Effect of Extraction Method on the Oxidative Stability of Camelina Seed Oil Studied by Differential Scanning Calorimetry

Camelina seed is a new alternative omega‐3 source attracting growing interest. However, it is susceptible to oxidation due to its high omega‐3 content. The objective of this study was to improve the oxidative stability of the camelina seed oil at the extraction stage in order to eliminate or minimize the use of additive antioxidants. Camelina seed oil extracts were enriched in terms of natural antioxidants using ethanol‐modified supercritical carbon dioxide (SC‐CO₂) extraction. Oxidative stability of the camelina seed oils extracted by ethanol modified SC‐CO₂ was studied by differential scanning calorimeter (DSC), and compared with cold press, hexane, and SC‐CO₂ methods. Nonisothermal oxidation kinetics of the oils obtained by different extraction methods were studied by DSC at varying heating rates (2.5, 5, 10, and 15 ° C/min). Increasing ethanol level in the ethanol‐modified SC‐CO₂ increased the oxidative stability. Based on oxidation onset temperatures (T_on), SC‐CO₂ containing 10% ethanol yielded the most stable oil. Oxidative stability depended on the type and content of the polar fractions, namely, phenolic compounds and phospholipids. Phenolic compounds acted as natural antioxidants, whereas increased phospholipid contents decreased the stability. Study has shown that the oxidative stability of the oils can be improved at the extraction stage and this may eliminate the need for additive antioxidants.     

Extraction of antioxidants from several berries pressing wastes using conventional and supercritical solvents

The solid waste generated in industrial berry juice production was considered as a low cost raw material for the extraction of natural antioxidants. Berries contain phenolic compounds with high antioxidant potential, including anthocyanins, proanthocyanidins, flavonols, catechins, benzoic and cinnamic acids. The solid residues generated from blueberry, cranberry and raspberry after pressing were extracted by conventional solvent extraction or by supercritical CO₂ (SC–CO₂) extraction. The effect of particle size and extraction time on the extraction yield, phenolic yield and phenolic content of the extracts produced by conventional solvents was assessed. Supercritical CO₂ extraction was performed during 2 h operating in the range 80–300 bar at 60 °C using 2.5 L CO₂/h. Maximum solubles yield of 5.20% were extracted from raspberry wastes at 200 bar, 3.89% from cranberry wastes at 250 bar and 1.4% from blueberry wastes at 200 bar. The highest phenolic content of the extracts was observed for blueberry pomace in the trap, with 9 grams of gallic acid equivalents per 100 g of extract. The ABTS (2, 2′-azino-bis-[3-ethylbenzotiazol-6-sulfonic acid]) and DPPH (α,α-diphenyl-β-picrylhydrazyl) radical scavenging capacity of the SC–CO₂ extracts was moderate in comparison with the activity of conventional solvent extracts.     

Extraction of boldo (Peumus boldus M.) leaves with supercritical CO2 and hot pressurized water

High-activity fractions in boldo leaves were extracted with supercritical CO₂ (SC-CO₂) and hot pressurized water (HPW). Total yield after 3 h of extraction (0.6–3.5%) in low-pressure SC-CO₂ experiments increased with process pressure (60–150 bar) and decreased with temperature (30–60 °C), as expected. The extract obtained with SC-CO₂ at 50 °C and 90 bar contained approximately 50% of essential oil components. In higher pressure experiments with solvent mixtures, the yield increased with pressure (300–450 bar) and modifier concentration (2–10% ethanol), ranging 0.14–1.95 ppm for the alkaloid boldine and 1.8–4.8% for total solids following 1.5 h treatment at 50 °C. Boldine recovery was solubility-controlled, reaching 7.4 ppm after 7-h extraction at 450 bar and 50 °C using an ethanol–SC-CO₂ mixture (5% co-solvent). Boldine solubility and yield decreased when using pure CO₂ at higher pressure (600 bar, 50 °C). The extract yield after 3 h batch-wise HPW extraction increased from 36.9% at 100 °C to 53.2% at 125 °C, and then decreased as temperature was increased to 175 °C. Boldine yield decreased from 26.8 ppm at 100 °C to 0.7 ppm at 125 °C, and was negligible at ⩾150 °C. The essential oil yield increased to a maximum at 110 °C and was negligible at ⩾150 °C also. The ranking of antioxidant potency of various extracts was as follows: HPW at 110 °C > methanol (soxhlet extraction) ≫ high-pressure SC-CO₂ with or without polar co-solvent > low-pressure SC-CO₂.     

Extraction of fennel (Foeniculum vulgare Mill.) seeds with supercritical CO2: Comparison with hydrodistillation

Ground fennel (Foeniculum vulgare Mill.) seeds, growing wild in Montenegro, were extracted with supercritical CO₂ (SC-CO₂) at a flow rate of 0.2 kg CO₂/h under varying extraction conditions in order to determine yield, composition and organoleptic characteristics of extract. The extracts obtained were compared to fennel seed oil isolated by hydrodistillation. In the SC-CO₂, extracts as well in the hydrodistilled oil, the major compounds were trans-anethole (68.6–75.0%) and (62.0%), methylchavicol (5.09–9.10%) and (4.90%), fenchone (8.40–14.7%) and (20.3%), respectively. With pressure varying from 80 to 150 bar and temperature varying from 40 to 57 °C, it was found that, for the selected herb material, the optimal conditions of SC-CO₂ extraction (high percentage of trans-anethole, with significant content of fenchone and reduced content of methylchavicol and co-extracted cuticular waxes) are: pressure, 100 bar; temperature, 40 °C; extraction time, 120 min. Organoleptic tests confirmed that hydrodistilled oil possessed a less intense fennel seed aroma than extracts obtained by SC-CO₂.     

Enhanced inactivation of pectin methyl esterase in orange juice using modified supercritical carbon dioxide treatment

The aim of the study is to quantify the effect of ethanol addition and exposure surface on the inactivation of pectin methyl esterase (PME), a juice clarifying enzyme, in orange juice using supercritical carbon dioxide (SC‐CO₂). Addition of ethanol to the SC‐CO₂ at 2% (v/v) caused greater inactivation than SC‐CO₂ alone, with a maximum reduction of PME activity of 97% at 30 MPa and 40 °C for 60 min. As the surface area to volume ratio was increased, the rate of inactivation of PME increased. Analysis of first‐order reaction kinetic data revealed that D values were greatly influenced by ethanol addition and agitation. With the addition of 2% ethanol, the D value reduced by half, that is, 56 min from 109 min. With impeller agitation of the sample at 1100 ± 100 rpm, the D value for PME was further reduced to 43 and 30 min without and with ethanol, respectively. The activity of PME treated with SC‐CO₂ remained unchanged after 14 days of storage at 4 °C. Treatment did not significantly change pH or colour, but did significantly increase the cloud values of the juice, resulting in a cloud stabilised juice with similar qualities to fresh juice.     

Free radical-scavenging activity of Aloe vera (Aloe barbadensis Miller) extracts by supercritical carbon dioxide extraction

The free radical-scavenging activities of extracts of Aloe vera of leaf skin by supercritical CO₂ extraction and solvent extraction were determined. An orthogonal array design matrix of L₉ (3⁴) was considered to optimize supercritical carbon dioxide extraction processing at a CO₂ flow rate of 12–36 l h⁻¹, 35–45 MPa and 32–50 °C. The optimum extracted yield of 1.47% was provided at 50 °C 36 l h⁻¹, 35 MPa and 20% of modifier of methanol. These four factors were all demonstrated to be significantly crucial in the supercritical carbon dioxide extraction operation, as two-variable interactions. The extracts of A. vera rind by supercritical carbon dioxide extraction and solvent extracts provided significantly higher free radical-scavenging activities of 33.5% and 39.7%, respectively, than extracts of A. vera gel extracted by ethanol with a free radical-scavenging activity of 14.2%. The inhibition percentage of extracts of A. vera and reference antioxidants followed the decreasing order: Trolox (76.8%) > ethanol extracts of A. vera skin (39.7%) > BHT (35.9%) > the extract of supercritical carbon dioxide extraction (33.5%) >α-tocopherol (25.6%) > ethanol extracts of A. vera pulp (14.2%). Compared to BHT and α-tocopherol, the extracts of A. vera skin, by supercritical carbon dioxide extraction and ethanol, showed stronger antioxidant activities. Components in the rind of A. vera are responsible for the higher antioxidant activity of A. vera extracts.     

Chemical Properties and Oxidative Stability of Perilla Oils Obtained From Roasted Perilla Seeds As Affected by Extraction Methods

Abstract: The chemical properties and oxidative stability of perilla oils obtained from roasted perilla seeds as affected by extraction methods (supercritical carbon dioxide [SC‐CO₂], mechanical press, and solvent extraction) were studied. The SC‐CO₂ extraction at 420 bar and 50 °C and hexane extraction showed significantly higher oil yield than mechanical press extraction (P < 0.05). The fatty acid compositions in the oils were virtually identical regardless of the extraction methods. The contents of tocopherol, sterol, policosanol, and phosphorus in the perilla oils greatly varied with the extraction methods. The SC‐CO₂‐extracted perilla oils contained significantly higher contents of tocopherols, sterols, and policosanols than the mechanical press‐extracted and hexane‐extracted oils (P < 0.05). The SC‐CO₂‐extracted oil showed the greatly lower oxidative stability than press‐extracted and hexane‐extracted oils during the storage in the oven under dark at 60 °C. However, the photooxidative stabilities of the oils were not considerably different with extraction methods.     

Effect of fruit ripeness and method of fruit drying on the extractability of avocado oil with hexane and supercritical carbon dioxide

BACKGROUND: Oil yield from avocado fruit may be influenced by fruit pre‐treatment and extraction method. Unripe and ripe avocado fruit pieces were deep‐frozen at ? 20 °C and either freeze‐dried or oven‐dried (80 °C). Oil yield from these samples was determined after extraction with hexane and supercritical carbon dioxide (SC‐CO₂). The fruit samples were examined using scanning electron microscopy before and after oil extraction. RESULTS: Average oil yield from ripe fruit (freeze‐dried and oven‐dried combined) was 72 g kg^?1 higher than from unripe fruit for SC‐CO₂ extracts and 61 g kg^?1 higher for hexane extracts. This may be due to enzymatic degradation of parenchyma cell walls during ripening, thus making the oil more available for extraction. Freeze‐dried samples had a mean oil yield 55 g kg^?1 greater than oven‐dried samples for SC‐CO₂ extracts and 31 g kg^?1 higher for hexane extracts. However, oil yields from ripe fruit (freeze‐dried and oven‐dried) subjected to hexane extraction were not significantly different. All hexane extracts combined had a mean oil yield 93 g kg^?1 higher than SC‐CO₂ extracts. CONCLUSION: SC‐CO₂ may be more selective and may create paths of least resistance through the plant material. Hexane, on the other hand, is less selective and permeates the whole plant material, leading to more complete extraction and higher oil yields under the experimental conditions. Copyright © 2007 Society of Chemical Industry     

In vitro inhibitory effects of cranberry bean (Phaseolus vulgaris L.) extracts on aldose reductase, α‐glucosidase and α‐amylase

The in vitro inhibitory activities of different seed extracts prepared from cranberry bean mutant SA‐05 and its wild‐type variety Hwachia against aldose reductase, α‐glucosidase and α‐amylase were examined. The results indicated that the polyphenolics‐rich extracts obtained using 800 g kg^?1 methanol and 500 g kg^?1 ethanol demonstrated inhibitory activities against aldose reductase (IC₅₀ of 0.36–0.46 mg mL^?1) and α‐glucosidase (IC₅₀ of 1.32–1.94 mg mL^?1). The 500 g kg^?1 ethanol extracts also showed α‐amylase inhibitory activities (IC₅₀ of 70.11–80.22 μg mL^?1). Subsequent extracts, prepared further with NaCl and H₂O from precipitates of 800 g kg^?1 methanol or 500 g kg^?1 ethanol extracts, exhibited potent α‐amylase inhibitory activities (IC₅₀ of 17.68–38.68 μg mL^?1). A combination of 500 g kg^?1 ethanol extraction plus a subsequent H₂O extraction produced highest polyphenolics and α‐amylase inhibitors. The SA‐05 α‐amylase inhibitor extracts showed greater inhibitory activities than that of Hwachia. Thus, cranberry bean mutant SA‐05 is an advantageous choice for producing anti‐hyperglycaemic compounds.     

Optimisation of supercritical CO2 extraction of grape seed oil using response surface methodology

The aim of this study was to use waste from the wine production process with special accent on grape seeds and new green technology. Supercritical CO₂ was considered as a green solvent in extraction of grape seed oil. The effects of different extraction process parameters on oil yield and antioxidant activity were investigated. Extraction optimisation was conducted using response surface methodology (RSM). Extraction pressure has proven to be the most significant factor influencing oil yield and antioxidant activity (P < 0.0001). The optimal conditions for obtaining the highest oil yield and antioxidant activity within the experimental range of the variables studied were at extraction pressure of 400 bar and temperature of 41 °C. Under these optimal conditions, the predicted extraction oil yield was 14.49% and DPPH 37.07%. Applying this green extraction method, the oil from grape seeds was totally extracted. The produced oil was of satisfactory quality, and the content of α‐tocopherol in obtained grape seed oil at optimal extraction conditions was 36.05 mg kg^?1.     

Supercritical CO2 extraction optimization of pomegranate (Punica granatum L.) seed oil using response surface methodology

This study examined extraction of pomegranate seed oil by using supercritical carbon dioxide. Response surface methodology was used to evaluate the effects of the process parameters, namely extraction pressure, temperature and CO₂ flow rate on the yield of pomegranate seed oil. The extraction parameters were optimized with a central composite design experiment. The linear term of pressure, followed by the linear term of CO₂ flow rate, the quadratic terms of pressure, temperature and CO₂ flow rate and the interactions between pressure and temperature, as well as CO₂ flow rate and temperature, had significant effects on the oil yield (p < 0.05). Maximum yield of pomegranate seed oil from the mathematical model was predicted to be 156.3 g/kg dry basis under the condition of pressure 37.9 MPa and temperature 47.0 °C with CO₂ flow rate of 21.3 L/h. The fatty acid composition and the tocopherols' content of pomegranate seed oil extracted using supercritical CO₂ were compared with those obtained by Soxhlet method. Minor difference was found in the fatty acid composition of the oils extracted by the two methods. The content of total tocopherols was about 14% higher in the oil extracted with supercritical CO₂ than that obtained by Soxhlet extraction.     

Supercritical CO₂extraction of oleoresin from marigold (Tagetes erecta L.) flowers and determination of its antioxidant components with online HPLC-ABTS(·+) assay

BACKGROUND: Marigold is a traditional medicine herb which shows good pharmacological activity in many aspects. It is very important to obtain and investigate the specific bioactive compounds from marigold. The objective of the study was to extract the oleoresin from marigold with supercritical CO₂ (SC‐CO₂) at different pressures and temperatures, detect the fatty acid composition by gas chromatography–mass spectrometry and investigate the antioxidative components in the extracts by combined online high‐performance liquid chromatography‐2,2‐azinobis‐(3‐ethylbenzothiazolin‐6‐sulfonic acid (HPLC‐ABTS^?+) post‐column assay and HPLC‐tandem mass spectrometry. RESULTS: For the pressure range (20–40 MPa) and temperature range (30–70 °C), 30 MPa/70 °C gave the highest yield of oleoresin (58.9 g kg^?1). The dominant fatty acids of marigold flower oleoresin were linoleic acid (>26.41%), palmitic acid (>24.22%) and oleinic acid (>20.12%). Significant effects of the extraction pressure and temperature on the antioxidant activity were observed (P < 0.05). Lutein esters, α‐tocopherol, β‐tocopherol, γ‐tocopherol and δ‐tocopherol were the dominant antioxidant compounds in the extracts. CONCLUSION: The study has shown that the yield and total antioxidant activity of the marigold extracts were affected by the pressure and temperature of SC‐CO₂, and that online HPLC technique could be used as an efficient and rapid method for separation and identification of bioactive compounds from a complex mixture. Copyright © 2011 Society of Chemical Industry     

Bioactive compounds extracted by liquid and supercritical carbon dioxide from citrus peels

This work investigated the extraction of bioactive compounds from citrus peels, an agri-food waste. Carbon dioxide (CO₂), an eco-friendly solvent, was used under liquid and supercritical conditions to perform the extractions from orange, tangerine and lemon peels. The possibility of using ethanol as a cosolvent at small percentages up to 20% was also studied. The extraction yield, total polyphenolic content, individual polyphenolic profile, antiradical activity and volatile organic compounds of the extracts were evaluated. The highest yields were obtained when 20% ethanol was used as a cosolvent in both liquid (at 20 MPa and 20 °C) and supercritical (at 30 MPa and 60 °C) CO₂ extraction. In addition, the extracts obtained with liquid CO₂ + 20% ethanol showed the highest content of naringin (35.26, 44.05 and 19.86 mg g^-1 in orange, tangerine and lemon peel extracts, respectively) and terpenes, in particular limonene. This type of extract also showed the highest antiradical activity (31.78–59.51 µmolTE g^-1) as measured by both ABTS·+ and DPPH·. These findings show that the extraction with a liquid CO₂ and ethanol mixture could be a valid alternative to traditional solvent extraction using 80% less organic solvent and producing extracts with high antiradical capacity and rich in volatile organic compounds.     

Extraction behaviors of caffeine and chlorophylls in supercritical decaffeination of green tea leaves

The decaffeination of green tea using supercritical carbon dioxide (SC-CO₂) was optimized by response surface methodology (RSM) for the maximal removal of caffeine, and the coextration of chlorophylls was also monitored during decaffeination. The experimental conditions for the SC-CO₂ extraction of caffeine were set up according to the Box-Behnken design of RSM. The relationships between the extraction yield of caffeine and various parameters used for the SC-CO₂ extraction such as pressure, temperature and concentration of ethanol were studied at a fixed CO₂ flow rate. The extraction yields of caffeine and total chlorophyll were significantly influenced by extraction pressure, temperature and concentration of cosolvent, and their extraction yields behaved almost in parallel at different extraction conditions that were obtained by varying pressure, temperature and ethanol cosolvent concentration. At the optimal decaffeination conditions such as 3.0 g of 95% (v/v) ethanol cosolvent per 100 g of CO₂, 23 MPa, 63 °C and an extraction duration of 120 min for 10 g of green tea leaves, the extraction yields for caffeine and catechins were 96.60% (w/w) and 40.61% (w/w), respectively, and the substantial coextraction of total chlorophyll (43.09% of the total amount) was also observed during the decaffeination process.     

Apparent solubility of lycopene and β-carotene in supercritical CO2, CO2 + ethanol and CO2 + canola oil using dynamic extraction of tomatoes

Lycopene and β-carotene were extracted from freeze-dried tomatoes (skin + pulp) with pure SC CO₂ and SC CO₂ + 5% w/w co-solvent at 40 °C, 400 bar and flow rates of 0.5 and 1.2 L/min. The apparent solubility of lycopene and β-carotene in the multicomponent complex system was determined from dynamic extraction experiments using a laboratory-scale supercritical extraction system. Solubility of pure lycopene and β-carotene in SC CO₂ (binary system) was reported in the literature to be of the order of 10⁻⁶ mole fraction. The apparent solubility of lycopene extracted from tomatoes with SC CO₂ (multicomponent complex system) under the same conditions was almost one order of magnitude smaller. The apparent solubility obtained using oil as a co-solvent was higher than that obtained with ethanol as a co-solvent or pure SC CO₂. The differences in solubility are mainly due to the polarity of the co-solvent and the impact of the tomato matrix in the multicomponent complex system.     

Influence of solvent and temperature on extraction of phenolic compounds from grape seed,antioxidant activity and colour of extract

This study was aimed to investigate the influence of solvent (water and ethanol in concentration: 50%, 70% and 96%) and extraction temperature (25–80) °C on polyphenols extraction of grape seed (Vitis vinifera L. cv. “Frankovka”) cultivated in Eastern Croatia. The best results were reached using 50% ethanol at 80 °C. The most abundant individual polyphenolic compound was catechin which makes the average of 45.11% of the total phenolic content followed by epicatechin (34.45%), procyanidin B₂ (12.90%), gallic acid (5.34%), gallocatechin (1.58%), epicatechin gallate (1.01%). The antioxidant activity of extracts was determined by DPPH‐method and it was highly dependent on extraction solvent and temperature. The total extractable proanthocyanidins content of extract had the highest positive correlation (r = 0.994) with antioxidant activity, which indicated that these compounds might be the most important antioxidant in examined grape seed extracts. Relationship between phenolic content and colour of extracts was observed.     

Optimisation of ultrasound extraction for flavonoids from semen astragali complanati and its identification by HPLC‐DAD‐MS/MS

The optimisation of ultrasound extraction of semen astragali complanati flavonoids was studied by measuring characteristic absorbance at 266 nm as the response and using response surface methodology (four‐variable, three‐level Box–Behnken design, BBD) in this article. The optimal conditions were obtained as 52 °C, 34 min, 26:1 (mL:g) and 100 mesh (0.120–0.150 mm) for extraction temperature, extraction time, solvent‐to‐sample ratio as well as particle size, respectively. Under these conditions, validation experiments were carried out and the experimental value of A₂₆₆ was 0.9907 ± 0.032 (n = 3), which corresponded to an experimental extraction yield of 7.08%. Compounds in the extracts obtained with the optimum extraction conditions were identified by high‐performance liquid chromatography coupled with diode array and mass spectrometry detectors (HPLC–DAD–MS). Among the 14 compounds that were tentatively identified in the extracts according to their ultraviolet‐visible spectroscopy, mass spectrometry and related literature reports, four were reported for the first time.     

Tocol Composition and Supercritical Carbon Dioxide Extraction of Lipids from Barley Pearling Flour

Samples of whole grain and 35% pearling flour of 20 different barley varieties grown in Alberta were analyzed for their lipid contents. Total lipid contents of whole grains were within 1.9% to 3.0% (w/w), whereas those of the 35% pearling flour were 4.3% to 7.9%. Lipids of 35% pearling flour fraction of Tercel barley were extracted using supercritical carbon dioxide (SC‐CO₂) at different pressures (24, 45, and 58 MPa) and temperatures (40 and 60 °C) for 3 h. Lipid recoveries of 73% to 97% were achieved using SC‐CO₂ extraction under different operational conditions. Tocol contents and compositions of whole grain, 35% pearling flour, and SC‐CO₂ extracts were analyzed using HPLC. Tocol content of the whole grain was 53.8 to 124.9 μg/g and that of the pearling flour was 195 to 363 μg/g of flour. The hulless barley varieties were higher in tocols, with waxy, double waxy and Tercel varieties having the highest levels (P < 0.05). The ratios of total tocotrienols to total tocopherols varied within 1.6 to 3.9 range. Tocol concentrations of SC‐CO₂ extract fractions varied from 1171 to 4391 μg/g extract depending on the operational conditions. Barley oil is a good natural source of different tocol isomers rich in tocotrienols.     

Influence of hot‐air treatment,superatmospheric O2 and elevated CO2 on bioactive compounds and storage properties of fresh‐cut pomegranate arils

The impact of heat treatment using hot air (HT 45 °C and 55 °C for 1 h) and two active modified atmosphere packaging (MAP) conditions of high oxygen atmosphere (HOA: 80 kPa O₂, 20 kPa N₂) and high CO₂ atmosphere (HCA: 20 kPa CO₂, 80 kPa N₂), individually or combined, on the antioxidant capacity, polyphenols, vitamin C content, total anthocyanins, polyphenoloxydase (PPO) activity and shelf life of fresh‐cut (FC) pomegranate arils stored for 14 days at 4 °C was studied. The results indicate that HT 45 °C along with HOA inhibited PPO activity and prevented loss of antioxidant capacity, vitamin C and phenolic compounds in arils, in comparison with control and HT 55 °C. All treatments reduced the accumulation of anthocyanins, but HCA‐treated arils lost more anthocyanins besides having worse a* colour parameter values. No significant differences in titrable acidity (TA) and total soluble solids (TSS) were observed between treatments. The combination of HOA and HT 45 °C enhanced the benefits of applying each treatment separately and could be useful to improve and extend postharvest life of pomegranate FC arils.     

Original article: Extraction of lipid from scallop (Patinopecten yessoensis) viscera by enzyme‐assisted solvent and supercritical carbon dioxide methods

In the present study, lipid was extracted from scallop (Patinopecten yessoensis) viscera by using the enzyme‐assisted solvent method and the supercritical carbon dioxide (SC‐CO₂) method. Soxhlet extraction with ethyl ether produced a yield of 23.7 ± 0.6 g of lipid 100 g^?1 of dry matter. Enzyme‐assisted solvent extraction allowed recovering 60.6 ± 1.5% of P. yessoensis viscera lipid from the samples treated with papain, whereas a lipid recovery rate of 78.3 ± 0.6% was achieved by SC‐CO₂ extraction. The lipid extracted was divided into the unsaponifiable fraction (sterol) and the saponifiable fraction (fatty acid) and analysed by gas chromatography mass spectrometry. Results indicated that the fatty acid composition and sterol composition for lipids extracted by different methods were slightly different. Eicosapentaenoic acid and docosahexaenoic acid were dominant polyunsaturated fatty acids accounting for 35–40% of the total fatty acid.