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1.
E. Molina Grima A. Robles Medina A. Giménez Giménez J. A. Sánchez Pérez F. Garcia Camacho J. L. García Sánchez 《Journal of the American Oil Chemists' Society》1994,71(9):955-959
Seven solvent mixtures have been used to extract the lipid fraction of lyophilized biomass ofIsochrysis galbana. Six of them were composed of biocompatible solvents. Each method was carried out under relaxed operating conditions (i.e.,
one hour at room temperature) with extraction in a nitrogen atmosphere to prevent autooxidation and degradation of polyunsaturated
fatty acids (PUFAs). Apart from the well-established Bligh and Dyer method [Can. J. Biochem. Physiol. 37:911 (1959)] (Cl3CH/MeOH/H2O, 1∶2∶0.8, vol/vol/vol), which rendered the highest yield of lipids (93.8%), ethanol (96%) and hexane/ethanol (96%), 1∶2.5
vol/vol produced the best results (84.4 and 79.6%, respectively). To obtain free fatty acids, KOH was added to the solvent
mixtures used to extract the total lipids, except for Cl3CH/MeOH/H2O, and direct saponification was carried out at 60°C for 1 h or at room temperature for 8 h. The highest yields obtained by
direct saponicification were 81% with hexane/ethanol (96%), 1∶2.5, vol/vol and 79.8% with ethanol (96%). Partial yields of
the mainn-3 PUFAs found inI. galbana, stearidonic acid (SA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), were calculated for both extraction methods.
For lipid extraction with ethanol (96%), yields of 91, 82 and 83% were obtained for SA, EPA and DHA, respectively. When direct
saponification was used, hexane/ethanol (96%; 1∶2.5, vol/vol) produced the best yields of (91, 79 and 69% for SA, EPA and
DHA, respectively). 相似文献
2.
M. Cartens E. Molina Grima A. Robles Medina A. Giménez Giménez J. Ibáñez González 《Journal of the American Oil Chemists' Society》1996,73(8):1025-1031
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
3.
A. Robles Medina A. Giménez Giménez F. García Camacho J. A. Sánchez Pérez E. Molina Grima A. Contreras Gómez 《Journal of the American Oil Chemists' Society》1995,72(5):575-583
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
4.
Antonio Ramírez Fajardo Luis Esteban Cerdán Alfonso Robles Medina Fracisco Gabriel Acién Fernández Pedro A. González Moreno Emilio Molina Grima 《European Journal of Lipid Science and Technology》2007,109(2):120-126
Ethanol was used for the extraction and purification of lipids from the biomass of the microalga Phaeodactylum tricornutum. This microalga is an oil‐rich substrate with a high proportion of eicosapentaenoic acid (EPA). The process consisted of two steps. First, ethanol (96% vol/vol) was used to extract the lipids from the lyophilized biomass. Second, a biphasic system was formed by adding water and hexane to the extracted crude oil. In this way, most of the lipids were transferred to the hexanic phase while most impurities remained in the hydroalcoholic phase. The first step was carried out by two consecutive extractions at room temperature, each with 5 mL ethanol per gram of biomass, for 10 and 1.25 h, respectively. Under these conditions, over 90% of the saponifiable lipids in the biomass were extracted. In the second step, the percentage of water in the hydroalcoholic phase, the hexane/hydroalcoholic phase ratio and the number of extraction steps were optimized. A water content of 40% vol/vol in the hydroalcoholic phase provided the highest lipid recovery. A recovery yield of 80% was obtained by four consecutive extractions with a hexane/hydroalcoholic phase ratio of 0.2 (vol/vol). Equilibrium distribution data of the lipids between the hydroethanolic and the hexanic phases were also obtained in order to predict the lipid recovery yield of the extraction. This process is an alternative to the traditional methods of lipid extraction, which uses less toxic solvents and reduces the total amount of solvents used. 相似文献
5.
Milan Čertík Peter Andráši Ján Šajbidor 《Journal of the American Oil Chemists' Society》1996,73(3):357-365
The effect of extraction procedures on the lipid yield and fatty acid composition of total lipid and main lipid structures
(phospholipids, diacylglycerols, triacylglycerols, free fatty acids, and sterol esters) of fungal biomass (Mucor mucedo CCF-1384) containing γ-linolenic acid (GLA) was investigated. Seventeen extraction methods, divided into three groups, were
tested: six with chloroform/methanol, five with hexane/alcohols, and six with common solvents or mixtures. The chloroform/methanol
procedure (2∶1) was selected as standard, where lipid yield (TL/DCW, total lipid per dry cell weight) was 17.8%, considered
to be 100% of lipids present. All chloroform/methanol extractions yielded more than 83% recorvey of lipids. Use of hexane/isopropanol
solvent systems led to a maximum of 75% recovery. The best lipid yield was achieved by a two-step extraction with ethanol
and hexane (120%). Extraction efficiency of the other solvent systems reached a maximum of 73%. Triacylglycerols were the
main structures of lipid isolated; only methanol-extracted lipid contained 58.5% phospholipids. The fatty acid content of
total recovered lipid was variable and depended on both the lipid class composition and the solvent system. GLA concentrations
in total lipids isolated by hexane/alcohol procedures (7.3–10.7%) are comparable with classical chloroform/methanol systems
(6.5–10.0%). The maximal GLA yield was obtained with chloroform/methanol/n-butanol/water/0.1 M ethylenediaminetetraacetic acid (EDTA) (2∶1∶1∶1∶0.1, by vol) and after two-step extraction with ethanol
and hexane (14.3 and 13.7 g GLA/kg DCW, respectively). The highest GLA content was analyzed in the phospholipid fraction (16.1%)
after using chloroform/methanol/n-butanol/water/0.1 M EDTA (2∶1∶1∶1∶0.1, by vol). Remarkably low concentrations of polyunsaturated fatty acids were determined
in the free fatty acid fraction. 相似文献
6.
Dennis J. O’Brien Gerard E. Senske 《Journal of the American Oil Chemists' Society》1994,71(9):947-950
Utilization of lipids containing eicosapentaenoic acid (EPA) produced by microorganisms requires processes for their efficient
recovery from microbial cells. Recovery of EPA from mycelia of the fungusPythium irregulare by solvent extraction with hexane-isopropanol (HIP) in a pilot-plant colloid mill was investigated. Extraction efficiencies
of 96% for lipid and EPA were achieved with a 3∶2 (vol/vol) HIP mixture by milling wet, filtered mycelia for 5 min at a solvent/dry
solids ratio of 100 L/kg. The process yielded a crude extract that contained up to 96% lipid and an EPA content as high as
24% (with no selectivity for EPA). 相似文献
7.
Douglas G. Hayes Kenneth D. Carlson Robert Kleiman 《Journal of the American Oil Chemists' Society》1996,73(9):1113-1119
The lipolysate from immobilizedRhizomucor miehei lipase (Lipozyme
tm
)-catalyzed hydrolysis of lesquerella oil contains typically 35% free fatty acid (FFA), 2% monoglyceride, 25% diglyceride
(DG), and 38% triglyceride (TG). Of the FFA, 75–80% are hydroxy acids (HFA). Various methods for isolating HFA from the lipolysate
were examined, and a novel saponification/extraction method was developed. Lipolysate was mixed with 4 vol equivalents each
of KOH/phosphate buffer and polar organic solvent. Hexane was then added to enhance phase separation. Three phases formed:
a lower aqueous phase containing nothing of interest, a polar organic solvent middle phase that contained mostly fatty acid
soaps, and a hexane-rich upper phase that contained mostly DG and TG, which can be recycled to a relipolysis step. The middle
phase, when treated with concentrated hydrochloric acid, NaCl-saturated water, and hexane, released the FFA into the hexane.
This fraction, referred to as the “Product” contained >99% of the FFA released in the lipolysis. “Product” consisted of 85–90%
FFA, of which 75–80% was HFA. The other 10–15% of the “Product” consisted of partial glycerides and TG. The most critical
parameters for the extraction are the pH of the aqueous solution and the polarity of the organic solvent (acetone was found
to be the best choice). Additional purification steps for the “Product” are discussed. 相似文献
8.
Gudmundur G. Haraldsson Björn Kristinsson Ragnheidur Sigurdardottir Gudmundur G. Gudmundsson Harald Breivik 《Journal of the American Oil Chemists' Society》1997,74(11):1419-1424
The objective of this study was to investigate the use of lipases as catalysts for producing concentrates of eicosapentaenoic
acid (EPA) and docosahexaenoic acid (DHA) from fish oil as an alternative to conventional chemical procedures. Transesterification
of fish oil with ethanol was conducted under anhydrous solvent-free conditions with a stoichiometric amount of ethanol. Among
the 17 lipases tested, the results showed that Pseudomonas lipases had the highest activity toward the saturated and monounsaturated fatty acids in the fish oil, much lower activity
toward EPA and DHA and, at the same time, good tolerance toward the anhydrous alcoholic conditions. With 10 wt% of lipase,
based on weight of the fish oil triacylglycerol substrate (15% EPA and 9% DHA initial content), a 50% conversion into ethyl
esters was obtained in 24 h at 20°C, in which time the bulk of the saturated and monounsaturated fatty acids reacted, leaving
the long-chain n-3 polyunsaturated fatty acids unreacted in the residual mixture as mono-, di-, and triacylglycerols. This
mixture comprised approximately 50% EPA+DHA. Total recovery of DHA and EPA was high, over 80% for DHA and more than 90% for
EPA. The observed fatty acid selectivity, favoring DHA as a substrate, was most unusual because most lipases favor EPA. 相似文献
9.
Saeree Jareonkitmongkol Sakayu Shimizu Hideaki Yamada 《Journal of the American Oil Chemists' Society》1993,70(2):119-123
A Δ12 desaturase-defective mutant of an arachidonic acid (AA)-producing fungus,Mortierella alpina 1S-4, converted α-linolenic acid (18:3ω3) to 5(Z),8(Z),11(Z),14(Z),17(Z)-eicosapentaenoic acid (EPA). On submerged cultivation at 20°C for 10 d in a 5-L fermentor containing medium comprising 1%
glucose, 1% yeast extract and 3% (vol/vol) linseed oil, EPA production amounted toca. 1 g/L culture broth (64 mg/g dry mycelium), which accounted forca. 20% of the total mycelial fatty acids. AA content was 26 mg/g dry mycelium (0.4 g/L), accounting for 7.8% of the total mycelial
fatty acids. The other major mycelial fatty acids were palmitic acid (4.5%), oleic acid (20.4%), linoleic acid (10.0%), 18:3ω3
(20.3%) and lignoceric acid (4.3%). Most of the EPA produced (ca. 90 mol%) was in triglyceride form. 相似文献
10.
This study deals with the covalorization of spent bleaching clay (SBC) and palm fatty acid distillate (PFAD), the by-products of palm oil-refining plants (3 Mt. year−1), through soap manufacture. Obtained SBC and PFAD samples show differing acidity and saponification values depending on their content of free fatty acids and of acylglycerols. The SBC sample had an acidity of 60.5% and a saponification value of 182 mg KOH g−1 of oil, and the PFAD sample has an acidity of 88.4% and a saponification value of 204 mg KOH g−1 of oil. Soaps are prepared using the stoichiometric amount of NaOH, under varying proportion of water introduced through the basic solution. The overall reaction (neutralization and saponification) is complete (99.9%) with PFAD, whereas the yield reaches only 56.1% with SBC. When mixing SBC and PFAD, for example under a 1:1 weight ratio, the overall reaction completion (87.7%) is surprisingly higher than expected based on the computed individual reaction yields (78%), showing a synergistic effect of about 10% on the course of the saponification reaction of acylglycerols in SBC. The water content was found to be a critical parameter, 30% w/w of added water providing the highest yield. These results show an innovative way for covalorizing two important by-products of palm oil industrial processing as a single final product. By-products of the physical refining of other oils could also be valorized following the same method. 相似文献
11.
Structured lipids (SL) containing n-3 polyunsaturated (eicosapentaenoic or docosahexaenoic) and mediumchain (caprylic) fatty
acids were synthesized in gram quantities and characterized. Tricaprylin was mixed with n-3-rich polyunsaturated fatty acids
in a 1:2 molar ratio and transesterified by incubating at 55°C in hexane with SP 435 lipase (10% by wt of total substrates)
in a 125-mL Erlenmeyer flask as the bioreactor. After several batches of reaction, the products were pooled and hexane was
evaporated. Short-path distillation was used for purification of synthesized SL. The distillation conditions were 1.1 Torr
and 170°C at a feed flow rate of 3 mL/min. Up to 240 g of SL was isolated and deacidified by alkaline extraction or ethanol-water
solvents. The fatty acid profile, free fatty acid value, saponification number, iodine value, peroxide value, thiobarbituric
acid, and conjugated diene contents were determined. Oxidation stability, with α-tocopherol as antioxidant, and the oxidative
stability index were also determined. 相似文献
12.
不同亚临界溶剂从微拟球藻湿藻泥中提取油脂 总被引:2,自引:0,他引:2
以微拟球藻(Nannochlorsis sp.)湿藻泥为原料,研究了亚临界乙醇、亚临界乙醇-正己烷共溶剂及硫酸辅助亚临界乙醇-正己烷共溶剂3种萃取体系对微藻油脂提取的影响. 结果表明,亚临界乙醇-正己烷比亚临界乙醇对湿藻细胞有更高的油脂萃取率和低的溶剂用量,加入少量硫酸可进一步提高油脂的提取率、降低溶剂用量. 微拟球藻湿藻泥(含水约70%)优化提取条件为,正己烷/乙醇体积比3:1,液固比(溶剂/藻细胞干重)7 mL/g,加入藻细胞干重6%的硫酸,1.5 MPa下90℃萃取30 min,在此条件下油脂提取率可达90%以上. 3种萃取体系获得的微藻油脂均以甘油三酯为主,甘油三酯的脂肪酸主要为C16:0, C18:1和C16:1,其中硫酸辅助亚临界共溶剂萃取的微藻油脂中甘油三酯含量最高,约占总脂的86%以上. 相似文献
13.
Angélica Ganga Susana Nieto Julio Sanhuez Claudio Romo Hernán Speisky Alfonso Valenzuela 《Journal of the American Oil Chemists' Society》1998,75(6):733-736
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
14.
Zvi Cohen 《Journal of the American Oil Chemists' Society》1994,71(9):941-945
Interest in the polyunsaturated fatty acid eicosapentaenoic acid (EPA) as a therapeutic agent is steadily increasing. The
microalgaMonodus subterraneus produces EPA, which is concentrated mainly in the galactolipid fraction, as its major fatty acid. Nitrogen starvation increased
the fatty acid content but reduced the proportion and content of EPA to 19.5% (of fatty acids) and 1.8% (of dry weight), respectively.
Cultivation under low light intensity or high biomass concentration enhanced the proportion of EPA up to 36.7% of fatty acids
and the content to 4.4% of dry weight. Maximal EPA productivity of 25.7 mg·L−1·d−1 was obtained at the biomass concentration that resulted in the highest biomass productivity.M. subterraneus is thus one of the most promising candidates for phototrophic production of EPA. 相似文献
15.
H. Kim S. R. Gandhi R. A. Moreau J. D. Weete 《Journal of the American Oil Chemists' Society》1998,75(11):1657-1665
Lipids of the marine oomycetous microbe Haliphthoros philippinensis were characterized by chromatographic and spectroscopic techniques. Total lipid content of this organism was relatively low
and not very responsive to manipulation of the culture conditions. Neutral lipid comprised 21% of the total lipid and the
polar lipids were mainly phosphatidylcholine (44%), phosphatidylethanolamine (15%), and a ceramide-phosphorylethanolamine
(19%). Palmitic (16:0) was the primary saturated fatty acid at 25% of the total fatty acids, and arachidonic acid (20:4n-6,
ARA) and eicosapentaenoic acid (20:5n-3, EPA) were the major unsaturated fatty acids at 19 and 21%, respectively. Fucosterol
was the principal sterol at 59% of the total sterols. The effects of several cultivation variables on growth and EPA production
by this species were investigated. Among those tested, glucose and sodium glutamate were the most efficient carbon and nitrogen
sources for growth, respectively. When the mycelium was cultivated for 6 d to produce biomass under optimal growth conditions,
and then transferred to low temperature for an additional 13 d without glucose, the EPA content reached 31% of the total fatty
acids and the yield was 203 mg/L. When the same experiment was performed with glucose supplementation during the low-temperature
phase, EPA composed 27% of total fatty acids and yield reached 316 mg/L, or a 285% increase over that from mycelium cultured
for 6 d at 24°C, and 56% over that cultured at 16°C for 13 d. ARA production did not respond accordingly. 相似文献
16.
17.
Norman S. Radin 《Lipids》1974,9(5):358-360
A convenient method for large or small scale preparation of psychosine from cerebroside has been developed by adaptation of
published procedures. Cerebroside is refluxed with butanol and aqueous KOH, then the KOH is removed with perchloric acid.
The fatty acids are removed by extraction with hexane and the excess perchloric acid is removed by partitioning between chloroform,
ethanol, and water. 相似文献
18.
Jos Luis Guil‐Guerrero Antonio Gimnez‐Gimnez Alfonso Robles‐Medina María del Mar Rebolloso‐Fuentes El‐Hassan Belarbi Luis Esteban‐Cerdn Emilio Molina‐Grima 《European Journal of Lipid Science and Technology》2001,103(5):271-278
The free fatty acids eicosapentaenoic acid (C20:5ω3, EPA) and docosahexaenoic acid (C22:6ω3), obtained from the microalgae Phaeodactylum tricornutum, and the EPA methyl ester were compared with regard to their extent of peroxidation using different storage conditions. Several series were stored according to selected variables: hexane addition versus no addition, 4 °C versus 25 °C, and antioxidant addition (octyl gallate) versus no antioxidant addition, always in the dark. Previously, the EPA and methyl EPA structures were confirmed by NMR spectra to discard the formation of conjugated dienes after the downstream process. The results showed that the stability was higher for methyl EPA than for the free fatty acid, and that peroxidation can be retarded by low temperature storage and mainly by hexane addition. The peroxidation process was evaluated by the peroxide value (spectrophotometric method by iodine absorption), although the conjugated diene absorbance and the loss in percentage of the fatty acid have been tested as good indicators of the peroxidation process. A simple kinetic model that explains the peroxidation process during the initiation and propagation steps is given. 相似文献
19.
Combined Urea Complexation and Argentated Silica Gel Column Chromatography for Concentration and Separation of PUFAs from Tuna Oil: Based on Improved DPA Level
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Hongyan Mu Jun Jin Dan Xie Xiaoqiang Zou Xiaosan Wang Xingguo Wang Qingzhe Jin 《Journal of the American Oil Chemists' Society》2016,93(8):1157-1167
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
20.
Separation of eicosapentaenoic acid and docosahexaenoic acid in fish oil by kinetic resolution using lipase 总被引:5,自引:0,他引:5
Gudmundur G. Haraldsson Björn Kristinsson 《Journal of the American Oil Chemists' Society》1998,75(11):1551-1556
The objective of this study was to investigate the use of lipases as catalysts for separating eicosapentaenoic acid (EPA)
and docosahexaenoic acid (DHA) in fish oil by kinetic resolution. Transesterification of various fish oil triglycerides with
a stoichiometric amount of ethanol by immobilized Rhizomucor miehei lipase under anhydrous solvent-free conditions resulted in a good separation. When free fatty acids from the various fish
oils were directly esterified with ethanol under similar conditions, greatly improved results were obtained. By this modification,
complications related to regioselectivity of the lipase and nonhomogeneous distribution of EPA and DHA into the various positions
of the triglycerides were avoided. As an example, when tuna oil comprising 6% EPA and 23% DHA was transesterified with ethanol,
65% conversion into ethyl esters was obtained after 24 h. The residual glyceride mixture contained 49% DHA and 6% EPA (8:1),
with 90% DHA recovery into the glyceride mixture and 60% EPA recovery into the ethyl ester product. When the corresponding
tuna oil free fatty acids were directly esterified with ethanol, 68% conversion was obtained after only 8h. The residual free
fatty acids comprised 74% DHA and only 3% EPA (25:1). The recovery of both DHA into the residual free fatty acid fraction
and EPA into the ethyl ester product remained very high, 83 and 87%, respectively. 相似文献