A comparison of selected methods for determining eicosapentaenoic acid and docosahexaenoic acid in cereal-based foods

The accuracy of four transesterification methods and four extraction methods for determining the eicosapentaenoic acid and docosahexaenoic acid contents of cereal-based foods enriched with fish oil containing these fatty acids was investigated. The four enriched test foods were a flaked breakfast cereal, a snack bar, bread and muffins. The accuracy of the transesterification methods was tested using several commercial fish oils. The recovery of eicosapentaenoic acid and docosahexaenoic acid in the fish oils ranged from 97% to 104% depending on the transesterification method used. For the extraction methods, the recovery of eicosapentaenoic acid and docosahexaenoic acid across all food products ranged from 59% to 101% and 74% to 98% respectively depending on the extraction method used. Overall, the solvent mixture direct method was the most accurate extraction method across all the foods. However, the application of different extraction methods for different food types may be optimal when accurate analysis of eicosapentaenoic acid and docosahexaenoic acid in foods is required.     

Design and implementation of a continuous microwave heating system for ballast water treatment

A continuous microwave system to treat ballast water inoculated with different invasive species was designed and installed atthe Louisiana State University Agricultural Center. The effectiveness of the system to deliver the required heating loads to inactivate the organisms present was studied. The targeted organisms were microalgae (Nannochloropsis oculata), zooplankton at two different growth stages (newly hatched brine shrimp-Artemia nauplii and adult Artemia), and oyster larvae (Crassosstrea virginica). The system was tested at two different flow rates (1 and 2 liters per min) and power levels (2.5 and 4.5 kW). Temperature profiles indicate that, depending on the species present and the growth stage, the maximum temperature increase will vary from 11.8 to 64.9 degrees C. The continuous microwave heating system delivered uniform and near-instantaneous heating at the outlet proving its effectiveness. The power absorbed and power efficiency varied for the species present. More than 80% power utilization efficiency was obtained at all flow rate and microwave power combinations for microalgae, Artemia nauplii and adults. Test results indicated that microwave treatment can be an effective tool for ballast water treatment, and current high treatment costs notwithstanding, this technique can be added as supplemental technology to the palette of existing treatment methods.     

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.     

微藻营养价值及其在水产生物营养强化中的应用

微藻营养丰富,易于大规模培养,生产成本低,投喂方便,而且能够净化调节养殖水体,作为鱼、虾、蟹、贝类等水产生物的饵料,具有无可替代的作用。本文就微藻中蛋白质、碳水化合物、脂类、色素、维生素和矿物质等主要营养成分的研究进展,以及微藻作为生物饵料在水产生物营养强化中的应用进行综述,以期为水产生物营养学研究与生物饵料的应用提供参考。      

8种海洋微藻中EPA和DHA含量的测定

鉴于鱼油资源的不足，为寻找EPA和DHA的替代资源．进行了利用海洋微藻生产EPA和DHA的研究。对几种海洋微藻进行培养，时数期末期收获，提取脂肪酸后利用气相色谱法测定，结果表明：海洋微藻可以作为EPA和DHA的生物替代资源。     

尿素包合法富集鱼油中的EPA和DHA的研究

用尿素包合法（脲包法）对大连鱼油中的ＥＰＡ和ＤＨＡ进行富集，得到较佳操作条件为温度０℃，脲酯比１３，鱼油甲酯为脲包客体，以甲醇作溶剂。一次富集产品中（ＥＰＡ＋ＤＨＡ）浓度和收率分别达到６０％和９０％以上     

Comparison of Polyunsaturated Fatty Acids Content in Filets of Anadromous and Landlocked Sockeye Salmon Oncorhynchus Nerka

Abstract: Fatty acid composition and content of 2 forms of sockeye salmon Oncorhynchus nerka from lakes in Kamchatka Peninsula (Russia) were compared. One form of sockeye salmon was anadromous (“marine”), that is, adult fish migrated in ocean to feed and grow and than return in the lake to breed. Fish of another form, kokanee, never migrate in the ocean. Per cent levels of the main indicators of nutritive value, eicosapentaenoic acid (EPA, 20:5n‐3), and docosahexaenoic acid (DHA, 22:6n‐3), were significantly higher in the landlocked O. nerka. However, concentrations of EPA and DHA per wet weight of filets were higher in the marine form, because of the relatively higher content of sum of fatty acids in their muscle tissue. As concluded, fish fed in marine environment had higher contents of long‐chain n‐3 fatty acids per wet weight than fish of the same species, fed in fresh waters. In general, both the anadromous sockeye salmon and the landlocked kokanee salmon can be recommended for human diet as a valuable product concerning contents of EPA and DHA. Practical Application: The long‐chain polyunsaturated acids (PUFA) have been specifically recommended for humans to prevent cardiovascular disease and psychiatric disorders. Fish are known to be the main source of PUFA in human diet. Data on PUFA content in diverse food fish is essential to compare the benefits they offer for consumers’ health. We compared PUFA contents in 2 forms of popular food fish Oncorhynchus nerka, migrating sockeye salmon and landlocked kokanee salmon, and found that both forms are valuable product concerning PUFA content.     

Anisakis simplex larva killed by high-hydrostatic-pressure processing

Anisakis simplex is a common nematode parasite present in many marine fish, including finfish and squid. It can pose a public health problem if it is not destroyed during food processing. Anisakis larvae were isolated from fish tissue, and their survival of high-pressure treatments in distilled water and physiological isotonic solution was assayed. Treatment at a pressure of 200 MPa for 10 min at a temperature between 0 and 15 degrees C kills all Anisakis larvae, with a lack of motility being used as an indicator of larval death. Lower pressures can be successfully employed down to 140 MPa, but with lower pressures, the treatment time must be increased by up to I h to kill all larvae. Meanwhile, most larvae treated for >10 min at pressures of >120 MPa were dead, with the autofluorescence method being used to determine death. Cycles of compression and decompression increase the destruction of larvae compared with a single pressure treatment for a similar treatment time. Our results indicate that high-pressure treatment is an alternative nonthermal method for killing this nematode. The possible mechanism of death and damage by pressure is discussed, and uses for this treatment in food processing are suggested.     

Evaluation of the potential use of discard species for fish silage and assessment of its oils for human consumption

Waste or by-products contains a substantial amount of nutrients. Fish silage is an alternative way for assessment of fish discards and waste generated in the fish processing industries. The aim of the study was to evaluate the potential use of discard species (Equulites klunzingeri, marine fish and Carassius gibelio, freshwater fish) for fish silage and chemical quality of fish oil extracted from fish silages prepared with acid and fermented methods. Lipid quality of fish oils extracted from fish silages with LAB strains was evaluated in terms of thiobarbituric acid (TBA), peroxide value (PV), p-Anisidine (AV), totox values and fatty acid composition. The results showed that PV, TBA, AV and totox values of all extracted fish oils were within the acceptable limits for edible oils. Recovered fish oils from silage contained high level of polyunsaturated fatty acids (PUFAs), especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), serving as a source of good quality fish oil for human consumption.     

Functional biscuits with PUFA‐ω3 from Isochrysis galbana

BACKGROUND: Sweet biscuits, a traditional and nutritious food, can be healthy and very attractive when redesigned to be prepared with the addition of a natural product, the microalgal biomass of Isochrysis galbana. This marine microalga is recognised as a rich source of polyunsaturated fatty acids (PUFAs), mainly eicosapentaenoic acid (EPA; 20:5ω3), and is a promising ingredient in the food and feed industries. The importance of PUFA‐ω3 (an alternative to fish oils) in food, and the need to increase the daily intake of these substances to promote a healthier lifestyle is now well known. RESULTS: Traditional butter biscuits were enriched with I. galbana biomass (1% and 3%) and evaluated in terms of colour, texture and fatty acid profile, within 3 months of storage. I. galbana biscuits presented total levels of 100 mg 100 g^?1 and 320 mg 100 g^?1 of PUFA‐ω3 (EPA + DPA (docosapentaenoic acid; 22:5ω3) + DHA (docosahexaenoic acid; 22:6ω3) for 1% and 3% I. galbana, respectively. CONCLUSION: The enhancement of texture properties, the high stability of colour and texture and the good profile of polyunsaturated fatty acids, with emphasis on EPA and DHA, of the biscuits obtained, reveal a new food market niche opportunity. Copyright © 2008 Society of Chemical Industry     

海水鱼内脏高值化利用的研究现状与发展趋势

近年来,我国海水鱼类捕捞与养殖产业发展快速,海水鱼类加工过程产生的大量副产物,只有小部分作为饲料,大部分被废弃造成环境污染。而海水鱼内脏含有丰富的生物活性肽、酶以及脂质等可以被有效利用的成分,有必要对其进行开发利用。本文综述了近年来国内外学者对海水鱼内脏在生物活性肽如抗氧化肽、抗疲劳肽、抗高血压肽,内脏酶如蛋白酶、超氧化物歧化酶、胆碱酯酶、酸（碱）性磷酸酶,脂质中磷脂、脂肪酸、不皂化的脂质提取工艺与运用方面的研究进展,并对海水鱼内脏今后的高值化开发利用提出建议,以期为海水鱼内脏的高值化利用,促进海水鱼产业的零废弃高值高质加工提供参考。     

PUFAs in Fish: Extraction,Fractionation, Importance in Health

ABSTRACT: Polyunsaturated fatty acids (PUFAs), especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are currently in demand in the pure form and actively being studied to understand their potential roles in human health. Arachidonic acid, 20:4 (n‐6), and DHA, 22:6 (n‐3), are important in normal neurodevelopment and visual function. Infants fed formula often have low blood lipid 20:4 (n‐6) and 22:6 (n‐3). Consumption of fish oils may increase the 20:5 (n‐3) (EPA) and 22:6 (n‐3) (DHA) in human blood. Some marine fish oils contain higher amounts of arachidonic acid, EPA, and DHA. PUFA contents in different marine fishes and methods for their extraction and fractionation, in terms of fatty acid constituents in the form of methyl esters, are covered in this review. Emphasis is given to the fractionations of EPA and DHA by means of supercritical fluid extractions (SFE). The advantages of SFE compared to conventional methods are discussed in this review. PUFAs are usually extracted at about 10 to 30 MPa and at 40 to 80 °C. SFE is a promising and currently the best technique to extract PUFAs, especially EPA and DHA, from marine and freshwater fish.     

BIOCHEMICAL COMPOSITION OF LARGE YELLOW CROAKER (PSEUDOSCIAENA CROCEA) CULTURED IN CHINA

The biochemical composition of dorsal muscle from large yellow croaker ( Pseudosciaena crocea ) cultured in China was studied. The comparison was made between the fish fed raw fish (RF) and commercial feed (CF). Two-year-old fish cultured in floating net cages were sampled for analysis. Moisture, protein, lipid and ash contents were determined. Amino acid composition was determined by an automatic amino acid analyzer. Fatty acid profile was determined by gas chromatography. The analysis results showed that fish in the CF group had lower levels of crude fat content and essential amino acids content ( P <  0.05). The percentages of total saturated fatty acids and monounsaturated fatty acids were significantly higher, while the corresponding total polyunsaturated fatty acids content was significantly lower in the CF group. In the two groups, eicosapentaenoic acid, docosahexaenoic acid content and the ratio of n-3 to n-6 fatty acids were found to be generally high.

PRACTICAL APPLICATIONS

Large yellow croaker ( Pseudosciaena crocea ) is popularly cultured in China. It is mainly reared with raw fish and commercial feed. This study examined the biochemical composition of fillets from large yellow croaker. It was found that the fish species possess high nutritive value, which is very beneficial for human nutrition and health. This article also explored the effects of diets on flesh quality, which can be useful in the seafood production and feed industry.     

A method to detect the parasitic nematodes from the family Anisakidae, in Sardina pilchardus, using specific primers of 18 S DNA gene

Anisakiasis is the infestation of man by the third larval stage of the Anisakidae family parasites, caused by the consumption of raw or undercooked seafood. The hosts of the third larvae parasite are marine fishes, among which Sardina pilchardus is of high commercial interest in many countries. So, the detection of anisakid larvae in fisheries products (fresh and processed) is of great interest to a rapid and feasible diagnosis of parasitism. Currently, there are different types of parasite detection methods but they are all difficult and tedious. The aim of this work was to detect, using DNA-based techniques, the presence of anisakid larvae in the entire fish host. Three pairs of primers were designed in the 18 S DNA gene taking into account the maximum matching between the anisakid species sequences and the minimum matching concerning for both the fish species and some other groups of organisms that parasitize fish (non-anisakid nematodes, trematodes, and cestodes). Experimental mixtures of parasite and fish host were made and the sensitivity of anisakid DNA detection tested by PCR. All the above primers and two others combinations of them were specific for the nematode group within the studied species, and the sensitivity of detection was on the order of 1 part of nematode to 100 000 parts of fish (anisakid weight:fish sample fresh weight = 1:≈100 000).     

六种鱼鱼头磷脂的组成及脂质脂肪酸分析

为研究海水鱼和淡水鱼鱼头磷脂及脂质脂肪酸组成的差异,以海水鱼(马鲛鱼、巴浪鱼、金鲳鱼)和淡水鱼(罗非鱼、鲫鱼、鲢鱼)鱼头为研究对象,利用Floch法提取6种鱼鱼头总脂;硅胶柱层析法将总脂分离收集中性脂、糖脂和磷脂;薄层层析(thin layer chromatography,TLC)分析比较6种鱼鱼头磷脂种类的分布、组成;气相色谱(Gas chromatography,GC)分析6种鱼鱼头脂质的脂肪酸组成。结果表明,6种鱼鱼头中提取率最高的脂质类型为中性脂,占总脂的48.98%~77.84%,其次为磷脂,占总脂的5.93%~22.86%,糖脂提取率最低,占总脂的3.67%~15.91%。鱼头磷脂中共检出4种磷脂组分,分别为磷脂酰乙醇胺(Phosphatidylethanolamine,PE)、磷脂酰胆碱(Phosphatidylcholine,PC)、鞘磷脂(Sphingomyelin,SM)、溶血磷脂酰胆碱(Lysophosphatidylcholine,LPC),其中PC明显高于其他磷脂组分。脂质中均含有较高含量的多不饱和脂肪酸(Poly-unsaturated fatty acid,PUFA),其中以二十二碳六烯酸(docosahexaenoic acid,DHA)为主,且均含有二十碳五烯酸(eicosapntemacnioc acid,EPA),海水鱼和淡水鱼鱼头磷脂中DHA和EPA占总脂肪酸的比例最高,分别为18.39%~21.43%和5.61%~10.38%,且海水鱼鱼头中以DHA和EPA为主的PUFA含量高于淡水鱼鱼头。因此,海水鱼鱼头是提取n-3多不饱和脂肪酸的潜在资源,尤其是制备n-3多不饱和脂肪酸型磷脂的良好来源。     

Nutritional Evaluation of Lipids in Fish from Temperate Australian Waters

Fatty acid compositions and lipid levels of five common table varieties of marine fish from temperate Australian waters were determined. Nutritionally important values were calculated and compared with those of species from similar waters in the northern hemisphere. P/S and n-3/n-6 ratios, and the levels of arachidonic (AA) and docosahexaenoic (DHA) acids in the lipids were comparable for the two, but the Australian species had lower eicosapentaenoic acid (EPA) levels. Oils from Australian fish were shown to have nutritional properties as beneficial as their northern hemisphere counterparts.     

UV-B damages eyes of barnacle larvae and impairs their photoresponses and settlement success

The impact of enhanced UV-B radiation on marine ecosystems due to ozone depletion has caused growing global concern. Barnacle larvae have evolved complex photoreceptors and elaborate phototactic behaviors, which enable them to identify suitable habitats for feeding and settlement. For the first time, we demonstrate that environmentally realistic levels of UV-B radiation can induce ocular damage in barnacle larvae, thereby impairing the phototactic behavior of naupliar larvae and reducing settlement success of cypris larvae. Significant disruptions of rhabdomeres (the photosensitive structures in which phototransduction takes place) occurred in the retinular cells of naupliar eyes when naupliar larvae were exposed to a UV-B dose of 7.2 kJ m(-2), and impairment was dependent upon dose rather than irradiance. Our experimental data also showed that phototaxis of nauplii was ca. 4 times more sensitive to UV-B than settlement of cyprids. Since barnacles play an important role in the function and structure of coastal systems worldwide, any impairment of phototactic and settlement behavior of the larvae would pose a significant threat to the sustainability of this ecologically important species. The fact that enhanced UV-B radiation can induce ocular damage and subsequent phototactic impairment in barnacle larvae suggests that UV-B may also cause similar damage to other zooplankton species.     

利用微藻培养生产DHA的进展

DHA(二十二碳六烯酸)是一种重要的必需多不饱和脂肪 酸。它具有多种与我们身体健康有密切关系的生理功能, 是婴幼儿健康成长过程中不可缺少的营养因子,同时对 防治心脑血管疾病和抗癌也有很好的功效。传统的DHA 产品主要来源于鱼油,但对鱼类的过度捕捞已造成严重 的环境和资源问题,并且鱼油含有多种有毒的有机污染 物(如二恶英)与重金属,从而使鱼油来源的DHA在质量 和安全性上备受质疑。目前,利用微藻生产DHA成为一 个新趋势。本文综述了微藻生产DHA的方法。      

Fatty Acid Composition of 12 Fish Species from the Black Sea

Abstract: The long‐chain polyunsaturated fatty acids docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) are healthful to humans, particularly in promoting growth and cognitive development in infants and young children, and in reducing the risk of cardiovascular disease. Though the populations who inhabit the Trabzon province of Turkey include seafood from the Black Sea in their diet, knowledge of the fatty acid composition and content of these fish is scant. Fatty acid analysis was performed on freeze‐dried muscle tissue of 12 species of fish purchased in markets in Trabzon. The fat content varied from 0.2% (garfish) to 12% (shad) of dry weight. The highest DHA and DHA plus EPA contents were found in horse mackerel 16.1 and 20.6 mg/g dry weight, respectively. Only in sea bass and sea bream did the essential fatty acid linoleic acid account for more than 10% of the fatty acid total. For all 12 species, arachidonic acid accounted for 0.09% to 7.64% of the fatty acid total. Oleic acid varied greatly from 0.14% (garfish) to 32.7% (shad). The omega‐3/omega‐6 fatty acid ratio ranged from 0.8 to 25. A 100 g serving of fresh horse mackerel would contribute 586 mg of DHA to the diet, which exceeds the recommended daily intake of 200 to 300 mg of DHA for pregnant and lactating women. These data indicate that some, but not all, of the 12 fish species from the Black Sea fish we studied could contribute significantly to satisfy the DHA and EPA needs of the inhabitants of the eastern Black Sea region of Turkey. Practical Application: The information in the present paper will be of practical value from a health perspective for populations who consume these fish and for food producers, as well as scholars interested in fishery and aquaculture and biodiversity and marine ecology when we consider an increasing pollution of our marine ecosystem in our green planet.     

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