γ-Linolenic acid concentrates from borage and evening primrose oil fatty acidsvia lipase-catalyzed esterification

γ-Linolenic acid (GLA, all-cis 6,9,12-octadecatrienoic acid) has been enriched from fatty acids of borage (Borago officinalis L.) seed oil to 93% from the initial concentration of 20% by lipase-catalyzed selective esterification of the fatty acids withn-butanol in the presence ofn-hexane as solvent. The immobilized fungal lipase preparation, Lipozyme, used as biocatalyst, preferentially esterified palmitic, stearic, oleic and linoleic acids and discriminated against GLA, which was thus concentrated in the unesterified fatty acids fraction. In the absence of hexane, concentrate containing about 70% GLA was obtained. When the reaction conditions, optimized for borage oil fatty acids, were applied to fatty acids of evening primrose (Oenothera biennis L.) oil, concentrates containing 75% GLA were obtained. From both oils, GLA concentrates were prepared efficiently in short reaction times (1–3 h) at 30–60°C. The process can be applied for the production of GLA concentrates for dietetic purposes.     

Supercritical extraction of evening primrose oil: Experimental optimization via response surface methodology

Supercritical carbon dioxide (CO₂) effective extraction parameters (pressure, temperature, static extraction time, and dynamic extraction time) of oil recovery from evening primrose seeds were optimized via response surface methodology (RSM). The results of this study indicated that the linear terms of static and dynamic time and the quadratics of temperature and pressure, as well as the interactions of temperature and static time, pressure and temperature had a significant effect on the oil recovery. The optimum extraction conditions of 14.2 MPa, 47.3°C, 30 min (static extraction time) and 150 min (dynamic extraction time) were obtained. Applying the optimum conditions, a mean experimental recovery of 92.98% (triplicate experiment) was achieved, which is well compatible with the RSM‐predicted value (93.61%). The fatty acid composition of extracted evening primrose oil using supercritical CO₂ was compared with that obtained by Soxhlet method in which minor difference was observed. © 2011 American Institute of Chemical Engineers AIChE J, 2011     

Enrichment of γ-linolenic acid from evening primrose oil and borage oilvia lipase-catalyzed hydrolysis

Lipase-catalyzed selective partial hydrolysis of evening primrose (Oenothera biennis L.) seed oil and borage (Borago officinalis L.) seed oil led to an increase in the level of γ-linolenic acid (GLA; 18∶3n−6) in the unhydrolyzed acylglycerols. Thus, in evening primrose oil, the GLA level could be raised from 9.4% in the starting material to 46.5% in the unhydrolyzed acylglycerols by means of a lipase fromCandida cylindracea. Selective hydrolysis of borage oil with Pancreatin led to an increase in the GLA content from 20.4% in the oil to 33.5% in the unhydrolyzed acylglycerols. Partial hydrolysis of borage oil with lipase fromC. cylindracea raised the GLA content of the acylglycerols to 47.8%.     

Supercritical carbon dioxide extraction of evening primrose oil

The oil extracted from the seeds ofOenothera biennis L. (evening primrose) is a major commercial source of gamma-linolenic acid, a fatty acid having potential therapeutic value in the treatment of several diseases. This fatty acid is prone to oxidation and thermal rearrangement; therefore, the conventional recovery of the oil via mechanical expression and hexane extraction must be carried out under very mild and controlled conditions. In this study, supercritical fluid extraction with carbon dioxide has been employed as an alternative method to recover evening primrose oil (EPO). Extractions were performed over the pressure range of 20–70 MPa and at temperatures from 40 to 60°C, with a CO₂ mass flow rate of 18 g/min. The experimental data permitted the determination of EPO solubility in supercritical CO₂ at the tested extraction conditions. Supercritical fluid Chromatographic analysis of fractions collected during the extraction showed a subtle shift in the triglyceride composition. Fatty acid methyl ester analysis on similar fractions indicated that the fatty acid content was invariant with respect to extraction time. The mention of firm names or trade products does not imply that they are endorsed or recommended by the U.S. Department of Agriculture over other firms or similar products not mentioned.     

Purification of GLA-Triglycerides from Evening Primrose Oil by Gravimetric Column Chromatography

Gravimetric normal-phase silver ion–silica gel column chromatography has been used for the novel application of purification of GLA-containing triglycerides (GLA-TGs) from evening primrose seed oil (EPO). Gradient elution with increasing polarity enabled separation of valuable TG species containing γ-linolenic acid (GLA, 18:3n-6). Enzymatic hydrolysis revealed the distribution of fatty acids (FAs) in the isolated TG species, with GLA in the sn-2 position in different percentages, depending on the degree of unsaturation. A novelty of this work was the successful use of the procedure to improve the purification of raw GLA species from EPO up to preparative scale, thus enabling use of this methodology for industrial purposes.     

Comparison of Supercritical Fluid and Hexane Extraction Methods in Extracting Kenaf (<Emphasis Type="Italic">Hibiscus cannabinus</Emphasis>) Seed Oil Lipids

The objective of this study was to investigate and compare fatty acids, tocopherols and sterols of kenaf seed oil extracted by supercritical carbon dioxide and traditional solvent methods. Fatty acids, tocopherols and sterols were determined in the extracted oils as functions of the pressure (400 bar, 600 bar), temperature (40 °C, 80 °C) and CO₂ flow rate (25 g/min) using a 1-L extraction vessel. Gas chromatography was used to characterize fatty acids and sterols of the obtained oils while tocopherols were quantified by HPLC. No differences were found in the fatty acid compositions of the various oil extracts and the main components were found to be linoleic (38%), oleic (35%), palmitic (20%) and stearic acid (3%). Extraction of tocopherols using high pressure (600 bar/40 °C, 600 bar/80 °C) gave higher total tocopherols (88.20 and 85.57 mg/100 g oil, respectively) when compared with hexane extraction which gave yield of 62.38 mg/100 g oil. Extraction of kenaf seed oil using supercritical fluid extraction at high temperature (80 °C) gave higher amounts of sterols when compared with hexane extraction.     

A Comparative Study on Response Surface Optimization of Supercritical Fluid Extraction Parameters to Obtain Portulaca Oleracea Seed Oil with Higher Bioactive Content and Antioxidant Activity Than Solvent Extraction

Portulaca oleracea (purslane) seed oil is a rich source of omega-6 and omega-3 fatty acids. Extraction of the purslane seed oil while preserving its high nutritive quality has been a challenge since conventional solvent extraction has many adverse effects on bioactive content. This study aims the optimization of purslane seed oil supercritical fluid extraction (SFE) conditions and to compare purslane seed oils obtained with SFE and conventional solvent extraction in terms of oil yield, along with the purslane seed oil quality and bioactive content. For this purpose, the SFE process parameters (pressure, temperature, static time, and dynamic time) are optimized for oil yield, omega-6, omega-3, and antioxidant activity using response surface methodology (RSM). Optimum SFE pressure, temperature, static time, and dynamic time levels are determined as 350 bar, 50 °C, 20 min, and 90 min, respectively. Oil yield and physicochemical quality properties of conventional solvent extract and SFE samples are determined and compared. Consequently, samples obtained via SFE and solvent extraction have similar quality properties. Distinctly, SFE allows an extraction with 5.6% higher total phenolic compound (TPC) and 33% higher antioxidant activity than solvent extraction. Practical Applications: In the study, the extraction of purslane oil using supercritical fluid extraction is optimized with different approaches. At optimum conditions, purslane oil is extracted and all physicochemical properties and the process efficiency (yield) are compared with the solvent-extracted samples. The results of this study make supercritical fluid extraction of purslane seed oil possible since all optimum operating conditions of a pilot-sized extractor are reported in the study. It is believed that the results provide a good starting point for industrial operations. Moreover, researchers also believe that research studies unveiling the new potential oil-bearing seeds are important to overcome the vegetable oil shortage that emerged this year.     

Borage and evening primrose oil

The paper gives a short overview about the production and composition of borage (Borago officinalis) and evening primrose (Oenothera biennis) oil considering special aspects of the production as cold‐pressed oil. Both oils are characterized by a remarkable amount of γ‐linolenic acid, which has some nutritional advantages. The fatty acid composition of evening primrose oil is dominated by linoleic acid with about 72% and about 13% γ‐linolenic acid, while borage oil consists of twice the amount of γ‐linolenic acid and only 38% linoleic acid. The amount of saturated fatty acids is higher in borage oil. The tocopherol composition of both oils is dominated by γ‐tocopherol, with borage oil containing twice the amount compared to evening primrose oil.     

Deacidification of black cumin seed oil by selective supercritical carbon dioxide extraction

The deacidification of high-acidity oils from Black cumin seeds (Nigella sativa) was investigated with supercritical carbon dioxide at two temperatures (40 and 60°C), pressures (15 and 20 MPa) and polarities (pure CO₂ and CO₂/10% MeOH). For pure CO₂ at a relatively low pressure (15 MPa) and relatively high temperature (60°C), the deacidification of a highacidity (37.7 wt% free fatty acid) oil to a low-acidity (7.8 wt% free fatty acid) oil was achieved. The free fatty acids were quantitatively (90 wt%) extracted from the oil and left the majority (77 wt%) of the valuable neutral oils in the seed to be recovered at a later stage by using a higher extraction pressure. By reducing the extraction temperature to 40°C, increasing the extraction pressure to 20 MPa, or increasing the polarity of the supercritical fluid via the addition of a methanol modifier, the selectivity of the extraction was significantly reduced; the amount of neutral oil that co-extracted with the free fatty acids was increased from 23 to 94 wt%.     

Modeling and optimization of process parameters for supercritical CO2 extraction of Argemone mexicana (L.) seed oil

This research article deals with the determination of optimal conditions of extraction parameters (e.g. temperature (60–100?°C), pressure (200–350?bar), particle size (0.5–1.0?mm), flow rate-CO₂ (5–15?g/min), and the % of co-solvent (0.0–10% of flow rate-CO₂) resulting to the optimal cumulative extraction yield during the supercritical fluid extraction of Argemone mexicana (L.) seed oil with and without a modifier (ethanol) using a supercritical carbon dioxide as solvent. A “five-factors-three-levels” Box-Behnken design under the response surface methodology was used to show independent and interactive effects of extraction parameters. A mathematical regression model was expressed properly by a quadratic second-order polynomial equation. The maximum oil yield (42.86%) from A. mexicana seeds was obtained with the optimal conditions (85?°C, 305?bar, 0.75?mm, 11?g/min, and 9% of flow rate-CO₂) of extraction parameters. The fatty acids analysis of the seed oil was done using gas chromatography and found its suitability as bio-fuel.     

Extraction of Nitraria tangutorum seed lipid using different extraction methods and analysis of its fatty acids by HPLC fluorescence detection and on‐line MS identification

The seed lipid of Nitraria tangutorum was extracted by supercritical carbon dioxide extraction, microwave‐assisted reflux extraction, ultrasound‐assisted extraction, or solvent reflux extraction. The experimental parameters of supercritical carbon dioxide extraction including pressure, temperature, particle size, and extraction time were investigated. A facile and sensitive method for the simultaneous determination of 30 saturated and 9 unsaturated fatty acids by HPLC with fluorescence detection after pre‐column derivatization was developed. Fatty acid derivatives were separated on a reversed‐phase Eclipse XDB‐C₈ column in conjunction with gradient elution. Identification of fatty acid derivatives was carried out by on‐line APCI/MS in positive‐ion mode. Excellent quantitative linear responses of the 39 fatty acids were observed in the range of 0.014 to 14 μmol/L with correlation coefficients higher than 0.9992. Limits of detection were in the range of 0.32–3.7 nmol/L (S/N = 3). The fatty acids in Nitraria tangutorum seed lipid with or without saponification extracted by the four different methods were determined and compared. The results indicated that the mass percentage of unsaturated fatty acids (mainly oleic acid, linoleic acid and linolenic acid) in Nitraria tangutorum seed lipid was up to 79%, and the best method was supercritical carbon dioxide extraction.     

Ecological and simultaneous seed oil extraction/saponification/γ‐linolenic acid concentration

The essential fatty acid γ‐linolenic (GLA, C18:3n‐6), which has several pharmaceutical properties, has been concentrated from the seed oil of three plant species, Borago officinalis, Anchusa azurea and Echium fastuosum. The process was effected through one single and ecological step: simultaneous seed oil extraction/saponification/GLA concentration. Finally, the mother liquor containing the GLA concentrate was stored at low temperature to crystallize saturated fatty acids and further increase GLA purity. Two variables affecting the process were found: water content in the saponification mixture and filtration temperature. Best results were obtained from B. officinalis (GLA purity 68%, GLA yield 64%), although closely followed by the concentrates from the other species.     

Particle size effects on supercritical CO<Subscript>2</Subscript> extraction of oil-containing seeds

Rosehip seeds were milled, sieved, and extracted with 26.3 g/g substrate/h of supercritical carbon dioxide (CO₂) at 40°C and 300 bar. The extraction kinetics were characterized by an initial solubility-controlled period (8.78 g oil/kg CO₂ at 40°C and 300 bar), followed by a transition period to a final mass transfer-controlled process. The integral yield of oil approached an asymptotic value that was dependent on the particle size of the substrate: 57.1 g oil/kg dry oil-free substrate (large particles), 171.0 g/kg (medium-size particles), or 391.5 g/kg (small particles). Based on gravimetric determinations and microscopic analysis, our size-classification process segregated seed parts having different oil contents. Particles ≥0.85 mm were mainly composed of tough, lignified testa fragments devoid of oil, whereas particles ≤0.425 mm contained mostly brittle, oil-rich germ fragments. The segregation of seed in fractions with different oil contents may be a common occurrence in supercritical extraction experiments, especially for seeds with thick and/or hard testa and small germ, whose fractions can be separated by sieving.     

Production of phytosterol esters from soybean oil deodorizer distillates

Enzymatic esterification and supercritical fluid extraction was used to produce phytosterol esters from soybean oil deodorizer distillates. The raw material was first subjected to a two‐step enzymatic reaction; the product obtained mainly comprised fatty acid ethyl esters, tocopherols and phytosterol esters, together with minor amounts of squalene, free fatty acids, free sterols and triacylglycerols. The phytosterol esters were then purified from this mixture using supercritical carbon dioxide. Experimental extractions were carried out in an isothermal countercurrent column (without reflux), with pressures ranging from 200 to 280 bar, temperatures of 45–55 °C and solvent‐to‐feed ratios from 15 to 35 kg/kg. Using these extraction conditions, the fatty acid esters were completely extracted and, thus, the fractionation of tocopherols and phytosterol esters was studied. At 250 bar, 55 °C and a solvent‐to‐feed ratio of 35, the phytosterol esters were concentrated in the raffinate up to 82.4 wt‐% with satisfactory yield (72%).     

Effect of Dietary Replacement of Soybean Oil with Different Sources of Gamma‐Linolenic Acid on Fatty Acid Composition of Nile Tilapia

Gamma‐linolenic acid (GLA) plays an important role in the prevention and/or treatment of certain diseases. In this work, we investigate the incorporation of GLA from supplemented feed diets with borage oil (BO) and evening primrose oil (EPO) as substitutes for soybean oil (SO) into the composition of tilapia fillet lipids. High contents of PUFA and n‐6 fatty acids were quantified in fish fillet after 30 days of treatment with SO, BO, and EPO. Feed diets containing BO and EPO were efficient in the incorporation of GLA into fish. Compared to the initial day of the experiment, the increase of GLA was significant (from 6.43 to 13.99 and 15.12 mg g^?1, in lipids of fish treated for 30 days with BO and EPO, respectively). The increase of GLA was also observed in fish which were fed with SO diet (6.43–11.43 mg g^?1). Principal component analysis (PCA) allowed the separation of the treatments and discriminated BO and EPO in a group of fish that received the GLA supplemented diet. In addition to GLA, n‐3 fatty acids were important in the characterization of SO diet and affected the separation of BO and EPO from SO in the PCA score plot.     

Antioxidant activity of evening primrose phenolics in sunflower and rapeseed oils

Crude ethanol/ethyl acetate extracts of industrial evening primrose (Oenothera biennis L.) seed meal were separated into six fractions using the Sephadex LH‐20 column chromatography and 96% aqueous ethanol as a mobile phase. Their antioxidant activities were tested in sunflower and rapeseed oils by using an Oxidograph apparatus at a temperature of 110 °C. Only the fractions III and IV displayed a pronounced antioxidant activity while the other fractions were either inactive or even pro‐oxidative. The active fractions contained phenolic acids and their esters; gallic acid, methyl and ethyl gallates, protocatechuic acid and its methyl ester were identified by GC/MS. Catechin was present, too, but exhibited only moderate antioxidant activity in sunflower oil.     

超临界二氧化碳萃取葡萄籽油工艺优化

为了回收利用葡萄酒酿造过程产生的副产品中的有效成分,本文利用超临界CO₂萃取技术从葡萄籽中提取含有不饱和脂肪酸的葡萄籽油,意在考量超临界CO₂技术在萃取葡萄籽油方面的作用。设计单因素实验,研究了萃取压力、萃取温度、CO₂流量以及停留时间对葡萄籽油萃取率的影响。单因素实验结果表明萃取压力对萃取结果的影响最为显著。萃取温度和CO₂流量对萃取率的影响都存在最佳值,当温度和流量超过最佳值,萃取率开始降低。在单因素实验的基础上进行响应面实验,采用中心复合设计进行实验方案设计以优化萃取葡萄籽油工艺。对响应面实验结果进行方差分析,建立多元回归模型,模型P值<0.0001,预测超临界CO₂萃取葡萄籽油的最佳萃取条件为：萃取压力28MPa、萃取温度321 K、CO₂流量15.5L/h,停留时间155min,萃取率达到14.12%。     

Supercritical extraction of borage seed oil coupled to conventional solvent extraction of antioxidants

This paper describes the extraction of borage seed oil by supercritical carbon dioxide (SC-CO₂) and the further extraction of antioxidants from the SC-CO₂-defatted borage meal with organic solvents (water, methanol, ethanol and ethyl acetate). The optimal conditions for oil extraction were obtained at 303 and 323 K at 200 bar, 2.5 h and a continuous flow of CO₂ of 1.5 L/h introduced through the bottom when the operating pressure and temperature were reached, attaining a yield of 60%. Borage oil is rich in unsaturated fatty acids; oleic acid, linoleic acid and linolenic acid accounted for 74% of the total fatty acid content under the above conditions. The highest extraction yield was achieved using water or methanol as extracting solvent from the SC-CO₂-defatted borage meal at 303 K and pressures of 200 and 150 bar for water and methanol, respectively. The most potent extracts, according to all methods tested, were obtained with water and methanol.     

Supercritical CO2 extraction of omega-3 rich oil from Sacha inchi (Plukenetia volubilis L.) seeds

Supercritical carbon dioxide (SC-CO₂) was employed to extract omega-3 rich oil from Sacha inchi (Plukenetia volubilis L.) seeds and partially defatted cake. For ground seeds, the supercritical extraction was carried out at temperatures of 40, 50 and 60 °C and pressures of 300 and 400 bar, and for the cold pressed partially defatted cake, the extraction was carried out with 300 bar at 40 °C and with 400 bar at 60 °C. The global extraction yields (X₀), oil solubility, fatty acid composition of the oil and tocopherol content were determined. The seed samples used in this work contained 54.3% oil, of which 50.5% was linoleinc acid (ω-3). The maximum extraction recovery for the seeds as 92% at 400 bar and 60 °C, but on one occasion a recovery of 99.1% oil was obtained when cold pressed extraction was employed, followed by supercritical extraction at 400 bar and 60 °C. A high tocopherol content of about 2–3 g/kg of oil was obtained.     

Tunisian Pistacia atlantica Desf. Extraction Process: Impact on Chemical and Nutritional Characteristics

Plant materials have been used in different fields such as therapeutics, cosmetics, and energy for ages. Several studies have investigated seeds, whether common or not, in order to ensure a better valuation of natural resources. Among these, Pistacia atlantica Desf. has been the subject of several works on its characterization and valorization. Among the current trends in sustainable development and environmental protection, valorizing natural wild plants via green chemistry has become prevalent. One of these plants, Pistacia atlantica Desf., is a tree that grows in arid and semi-arid areas, notably in Tunisia, and produces seeds rich in oil. In this study extracting the oil from its seeds is tried by three methods (supercritical carbon dioxide (CO₂), pressure, and hexane), and the efficiency of these extraction processes is compared in order to obtain the best yield and maximize its valorization in a variety of industrial fields. The obtained oil is found to be rich in polyunsaturated fatty acids, namely linoleic and oleic acids, with a similar acidic composition among all extraction methods. The tocopherol composition of the oil is determined using high performance liquid chromatography. The total polyphenol content is determined using the Folin-Ciocalteu colorimetric analysis method. The results show that the seed oil of Pistacia atlantica Desf. extracted by supercritical CO₂ gives the highest extraction yield (25%) and the lowest acidity and peroxide values with a high degree of oxidation at 232 and 270 nm. This method also gives the highest content of alpha, gamma, and delta tocopherol as well as total phenolic content compared to the other extraction methods. The composition of chlorophylls and carotenes in the seed oil of Pistacia atlantica Desf. is determined. Besides, the analysis of the sterol composition reveals that β-sitosterol is still prevailing. Among all the tested extracts, the supercritical CO₂ extract demonstrates the best antioxidant performance against the tested radicals. The oil extracted by supercritical carbon dioxide (CO₂) is of a higher quality compared to that extracted by pressure and by hexane. Practical applications : The Pistacia atlantica Desf. oil exhibits interesting physicochemical and biological characteristics. The type of extraction affects the quality of the major and minor components in the seeds. However, the supercritical CO₂ method produces a better oil quality with the presence of antioxidants such as tocopherols and polyphenols. In fact, it is found that the oil extracted by the three methods has an important sterolic profile with the predominance of β-sitosterol. According to the classification of vegetable oils, unsaturated fatty acids of atlas pistachio oil can be categorized as oleo linoleic oil, which enhances its nutritional value. Having these characteristics, the use of this oil can be considered in agrifood products.