Quantitative extraction of pecan oil from small samples with supercritical carbon dioxide

A procedure to determine total oil content of pecan was developed for samples weighing 500 and 10 mg by supercritical fluid extraction (SFE) with carbon dioxide as the extraction solvent, and chilled hexane as the trapping solvent. Fatty acid methyl esters (FAMEs) were prepared from the total lipid fraction by using either an aliquot (500 mg starting weight) or the entire extract (10 mg starting weight). Total oil content obtained for either sample size with SFE was similar to that obtained with an organic solvent extraction technique. The fatty acid composition for the total lipid fraction of oils extracted with SFE was the same as for oils extracted with organic solvents, and oil composition did not change during SFE. Both oil yield and fatty acid composition were similar to those reported previously for pecan. Samples could be extracted and placed into FAME-derivatizing reagents in one day, and fatty acid composition of the total lipid fraction could be determined by gas-liquid chromatography the next day. The procedure, as demonstrated for pecan, should be suitable for other oilseeds, especially those containing low amounts of water.     

Liquefied gases and supercritical fluids in oilseed extraction

Soybean oil and numerous other vegetable oils can be extracted from crushed seeds by means of liquefied gases or supercritical fluids. The oils are recovered by lowering the pressure or increasing the temperature, or both. Supercritical carbon dioxide is ideally suited for the food industry as it is nontoxic and nonflammable. Moreover, it can be removed easily from the oil as well as the meal. The oils extracted with supercritical carbon dioxide contain much lower proportions of phospholipids than those obtained by conventional processing with hexane. The addition of acetone or another carrier or entrainer aids in the fractional extraction of lipids differing in polarity. The range of applicability of liquefied gases and supercritical fluids in the extraction and fractionation of lipids should be explored further to develop industrial processes using these solvents.     

Ethanol-Modified Supercritical Carbon Dioxide Extraction of the Bioactive Lipid Components of <Emphasis Type="Italic">Camelina sativa</Emphasis> Seed

Camelina sativa seed is an underutilized oil source that attracts a growing interest, but it requires more research on its composition and processing. Its high omega‐3 content and growing demand for clean food processing technologies make conventional oil extraction less attractive. In this study, the effect of extraction methods on the bioactive lipid composition of the camelina seed lipid was investigated, and its bioactive lipid composition was modified at the extraction stage using ethanol‐modified supercritical carbon dioxide (SC‐CO₂). Ethanol‐modified SC‐CO₂ extractions were carried out at varying temperatures (50 and 70 °C), pressures (35 and 45 MPa), and ethanol concentrations (0–10%, w/w), and were compared to SC‐CO₂, cold press, and hexane extraction. The highest total lipid yield (37.6%) was at 45 MPa/70 °C/10% (w/w) ethanol. Phospholipids and phenolic content increased significantly with ethanol‐modified SC‐CO₂ (p < 0.05). SC‐CO₂ with 10% (w/w) ethanol concentration selectively increased phosphatidylcholine (PC) content. Apparent solubility of camelina seed lipids in SC‐CO₂, determined using the Chrastil model, ranged from 0.0065 kg oil/kg CO₂ (35 MPa/50 °C) to 0.0133 kg oil/kg CO₂ (45 MPa/70 °C). Ethanol‐modified SC‐CO₂ extraction allowed modification of the lipid composition that was not possible with the conventional extraction methods. This is a promising green method for extraction and fractionation of camelina seed lipids to separate and enrich its bioactives.     

Insights into the physicochemical properties of coffee oil

The lipid fraction of roasted coffee is an interesting ingredient that could be used in a large number of food formulations. Coffee oil has peculiar flavouring as well as nutraceutical characteristics. The feasibility of the use of coffee oil as ingredient greatly depends not only on its chemical characteristics but also on its physical properties. The crystallisation and melting properties of the coffee oil extracted from Arabica roasted coffee powder were determined by using synchrotron X‐ray diffraction coupled with differential scanning calorimetry. The fatty acid composition and the flavour profile were also assessed by using GC and GC‐MS analyses, respectively. The main fatty acids found in coffee oil are linoleic and palmitic acid. Significant amounts of stearic and oleic acid are also present. These chemical characteristics are linked to the phase transition behaviour. The crystallisation of coffee oil occurs at 6.5 ± 0.3 °C, independently of the cooling rate applied (from 0.5 to 10 °C/min). A unique crystalline structure was identified: a double chain length (2L) β' structure (55.29 Å). The sole formation of the β' form indicates that this metastable crystal is the only one that one should expect in foods containing coffee oil stored below 7 °C.     

Supercritical fluid extraction of lipids from spent coffee grounds

Supercritical fluid extraction of lipids from spent coffee grounds was studied in this work. Extraction experiments were carried out with supercritical carbon dioxide at different pressure and temperature conditions to study the influence of those process parameters on the extraction rate and oil composition. Supercritical carbon dioxide extracted up to 85% of the total amount of oil of spent coffee grounds after 3 h of extraction (corresponding to a maximum yield of 15.4 g_oil/100 g_{dry spent coffee}). The fatty acid composition of the extracted oil showed the presence of fatty acids of C14, C16, C18, and C20 carbon chains. Palmitic (C16:0) and linoleic (C18:2) acids were the major fatty acids and comprise about 35% each of the total fatty acid content of the oil. A soxhlet extraction with n-hexane was done for comparison resulting in a maximum yield of oil of 18.3 g_oil/100 g_{dry spent coffee}. Finally, a diffusional model that takes into account the properties of the substrate, the solute partition between the solid and the supercritical phase, and the mass transfer coefficient and axial dispersion in the fluid phase was applied to this system and a good agreement with experimental results was obtained.     

Extraction of lipids and cholesterol from squid oil with supercritical carbon dioxide

The oil obtained from waste squid viscera consists of multi-compounds such as EPA, DHA and other valuable polyunsaturated fatty acids. The refining of this squid oil, using supercritical carbon dioxide plus ethanol, was performed in a semi-continuous flow extractor at 8 to 17 MPa and 25 to 50 °C. When 1.5% w/w ethanol was added to the solvent, the solubility of lipids was increased by up to 50% over the neat CO₂ value. The extraction curves indicated mass transfer to be solubility limited. Cholesterol was co-extracted with the lipids but, with its lower solubility, less than 54% appeared in the refined oil. The results of the carbon dioxide/multi-compound squid oil system at applied to the extraction conditions were correlated with the mole fraction of the cholesterol and the density of the pure solvent.     

Pyrolysis kinetics and physicochemical properties of agropellets produced from spent ground coffee blended with conventional biomass

Spent coffee grounds (SCG), a processing by-product from the coffee industry, were evaluated as a potential feedstock for preparing agropellets for energy production. Hence, pure SCG and a SCG/sawdust blend were transformed into pellets. The latter thermal and chemical properties such as calorific value, ash content, bulk density, fixed carbon and elemental analysis were obtained. Thermogravimetric analyses were conducted in order to determine pyrolysis kinetics and combustion characteristics in order to study the agropellets performance.     

New poly(lactic acid) composites produced from coffee beverage wastes

In this study, aiming to reduce the environmental impact of plastics, new composite materials containing recycled fibers from used paper coffee cups and oil extracted from spent coffee grounds (SCG) were produced. Accordingly, the cellulose fibers were chemically modified using lactic acid to be used as poly(lactic acid) filler reinforcement. The obtained results revealed that its addition improved the mechanical properties of the ensuing composites. The addition of 30% wt/wt of unmodified and modified fibers increased the Young modulus by 53% and 72%, respectively. In addition, enhanced biodegradability was obtained due to higher water absorption (up to 4% wt/wt). In parallel, coffee oil was used as a plasticizer and the affinity between the plasticizer and polymer matrix was confirmed by the lack of phase separation, by the improved flexibility of derived materials (the addition of 40% wt/wt of plasticizer increased the elongation at break by 86%) and by the better processability of the ensuing materials (the addition of 30% wt/wt of plasticizer increased the MFI by 205%). Overall, the results suggest that the use of modified cellulose fibers and the addition of SCG oil-based plasticizer can be promising routes to produce eco-friendly plastics.     

Optimization of Supercritical Extraction of Linalyl Acetate from Lavender via Box‐Behnken Design

Essential oil was extracted from lavender using supercritical carbon dioxide by means of a newly developed periodic static‐dynamic (PSD) procedure and the conventional semicontinuous (SC) technique. Applying GC‐FID analysis in conjunction with Box‐Behnken design, an optimum overall extraction yield (94.4 %) was obtained via PSD in contrast to 90 % for the SC method. The results indicate that supercritical fluid extraction is a viable technique for separation of constituents such as linalyl acetate, linalool, fenchone, and camphor for pharmaceutical and medicinal applications. Furthermore, a substantial reduction of energy consumption and solvent consumption is achieved with the developed PSD process compared to the conventional SC method.     

Fractionation of Gluten Lipids with Supercritical Carbon Dioxide

Gluten lipids are of two kinds, polar and nonpolar. Both groups consist of a large number of lipids. Gluten lipids can be extracted by conventional solvents as ethanol but also by supercritical carbon dioxide. The high density and the good mass transport properties make the supercritical fluid an excellent solvent. Ethanol extracted gluten lipids have been fractionated with supercritical CO₂ at different pressures and constant temperature. The extract contains triglycerides and free fatty acids, and a more concentrated fraction of polar lipids is left in the extraction vessel. While both polar and nonpolar lipids are soluble in ethanol, only nonpolar lipids are dissolved by supercritical CO₂. An addition of a small amount of ethanol to the CO₂, can, however, increase the solubility of the polar lipids.     

Lipase-catalyzed alcoholysis with supercritical carbon dioxide extraction 2: Phase behavior

The phase behavior of systems containing ethanol plus lipid samples with different lipid compositions plus carbon dioxide was studied visually at 40°C and pressures of 0.01, 9, 15, and 23 MPa by means of a high-pressure sapphire cell. The systems studied represent the main components present in a lipase-catalyzed alcoholysis reaction of cod liver oil in supercritical carbon dioxide. Two phases, a vapor and a liquid phase, were observed in all systems studied at supercritical conditions.     

Supercritical carbon dioxide fractionation of fish oil fatty acid ethyl esters

Fractionation of fish oil fatty acid ethyl esters was investigated with the aim of obtaining a lipid fraction enriched in ω-3 fatty acids and with a suitable EPA/DHA ratio. The results obtained highlight the possibility of modifying the original fatty acid ethyl esters concentration by optimizing the extraction conditions in terms of pressure, temperature, and supercritical carbon dioxide flow rate. Supercritical fluid fractionation (SFF) appears to be a useful processing technique for changing the composition of lipids in order to obtain high value functional products. The use of proper fractionation temperatures and pressures along the column influenced the solvent-to-feed ratio to obtain fractions with suitable composition for market requirements.     

Sub‐and Supercritical CO2‐Extraction of Hypericum perforatum L.

The extraction of Hypericum perforatum L. by liquid carbon dioxide (p = 80 bar, t = 15 °C) gave almost the same extract yield (1 %, w/w) as by supercritical (p = 100 bar, t = 40 °C) carbon dioxide, containing the same percentages of essential oil (about 6.4 %, w/w). The increase of the extract yield at higher pressure (250 to 350 bar) is due to the increase of extragent density, i.e., solubility. By increasing the grinding degree of the drug, a higher extract yield is obtained in the supercritical range under high pressure. GC‐MS analysis of the extract composition showed that the non‐terpene compounds have the highest contribution. The oil content in the drug, determined by steam distillation, was 0.058 %, w/w. The oil content in the extracts, calculated for the drug, was significantly higher (1.2 to 1.9 times).     

Extraction of pomegranate seed oil using subcritical propane and supercritical carbon dioxide

Extraction of oil from pomegranate seeds as a waste product of the juice industry using supercritical carbon dioxide and subcritical propane was studied in this work. The influence of the main operating conditions of extraction, namely, the temperature and pressure of extraction on the oil extraction yield and the correspondent fatty acid profile were analyzed and reported here. Soxhlet extraction with n-hexane was done for comparison with supercritical extraction resulting in a maximum yield of oil of 22.31 wt %. Supercritical carbon dioxide and subcritical propane extracted up to 58.53% (corresponding to maximum yield of 13.06 wt %) and 76.73% (corresponding to maximum yield of 17.12 wt %) of the total amount of pomegranate seed oil as measured using Soxhlet extraction, respectively. Results indicated that the subcritical propane is a suitable and selective solvent for the extraction of the pomegranate seed oil in function of smaller times and pressures employed compared to carbon dioxide extraction. The fatty acid composition of the extracted oil showed the presence of fatty acids of C₁₆, C₁₈, C₂₀, C₂₂, and C₂₄ carbon chains. Punicic (C_18.3) was the major fatty acids and comprise up to 70% of the total fatty acid content of the extracted oil among all samples. Finally, Lack??s plug flow model as developed by Sovova was applied to both extraction systems and a good agreement with the experimental results was obtained.     

Squalene recovery from olive oil deodorizer distillates

Olive oil deodorization distillate contains squalene in a concentration range of 10 to 30 wt%. A process for its recovery by supercritical carbon dioxide extraction is described. The process consists mainly of converting the free fatty acids and the methyl and ethyl esters normally occurring in this by-product into their corresponding triglycerides. The latter are then extracted with supercritical carbon dioxide to provide a highly enriched squalene fraction. The process has been carried out on a pilot-plant scale with a column operating in the contercurrent mode. The relationship between the experimental conditions and squalene purity and yield has been studied. Analytical methods were used for the determination of squalene and other components in the fractions. By use of this process, squalene can be recovered in high purity and yields of about 90%.     

超临界CO2和植物油脱臭馏出物相平衡研究

研究了植物油脱臭馏出物在超临界CO2中的相平衡问题。基于组分的相似性把含有复杂组分的植物油脱臭馏出物简化为两种虚拟组分,用改进的混合规则和超临界组分的能量参数计算式,结合PR状态方程进行计算：理论计算与实验数据相吻合,为间歇式或连续逆流式超临界CO2萃取分离的设计提供了依据。     

In-line and off-line trapping of lipids extracted from chicken liver by supercritical carbon dioxide

This supercritical fluid extraction study determined the retentive properties of neutral alumina sorbent as an in-line trap for lipids in the dynamic state over a pressure range of 490–680 bar and temperatures of 40 and 80°C. Lipids were extracted from a chicken liver matrix using supercritical carbon dioxide over a 40-min period at a flow rate of 3 L/min (expanded gas), then were quantified by high-performance liquid chromatography using an evaporative light-scattering detector. Approximately 30 and 18%, respectively, of the total extracted lipids were trapped on the in-line alumina sorbent bed at 40°C as the operating pressure increased from 490 to 680 bar, while the remaining lipids were trapped off-line after CO₂ decompression. The major lipid classes trapped in-line were fatty acids and cholesterol, whereas only minor amounts of the less polar lipid classes such as sterol esters and triacylglycerols were retained. At 80°C and 680 bar, less than 1.5% of the extracted total lipids was trapped in-line, indicating the lack of adsorptive selectivity for lipids by alumina under these conditions.     

Formation of poly‐vinyl‐alcohol structures by supercritical CO2

Poly‐vinyl‐alcohol (PVA) porous structures have been prepared using a supercritical phase inversion process in which supercritical carbon dioxide (SC‐CO₂) acts as the nonsolvent. First, we tested the versatility of the SC‐CO₂ phase inversion process, forming PVA/dimethylsulfoxide (DMSO) solutions with polymer concentrations ranging from 1 to 35% (w/w) and changing the process parameters. We worked at temperatures from 35 to 55°C and pressures from 100 to 200 bar obtaining different membranes morphologies: dense films, membranes with coexisting morphologies, and microparticles. However, we did not produce symmetric or asymmetric porous membranes. To obtain this result, we used casting solutions formed by adding acetone to DMSO with the aim of modifying the affinity between SC‐CO₂ and the liquid solvent. In this series of experiments, we obtained asymmetric membranes with skin layer thicknesses lower than 10 μm. The results obtained in this work have been explained considering that the membranes formation mechanism is related to the kinetics of the process; i.e. the affinity between the solvent (mixture of solvents) and SC‐CO₂. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Structure,morphology, thermal,and sorption characteristics of epoxidized natural rubber conjugated spent coffee via one-pot synthesis

The present work highlights the preparation of the epoxidized natural rubber conjugated spent coffee biocomposites (ENR-g-SC) via one-pot synthesis to control petroleum oil spills. The structural determination of the spent coffee grafted epoxidized natural rubber (ENR-g-SC) was confirmed through FTIR and ¹H-NMR spectroscopic analyses. The thermal performance, tensile tests, and morphological properties of the synthesized (ENR-g-SC) biocomposites were performed. The data revealed that ENR-g-SC biocomposite with 20 phr of spent coffee (SC) exhibited the highest tensile properties due to maximal chemical linkages of spent coffee and epoxide groups in ENR. The epoxidized natural rubber conjugated spent coffee copolymers were evaluated as oil sorbers for oil absorbency applications in chloroform, toluene, and 10% crude petroleum diluted with toluene. The data revealed that the oil absorbency increased slightly with chloroform or toluene instead of 10% crude oil diluted with toluene. Furthermore, swelling and network parameters including the maximum oil absorbency (Q_max), swelling rate constant (k), polymer-solvent interaction (χ), effective crosslink density (ύe), equilibrium modulus of elasticity (G_T), and average molecular weight between crosslinks (M_c) and theoretical crosslink density (ύ_t) were determined, and correlated to the efficiency of the synthesized epoxidized natural rubber conjugated spent coffee.     

Supercritical fluid processing of fish oils: Extraction of polychlorinated biphenyls

Polychlorinated biphenyls can be extracted from fish oils with supercritical carbon dioxide at quite modest temperature and pressure with little yield loss of the fish oils. The distribution coefficient, viz, the ratio of the concentration of polychlorinated biphenyls in the carbon dioxide and fish oil phases, respectively, was measured to be about 0.01 (wt basis). The selectivity of carbon dioxide for polychlorinated biphenyls was found to be very high, about 13 at a concentration of about 10 ppm.