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1.
Eicosapentaenoic acid (EPA, 20:5n‐3), docosapentaenoic acid (DPA) isomers (22:5n‐6 and 22:5n‐3) and docosahexaenoic acid (DHA, 22:6n‐3) derived from tuna oil were concentrated by three stages of urea fractionation at various crystallization temperatures and different fatty acid/urea ratios. Thereafter, polyunsaturated fatty acids concentrate containing comparatively enriched DPA levels was purified by argentated silica gel column chromatography. A product containing 22.2 ± 0.6 % EPA, 4.6 ± 0.0 % DPAn‐6, 5.9 ± 0.1 % DPAn‐3 and 42.3 ± 1.2 % DHA was obtained at 1:1.6 fatty acid/urea ratio (w/w) by crystallization at ?8 °C for 16 h, ?20 °C for 8 h, and ?8 °C for 16 h. A DPA isomer concentrate containing 26.1 ± 0.5 % DPAn‐6 and 22.3 ± 0.4 % DPAn‐3 was achieved by argentated silica gel chromatography in the 6 % acetone/n‐hexane solvent fraction (v/v), and the recovery of both fatty acids was 66.1 ± 3.2 and 70.7 ± 2.2 %, respectively. Furthermore, 91.9 ± 2.5 % EPA and 99.5 ± 2.1 % DHA with recoveries of 47.8 ± 2.0 and 56.7 ± 3.3 %, respectively, were obtained in various fractions.  相似文献   

2.
The solvent crystallization and the urea complexation of the Uruguayan fur seal oil (Arctocephalus australis Zim.), in order to obtain enriched omega-3 PUFAs concentrates were studied. The fractionation at –6°C of fur seal oil or its fatty acids dissolved in ethanol or acetone, is not suitable to obtain a PUFAs concentrate. Ethanol as a solvent and a two steps process (the second step consists of the addition of urea to the obtained NUCF) is the most useful procedure to obtain a concentrate of high PUFAs content using urea complexation of the free fatty acids from marine oils. When the concentrate is obtained from fur seal fatty acids, the total PUFAs content is of 90% with an overall yield of 17%. The recovery efficiency of total PUFAs is 78%. This procedure is very simple and relatively cheap.  相似文献   

3.
In fish and poultry processing, viscera are generally considered as a waste product and often discarded. Chicken and hilsa fish (Hilsa ilisa) viscera were used for the production of polyunsaturated fatty acids (PUFA) linoleic (18:2n-6), eicosapentaenoic (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3). Free fatty acids (FFA) were extracted by alkaline hydrolysis of chicken and fish viscera; yields were 5.2 and 5.9% (w/w) respectively. PUFA concentrates were obtained by a two step process—deduction of saturated fatty acids (FA) by low temperature crystallization in acetone followed by urea inclusion compound-based fractionation. Acetone treatment removed 90 and 96% of saturated FA in chicken and fish viscera respectively with FA to acetone ratio of 1:12 (w/v). Using an urea to FA ratio (w/w) of 4.0, chicken viscera produced a maximum of 84.1% of PUFA concentrates containing 82.1% of linoleic acid with a yield of 10% where as in the case of fish viscera the maximum PUFA concentrates were 91.3% containing 78.2% of EPA-DHA with the yield of 11%. Thus, the utilization of poultry and fish processing waste into the production of PUFA concentrates has been shown.  相似文献   

4.
The effect of weight ratio of urea to fatty acids and the urea-fatty acid adduct crystallization temperature on the enrichment of eicosapentaenoic acid from marine oil fatty acids was studied. The optimum ratio of urea to fatty acids was found to be 3 : 1 for laboratory scale preparations and the optimum temperature for the formation of urea-fatty acid adduct was 1°C. At very low temperatures (?12, ?18, ?35°C) the recovery efficiency for EPA was reduced. Using these optimum values, enrichment of EPA and other n-3 polyunsaturated fatty acids via urea complexation was carried out on a pilot plant scale in a variety of North Atlantic and North Pacific fist oils and a seal oil. Irrespective of hte type of starting oil, all the oils gave a concentrate with 69–85% total n-3 PUFA with an overall yield of 17–20%. Menhaden is clearly an ideal oil for preparation of EPA concentrate, as the starting oil usually has a higher proportion of EPA to DHA than most of the other commercial fish oils.  相似文献   

5.
n-3 Polyunsaturated fatty acids (n-3 PUFA) from the marine microalgaIsochrysis galbana were concentrated and purified by a two-step process—formation of urea inclusion compounds followed by preparative high-performance liquid chromatography. These methods had been developed previously with fatty acids from cod liver oil. By the urea inclusion compounds method, a mixture that contained 94% (w/w) stearidonic (SA), eicosapentaenoic (EPA), plus docosahexaenoic (DHA) acids (4:1 urea/fatty acid ratio and 4°C crystallization final temperature) was obtained from cod liver oil fatty acids. Further purification of SA, EPA, and DHA was achieved with reverse-phase C18 columns. These isolations were scaled up to a semi-preparative column. A PUFA concentrate was isolated fromI. galbana with methanol/water (80:20, w/w) or ethanol/water (70:30, w/w). With methanol/water, a 96% EPA fraction with 100% yield was obtained, as well as a 94% pure DHA fraction with a 94% yield. With ethanol/water as the mobile phase, EPA and DHA fractions obtained were 92% pure with yields of 84 and 88%, respectively.  相似文献   

6.
The aims of this study were to compare three treatments in the chemical hydrolysis reaction of bleached oil from carp (Cyprinus carpio) heads and to obtain polyunsaturated fatty acid concentrates by urea complexation. The three treatments were carried out with different oil:ethanol molar ratios. In the treatment with a 1:39 molar ratio, a higher yield of free fatty acids was found. These fatty acids were submitted to urea complexation (−10 °C for 20 h, and urea–fatty acid ratio of 4.5–1). There was a 31.4% increase in monounsaturated and polyunsaturated fatty acids (MUFA and PUFA) content and a 75% decrease in saturated fatty acids (SAF) content. An increase of 85.4% in the EPA + DHA content was found. The non-urea complexing fraction can be considered a rich source of MUFA and PUFA with a total amount of 88.9%.  相似文献   

7.
Oil sources (canola, sunflower, and flax‐seed oil) characterized by unsaturated fatty acids are gelled by using cinnamic acid. The physical characteristics and crystallization kinetics of cinnamic acid‐based organogels are investigated. A phase diagram with cinnamic acid concentrations ranging from 1% to 7% (w/w) shows that both canola and sunflower oil organogels are formed at 3.0% (w/w) cinnamic acid at 5 °C. The flax‐seed oil organogels are formed at 4.0% (w/w) at 5 °C. Firmness is shown to be dependent on the fatty acid composition and viscosity of the oil. Flax‐seed oil with a higher degree of unsaturation and lower viscosity tends to produce harder organogels. This result is consistent with the observations of polarized light microscopy. The organogels have low solid fat content at 35 °C which is close to the human body temperature, and no effect of oil type is found. The X‐ray diffraction measurements show β'‐form crystal exists in three types of organogels. The thermal properties vary in different types of organogels. The crystallization kinetics results suggest that three types of organogels crystallize by 1D and 2D mixed growth and instantaneous nucleation. Practical Applications: These findings provide in‐depth characteristics of cinnamic acid‐based organogels, which are a substitute for solid fats.  相似文献   

8.
A simple and relatively inexpensive procedure to obtain 90% eicosapentaenoic acid + docosahexaenoic acid concentrates from sardine oil involved a two-step winterization of the oil (10 and 4°C), followed by saponification and selective precipitation of saturated and less unsaturated free fatty acids by an ethanolic solution of urea. Antioxidant effects of butylated hydroxytoluene, dl-α-tocopherol, and two natural antioxidants, quercetin and boldine, added to the concentrate (0.5% wt/vol), were compared in the Rancimat at 60°C. dl-α-Tocopherol was unable to inhibit concentrate oxidation. Butylated hydroxyanisole and butylated hydroxytoluene had induction periods of 1.7–1.8 h compared to the control (1.0 h). A mixture of quercetin + boldine (2:1 w/w) significantly increased the induction period to 4.5 h.  相似文献   

9.
An attempt was made to enrich arachidonic acid (AA) from Mortierella single-cell oil, which had an AA content of 25%. The first step involved the hydrolysis of the oil with Pseudomonas sp. lipase. A mixture of 2.5 g oil, 2.5 g water, and 4000 units (U) Pseudomonas lipase was incubated at 40°C for 40 h with stirring at 500 rpm. The hydrolysis was 90% complete after 40 h, and the resulting free fatty acids (FFA) were extracted with n-hexane (AA content, 25%; recovery of AA, 91%). The second step involved the selective esterification of the fatty acids with lauryl alcohol and Candida rugosa lipase. A mixture of 3.5 g fatty acids/lauryl alcohol (1:1, mol/mol), 1.5 g water, and 1000 U Candida lipase was incubated at 30°C for 16 h with stirring at 500 rpm. Under these conditions, 55% of the fatty acids were esterified, and the AA content in the FFA fraction was raised to 51% with a 92% yield. The long-chain saturated fatty acids in the FFA fraction were eliminated as urea adducts. This procedure raised the AA content to 63%. To further elevate the AA content, the fatty acids were esterified again in the same manner with Candida lipase. The repeated esterification raised the AA content to 75% with a recovery of 71% of its initial content.  相似文献   

10.
尿素包合法富集分离花生四烯酸的工艺研究   总被引:1,自引:0,他引:1  
为提高尿素包合法富集花生四烯酸(AA)效率,研究了降温速度、甲醇用量、尿酯比及结晶温度对花生四烯酸(AA)晶体大小、收率及纯度的影响。结果表明,当结晶温度为-7℃,降温速度为10℃/h,m(脂肪酸甲酯)∶m(尿素):v(甲醇)为1 g∶2 g∶20 mL时,AA生成大颗粒晶体。AA的质量分数w(AA)=87.0%,收率为88.7%。杂质主要为亚麻酸(w=9.21%)。产品总不饱和脂肪酸质量分数大于99%。  相似文献   

11.
Milk fat is known to contain one of the highest number of fatty acids of all edible oils. Some of these fatty acids are known to be valuable (e.g. conjugated linoleic acids, furan fatty acid) and other as undesirable (e.g. saturated and some trans-fatty acids) food ingredients. However, a comprehensive picture on the presence of many trace fatty acids has not been achieved. For this reason we have developed an analysis scheme based on the conversion of the fatty acids into methyl esters. The fatty acid methyl esters were then fractionated by urea complexation. Both the filtrate of the urea complexation (~4 % of the sample weight) and the original sample were fractionated by high-speed counter-current chromatography (HSCCC). The resulting fractions were analyzed by GC/MS analysis. With this method 430 fatty acids were detected in one single butter sample. More than 230 fatty acids had two or more double bonds. In addition to the widely known spectrum of fatty acids we also detected a range of cyclohexyl fatty acids (five homologues) and methyl-branched fatty acids (including short chain and even-numbered anteiso-fatty acids), conjugated tetradecadienoic acids along with the novel ω-oxo-fatty acids (seven homologues). The reported relative retention time on the polar column may serve as a data base for the screening of other samples for this profusion of fatty acids.  相似文献   

12.
An attempt was made to enrich arachidonic acid (AA) from Mortierella single-cell oil, which had an AA content of 25%. The first step involved the hydrolysis of the oil with Pseudomonas sp. lipase. A mixture of 2.5 g oil, 2.5 g water, and 4000 units (U) Pseudomonas lipase was incubated at 40°C for 40 h with stirring at 500 rpm. The hydrolysis was 90% complete after 40 h, and the resulting free fatty acids (FFA) were extracted with n-hexane (AA content, 25%; recovery of AA, 91%). The second step involved the selective esterification of the fatty acids with lauryl alcohol and Candida rugosa lipase. A mixture of 3.5 g fatty acids/lauryl alcohol (1:1, mol/mol), 1.5 g water, and 1000 U Candida lipase was incubated at 30°C for 16 h with stirring at 500 rpm. Under these conditions, 55% of the fatty acids were esterified, and the AA content in the FFA fraction was raised to 51% with a 92% yield. The long-chain saturated fatty acids in the FFA fraction were eliminated as urea adducts. This procedure raised the AA content to 63%. To further elevate the AA content, the fatty acids were esterified again in the same manner with Candida lipase. The repeated esterification raised the AA content to 75% with a recovery of 71% of its initial content.  相似文献   

13.
This paper reports on the synthesis of triglycerides by enzymatic esterification of polyunsaturated fatty acids (PUFA) with glycerol. A PUFA concentrate obtained from cod liver oil was used to optimize the reaction to favor triglyceride synthesis with lipases. The type and amount of lipase and organic solvent, glycerol content, temperature, water content, and amount and time of addition of molecular sieves were studied. The optimal reaction mixture and conditions were: 9 mL hexane, 60°C, 0.5% (vol/vol) water, 1 g molecular sieves added after 24 h of reaction, glycerol/fatty acid molar ratio 1:3 and 100 mg of Novozym 435 (Novo Nordisk A/S) lipase. Under these conditions, an enriched triglyceride yiedl of 84.7% containing 27.4% eicosapentaenoic acid and 45.1% docosahexaenoic acid was obtained from a cod liver oil PUFA concentrate.  相似文献   

14.
The adsorption equilibria are discussed for fatty acids 16∶1n?7, 16∶2n?4, and 20∶5n?3 (eicosapentaenoic acid, EPA). These fatty acids are major components of a polyunsaturated fatty acid concentrate from the microalga Phaeodactylum tricornutum. The solvents used were methanol/water (1% acetic acid) mixtures of different compositions, and the adsorbents used were chromatographic reversed-phases octylsilyl C8, octadecylsilyl C18, and dodecylsilyl C22 of different particle and pore sizes. The kinetic studies showed that equilibrium was attained instantaneously, suggesting an absence of mass transfer limitations. The equilibrium data were fitted by the Freundlich isotherm. The separation efficiency of EPA from 16∶1n?7 and 16∶2n?4 in all the adsorbent-solvent systems was compared in terms of the separation factors αEPA/16:2n-4=K EPA/K 16:2n-4 and α16:1n-7/EPA=K 16:1n-7/K EPA, where K i is the fatty acid distribution ratio between the stationary and the liquid phases. The EPA separation from 16∶1n?7 and 16∶2n?4 by liquid chromatography could be predicted using the Craig model for the various solvent-adsorbent combinations. The best adsorbents for purifying EPA were: C18, PEP, 8 μm, 100 Å, and C22, 10 μm, 100 Å, and the best solvent was methanol/water (1% acetic acid) 75∶25, w/w.  相似文献   

15.
Highly unsaturated fatty acids (HUFA), including eicosapentaenoic acid (EPA, 20:5n‐3), docosapentaenoic acid (DPA, 22:5n‐3 and 22:5n‐6) and docosahexaenoic acid (DHA, 22:6n‐3), play an important role in human health and nutrition. In this study, concentration of HUFA in free fatty acids (FFA) form by low‐temperature crystallization was investigated. For this purpose, tuna oil (7.1% EPA, 26.8% DHA) was first converted into corresponding FFA. Subsequently, crystallization conditions of various solvent types, the ratio of FFA to acetonitrile, operation temperature and crystallization time were optimized at a small scale of 2 g tuna oil fatty acids. Taking purity and yield into account, the optimum conditions were a 1:10 ratio of FFA to acetonitrile (w/v), ?60 °C, and 1 h. The optimal conditions resulted in concentrations of EPA, DHA and HUFA of 15.1, 58.4 and 79.6%, respectively, with corresponding yields of 61.5, 61.8 and 60.7%, respectively. Crystallization was carried out under the optimal conditions at a large scale of 200 g tuna oil FFA, and a similar concentration result was achieved. After evaporating away the solvent, the residual amount of acetonitrile met the US Pharmacopoeia requirement of <410 ppm. The process for enrichment of HUFA is readily scalable, effective and time‐saving.  相似文献   

16.
Eicosapentaenoic acid (EPA, 20∶5n-3) was obtained from the marine microalgaePhaeodactylum tricornutum by a three-step process: fatty acid extraction by direct saponification of biomass, polyunsaturated fatty acid (PUFA) concentration by formation of urea inclusion compounds, and EPA isolation by semipreparative high-performance liquid chromatography (HPLC). Alternatively, EPA was obtained by a similar two-step process without the PUFA concentration step by the urea method. Direct saponification of biomass was carried out with two solvents that contained KOH for lipid saponification. An increase in yield was obtained because the problems associated with emulsion formation were avoided by separating the biomass from the soap solution before adding hexane for extraction of insaponifiables. The most efficient solvent, ethanol (96%) at 60°C for 1 h, extracted 98.3% of EPA. PUFA were concentrated by the urea method with a urea/fatty acid ratio of 4∶1 at a crystallization temperature of 28°C and by using methanol and ethanol as urea solvents. An EPA concentration ratio of 1.73 (55.2∶31.9) and a recover yield of 78.6% were obtained with methanol as the urea solvent. This PUFA concentrate was used to obtain 93.4% pure EPA by semipreparative HPLC with a reverse-phase, C18, 10 mm i.d.×25-cm column and methanol/water (1% acetic acid), 80∶20 w/w, as the mobile phase. Eighty-five percent of EPA loaded was recovered, and 65.7% of EPA present inP. tricornutum biomass was recovered in highly pure form by this three-step downstream process. Alternatively, 93.6% pure EPA was isolated from the fatty acid extract (without the PUFA concentration step) with 100% EPA recovery yield. This two-step process increases the overall EPA yield to 98.3%, but it is only possible to obtain 20% as much EPA as that obtained by three-step downstream processing.  相似文献   

17.
Purification of docosahexaenoic acid (DHA) was attempted by a two-step enzymatic method that consisted of hydrolysis of tuna oil and selective esterification of the resulting free fatty acids (FFA). When more than 60% of tuna oil was hydrolyzed with Pseudomonas sp. lipase (Lipase-AK), the DHA content in the FFA fraction coincided with its content in the original tuna oil. This lipase showed stronger activity on the DHA ester than on the eicosapentaenoic acid ester and was suitable for preparation of FFA rich in DHA. When a mixture of 2.5 g tuna oil, 2.5 g water, and 500 units (U) of Lipase-AK per 1 g of the reaction mixture was stirred at 40°C for 48 h, 83% of DHA in tuna oil was recovered in the FFA fraction at 79% hydrolysis. These fatty acids were named tuna-FFA-Ps. Selective esterification was then conducted at 30°C for 20 h by stirring a mixture of 4.0 g of tuna-FFA-Ps/lauryl alcohol (1:2, mol/mol), 1.0 g water, and 1,000 U of Rhizopus delemar lipase. As a result, the DHA content in the unesterified FFA fraction could be raised from 24 to 72 wt% in an 83% yield. To elevate the DHA content further, the FFA were extracted from the reaction mixture with n-hexane and esterified again under the same conditions. The DHA content was raised to 91 wt% in 88% yield by the repeated esterification. Because selective esterification of fatty acids with lauryl alcohol proceeded most efficiently in a mixture that contained 20% water, simultaneous reactions during the esterification were analyzed qualitatively. The fatty acid lauryl esters (L-FA) generated by the esterification were not hydrolyzed. In addition, L-FA were acidolyzed with linoleic acid, but not with DHA. These results suggest that lauryl DHA was generated only by esterification.  相似文献   

18.
A multi‐stage temperature‐programmed fractionating crystallization process was carried out to examine the effects of the presence of stearic acid (SA), oleic acid (OA), and linoleic acid (LA) on the separation of elaidic acid (EA). The results showed that the efficiency of fractionating crystallization of EA depended largely on the crystallization temperature, initial concentration of EA and presence of SA. The content of SA plays very important role for the fractionating performance. It was a characteristic observation that only when SA <2%, substantial crystallization of EA (>50% in stepwise crystal fractions) were obtained regardless of the initial concentration of SA. In general, SA induced crystallization of EA in earlier stage but delayed further crystallization of EA in later stage; the crystallization of EA was independent from co‐existing OA and LA. After reduction of EA content in solution to certain extent (7–10%, at ?20°C), further reduction of EA content requires much lower crystallization temperatures (trans‐fatty acids (TFA) from partially hydrogenated soybean oil (PHSO) is of high commercial interest. One of the strategies is to selectively release TFAs as free fatty acids from PHSO enzymatically. However, all commercially available enzymes are far away from qualified to selectively release TFAs, where there are always substantial non‐trans FAs hydrolyzed simultaneously. Therefore, developing post‐processing technology is requisite in order to recover those non‐trans fatty acids. Thus, this model system was designed based on FA composition characteristic of PHSO, which aimed to acquire some basic data and experience that lack in available literatures, so as to serve designing efficient practical process for removing trans‐fatty acid moieties from PHSO. The results from this work may be of general value to achieve a better understanding of fractionating crystallization behaviors of different FAs, relationship with individual molecular feature and property, and their interference effects, which might contribute to the design of practically feasible protocol to remove TFAs from PHSO and recover non‐trans FAs at the same time.  相似文献   

19.
Fatty acids in the microalga Phaeodactylum tricornutum were isolated using an optimized three-step method: extraction of crude fatty acid potassium salts made by direct saponification of lipids in the microalgal biomass with KOH/ethanol (96%, vol/vol), separation of unsaponifiable lipids by extraction with hexane, and final purification of fatty acids by acidification of the alcoholic solution of potassium soaps followed by extraction of fatty acid into hexane. Direct saponification was carried out in ethanol (96%, vol/vol) using 2.09 mL ethanol (96%) per gram of wet biomass (10 mL/g of dry biomass) mixed with 0.4 g KOH/g of biomass. Under these conditions the fatty acid yield was 87%. The optimal water content of the alcoholic solution for extraction of the unsapononifiables was established as 40%, w/w. Data on equilibrium carotenoid distribution between the alcoholic (40%, w/w water) and hexane phases were determined. These data allow prediction of the carotenoid yields with different volumes of hexane in several extraction steps. The optimal pH of the alcoholic solution before extracting the purified fatty acid was established as pH 6, and the equilibrium fatty acid distribution between the alcoholic and hexane phases was determined. This optimized method permited a 20% reduction in the production costs of highly purified eicosapentaenoic acid (EPA) in the three-step preparative process (extraction of fatty acid, concentration of polyunsaturated fatty acids by the urea method, and EPA fractionation through preparative high-performance liquid chromatography) previously developed by the authors.  相似文献   

20.
An infant formula fat analog with capric acid mostly esterified at the sn‐1,3 positions, and substantial amounts of palmitic, docosahexaenoic (DHA), and arachidonic (ARA) acids at the sn‐2 position, was prepared by physically blending enzymatically synthesized structured lipids (SL) with vegetable oils. The components of the blend included high sn‐2 palmitic acid SL enriched with capric acid (SLCA), canola oil (CAO), corn oil (CO), high sn‐2 DHA (DHAOm), and high sn‐2 ARA (ARAOm) enzymatically modified oils. Each component was proportionally blended to match the fatty acid profile of commercial fat blends used for infant formula. The infant formula fat analog (IFFA1) was characterized for total and positional fatty acids (FA), triacylglycerol (TAG) molecular species, thermal behavior, and tocopherol content. IFFA1 contained 17.37 mol% total palmitic acid of which nearly 35 % was located at the sn‐2 position. The total capric acid content was 13.93 mol%. The content of DHA and ARA were 0.49 mol% (48.18 % at sn‐2) and 0.57 mol% (35.80 % at sn‐2), respectively. The predominant TAG were OPO (24.09 %), POP (15.70 %), OOO (11.53 %), and CLC (7.79 %). The melting completion and crystallization onset temperatures were 18.65 and ?2.19 °C, respectively. The total tocopherol content was 566.45 μg/g. This product might be suitable for commercial production of infant formulas.  相似文献   

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