SFAs)和单不饱和脂肪酸(MUFAs)含量较高,且与组织脂肪含量密切相关;而多不饱和脂肪酸(PUFAs)、n-3系多不饱和脂肪酸(n-3 PUFAs)和n-6系多不饱和脂肪酸(n-6 PUFAs)含量较低,且与组织脂肪含量关系不大;大黄鱼和银鲳各肌肉组织中的n-3 PUFAs、二十碳五烯酸(EPA)和二十二碳六烯酸(DHA)含量以及n-3/n-6值高于莫桑比克罗非鱼和草鱼,并与组织脂肪含量呈正相关;冬季草鱼腹部肌肉、莫桑比克罗非鱼尾部肌肉以及日本鳗鲡和银鲳的肝脏中的n-3 PUFAs含量较夏季高。研究表明,脂肪酸组成与物种、食性、水域环境以及季节温度和组织部位均有关系。从补充n-3 PUFAs摄入的角度分析,日本鳗鲡、大黄鱼和银鲳营养价值高于莫桑比克罗非鱼和草鱼,冬季鱼类的营养价值高于夏季。     

Effects of Chilled Storage,Freezing Rates,and Frozen Storage Temperature on Lipid Oxidation in Meat Blocks from Cultured Bluefin Tuna Thunnus thynnus

ABSTRACT

The effects of a short chilled storage period before freezing, frozen storage temperature, and freezing rate on lipid oxidation of bluefin tuna (Thunnus thynnus) meat during frozen storage were investigated. After 12-months storage, all samples had increased in peroxide value though they were less at the lower temperatures (?45 and ?60°C). Peroxide values in all samples stored at ?20°C increased after 3 months storage, particularly those processed and stored 51 h after harvest. The lowest increase in peroxide value occurred in the samples frozen rapidly 3 h after harvest. Vitamin E levels decreased faster during frozen storage at ?20°C. There were no apparent differences in levels of triacylglycerides nor in n-3 fatty acid levels between treatments, storage periods, and storage temperatures. After 12-months storage, headspace oxidative volatiles were highest in samples stored at ?20°C and lowest in those stored at ?60°C. Lipid oxidation in tuna meat stored at ?45°C is similar to that at ?60°C, and rapid freezing rather than slow freezing should be used.     

Proximate Composition and Nutritional Profile of the Black Sea Anchovy (Engraulis encrasicholus) Whole Fish,Fillets, and By-Products

ABSTRACT

In this study, the proximate composition and nutritional profile of the Black Sea anchovy and its by-products were investigated. The total yield of by-products from anchovy was about 32% of the whole fish based on wet weight. The protein and fat contents of anchovy by-products were 13.39 and 10.02% for head, 16.47 and 15.50% for frame, and 12.05 and 23.90% for viscera, respectively. Significant differences were detected among the pH and color properties of anchovy whole fish, fillet, and by-products. Profiles of amino acids, fatty acids, and minerals of anchovy by-products showed they are rich sources of lysine (6–7% of total amino acids), leucine (5–6% of total amino acids), and a number of essential amino acid, polyunsaturated fatty acids (about 32–40% of total fatty acids), n-3 fatty acids (about 27–34% of total fatty acids), eicosapentaenoic acid + docosahexaenoic acid (about 26–32% of total fatty acids), and various minerals (P, Fe, Ni, Ca, Mn, Na, and Zn). These results revealed that anchovy by-products can be utilized for the production of value-added products such as protein powder, protein hydrolyzates, fish oils, and mineral supplements.     

磷对生长期草鱼肌肉理化参数、游离氨基酸、呈味核苷酸和游离脂肪酸组成的影响

[目的]本实验探索了磷对生长期草鱼肌肉常规营养组成和理化特性,肌肉中游离氨基酸、呈味核苷酸和游离脂肪酸组成的影响。[方法]实验选择初始体重为（256.22 ± 0.60 g）的健康草鱼540尾,随机分为6组,每组3个重复,分别饲喂含有效磷0.95（基础饲料组,未添加）、2.46、3.96、5.68、7.10和8.75 g/kg的饲料60天。[结果]结果显示,饲料中适宜水平的磷显著提高了生长期草鱼肌肉蛋白质、水分、羟脯氨酸、∑氨基酸、∑鲜味氨基酸（UAAs）、∑甜味氨基酸（SAAs）、肌苷酸（IMP）、∑不饱和脂肪酸、∑多不饱和脂肪酸（PUFA）含量以及pH0和pH12,而肌肉剪切力、组织蛋白酶B和L活力、乳酸、饱和脂肪酸（SFA）含量显著降低（P < 0.05）。适宜水平的磷还显著提高了PUFA/UFA及n-3 PUFAs/n-6 PUFAs比值,IMP和∑呈味氨基酸（UAAs+SAAs） 的滋味活性值（TAV）均大于1。[结论]结果表明,适宜水平有效磷提高了生长期草鱼（254.56-898.23 g）肌肉蛋白质含量、肌肉嫩度、系水力和pH值,增加肌肉风味氨基酸、核苷酸和脂肪酸含量,进而提高鱼类肌肉品质。     

Standardizing catch and effort data of the Taiwanese distant-water longline fishery in the western and central Pacific Ocean for bigeye tuna, Thunnus obesus

Catch per unit effort (CPUE) is often used as an index of relative abundance in fisheries stock assessments. However, the trends in nominal CPUE can be influenced by many factors in addition to stock abundance, including the choice of fishing location and target species, and environmental conditions. Consequently, catch and effort data are usually ‘standardized’ to remove the impact of such factors. Standardized CPUE for bigeye tuna, Thunnus obesus, caught by the Taiwanese distant-water longline fishery in the western and central Pacific Ocean (WCPO) for 1964–2004 were derived using three alternative approaches (GLM, GAM and the delta approach), and sensitivity was explored to whether catch-rates of yellowfin tuna and albacore tuna are included in the analyses. Year, latitude, and the catch-rate of yellowfin explained the most of the deviance (32–49%, depending on model configuration) and were identified consistently among methods, while trends in standardized catch-rate differed spatially. However, the trends in standardized catch-rates by area were found to be relatively insensitive to the approach used for standardization, including whether the catch-rates of yellowfin and albacore were included in the analyses.     

Enrichment of C20-22 Polyunsaturated Fatty Acids from Refined Liver Oil of Leafscale Gulper Shark,Centrophorus squamosus

The C_20-22 polyunsaturated fatty acids (C_20-22 PUFAs), mainly eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3), were concentrated from the refined liver oil of deep sea leafscale gulper shark, Centrophorus squamosus, by sequential processes of winterization, urea complexation, and argentation chromatography. Winterization at 4°C using acetonitrile as solvent showed significant reduction of the total saturated fatty acid content (12%) with a concomitant increase of polyunsaturated fatty acids (36.3%). The urea complexation process significantly enriched the total polyunsaturated fatty acids (49.5%), with a reduction in saturated fatty acids (83.9%). Silica gel based argentation chromatography further concentrated the esters of C_20-22 PUFA (>99 percent purity). Nuclear Magnetic Resonance spectroscopy was used as a chemical fingerprinting tool to study the enrichment of C_20-22 PUFAs at various stages of the purification process. An increase in the proton signal intensity at the olefinic region (at δ 4–6) and a decrease in the aliphatic signals (at δ 0.5–2) showed that the process successfully enriched the C_20-22 PUFAs.

Abbreviations: PUFA, polyunsaturated fatty acid; EPA, eicosapentaenoic acid; DHA, docosahexaenoic acid; FAME, fatty acid methyl esters; SFA, saturated fatty acid; MUFA, monounsaturated fatty acid; NMR, nuclear magnetic resonance; GCMS, gas chromatography mass spectrometry; FFA, free fatty acid.     

世界主要金枪鱼捕捞产量分析

根据FA0 1950 ～ 2011年世界主要金枪鱼类渔业生产数据统计,将长鳍金枪鱼、黄鳍金枪鱼、大眼金枪鱼和鲣鱼等8种世界主要金枪鱼类每10年的产量总和按不同鱼种和海域进行了总结.结果显示,鲣鱼的累计总产量最高,其平均年产量涨幅最快;除马苏金枪鱼年平均产量有所下降,北方蓝鳍金枪鱼保持稳定外,其他主要金枪鱼类均有增长,但平均增长率最高的是青干金枪鱼.各主要渔区中以中西太平洋海域累计总产量最高,平均年产量有上升趋势,大西洋海域以中东大西洋为产量最高,印度洋海域以西印度洋为产量最高,平均增长率以印度洋海域为最高,其他海域相对持平.我国（包括台湾省）捕获累计总产量最高的是鲣鱼,为418×104 t,占世界总产量比例最高的是长鳍金枪鱼,为22.9％.我国（包括台湾省）主要金枪鱼类捕获总产量占世界总产量比例最高为东南大西洋海域,最低为东南太平洋海域.论文结合世界主要金枪鱼类以及主要捕捞海域的开发现状和我国国情,提出我国目前面临的几点困难以及发展壮大我国金枪鱼渔业的建议.