Seasonal variations on total fatty acid composition of fillets of zander (Sander lucioperca) in Beysehir Lake (Turkey)

Seasonal variations on total fatty acid compositions of zander, Sander lucioperca in Beysehir Lake, were determined by using GC. Polyunsaturated fatty acids (PUFA) were found to be higher than saturated (SFA) and monounsaturated fatty acids (MUFA) in all seasons. Palmitic acid was the major SFA (57.0–64.0% of total SFA) in all seasons. Oleic acid was identified as the major MUFA (45.0–58.0% of total MUFAs). Docosahexaenoic acid (DHA), linoleic acid (LA), eicosapentaenoic acid (EPA), and arachidonic acid (AA) were the most abundant PUFA. Relating to the total fatty acid composition of zander, the percentages of DHA, LA, AA, and EPA ranged between 17.1–23.3%, 5.40–15.4%, 6.72–9.94% and 4.22–5.93% of total lipid, respectively. The percentages of total ω3 fatty acid were higher than those of total ω6 fatty acid in the fatty acid composition of zander with ω3/ω6 ratios of 1.49, 1.45, 1.22, 0.72 in spring, autumn, winter, and summer, respectively. It was shown that the fatty acid composition and ω3/ω6 fatty acids ratio in the muscle of zander were significantly influenced by spawning and season.     

Seasonal variations in total fatty acid composition of muscles and eye sockets of tucunaré (Cichla sp.) from the Brazilian Amazon area

Seasonal variations in total fatty acid compositions of tucunaré, Cichla sp. in the Janauacá Lake of the Amazon basin were determined by GC. Saturated fatty acids (SFAs) were found to be at higher concentrations than monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs) in two seasonal periods. Major fatty acids were palmitic (16:0, 48.5–51.6% of total SFA), oleic (18:1ω9, 43.9–50.2% of total MUFA), docosahexaenoic (DHA, 22:6ω3, 13.5–27.9% of total PUFA) and arachidonic acid (AA, 20:4ω6, 16.0–19.6% of total PUFA). Polyunsaturated fatty acids were the most abundant in muscle during the flood period, and more especially fatty acids 22:6ω3 (10%) and 20:4ω6 (7%). There were no significant variations amongst total lipid SFA, MUFA, and PUFA from eye sockets. The ω6 fatty acid percentages were always higher than the ω3 fatty acid percentages in tucunaré, with ω6/ω3 ratios varying between 1.02 and 1.6 in the flood and drought periods.     

Different specificity of two types of Pseudomonas lipases for C20 fatty acids with a Delta5 unsaturated double bond and their application for selective concentration of fatty acids

Two kinds of lipases, AK-lipase and HU-lipase, produced by two different Pseudomonas fluorescens strains, AK102 and HU380, respectively, were evaluated as to fatty acid hydrolysis specificity using six types of oil containing higher amounts of C20 fatty acids such as arachidonic acid (5,8,11,14-eicosatetraenoic acid, AA, or 20:4omega6), dihomo-gamma-linolenic acid (8,11,14-eicosatrienoic acid, DGLA, or 20:3omega6), 5,8,11,14,17-eicosapentaenoic acid (EPA or 20:5omega3), mead acid (5,8,11-eicosatrienoic acid, MA, or 20:3omega9), 8,11-eicosadienoic acid (20:2omega9) and 8,11,14,17-eicosatetraenoic acid (20:4omega3). Although HU-lipase did not show any specificity for C20 fatty acids with respect to the presence or absence of a Delta5 unsaturated bond, it exhibited comparatively low reactivity for 4,7,10,13,16,19-docosahexaenoic acid (DHA or 22:6omega3). In contrast, AK-lipase was less reactive for C20 fatty acids with a Delta5 unsaturated bond. However, the specificity of hydrolysis of AK-lipase gradually decreased as the reaction proceeded. Utilizing this fatty acid specificity, we concentrated either EPA or DHA from fish oils containing both EPA and DHA by means of lipase-catalyzed hydrolysis and urea adduction. Hydrolysis and urea adduction of refined cod oil including 12.2% EPA and 6.9% DHA with HU-lipase provided free fatty acids with 43.1% EPA and 7% DHA, respectively. The resulting yield of concentrated total fatty acids comprised 2.6% of the fatty acids from the cod oil. Thus, EPA was particularly concentrated in the fatty acids derived from refined cod oil on partial hydrolysis with HU-lipase followed by urea adduction. On the other hand, hydrolysis of cuttlefish oil with AK-lipase followed by urea adduction increase slightly the EPA composition from 14.2% to 16.8%, and markedly enhanced the composition of DHA from 16.3% to 44.6% in the hydrolyzed fatty acids. The yield of purified total fatty acids by urea concentrate was 9.4% of the fatty acids from the cuttlefish oil. Thus, DHA was particularly concentrated in the fatty acids derived from on partial hydrolysis with AK-lipase followed by urea adduction. We concluded that EPA and DHA concentrates can be easily and inexpensively obtained using HU-lipase and AK-lipase, respectively. Furthermore, it might be possible to separate and concentrate C20 polyunsaturated fatty acids (PUFAs) with or without a Delta5 double bond from PUFAs rich oils including both fatty acids.     

A comparative analysis of the fatty acid profiles in the liver and muscles of male and female Salmo trutta macrostigma

The fatty acid compositions of liver and muscle of male and female Salmo trutta macrostigma, in the Tohma River, Turkey, were determined by gas chromatography. There were quantitative differences between individual fatty acids in the tissues investigated, depending on the sex. The most abundant fatty acids in both tissues of both sexes were palmitic acid (C16:0; 19.0–21.6%), stearic acid (C18:0; 5.32–11.3%), C18:1 ω−7 (5.65–9.38%), oleic acid (C18:1 ω−9; 15.6–22.4%), eicosapentaenoic acid (EPA; C20:5 ω−3; 6.34–7.88%) and docosahexaenoic acid (DHA; C22:6 ω−3; 7.38–15.6%). The ω−3/ω−6 ratio in tissues were found to be 2.89 (♂) and 1.97 (♀) in liver, and 2.59 (♂) and 2.26 (♀) in muscle. S. trutta macrostigma may be a valuable food for human consumption in terms of fatty acids.     

Chemical compositions and nutritional value of Asian hard clam (Meretrix lusoria) from the coast of Andaman Sea

Chemical compositions and nutritive value of the edible portions including foot, mantle and viscera of Asian hard clam (Meretrix lusoria) harvested from the coast of Andaman Sea were determined. Proximate compositions varied with portions tested. Edible portions had moisture (76.23–84.22%) and protein (9.09–12.75%) as the major components. Carbohydrate (0.32–7.89%), fat (1.58–6.58%) and ash (1.23–2.58%) were also found at various levels, dependent upon portions. Myofibrillar proteins were observed as the major fraction in foot (40.54%) and mantle (31.65%), whilst non-protein nitrogen constituents were dominant in the viscera (36.85%). All portions contained a large amount of essential amino acids (167.66–187.63 mg/g sample), in which leucine (30.91–36.96 mg/g sample) and lysine (35.24–36.03 mg/g sample) were predominant. They were rich in polyunsaturated fatty acids (46.84–49.18% of total fatty acid) with high level of DHA (13.33–16.47 % of total fatty acids) and EPA (4.75–7.11% of total fatty acids). Cholesterol of 0.07–0.21% wet weight was detected. All portions were also rich in macro- (Na, K, Ca and Mg) and micro- (Fe, Zn, Cu and Cr) minerals. Therefore, Asian hard clam is an excellent source of several nutrients, which could be beneficial for the health of the consumers.     

Seasonal effects in the nutritional quality of the body structural tissue of cephalopods

The most commonly-consumed cephalopods around the world (the common cuttlefish, Sepia officinalis, European squid, Loligo vulgaris, common octopus, Octopus vulgaris and musky octopus, Eledone moschata) were evaluated in terms of seasonal variations in proximate and fatty acid compositions. The arms of the octopuses were used for this study, whereas the mantle of the other species (squids and cuttlefish) were used for the analyses. The lipid contents of species were found to be very low and considered as lean. The lowest lipid content was obtained from E. moschata (0.60–0.68%), whereas L. vulgaris gave the highest level of lipid (1.34–1.92%) throughout all seasons. Unlike lipid content, protein contents of cephalopods did not change across the seasons. The fatty acid compositions of each species ranged from 28.18% to 35.28% saturated (SFA), 4.36–9.47% monounsaturated (MUFAs) and 43.58–56.55% polyunsaturated acids (PUFAs). The highest proportions of fatty acids in cephalopods were myristic acid (C14:0, 0.96–2.96%), palmitic acid (C16:0, 15.53–25.20%), heptadecanoic acid (C17:0, 1.05–2.56%), stearic acid (C18:0, 4.32–9.96%), oleic acid (cis18:1 n−9, 1.80–4.29%), cis-11-eicosenoic acid (C20:1, 2.07–4.69%), linoleic acid (C18:2 n−6, 0.17–1.95%), arachidonic acid (C20:4 n−6, 1.48–11.65%), cis-5,8,11,14,17-eicosapentaenoic acid (EPA, C20:5 n−3, 7.86–16.97%) and cis-4,7,10,13,16,19-docosahexaenoic acid (DHA, C22:6 n−3, 20.99–39.00%). The results indicated that these cephalopod species are excellent protein sources and very rich in n−3 fatty acids.     

Supercritical carbon dioxide extraction of polyunsaturated fatty acids from Northern shrimp (Pandalus borealis Kreyer) processing by-products

This study investigated the potential of Northern shrimp (Pandelus borealis Kreyer) by-products as a source of omega-3 polyunsaturated fatty acids (ω-3 PUFAs). The by-products (heads, shell and tail) of processing accounted for approximately 50–60% of the catch. Supercritical CO₂ extraction (SFE) of the by-products at 35 MPa and 40 °C generated a deep red oil, rich in ω-3 PUFAs, specifically 7.8 ± 0.06% eicosapentaenoic acid (EPA) and 8.0 ± 0.07 % docosahexaenoic acid (DHA).     

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     

Fatty acid compositions of fish oil extracted from different parts of Indian mackerel (Rastrelliger kanagurta) using various techniques of supercritical CO2 extraction

Fatty acid compositions of fish oil extracted from different parts of Indian mackerel (Rastrelliger kanagurta) using various techniques of supercritical carbon dioxide (SC-CO₂) at optimised conditions (35 MPa, 60 °C, 2 ml/min) were analysed and compared to the results of Soxhlet extraction. The amount of polyunsaturated fatty acids (PUFA) recovered (as a percentage of total extracted fatty acids) were within the ranges of 73.24–74.68% in the skin, 68.36–69.37% in the flesh, 56.20–57.3% in the viscera and 61.21–62.09% in the heads. The greatest amount of the ω-3 fatty acids, especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), were found in fish skin followed by flesh, heads and viscera. The greatest amounts of EPA (9–12%) and DHA (10–14%) were obtained using the soaking and pressure swing techniques. The pressure swing and soaking techniques are the most effective techniques for extracting the ω-3 family of fatty acids from fish samples.     

Effect of way of cooking on content of essential polyunsaturated fatty acids in muscle tissue of humpback salmon (Oncorhynchus gorbuscha)

Contents of fatty acids in filets of unfrozen (control), boiled, fried, roasted and boiled in a small amount of water humpback salmon, collected from a wholesale market in Krasnoyarsk city (Siberia, Russia) were analyzed. Special attention was paid to essential polyunsaturated fatty acids of ω3 family: eicosapentaenoic, 20:5ω3 (EPA) and docosahexaenoic, 22:6ω3 (DHA). Heat treatment in general did not decrease content of EPA and DHA in humpback, except a modest reduction during frying. Cooked humpback appeared to be the valuable source of essential ω3 PUFAs, namely EPA and DHA. It was hypothesized that the absence of significant reduction of PUFAs’ contents in red flesh of fishes of Salmonidae family during heat treatment may be due to a high level of natural antioxidants which formed in the course of evolution as adaptation to their ecological niche.     

Seasonal Variations in Fatty Acid Composition of Different Tissues of Mirror Carp,Cyprinus Carpio,in Orenler Dam Lake,Afyonkarahisar, Turkey

The seasonal variations of fatty acids compositions in the muscle, liver, and ovarian tissues of mirror carp (Cyprinus carpio) living in Örenler Dam Lake were determined by using gas chromatography. The results obtained were subjected to statistical analyses by employing SPSS software and p < 0.05 was accepted as significant value. In the statistical analyses, multiple comparisons tests were performed. The results showed that monounsaturated fatty acids levels were found to be higher than that of polyunsaturated fatty acids and saturated fatty acids in all seasons. Palmitic and stearic acid levels were the highest in ovaries (19.95% in winter and 7.79% in summer, respectively). Oleic and palmitoleic levels were at the highest levels in liver tissues (34.53% in summer and 18.37% in winter, respectively). Docosahexaenoic (C22:6ω3, DHA), eicosapentaenoic (C20:5ω3, EPA), eicosatrienoic acid, and arachidonic (C20:4ω6, AA) levels were at the highest level as 17.27, 2.54, and 8.41% in ovaries in the winter and 6.37% in muscle tissues in the spring, respectively. ω3/ω6 ratios were 0.62–0.98 in muscle, 1.54–2.82 in the liver, and 2.82–3.89 in the ovaries. From the point of total fatty acid variations, the highest variations were observed as follows: muscle in spring (26.73%), liver in winter (33.85%), and ovaries in winter 36.38%.     

Comparative fatty acid profiles in edible parts of wild scallops from the Tunisian coast

Muscle and gonad fatty acid compositions from the Pectinids: Pecten jacobaeus, Chlamysvaria and Flexopectenglaber, from the Tunisian coast, were analysed. The recorded main fatty acid components in both organs for the three species were C16:0, C18:0, C18:1, C20:5ω3 and C22:6ω3. Meanwhile, high proportions of EPA and DHA were recorded in the muscle of C. varia (10.1–20.4%), P. jacobaeus (7.68–14.9%), whereas the highest rates (8.98–7.78%) were recorded in gonad for F. glaber. Highest ω3/ω6 ratios were recorded in muscle and gonad of C. varia (9.01 and 7.72, respectively). In P. jacobaeus, the muscle and the gonad had similar nutritional values. Muscle of C. varia had a better fatty acid composition than had the gonad, whilst the gonad value was higher than the muscle in the case of F. glaber.     

气相色谱法测定海豹油中EPA、DPA、DHA含量的方法学研究

目的：建立气相色谱检测海豹油中EPA、DPA和DHA的方法。方法：采用氢氧化钾-甲醇酯化法将海豹油中的脂肪酸快速、有效的转化成脂肪酸甲酯,并通过方法学实验验证其可行性。结果：EPA、DPA和DHA甲酯含量在10～2000μg/mL范围内,峰面积与EPA、DPA和DHA甲酯含量呈良好线性关系;加样回收率在96.93%～103.38%之间,相对标准偏差小于2%;结论：该方法可以快速、准确地同时测定EPA、DPA和DHA含量。     

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.     

Lipid profiles of oil from trout (Oncorhynchus mykiss) heads,spines and viscera: Trout by-products as a possible source of omega-3 lipids?

Lipid profiles of fish oil extracted from trout heads, spines and viscera using supercritical carbon dioxide and Randall extraction with hexane were measured. The amount of unsaturated fatty acids (as a percentage of total fatty acids) was within the range of 72.6–75.3% in all the substrates. A significant presence of the most important omega-3 fatty acids was detected. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) content in oil from spines, heads and viscera resulted to be 8.7% and 7.3%, 7.9% and 6.3%, and 6.4% and 6.0%, respectively. A low (≈3%), but worth noting, presence of lipids with omega-1 polyunsaturated fatty chains was observed in all the oils. Finally, significant differences were noticed in the relative amounts of triacylglycerides (TAG), diacylglycerides (DAG) and free fatty acids (FFA). Whereas oil from heads and spines was essentially composed of TAG (≈98%), in viscera oil the molar distribution ratio became TAG:DAG:FFA = 87:8:5.     

Seasonal changes in the proximate chemical compositions and fatty acids of chub mackerel (Scomber japonicus) and horse mackerel (Trachurus trachurus) from the north eastern Mediterranean Sea

The effects of seasonal variations on the proximate chemical compositions and fatty acid profiles of chub mackerel (Scomber japonicus) and horse mackerel (Trachurus trachurus) captured in the north‐eastern Mediterranean Sea were investigated. Protein fluctuations were observed in two species for all seasons. The lipid content of both species was lower in winter than in autumn and spring. In all seasons, the major fatty acids in both species were observed to be palmitic acid (16:0), stearic acid (18:0), oleic acid (18:1 ω9), eicosapentaenoic acid (20:5 ω3) and docosahexaenoic acid (20:6 ω3). Chub mackerel and horse mackerel exhibited seasonal fluctuations in their fatty acid contents. The fatty acid profile of the two species had a higher degree of unsaturation during winter. The levels of EPA in chub mackerel in winter, spring and autumn were 5.96%, 4.86% and 4.33%, respectively, while those of DHA were 24.94%, 18.75% and 17.12%, respectively. The levels of EPA in horse mackerel in winter, spring and autumn were 5.42%, 5.03% and 4.86%, respectively, while those of DHA were 14.96%, 13.31% and 11.10%, respectively. The PUFA (polyunsaturated fatty acids) values and ω3/ω6 ratios in the two species were highest in winter. The results indicate that chub mackerel and horse mackerel captured in the north‐eastern Mediterranean Sea, which are among the most important fish in Turkey and of international commercial value, are a good source of nutrition for human consumption in terms of their proximate chemical composition and fatty acids.     

Effect of boiling and frying on the content of essential polyunsaturated fatty acids in muscle tissue of four fish species

Frozen samples of common fish species, sea trout (Salmo trutta), from Norway and Siberia, herring (Clupea harengus pallasi), rock sole (Lepidopsetta bilineata) and cod (Gadus morhua maris-albi), collected from a wholesale market in Krasnoyarsk city (Siberia, Russia) were analyzed. Special attention was paid to long-chain essential polyunsaturated fatty acids: eicosapentaenoic, 20:5ω3 (EPA) and docosahexaenoic, 22:6ω3 (DHA). Heat-treatment (cooking and frying) did not in general significantly decrease the contents of EPA and DHA compared to raw fish species, except for a modest reduction in Norwegian trout during frying. Boiled trout appeared to be a more valuable fish dish for obtaining the officially recommended appropriate daily intake of EPA + DHA for humans. Herring and sole had intermediate values, while boiled cod had a comparatively low value.     

Seasonal dynamics of fatty acid content of a common food fish from the Yenisei river,Siberian grayling, Thymallus arcticus

Seasonal variations of fatty acid contents in muscle tissue of one of the main food fish species in Siberian rivers, grayling, Thymallus arcticus, were studied over 3 years. Under a comparatively low range of water temperature variations, spawning appeared to be the main cause of seasonal changes in contents of quantitatively prominent and essential fatty acids in fish filets. In general, fish accumulated essential polyunsaturated fatty acids (PUFA), such as eicosapentaenoic (EPA) and docosahexaenoic (DHA), in their muscle tissue before reproductive seasons and then the PUFA seemed to be transferred into gonads during their formation. Hard roe of Siberian grayling had 3–4 times higher PUFA contents, than had that of the muscle tissue. The fish species, T. arcticus, was found to be a valuable source of the essential PUFA, including EPA and DHA, for human diet.     

Fatty acids of neutral and phospholipids of three endangered trout: Salmo trutta caspius Kessler, Salmo trutta labrax Pallas and Salmo trutta macrostigma Dumeril

Total (TL), neutral (NL) and phospholipid (PL) amounts and fatty acid (FA) composition of female Salmo trutta caspius, Salmo trutta labrax and Salmo trutta macrostigma were investigated during one year. Twenty-three FAs were identified in both NLs and PLs. The principal FAs of both fractions were palmitic acid in saturated fatty acid, oleic acid in monounsaturated fatty acid, docosahexaenoic acid (DHA) in n-3 polyunsaturated fatty acids (n-3 PUFAs) and linoleic acid in n-6 PUFAs. The highest values for TLs, NLs and PLs were found in winter. As a general trend, the highest n-3/n-6 ratios and eicosapentaenoic acid (EPA) + DHA amounts were found in the winter and this coincided with the lowest gonado-somatic index.     

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