首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
Total lipid content and fatty acid composition were determined for wild and cultivated gilthead seabream and sea bass. Fatty acid analyses were carried out by gas chromatography‐ mass spectrometry. Respective total lipid content of flesh in cultivated gilthead seabream and sea bass were 1.7‐5.0‐times those of wild samples. Palmitic acid (C16:0) and oleic acid (C18:1n‐9) were the major fatty acids respectively among the saturated fatty acids and monounsaturated fatty acids of each fish species. It is noteworthy that both linoleic acid (C18:2n‐6) and arachidonic acid (C20:4n‐6) were predominant in total n‐6 polyunsaturated fatty acids in the respective cultivated and wild types. Eicosapentaenoic acid (C20:5n‐3) and docosahexaenoic acid (C22:6n‐3) amounts were significantly higher in flesh of cultivated fish than in wild fish.  相似文献   

2.
The effects of seasons on the lipid content and fatty acid compositions of five different shrimp and prawn species (green tiger prawn – Penaeus semisulcatus, kuruma prawn – Marsupenaeus japonicus, caramote prawn – Melicertus kerathurus, deepwater pink shrimp – Parapenaeus longirostris, speckled shrimp – Metapenaeus monoceros) were evaluated. Results showed that lipid content ranged from 0.89 to 1.55% in muscle, showing that all species were considered as lean. There were significant differences (p<0.05) in the levels of saturated fatty acids (SFA), monounsaturated fatty acids and polyunsaturated fatty acids (PUFA) in terms of season and species. They were rich in n‐3 fatty acids, especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The highest proportions of EPA were obtained from kuruma prawn (180.9 mg/100 g) in spring and deepwater pink shrimp (173.2 mg/100 g) and caramote prawn (146.3 mg/100 g) in summer. Kuruma prawn had the highest DHA in spring (140.8 mg/100 g) followed by deepwater pink shrimp (132.2 mg/100 g) and caramote prawn (129.6 mg/100 g) in summer. The results also showed that the seasons affected lipid content and the fatty acid composition of shrimp and prawn species. Practical Application: The beneficial effect of seafood consumption on human health has been related to the high content of n‐3 fatty acids, especially EPA (20:5n‐3) and DHA (22:6n‐3). The ratios of n‐6/n‐3, PUFA/SFA and EPA + DHA are considered as useful criteria for comparing relative nutritional and oxidation values of marine oils. In the current study, the influence of seasonality on the lipid content and the fatty acid compositions of shrimp and prawn were investigated in order to find the best source of n‐3 fatty acids during the year.  相似文献   

3.
The effective microbial production of copolyesters of 3‐hydroxybutyrate (3HB) and 4‐hydroxybutyrate (4HB) with high mole fractions of 4HB units by a wild‐type strain of Ralstonia eutropha H16 was investigated in culture solutions containing 4‐hydroxybutyric acid (4HBA) and various carbon substrates in the presence of a nitrogen source such as ammonium sulfate. The addition of glucose or acetic acid to the culture solution containing 4HBA in the presence of ammonium sulfate resulted in the production of random copolymers of P(3HB‐co‐4HB) with compositions of up to 82 mol% 4HB, but the yield of copolymers was less than 7 wt% of dried cell weights. In contrast, when n‐alkanoic acids such as propionic acid, butyric acid, valeric acid and hexanoic acid, being subject to β‐oxidation metabolism in the cell, were used as the co‐substrates of 4HBA in the presence of ammonium sulfate, a mixture of copolymers with two different 4HB compositions was produced, and copolyesters with compositions of 93–100 mol% 4HB were isolated from chloroform–n‐hexane insoluble fractions in the mixture of copolymers. Especially, when this wild‐type Ralstonia eutropha H16 was cultivated in a medium containing 4HBA (15 g litre−1), propionic acid (5 g litre−1) and ammonium sulfate (5 g litre−1), namely C/N (mol/mol) = 10, the P(4HB) homopolymer was produced at maximally 34 wt% of dry cell weight (7.8 g litre−1), and the conversion yield of 4HBA to P(4HB) homopolymer resulted in values as high as 21 mol%. © 1999 Society of Chemical Industry  相似文献   

4.
The biochemical behavior of wild‐type or genetically modified (presenting decreased expression of intracellular acyl‐CoA oxidases) Yarrowia lipolytica strains cultivated on commercial glucose was studied. Flask nitrogen‐limited cultures were performed favoring the production of organic acids (and potentially the accumulation of lipid). Nitrogen depletion induced secretion of citric acid, while intracellular lipid was not produced in high quantities. Maximum total citric acid up to 49 g/L (yield 0.85 g/g glucose) was produced. In some of the wild‐type strains, an increase of glucose in the medium also induced noticeable production of acetic acid. Increasing the amount of added glucose led to an increase in the total lipid quantity (%) produced, although in the stationary growth phase the concentration of lipid declined, indicating lipid degradation even for the genetically modified strains. Total lipid amount did not exceed the value of 14%, while neutral fractions increased with increase in glucose concentration. In all cases, the total microbial lipids and major lipid fractions were composed of C16 and C18 (principally unsaturated) fatty acids. Finally, in several of the strains cultured in media containing a low glucose concentration, unicellular morphology was observed, while at high glucose concentrations mycelia were predominant.  相似文献   

5.
Seasonal variations of proximate compositions, muscle lipids and fatty acids (FA) of seven seawater species (Silllago sihoma, Upeneus pori, Sparus aurata, Saurida undosquamis, Epinephelus auneus, Mullus barbatus, Solea solea) from the Mediterranean Sea, were determined in all seasons. The results showed that the fatty acid compositions of each species ranged from 26.41 to 38.70% saturated (SFA), 13.78 to 26.52% monounsaturated (MUFAs) and 25.02 to 50.83% PUFAs. The highest proportions of EPA were obtained from M. barbatus (8.34%) in spring, S. sihoma (7.54%), U. pori (6.75%), S. aurata (6.31%), S. undosquamis (5.12%), E. auneus (5.10%) in summer, and also S. solea (6.19%) in spring. The highest proportions of DHA were found in spring, ranging from 25.14% for M. barbatus to 34.87% for S. aurata, except for S. solea (30.44%) in winter and S. sihoma (15.83%) in summer. The results showed that from a quality point of view, all species were suitable for human nutrition, since muscle lipids are rich in EPA + DHA in all seasons. Practical application : The American and Canadian Dietetic Associations recommend two servings of fatty fish per week and a daily combined intake of EPA and DHA of 500 mg. This follows a trend of numerous publications and other guidelines recognizing the health benefits of long‐chain n‐3 PUFA from fish or marine microbial sources with respect to cardiovascular health, neurological diseases, infant health and development, inflammation and cancer and other health effects. The seven species analyzed here provide muscle lipids that are rich in EPA and DHA. Only minor season‐to‐season changes in the total content of n‐3 and n‐6 PUFA were observed for the same species. The results provide valuable information for preparing diet tables.  相似文献   

6.
The objective of the experiment with cattle was to produce high quality beef under different feeding conditions and to increase the concentration of essential fatty acids in muscle. In total 10 German Simmental (GS) bulls and 9 German Holstein (GH) steers were kept either on pasture (grass feeding) or in stable (concentrate feeding). Despite biohydrogenation in the rumen, linolenic acid (C18:3n‐3) contained in grass was absorbed and deposited into the lipids of muscle. This led to a significantly (p ≤ 0.05) higher content of n‐3 fatty acids in the muscle lipids of grazing cattle. The relative amount of total n‐3 fatty acids increased from 1.4 g/100 g fatty acid methyl ester (%FAME) in the intensively fed Simmental bulls to 5.5 %FAME in grass fed cattle. The n‐6/n‐3 ratio of pasture grazing GS bulls was 1.3 in contrast to 13.7 of the animals kept in the byre. The total n‐3 fatty acid concentration in beef muscle increased from 24.6 mg (concentrate) to 108.6 mg/100 g wet weight (grazing). In GH steers the total n‐3 fatty acid concentration was significantly (p ≤ 0.05) increased up to 86.3 mg/100 g wet weight in pasture grazing steers compared to 28.8 mg/100 g wet weight in animals fed the concentrate. The relative content (%FAME) of CLAcis‐9, trans‐11 (0.6 vs 0.56 %FAME in GS; 0.55 vs 0.52 %FAME in GH) in muscle was not significantly increased by grazing on pasture in comparison to concentrate feeding neither in GS bulls nor in GH steers, respectively.  相似文献   

7.
In this study, the proximate and fatty acid compositions of the muscle tissue of 186 samples of fish belonging to fifteen species of freshwater fish harvested in subalpine lakes (bleak, shad, crucian carp, whitefish, common carp, pike, black bullhead, burbot, perch, Italian roach, roach, rudd, wels catfish, chub and tench) were investigated. Most of the fish demonstrated a lipid content in the fillet lower than 2.0 g 100 g?1 wet weight (range 0.6–9.7). A strong relationship between feeding behavior and fatty acid composition of the muscle lipids was observed. Planktivorous fish showed the lowest amounts of n‐3 fatty acids (p < 0.05), but the highest monounsaturated fatty acid (MUFA) contents, in particular 18:1n‐9. Conversely, carnivorous fish showed the highest amounts of saturated fatty acids and n‐3 fatty acids (p < 0.05), but the lowest MUFA contents. Omnivorous fish showed substantial proportions of n‐3 fatty acids and the highest contents of n‐6 fatty acids. Principal component analysis showed a distinct separation between fish species according to their feeding habits and demonstrated that the most contributing trophic markers were 18:1n‐9, 18:3n‐3, 22:6n‐3 and 20:4n‐6. The quantitative amounts n‐3 polyunsaturated fatty acid in muscle tissues varied depending on the fish species, the lipid content and the feeding habits. Some species were very lean, and therefore would be poor choices for human consumption to meet dietary n‐3 fatty acid requirements. Nevertheless, the more frequently consumed and appreciated fish, shad and whitefish, had EPA and DHA contents in the range 900–1,000 mg 100 g?1 fresh fillet.  相似文献   

8.
Young, female nutrias (n = 13) were fed a diet supplemented with 0.36 mg/kg selenium in selenium‐enriched yeast (SeY; Sel‐Plex; Alltech, Inc., Nicholasville, KY) for 60 days (total Se concentration in the basal diet was ~0.1 mg/kg). Concentrations of fatty acids (FA) in the liver were compared to those of nutrias on a control diet (n = 11). Animals were sacrificed at 8 months of age and liver samples (approximately 30 g) were collected. The gas‐chromatographic analysis of tissue samples from the experimental group revealed a significant decrease in saturated fatty acids (p<0.001), monounsaturated fatty acid (p = 0.006), and polyunsaturated fatty acid (PUFA) (p = 0.02) compared to controls. The linoleic and linolenic acids, which are precursors of n‐6 and n‐3 PUFA, respectively, were significantly lower (p = 0.01 and p<0.001, respectively) in the supplemented group. The n‐6 to n‐3 PUFA ratio was significantly affected (p = 0.001) by the SeY dietary supplement (13.17 vs. 8.93, respectively).  相似文献   

9.
Total lipid contents, fatty acid compositions, phenolic profiles and antioxidants activities of seeds from Thapsia garganica, Orlaya maritima, and Retama raetam were investigated. The oil values were more than 26 %, except seeds of R. raetam (ca. 3 %). Unsaturated fatty acids accounted for the majority of the fatty acids (more than 75 %). Oleic and linoleic acid were the predominant fatty acids. Total phenolic compounds (24–104 mg GAE g?1 DR), total flavonoids (4–102 mg QE g?1g DR), total tannins (28–85 mg GAE g?1 DR) and condensed tannins (0.62–131 mg CE g?1 DR) were also determined. The antioxidant activities using different assays were evaluated. The predominant detected classes were the phenolic acids (42–85 %) and the flavonoids (11–48 %). The major phenolic acids were caffeic, trans‐4‐hydroxy‐3‐methoxycinnamic, p‐coumaric, and gallic acid. The predominant flavonoids were quercetin, luteolin, naringin, apigenin, and kaempferol. This study brings attention to the medicinal importance of these species as a source of oil and antioxidant molecules.  相似文献   

10.
The fatty acid compositions of flowering tops of Hypericum perforatum L. and Hypericum retusum Aucher (Guttiferae) were analyzed by gas chromatography and gas chromatography‐mass spectrometry. The major components were C16:0 (24.87%), C18:3 n‐3 (21.94%), 3‐OH‐C18:0 (18.46%) and 3‐OH‐C14:0 (14.22%) for H. perforatumL. and 3‐OH‐C14:0 (28.29%), C18:0 (16.47%) and C16:0 (14.17%) for H. retusum Aucher. Besides widespread plant fatty acids, 3‐hydroxy fatty acids, namely 3‐hydroxytetradecanoic acid (3‐OH‐C14:0) and 3‐hydroxyoctadecanoic acid (3‐OH‐C18:0) were also obtained.  相似文献   

11.
A comparative study was performed to determine the fatty acid, 4‐desmethylsterol and triterpenic alcohols compositions of three different Tunisian populations of Pistacia lentiscus fruit Rimel (RM), Korbous (KO), and Tebaba (TB). Fruits are rich in lipids, which varied from 39.37% (KO) to 42.48% (TB) on a dry weight basis. Qualitatively, fatty acid, sterol, mono‐ and dimethylsterol composition is identical for all populations. Oleic acid was the major fatty acid for all samples, accounting from 40.49% in TB population to 50.72% in RM population followed by the palmitic and linoleic acids. Other fatty acids are present at lower levels. Total sterol amount varied from 109.72 mg/100 g of oil (KO) to 434.26 mg/100 g of oil (RM) with an average of 248.74 mg/100 g of oil. The major 4‐desmethylsterol component in all studied Tunisian populations of P. lentiscus oil was ß‐sitosterol followed by campesterol in TB and KO, and by stigmasterol in RM. The amount of total triterpenic alcohols varied from 42.39 mg/100 g of oil in RM population to 70.41 mg/100 g oil in TB population. The quantitative difference in the fatty acids and 4‐desmethylsterols of the different populations studied could be due to the effect of geographic region and soil type.  相似文献   

12.
Phospholipids are recognised as an important source and transport form for metabolically active fatty acids. Therefore, detailed analysis of fatty acid profiles in plasma phospholipids as marker for dietary habits or interventions gains more and more importance. Appropriate analytical methods described so far are either expensive or susceptible to handling errors. We developed a method to separate plasma phospholipids by acetone fractionation combined with SPE in order to analyse the fatty acid compositions in phospholipid fractions of human plasma by GC analysis. The method has been validated in order to be applied to the routinely performed analysis of the samples of patients who will be participating in a dietary supplement study. The method presented here was successfully validated and is stable, efficient and reproducible. It can be used in a routine fashion to deliver the fatty acid profile [palmitic acid (16:0), heptadecanoic acid (17:0), stearic acid (18:0), oleic acid (18:1n‐9), linoleic acid (18:2n‐6), linolenic acid (18:3n‐3), arachidonic acid (20:4n‐6), eicosapentaenoic acid (20:5n‐3) and docosahexaenoic acid (22:6n‐3)] in plasma phospholipid samples. Using a sample volume of 500 µL, recovery of plasma phospholipids is 92 ± 11%; LOQ is 2.2 µg fatty acid/mL. A set of samples from cancer patients and healthy individuals was analysed and confirmed the applicability of the described method.  相似文献   

13.
14.
The production of volatile fatty acids by anaerobic digestion of solid potato waste was investigated using a batch solid waste reactor with a working capacity of 2 dm?3 at 37°C. Solid potato waste was packed into the digester and the organic content of the waste was released by microbial activity by circulating water over the bed, using batch loads of 500 g or 1000 g potato waste. The sequence of appearance of the volatile fatty acids was (acetic, propionic); (n‐butyric); (n‐valeric, iso‐valeric, caproic); (iso‐butyric). After 300 h digestion of potato waste on a small scale, the fermentation products were chiefly (mg g?1 total VFAs): acetic acid (420), butyric acid (310), propionic acid (140) and caproic acid (90), with insignificant amounts of iso‐butyric acid, n‐valeric and iso‐valeric acids. When the load of potato solids was increased, the volatile fatty acid content was similar, but butyric acid constituted 110 mg g?1 and lactic acid 400 mg g?1 of the total volatile fatty acids. The maximum soluble chemical oxygen demand (COD) achieved under the experimental conditions used was 27 and 37 g COD dm?3 at low and high loadings of potato solids, respectively. The total volatile fatty acids reached 19 g dm?3 of leachate at both loads of potato solid waste. Gas production was negligible, indicating that methanogenic activity was effectively inhibited. Copyright © 2004 Society of Chemical Industry  相似文献   

15.
In this study, proximate and fatty acid composition in the edible flesh of eight underutilized and five commercial freshwater fish species were compared in order to evaluate the potential of these fish for development of functional value-added fishery products. The lipid content (% dry weight basis) of investigated fish species ranged from 3.44 to 9.25 in underutilized and 3.73–7.68 in commercial species. In comparison with underutilized fish species, commercial species had higher levels of protein (P < 0.05). The high proportion of EPA+DHA was found with Goldfish (524 mg/100 g flesh), Wels (422 mg/100 g flesh), and Crucian carp (354 mg/100 g flesh), all of which belonged to underutilized group. All studied fish (save Lenkoran) showed values higher than the minimum recommended DHA/EPA value (0.45). The ratios of n-6/n-3 found in this study were much lower (save Goatfish) than those cited as a harmful value (4.0 as the maximum value). The PUFA/SFA value of the present fish samples was higher at 1.57 for Goatfish, 1.02 for Lenkoran, 0.68 for Wels, all of these fish belonging to the underutilized group. The highest atherogenic and thrombogenicity index values were generally obtained for commercial species. It seems in respect of comparability of these lipid quality indicators, the underutilized fish species could be highly recommended as an important source of polyunsaturated fatty acids and Max-EPA products for humans consumption.  相似文献   

16.
The proximate, physicochemical, and fatty acid compositions of seed oil extracted from khat (Catha edulis) were determined. The oil, moisture, crude protein, crude fiber, crude carbohydrate, and ash content in seeds were 35.54, 6.63, 24, 1.01, 30.4 %, and 1.32 g/100 g DW respectively. The free fatty acids, peroxide value, saponification value, and iodine value were 2.98 %, 12.65 meq O2/kg, 190.60 mg KOH/g, and 145 g/100 g oil, respectively. Linolenic acid (C18:3, 50.80 %) and oleic (C18:1, 16.96 %) along with palmitic acid (C16:0, 14.60 %) were the dominant fatty acids. The seed oil of khat can be used in industry for the preparation of liquid soaps and shampoos. Furthermore, high levels of unsaturated fatty acids make it an important source of nutrition especially as an animal product substitute for omega‐3 fatty acids owing to the high content of linolenic acid.  相似文献   

17.
The purpose of this study was to evaluate the main qualitative traits of European sea bass fattened in farms adopting different rearing techniques (offshore cages, inshore cages, land‐based basins) but fed the same diets in each production cycle, in a three year survey (2006, 2007, 2008). Three farms were chosen for each rearing technique and two sampling sessions of ten fish each were carried out for each rearing cycle. Proximate composition, fatty acid profile, and cholesterol content were evaluated in the fillet of marketable size fish as well as morpho‐biometric parameters and indices. Diets administered in 2008 had higher amounts of lipids, lower proportions of n–3 polyunsaturated fatty acids (PUFA) and higher proportions of n–6 PUFA compared to 2006 and 2007 diets. The chemical and fatty acid composition of the fish fillet was affected by the diet composition: fish fattened in 2008 exhibited statistically higher amounts of fat and cholesterol, lower proportions of n–3 PUFA and higher proportions of n–6 PUFA in comparison with fish cultivated in 2006 and 2007. Fish cultivated in cages, both offshore and inshore cages, exhibited leaner fillets, lower amounts of cholesterol and higher proportions of n–3 PUFA than fish cultivated in basins. Practical applications: In this study we have analyzed the combined effects of feeding and rearing systems of sea bass in a 3‐year survey for the first time. The results showed that feeding is the main factor affecting fish quality as regards both the chemical composition and the fatty acid profile. The partial substitution of fish meal and fish oil with vegetable sources, with the aim of saving the wild fish biomass as well as formulating less expensive diets, strongly alters the fillet composition. We also showed that the rearing system of fish in offshore cages makes it is possible to obtain better quality products.  相似文献   

18.
Thirty-four strains of docosahexaenoic acid (DHA)-producing microorganisms were newly isolated from brackish areas in Japan. These strains showing various compositions of fatty acids. Especially, the fatty acids produced by one of the strains, named D31, had a high DHA content (over 60 % of the total fatty acids) and the simple fatty acid composition (16:0, 18:0, 18:1 and DHA without any other polyunsaturated acids). Although most oleaginous microorganisms accumulate DHA as triacylglycerol, the strain D31 accumulated DHA mainly as a polar lipid (79.4 % of total DHA), especially as phosphatidylcholine (71.4 % of polar DHA). This strain D31 was identified as a related species of Crypthecodinium cohnii on the basis of phylogenetic analysis. Crypthecodinium sp. D31 showed high DHA productivity when cultivated in a medium containing glycerol as the carbon source and a mixture of yeast extract and polypeptone as the nitrogen sources, with a salinity that was equivalent to 50 % of that of seawater and a pH in the acidic range (<pH 6.0). Crypthecodinium sp. D31 is considered as a promising producer of high-purity DHA-containing phospholipids.  相似文献   

19.
The lipid content and fatty acid (FA) composition of seeds from the Asian ginseng Panax ginseng growing naturally in taiga forests of the Russian Far East and seeds from cultivated ginseng were studied in this work. The total lipid content of seeds from both wild and cultivated plants was 9–12 % of fresh weight. FA were analyzed as isopropyl esters on a polar capillary column BD‐225, which allows good separation of petroselinic and oleic acids. The structure of FAs was confirmed using GC–MS of fatty acid methyl ester (FAME) and 4,4‐dimethyloxazoline derivatives. In all the seed samples, the major FA was petroselinic acid 18:1(n‐12) which comprised more than 60 %; the contents of oleic and linoleic acids were lower (15–17 and 15–16 %, respectively). Earlier, a higher level (>80 %) of oleic acid had been reported for ginseng seeds. This discrepancy can be explained by an insufficient separation of these acids on standard columns used for GC of FAME. In general, seeds of wild and cultivated ginseng are very similar in lipid content and FA composition.  相似文献   

20.
The puffer fishes Chelonodon patoca, Sphaeroides oblongus, Lagocephalus lunaris, and L. inermis of Indian coastal waters are wasted in huge quantity. The livers of these fishes were investigated for their lipid contents and fatty acid compositions in different seasons. It was found that monsoon season is the suitable time to obtain the maximal lipids (40.1–48.8%) from their livers, an amount similar to cod liver lipid content (39.5–55.0%). The fatty acids were mostly saturates and monoenes (60–70%). Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) concentrations (7–12%) were high during monsoon season. Neutral lipids were the predominant lipid class (>80%) and comprised triglycerides (277–674 mg/g) and cholesterol (0.6–3.1 mg/g). Quality indices of puffer liver lipids, e.g., specific gravity, refractive index, acid value, iodine value, saponification value and unsaponifiable matter, were evaluated. Puffer liver lipids were quantitatively and qualitatively comparable to other commercially important marine fish oils. The overall study suggests the possibility of future commercial utilization of liver lipids from puffer, an unconventional, cheap, and easily available source.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号