Ethanol-modified Supercritical Carbon Dioxide Research Articles

Production of high-purity phospholipid concentrate from buttermilk powder using ethanol-modified supercritical carbon dioxide

A new strategy to concentrate phospholipids from buttermilk powder was developed using a food-grade green method based on ethanol-modified supercritical carbon dioxide (SC-CO2) extraction. The effects of extraction conditions, namely temperature (50 and 60°C), pressure (30 and 40 MPa), and ethanol concentration (10, 15, and 20%, wt/wt), on the total lipid yield and phospholipid content were investigated. The ethanol concentration had a more significant effect on the total lipid yield and phospholipid content than the temperature and pressure within the ranges studied. The highest phospholipid recovery was achieved at 60°C, 30 MPa, and 15% (wt/wt) ethanol with a total lipid yield of 6.3% (wt/wt), of which 49% (wt/wt) were phospholipids composed of dihydrosphingomyelin (5%), sphingomyelin (24%), phosphatidylethanolamine (22%), phosphatidylserine (2%), phosphatidylinositol (3%), and phosphatidylcholine (44%). The triacylglycerol compositions of extracts obtained by Folch and ethanol-modified SC-CO2 extractions were similar. A sequential pure SC-CO2 and ethanol-modified SC-CO2 extraction was carried out to separate nonpolar lipids in the first fraction, thereby concentrating phospholipids in the second fraction. This sequential extraction produced a highly concentrated phospholipid extract (76%, wt/wt). To the best of our knowledge, this is the highest phospholipid concentration reported from buttermilk powder. Thus, this phospholipid-rich extract can be used in the development of functional foods as a food-grade emulsifier with potential health-promoting effects.

Supercritical extraction with carbon dioxide and co-solvent from Leptocarpha rivularis

The aim of this work was to investigate the effect of temperature (40–60 °C), pressure (10–20 MPa) and co-solvent concentration (0–2 wt.%) on extraction yield from L. rivularis leaves using ethanol-modified supercritical carbon dioxide. Extraction assays were carried out in a Process Development Unit using a Box-Behnken design. Extraction yield ranged from 14.7 to 53.1 g/kg dry substrate, with the highest value being achieved at 60 °C, 20 MPa and 2 wt.%. The pressure and the co-solvent concentration had a significant effect on extract recovery. To complement the analysis, recognized bioactive compounds, such as the flavonoids quercetin, kaempferol and resveratrol and the terpenes α-thujone, β-caryophyllene and caryophyllene oxide were quantified in the selected extract. Antioxidant activity and the inhibition of key enzymes linked to diabetes mellitus (α-amylase and α-glucosidase) were exhibited by the extract. These results demonstrate the potential benefit of L. rivularis extract for human health.

Extraction of astaxanthin from engineered Camelina sativa seed using ethanol-modified supercritical carbon dioxide

Natural astaxanthin, a high-value carotenoid that is currently extracted mainly from marine organisms, was extracted from engineered camelina seed using ethanol-modified supercritical carbon dioxide (SC-CO2) for the first time, and compared with hexane and accelerated solvent extraction using hexane and ethanol. Response surface methodology (RSM) based on central composite rotatable design was employed to investigate the effect of pressure (30–45 MPa), temperature (40–60 °C), and ethanol concentration (10–35%, w/w). RSM-optimized conditions (41.6 MPa, 36.6 °C and 42.0% ethanol concentration) predicted the astaxanthin concentration as 437 μg/g oil, whereas the actual concentration was 421 ± 14 μg/g oil. Astaxanthin concentration in accelerated solvent extracted oil was significantly lower than that in ethanol-modified SC-CO2- and hexane-extracted oils (P < 0.05). Oils extracted with ethanol-modified SC-CO2 had the highest antioxidant activity. Results indicated that ethanol-modified SC-CO2 extraction method can be successfully used as a green method to extract astaxanthin from high oil feedstocks.

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 (Ton ), 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 vetiver essential oil by ethanol-modified supercritical carbon dioxide

In this study, the Response Surface Method with a Central Composite Design was applied to an investigation of the effects of ethanol concentration, pressure and temperature of ethanol-modified supercritical CO 2 extraction on vetiver oil yield and chemical components, and optimization of these conditions for the highest oil yield. An investigation of whether metals accumulated in vetiver roots would be co-extracted with essential oil by supercritical technology was also conducted. The results indicated that both pressure and concentration of added ethanol had significant linear effects on oil yield, while temperature and interactive effects were not significant. Oil yield increased with both pressure and amounts of added ethanol. The optimal conditions were determined to be 190 bar, 50 °C and 15% ethanol which produced 5.9% oil yield over three times the hydrodistilled yield, and nearly double that of pure SCE (without co-solvent). The operation of ethanol-modified SCE at lower temperature and pressure (100 bar, 40 °C and 15% ethanol) produced a similar yield (5.3%). This finding shows an alternative method for extracting high yields of vetiver essential oil without using very high pressure equipment. Chemical compositions of vetiver oil extracted within the experimental range of ethanol-modified SCE were not significantly different to those extracted by pure SCE. Another interesting result found in this study was that metals accumulated in vetiver roots were not co-extracted with essential oils by either ethanol-modified SCE or pure SCE. Therefore, SCE vetiver extracts are safe for a variety of applications in terms of heavy metal content in the products.

The best utilization of D. zingiberensis C.H. Wright by an eco-friendly process

An eco-friendly process for the best utilization of D. zingiberensis C.H. Wright tubers was developed. In the first stage, cellulose and ethanol were recovered by physical separation, multi-enzymes hydrolysis with yeast fermentation, and in the second stage diosgenin was separated using ethanol-modified supercritical carbon dioxide extraction. The new approach could not only recover 95% of diosgenin production, 95% of ethanol and 75% of cellulose, but also efficiently reduce 88% of COD in wastewater compared with the conventional method, which only extract diosgenin with discharging 80,000mg/l of COD into public sewers. The research indicates that the proposed system could be a clean and technological-efficient alternative to conventional processing of D. zingiberensis C.H. Wright tubers in industry.

Orthogonal array design for the optimization of supercritical fluid extraction of baicalin from roots of Scutellaria baicalensis Georgi

Supercritical fluid was used to extract baicalin from the roots of Scutellaria baicalensis Georgi. An orthogonal array design (OAD), OA(9)(3(4)), was employed as a chemometric method for the optimization of the supercritical fluid extraction of baicalin from the herbal medicine. Four parameters, namely, modifiers, temperature and pressure of supercritical fluid, and the dynamic extraction time, were studied and optimized by a three-level OAD in which the interactions between the parameters were neglected. Determinations of the extracts were performed by high-performance liquid chromatography. The effects of parameters were studied using analysis of variance. The results showed that selection of the modifier was the main factor in attaining higher yields of baicalin. While the other three factors had some effect on the extraction of the compound, the effect was much less than that of the modifiers. 1,2-Propanediol-modified supercritical fluid was more effective than 95% ethanol-modified supercritical carbon dioxide or methanol-modified supercritical carbon dioxide for the extraction of baicalin from the solid matrix. Finally, experimental conditions were proposed which can provide the highest extraction yield with respect to the considered factors.

Extraction of paeonol from Jisheng Shenqi Wan using supercritical fluid extraction

Supercritical carbon dioxide with or without methanol and 95% ethanol modifiers was used to extract paeonol from the pills of Jisheng Shenqi Wan and high-performance liquid chromatography (HPLC) was used to analyze the extract. The effect of temperature and pressure on the yield of paeonol was tested. The results show that the recovery of paeonol was improved by adding a polar modifier, such as methanol and 95% ethanol in supercritical fluid. The yield obtained after 120 min extraction with 95% ethanol modified-supercritical carbon dioxide was the highest (1.51, w/w at 60 degrees C and 400 bar), while that obtained with supercritical carbon dioxide only at 40 degrees C was the lowest from 0.67 to 0.83 over a range of 200-600 bar.

Extraction of berberine from rhizome of Coptis chinensis Franch using supercritical fluid extraction

Supercritical fluid was used to extract berberine from rhizome of Coptis chinensis Franch. The recovery of berberine was compared with various modifiers, i.e. methanol and 95% ethanol with and without surfactant Tween 80, and 1,2-propanediol. The results show that the yield obtained after 3 h extraction with 1,2-propanediol-modified supercritical carbon dioxide was the highest (from 6.91%, w/w at 200 bar to 7.53%, w/w at 500 bar), while that obtained with 95% ethanol modified-supercritical carbon dioxide was the lowest (from 0.15%, w/w at 300 bar to 0.19%, w/w at 600 bar). The recovery of berberine was not improved by adding 5% Tween 80 in supercritical fluid.

Recovery of oil components of okara by ethanol-modified supercritical carbon dioxide extraction

Recovery of the oil components of okara by ethanol-modified supercritical carbon dioxide extraction was investigated at 40–80 °C temperature and 12–30 MPa pressure. In a typical run (holding period of 2 h, continuous flow extraction of 5 h), results indicated that the oil component could be best obtained with a recovery of 63.5% at relatively low temperature of 40 °C and mild pressure of 20 MPa in the presence of 10 mol% EtOH as entrainer. Based on gas chromatography–mass spectrometry (GC–MS) analysis, the extracts consisted mainly of fatty acids and phytosterols, and traces of decadienal. Folin–Ciocalteau estimates of total phenols showed that addition of EtOH as entrainer increased the yield and the amount of phenolic compounds in the extracts. The amounts of two primary soy isoflavones, genistein and daidzein, in the extracts also increased with increasing amount of EtOH.

Ethanol-Modified Supercritical Carbon Dioxide Extraction of High-Value Oil from Okara

Ethanol-Modified Supercritical Carbon Dioxide Extraction of High-Value Oil from Okara