Supercritical carbon dioxide extraction of astaxanthin and other carotenoids from the microalga Haematococcus pluvialis

Supercritical carbon dioxide extraction of astaxanthin and other carotenoids from Haematococcus pluvialis was carried out, for several experimental conditions, using a semi-continuous apparatus. The microalga was previously freeze-dried and ground with a ball mill. The effects of pressure (200 and 300 bar), temperature (40 and 60 °C), degree of crushing, as well as the use of ethanol as a co-solvent (10%) on the extraction efficiency were assessed. Organic solvent extractions, using acetone, were also carried out in a vortex, on ground cells mixed with very small glass beads. Supercritical extraction from the completely crushed alga was compared with acetone and the highest recovery of carotenoids (92%) was obtained at the pressure of 300 bar and the temperature of 60 °C, using ethanol as a co-solvent.The extraction recovery increased with the pressure at 60 °C. On the other hand, the increase in temperature, at 300 bar, led to a slight improvement. The main carotenoid of Haematococcus pluvialis is the esterified astaxanthin (about 75%). Other carotenoids present are lutein, astaxanthin (free), β-carotene and canthaxanthin. All of them were recovered through supercritical fluid extraction with values higher than 90%, with the exception of canthaxanthin (about 85%), at a pressure of 300 bar and a temperature of 60 °C.     

Supercritical CO2 extraction of oil from Arctic charr side streams from filleting processing

Although Arctic charr side streams contain limited amounts of fish flesh, they are a rich fish oil source (46.3 ± 0.6%). The aim of the study was to investigate the potential for valorization of Arctic charr filleting side streams through the extraction of oil by supercritical CO₂ technology. The effect of temperature (40 °C and 80 °C) and pressure (20, 35 and 45 MPa) on the final extract after supercritical fluid extraction (SFE) was evaluated. Temperature increase enhanced the yield but decreased the antioxidant activity at 45 MPa, did not affect the yield and the antioxidant activity at 35 MPa, whereas yield was limited at 20 MPa and 80 °C. Extracts were rich in monounsaturated fatty acids (56.7–58.3%, especially oleic acid 37.2–38.0%), and polyunsaturated fatty acids (20.2–26.1%, especially DHA 7.3–11.4%). The presence of astaxanthin significantly preserved the extracts from oxidation.Industrial relevanceSupercritical carbon dioxide extraction is a green technology appropriate for the recovery of non-polar and heat sensitive compounds. The extracted Arctic charr oils were rich in polyunsaturated fatty acids and astaxanthin which inhibited oxidation in combination with the absence of oxygen and light during the process. This technology could be an excellent alternative for more sustainable valorization of fish processing side streams.     

Optimizing the Supercritical Fluid Extraction of Lutein from Corn Gluten Meal

Supercritical CO₂ was used to extract xanthophylls from corn gluten meal (CGM). Data from a Box-Behnken experimental design was used to model optimal lutein extraction based on extraction temperature (40–80 °C), pressure (5500–7500 psi), and fraction of ethanol co-solvent added (5–15% by volume of total solvent). Lutein extraction was also strongly correlated with zeaxanthin extraction with a correlation coefficient (r) of 0.995. The response surface model for lutein extraction indicated that the amount of co-solvent had the largest impact (p?<?0.001) on lutein extraction yield. Influence of temperature and pressure were limited to quadratic or interaction effects (p?<?0.15). The optimal lutein extraction conditions predicted with the model were a temperature of 40 °C, pressure of 6820 psi, and co-solvent (ethanol) addition of 15% by volume. At these conditions, lutein recovery from CGM was 2.6 times higher than the amount recovered with a quintuple extraction using ethanol and chloroform/dichloromethane (2:1). The strong linear effect of co-solvent addition suggests the possibility of further increasing lutein extraction with the addition of more co-solvent. CGM protein loss during extraction was also calculated and determined to be negligible.     

The efficiency and comparison of novel techniques for cell wall disruption in astaxanthin extraction from Haematococcus pluvialis

The efficiency of various techniques pulsed electric field (PEF), ultrasound (US), high‐pressure microfluidisation (HPMF), hydrochloric acid (HCl) and ionic liquids (ILs) for cell wall disruption in astaxanthin extraction from Haematococcus pluvialis was compared. The results indicated that ILs, HCl and HPMF treatment were shown the most efficient for cell disruption with more than 80% astaxanthin recovery. While the cell wall integrity of H. pluvialis cyst cell was less affected by US and PEF treatment. It was found that imidazolium‐based ILs showed the greater potential for cell disruption than pyridinium‐based and ammonium‐based ILs. Among all the ILs examined, 1‐butyl‐3‐methylimidazolium chloride ([Bmim] Cl) exhibited efficient cell disruption and capability of astaxanthin recovery at mild condition (pretreatment with 40% IL aqueous solution at 40 °C, followed by extraction with methanol at 50 °C) without extensive energy consumption and special facility requirement. In addition, recyclability of ILs was excellent.     

Proximate composition and extraction of carotenoids and lipids from Brazilian redspotted shrimp waste (Farfantepenaeus paulensis)

The chemical composition of redspotted shrimp (Penaeus paulensis) waste was investigated. The shrimp waste (freeze-dried heads, shells and tails) was found to have high protein (49% d.w.) and ash (27% d.w.) contents, but a low lipid content (4.9% d.w.) although the latter was higher than those found in other kinds of shrimp captured in Brazil. The fatty acid compositions showed that the lipids had a high content of unsaturated fatty acids, mainly EPA (C20:5; n-3) and DHA (C22:6; n-3). In order to establish an efficient and environmentally friendly recovery process for the astaxanthin (principal carotenoid and antioxidant present in the waste), the following processes were examined: traditional solvent extraction (TSE), super-critical fluid extraction (SC-CO₂) and super-critical fluid extraction with co-solvent (SC-CO₂ + ethanol). The temperature and pressure conditions for all the SC-CO₂ extractions were 50 °C and 30.0 MPa. The results showed that the mixture of 60% (v/v) n-hexane:isopropyl alcohol gave the highest (53 mg/kg waste) carotenoid extraction yield as compared to acetone, SC-CO₂ and SC-CO₂ + ethanol. The SC-CO₂ showed the lowest extraction yield of astaxanthin, but the addition of the entrainer (10% w/w) produced an important effect, increasing the astaxanthin extraction to values of 57.9%, similar to extraction with acetone (63.3%).     

Supercritical CO2 Extraction of Carotene and Lutein from Leaf Protein Concentrates

Supercritical fluid carbon dioxide was used to extract carotene and lutein from leaf protein concentrate (LPC). Extractions were performed using pressures of 10-70 MPa at 40°C and CO₂ flow rates of 5-6 L/min. Over 90% of the carotene contained in LPC was removed at extraction pressures in excess of 30 MPa. Removal of lutein from LPC required higher extraction pressures (70 MPa) and gas volumes to attain a 70% recovery level. Experimental results were rationalized with the aid of solubility parameter theory. The described process offers the possibility of obtaining a selective extraction of natural colorants, free of solvent residuals, which can be used as food dyes.     

Supercritical CO2 Extraction of Oil from Atlantic Mackerel (Scomber scombrus) and Protein Functionality

Supercritical carbon dioxide (SC-CO₂) extraction temperature and pressure for oil removal from freeze-dried, fall Atlantic mackerel muscle were optimized. The effect of extraction conditions on pH and water-binding potential (WBP) of the protein residue was evaluated. For the temperature range (35–55°C) and pressure interval (20.7–34.5 MPa), 34.5 MPa/35°C gave highest oil yield and concentration of ω-3 fatty acids. SC-CO₂ extraction at higher pressure levels caused slight decreases in protein residue pH. WBP of residual proteins was maximal at 1.49g H₂O/g protein for 34.5 MPa/45°C. The high lipid removal and retention of protein functionality in the residue after oil extraction may make such processes useful for future food applications.     

Coumarin Extraction from Cuscuta reflexa using Supercritical Fluid Carbon Dioxide and Development of an Artificial Neural Network Model to Predict the Coumarin Yield

Coumarin found in Cuscuta reflexa (a medicinal herb) is a phytochemical that possesses blood-thinning, anti-fungicidal and anti-tumor activities, and increases the blood flow in the veins and decreases capillary permeability. Supercritical fluid carbon dioxide extraction is an effective method for extraction and separation of organic compounds. Coumarin was extracted using supercritical fluid carbon dioxide associated with a small amount of a co-solvent methanol to increase the selectivity of carbon dioxide and identified by high-performance liquid chromatography comparing with authentic coumarin standard. Determination of proper extracting temperature, time, and pressure is essential for the maximum extract of coumarin yield. Coumarin was extracted under different extraction conditions of temperature (35–75 °C), time (30–150 min), and pressure (15,160–34,450 kPa). Central composite rotate design was used to plan the experimental extraction conditions. The highest yield of coumarin was 90.13 ± 0.11 (μg/g), while extraction was done at 55°C for 150 min under 24,805 kPa. A feed-forward multilayer backpropagation artificial neural network (ANN) model was developed for the prediction of coumarin yield (μg/g), where input variables were temperature, time, and pressure. Several configurations were evaluated while developing the optimal ANN model. The optimal ANN model consisted of one hidden layer and five neurons. This model was able to predict coumarin yield quantitatively. Prediction of coumarin yields using the ANN model was proven to be a simple, convenient, and accurate method.     

Selective extraction of phospholipids from whey protein phospholipid concentrate using supercritical carbon dioxide and ethanol as a co-solvent

In recent years, using dairy phospholipids (PL) as functional ingredients has increased because PL have nutritional benefits and functional properties. In this study, a novel 2-step supercritical fluid extraction (SFE) process was used to extract whey protein phospholipid concentrate (WPPC), a dairy co-product obtained during the manufacture of whey protein isolate, for PL enrichment. In the first step, nonpolar lipids in WPPC were removed using neat supercritical carbon dioxide (S-CO₂) at 41.4 MPa and 60°C. In the second stage, the feasibility of using the polar solvent ethanol as a co-solvent to increase the solubility of S-CO₂ extraction solvent was explored. A 3 × 3 × 2 factorial design with extraction pressure (35.0, 41.4, and 55.0 MPa), temperature (40 and 60°C), and concentration of ethanol (10, 15, and 20%) as independent factors was used to evaluate the extraction efficiency providing the most total PL, and the best proportion of each individual PL from the spent solids collected during S-CO₂ SFE. All lipid fractions were analyzed using thin-layer chromatography and high-performance lipid chromatography. The total amount of PL extracted from WPPC was significantly affected by ethanol concentration; the extraction pressure and temperature were nonsignificant. The optimal SFE condition for generating a concentrated PL lipid fraction was 35.0 MPa, 40°C, and 15% ethanol concentration; the highest amount of extracted PL averaged 26.26 g/100 g of fat. Moreover, adjusting SFE condition allowed successful recovery of a high concentration of sphingomyelin, phosphatidylcholine, and phosphatidylethanolamine, giving averages of 11.07, 10.07, and 7.2 g/100 g of fat, respectively, 2 to 3 times more than conventional solvent extraction. In addition, exhausted solids obtained after the SFE process were enriched with denatured proteins (72% on dry basis) with significantly more water-holding capacity and emulsifying capacity than untreated WPPC. Overall, this 2-stage SFE process using neat S-CO₂ and ethanol has the greatest potential to produce a PL-rich lipid fraction from WPPC.     

均匀设计优化超临界CO2提取含原花青素的葡萄籽油

以原花青素的提取率和葡萄籽的出油率为考察指标,利用均匀设计法对超临界CO2萃取时间、萃取压力、萃取温度进行了优化,得到最佳工艺条件为:萃取压力15 MPa,萃取时间3 h,萃取温度50 ℃;在最佳条件下葡萄籽出油率为(10.92±0.25)%,原花青素提取率为(23.4±7.2)mg/100 g.在加入无水乙醇夹带剂的前提下,利用超临界CO2萃取葡萄籽油,可以使油中含有原花青素,提高葡萄籽油的品质.     

Optimization of Supercritical Fluid Extraction of Phenolics from Date Seeds and Characterization of its Antioxidant Activity

Supercritical fluid extraction (SFE) was utilized for the first time to extract phenolics in date seeds. Orthogonal array design (OA₉ (3⁴)) was applied to optimize extraction variables including extraction temperature, extraction pressure, extraction time, and number of extraction. Optimum values of extraction variables were analyzed and number of extractions was found to have a significant effect on total phenolics content (TPC). Optimal SFE conditions for maximum yield of TPC were 50 °C, 350 bar, and two repeated extractions, each for 2 h. Under optimal condition, the TPC was increased to 441.57 mg gallic acid equivalents/100 g fresh weight. Several phenolic compounds were detected in date seeds including chlorogenic acid, rutin, ellagic acid, quercetin, and two unidentified compounds of phenolic acids. In addition, phenolics of date seeds showed a higher antioxidant activity than ascorbic acid at the same concentration in the range of 1.0–8.0 mg/L.     

Extraction of Lipid and Cholesterol from Fish Muscle with Supercritical Fluids

Supercritical fluid extraction (SFE) was explored as a method for removing lipids and cholesterol from fish muscle. Selected conditions of extraction pressure, time, temperature and sample size were evaluated for effective removal of lipid and cholesterol. Increasing carbon dioxide (CO₂) pressure from 2000 to 5000 psig and the temperature from 40° to 50°C had little effect on the extent of lipid removal. Increasing the extraction time from 3 hr to 9 hr increased lipid removal. Ethanol as an entrainer significantly enhanced lipid extraction at all pressures used. Supercritical carbon dioxide (SCO₂) and SCO₂ plus ethanol removed 78% and 97% of the lipids and 97% and 99% bf the cholesterol, respectively, from trout muscle. The solubility of the muscle proteins decreased following extraction.     

Application of response surface methodology to optimise supercritical carbon dioxide extraction of oil from rapeseed (Brassica napus L.)

Supercritical CO₂ fluid extraction technology was used to extract oil from rapeseed. Extraction temperature, pressure, time and the sample particle size were selected and optimised by response surface methodology. Conventional solvent extraction was applied as a comparative method. The maximum extraction yield of 32.65 ± 1.01% was achieved at a temperature of 40 °C and a pressure of 345 bar, using an extraction time of 3 h and a 60‐mesh particle size. The chemical compositions of rapeseed oil using esterification method were investigated by GC–MS. The result indicates that the main fatty acids are palmitic acid (2.60%), oleic acid (16.54%), linoleic acid (9.62%), linolenic acid (4.77%), eicosenoic acid (11.20%) and erucic acid (47.09%), respectively. Supercritical fluid extraction has been proved to be an effective technique for extracting oil from Brassica napus L.     

功能性米糠油超临界流体萃取工艺的研究

采用超临界流体选择性萃取技术提取功能性米糠油,对影响功能性成分亚油酸提取率的主要因素：萃取压力、温度、时间、物料粒度及夹带剂用量进行研究和分析,利用气相色谱法对萃取物中亚油酸进行定性定量分析。通过正交试验优化萃取工艺条件,当萃取压力35MPa、萃取温度40℃、萃取时间100min、物料粒度0.450mm、乙醇用量8% 时,米糠油提取量为17.53g/100g 米糠,亚油酸提取率为87.24%。米糠油中主要脂肪酸油酸41.52%、亚油酸40.81%。产品风味纯正、色泽橙黄、组织均匀不分层、富含亚油酸,可作为功能性油脂应用。     

Supercritical fluid extraction of grape seed: Process scale-up, extract chemical composition and economic evaluation

The scale-up of the supercritical fluid extraction (SFE) process for grape (Vitis vinifera L.) seed was studied from the laboratory (0.29 L) to the pilot scale (5.15 L) at 35 MPa and 313 K. The scale-up criterion adopted consisted of maintaining a constant solvent to feed ratio (S/F), and the criterion was successfully used to predict the approximate behavior of the SFE process from the laboratory at the pilot scale for a 17-fold scale-up. Linoleic acid was the major component of the extract; palmitic, stearic and oleic acids were also detected. The economic evaluation showed that it is viable to establish a SFE plant in Brazil for SFE processing of grape seed. From the technical-economic evaluation, for SFE of grape seed at 313 K/35 MPa, an extraction time of 240 min and S/F of 6.6 produced the best relationship between yield and cost.     

Optimisation of supercritical fluid extraction of flavonoids from Pueraria lobata

Supercritical carbon dioxide extraction was employed to extract flavonoids from Pueraria lobata. The optimal conditions for flavonoid extraction were determined by response surface methodology. Box–Behnken design was applied to evaluate the effects of three independent variables (pressure, temperature and co-solvent amount) on the flavonoid yield of P. lobata. Correlation analysis of the mathematical-regression model indicated that a quadratic polynomial model could be employed to optimise the supercritical carbon dioxide extraction of flavonoids. From response surface plots, pressure, temperature and co-solvent amount exhibited independent and interactive effects on the extraction of flavonoids. The optimal conditions to obtain the highest flavonoid yield of P. lobata were a pressure of 20.04 MPa, a temperature of 50.24 °C and a co-solvent amount of 181.24 ml. Under these optimal conditions, the experimental values agreed with the predicted values, using analysis of variance, indicating a high goodness of fit of the model used and the success of response surface methodology for optimising supercritical carbon dioxide extraction of flavonoids from P. lobata.     

Subcritical water extraction of phenolic compounds from flaxseed meal sticks using accelerated solvent extractor (ASE)

Subcritical water extraction (SWE) is a technique based on the use of water as an extractant, at temperatures between 100 and 374 °C and at a pressure high enough to maintain the liquid state. SWE provides higher selectivities, low cost, and shorter extraction times. In this study, phenolic compounds in flaxseed (Linum usitatissimum L.) meal sticks were extracted with subcritical water using accelerated solvent extractor. For this aim, the interactions between temperature (160, 170, and 180 °C) and extraction time (5, 15, 30, and 60 min) for subcritical water extraction of SDG lignan, total phenolics, and total flavonoids from flaxseed meal sticks were investigated. The highest extraction yield of SDG lignan (77.01 %) in subcritical water extracts was determined at 160 °C for 60 min. However, high extraction yields were obtained as 70.67 and 72.57 % at 170 and 180 °C for 15 min, respectively. Also, the highest extraction yield of total phenolics (70.82 %) and total flavonoids (267.14 %) were determined at 180 °C for 15 min. Besides, high correlations between SDG lignan–total phenolics, SDG lignan–total flavonoids, and total phenolics–total flavonoids were obtained from 0.86 to 1 in water extracts.     

Ionic liquid as an effective solvent for cell wall deconstructing through astaxanthin extraction from Haematococcus pluvialis

Haematococcus pluvialis is a proficient source of natural antioxidant astaxanthin. However, the efficient extraction of astaxanthin from this microalga remains a great challenge due to the presence of the tough and non-hydrolysable cell walls. In this study, ionic liquid (IL) pretreatment was used for deconstruction of cell wall method. Imidazolium-based ILs exhibited higher cell disruption capability than pyridinium-based and ammonium-based ILs. After the ILs determination, 1-butyl-3-methylimidazolium chloride ([Bmim] Cl) was the most efficient method for cell wall deconstruction that leads to the highest astaxanthin extractability. More than 80% astaxanthin was extracted from H. pluvialis under mild conditions (pretreatment with 40% IL aqueous solution at 35 °C, followed by methanolic extraction at 50 °C). In addition, [Bmim] Cl showed the excellent recyclability, and negligible loss of astaxanthin during IL pretreatment was observed. The present work demonstrates that the combination of IL pretreatment and organic solvent extraction was an energy efficient and eco-friendly process for the astaxanthin recovery from H. pluvialis.     

CO<Subscript>2</Subscript> supercritical fluid extraction and characterization of polysaccharide from bamboo (<Emphasis Type="Italic">Phyllostachys heterocycla</Emphasis>) leaves

CO₂ supercritical fluid technique with an ethanol modifier was used to extract bamboo (Phyllostachys heterocycla) leave’s polysaccharide (BLPs) regarding various operating conditions. Pressure (30, 40 and 50 MPa), extraction temperature (40, 45 and 50 °C), extraction time (2, 3 and 4 h) and modifier dosage (20, 25 and 30 mL) were important operating factors affecting the yield and total antioxidant activity of each BLPs extraction. The optimal parameters for harvesting the BLPs were an extracting time of 2 h plus 40 MPa pressure with 30 mL of ethanol modifier at 50 °C. In this case, 2.47% BLPs (in wt) was extracted. The BLPs, after purified by D101 macroporous resin and DEAE-cellulose column, with the average molecular weight of 5.05?×?104 Da are composed of rhamnose, fucose, arabinose, xylose, mannose, glucose, and galactose in the molar ratio of 1.318:2.100:1.189:1.016:1:4.776:1.318, respectively. It showed the best antioxidant activity, and its total antioxidant activity of the BLPs extracted was equivalent to 20.70 mg ascorbic acid [(VcE)/g]. In a word, our technique should be potential for producing the best yield and activity of bamboo (Phyllostachys heterocycla) leave’s polysaccharide.     

Effects of Pulsed Electric Field on Yield Extraction and Quality of Olive Oil

The effect of the application of pulsed electric field (PEF) treatments of different intensities (0–2 kV/cm) on Arbequina olive paste in reference to olive oil extraction at different malaxation times (0, 15, and 30 min) and temperatures (15 and 26 °C) was investigated. The extraction yield improved by 54 % when the olive paste was treated with PEF (2 kV/cm) without malaxation. When the olive paste was malaxated at 26 °C, the application of a PEF treatment did not increase the extraction yield as compared with the control. However, at 15 °C, a PEF treatment of 2 kV/cm improved the extraction yield by 14.1 %, which corresponded with an enhancement of 1.7 kg of oil per 100 kg of olive fruits. The application of a PEF treatment could permit reduction of the malaxation temperature from 26 to 15 °C without impairing the extraction yield. Parameters legally established (acidity, peroxide value, K_232, and K₂₇₀) to measure the level of quality of the virgin olive oil were not affected by the PEF treatments. A sensory analysis revealed that the application of a PEF treatment did not generate any bad flavor or taste in the oil.