Optimization of Eco-Friendly Reactive Dyeing of Cellulose Fabrics Using Supercritical Carbon Dioxide Fluid with Different Humidity

An eco-friendly dyeing of cotton fabrics with Reactive Golden Yellow K-2RA was carried out using supercritical carbon dioxide fluid with different humidity. Effect of dyeing temperature, pressure, time, dye concentration, and gas humidity on the dyeing properties of cellulose was investigated. The results indicated that good dyeing effect was achieved because of the nucleophilic substitution reaction of monochlorotriazine reactive group in Reactive Golden Yellow K-2RA and hydroxyl functional groups in cotton. The color strength of dyed samples was improved with the variation of dyeing conditions. An optimized eco-friendly dyeing of cellulose fabrics was recommended with a dyeing temperature of 90°C, a dyeing pressure of 20 MPa, a dye concentration of 5%, and gas humidity of 5% for 60 min in supercritical carbon dioxide fluid. Furthermore, acceptable washing, rubbing and light fastness rated over 4 were obtained.     

EFFECT OF SUPERCRITICAL CARBON DIOXIDE ON MICROBIAL POPULATIONS IN SINGLE STRENGTH ORANGE JUICE1

The effect of supercritical carbon dioxide on aerobic total plate count (TPC) of fresh-squeezed and quick-frozen single strength orange juice from Valencia oranges was studied. Orange juice was treated with SC CO₂ at different temperatures (35° to 60°C) and pressures (8.3 to 33.1 MPa). SC CO₂ treatment at 35°C reduced the TPC by 2 log cycles after 1 h treatment at 33 MPa. At 45°C and 33 MPa 2 log cycles reduction required 45 mins, and 15 mins treatment was sufficient at 60°C. D values of temperature control samples decreased as temperature increased, while that of supercritically treated juice decreased as pressure increased. D values at 35, 45 and 60°C of the supercritically treated juice at 33.1 MPa were calculated as 28, 22.6 and 12.7 min, respectively. The calculated values of z were 180°C, 167°C and 72°C at 8.3 MPa, 20.7 MPa and 33.1 MPa, respectively.     

Conditions for Extraction and Concentration of Beef Fat Volatiles with Supercritical Carbon Dioxide

Beef fat was fractionated using supercritical carbon dioxide at 40°C and pressures from 10.3–27.6 MPa. Fractions were analyzed for volatile content using purge and trap gas chromatography. One hundred six volatiles were identified. The concentrations of straight or branched-chain hydrocarbons, aldehydes, ketones, olefins, enals, lactones, and total volatiles were significantly influenced by extraction conditons. The control contained the least volatiles in each class analyzed. Total volatiles were concentrated over controls by 10–100 fold depending on treatment, with lowest pressure extraction conditions yielding highest concentrations of volatiles.     

Inactivation of Pectinesterase in Orange Juice by Supercritical Carbon Dioxide

Single strength orange juice was treated with supercritical carbon dioxide (CO₂) and the effect of process time, temperature and pressure on pectinesterase (PE) activity was determined. PE could be inactivated with supercritical CO₂ below temperatures necessary for thermal inactivation. Higher pressure, temperature and longer treatment time resulted in more inactivation. Inactivation kinetics showed activation energy was significantly reduced at SC C0₂ treatment at 31 MPa (97.4 KJ/mole), compared to identical treatments at atmospheric pressure (166.6 KJ/mole). D values ranged from 2673 min at atmospheric pressure and 40°C to 10 min at 31 MPa and 60°C. z value at atmospheric pressure was 8.8C°, and at 31 MPa 5.2C°.     

Supercritical Carbon Dioxide Extraction of Valuable Compounds from Citrus junos Seed

Extraction of Citrus junos seed was carried out at temperatures of 40–70 °C, pressures of 20–50 MPa, and CO₂ flow rate of 3 ml/min with supercritical carbon dioxide to obtain the valuable compounds. Seed oil was also extracted by using Soxhlet extraction with hexane as the solvent during 360 min for comparison with the efficiency of supercritical carbon dioxide extraction. Gas chromatography–mass spectrometry (GC–MS) was used to analyze the components present in the seed oil and Gas chromatography-flame ionization detector (GC-FID) was used to quantify their amounts. Among the conditions studied, the highest extraction yield was obtained at higher pressure and temperature (50 MPa and 70 °C). The extraction yield was about 29.5% of the seed, which was almost comparable to that of hexane Soxhlet extraction (33.8%). The results of the GC–MS analyses showed that the seed oil extracted contained N-methylanthranyl acid methyl, fatty acids (such as palmitic, stearic, oleic, linoleic, and linolenic acid), and physiologically active substances of β-sitosterol and squalene.     

Extraction of Volatile Compounds from Aqueous Solution using Micro Bubble, Gaseous, Supercritical and Liquid Carbon Dioxide

When separating volatile compounds from aqueous solution using supercritical carbon dioxide (SC CO₂), methods to bring SC CO₂ into contact with volatile compounds in the solution are very important. An extraction using micro bubble, gaseous, supercritical, and liquid CO₂ generated by a filter nozzle was carried out. Under optimal conditions (20 MPa, 35°C), > 95% of volatile compounds consisting of 6 to 12 carbon atoms could be removed by extraction for 40 min at CO₂ flow rate, 4.0 g/min. Extraction at 35°C could achieve either a selective or nonselective separation by adjusting the extraction pressure, since the effect of pressure on extraction ratio was most significant at 35°C.     

Enrichment of tocols from rice germ oil using supercritical carbon dioxide

An efficient process was developed for enrichment of tocols from rice germ oil (RGO) using supercritical carbon dioxide (SC‐CO₂). Tocols were efficiently enriched in residue by removal of fatty acid methyl ester from the esterified RGO using SC‐CO₂. The enrichment of tocols was carried out at an operating pressure of 12.4–15.8 MPa, an operating temperature of 40–60 °C and a carbon dioxide flow rate of 5.0 L min^?1. The combination of 13.8 MPa pressure and 60 °C temperature was selected as the most suitable for efficient enrichment of tocols. The level of tocols (1270 mg/100 g) in the residue obtained at these operating conditions was six times higher than the tocols level (192 mg/100 g) of the starting material, namely esterified RGO. There were no significant differences in relative percentages of tocols homologues between esterified RGO and the residue obtained by SC‐CO₂ extraction.     

超临界CO2提取葛缕子精油及其成分分析

目的:优化葛缕子精油的提取工艺并对其成分进行分析。方法:以葛缕子籽粒为原料,采用超临界CO₂技术提取葛缕子精油,并通过气相色谱—质谱(GC-MS)对精油挥发性成分进行分析。结果:超临界CO₂提取葛缕子精油的最佳工艺条件为提取釜温度50℃,分离釜温度40℃,提取釜压力30 MPa,分离釜压力0.4 MPa,二氧化碳流速20 g/min,提取时间90 min,此条件下精油得率为4.79%。与同时蒸馏萃取(SDE)法相比,超临界CO₂流体能快速扩散到样品颗粒内部并充分溶解其中的精油成分,具有提取时间短、得率高、无溶剂残留的优点。超临界CO₂法制备的葛缕子精油中,主要成分为D-柠檬烯(50.96%)和香芹酮(46.65%),挥发性成分种类及含量均高于同时蒸馏萃取法的。结论:超临界CO₂法比同时蒸馏萃取法更适合葛缕子精油的提取。     

Original article: Effects of continuous dense‐phase CO2 system on antioxidant capacity and volatile compounds of apple juice

The effects of different operating conditions applied to a continuous dense‐phase carbon dioxide (DPCD) system on antioxidant capacity and volatile compounds of apple juice were compared with current heat pasteurisation method. Only the microbial tests required by Italian Regulation to assure microbiological safety to ‘fruit juices and vegetables’ were performed, and DPCD‐treated (15 MPa, 35 °C, 15 min; 25 MPa, 35 °C, 15 min), heat‐pasteurised (75 °C, 15 s) and untreated apple juice samples were considered. The DPCD processing carried out at 15 MPa resulted as effective as 25 MPa in reducing microbial cells. Trolox equivalent of DPCD treated at 25 MPa (0.41 mm ) resulted significantly (P < 0.05) lower than DPCD treated at 15 MPa (0.48 mm ). Head space analysis of volatile compounds indicated the lowest decrease in apple aroma compounds (59% esters and 59% aldehydes) in DPCD treated at 15 MPa.     

Supercritical fluid extraction of oils from apple seeds: Process optimization,chemical characterization and comparison with a conventional solvent extraction

Oils from apple seeds were extracted with the application of supercritical fluid (SFE) and Soxhlet techniques. The effect of SFE experimental variables such as pressure (10–30 MPa), temperature (40–60 °C) and carbon dioxide flow rate (1–8 L/h) on the yield, antioxidant activity and total phenolic content was investigated using a central composite design. The experimental data were fitted with a second-order polynomial equation using regression analysis. The maximum yield, obtained at the optimum processing conditions (24 MPa, 40 °C, 1 L/h of carbon dioxide flow rate, 140 min) was 20.5 ± 1.5% (w/w). For comparison, the yield from Soxhlet extraction was 22.5 ± 2.5% (w/w). Both techniques produced an oil with a fatty acids profile rich in linoleic acid. However, the extract from SFE was higher in linoleic acid (63.76 ± 4.96 g/100 g_oil) than that achieved by Soxhlet (49.03 ± 3.85 g/100 g_oil). Despite the higher unsaturated fatty acids content, SFE extracts reported a higher oxidative stability (21.4 ± 1.2 h) compared to that one extracted by Soxhlet (12.1 ± 1.1 h). This result was expport addressing the extraction of apple seed oil by supercritical fluid at pressures lower tha The most abundant phenolic compound found in the extract was phloridzin (2.96 ± 0.046 μg/gs_eed in SFE oil and 1.56 ± 0.026 μg/g_seed in Soxhlet). Instead, amygdalin, one of the antinutrients present in seeds, was not detected in the SFE oil.Industrial relevanceThe present study provided results addressing the extraction of apple seed oil by supercritical fluid at pressures lower than 30 MPa. The process allowed extracting an oil that was rich in unsaturated fatty acids, oxidative stable thanks to the high antioxidant activity, and free from anti-nutritional compounds.     

Supercritical carbon dioxide extraction of okra (Hibiscus esculentus L) seeds

Pilot‐scale supercritical fluid extraction of okra seeds was carried out, using carbon dioxide as solvent, at temperatures of 40, 50 and 60 °C and pressures of 150, 300 and 450 bar. Laboratory‐scale Soxhlet extraction of the ground seeds was carried out with ethanol and n‐hexane. The yields of supercritical fluid extraction and n‐hexane Soxhlet extractions were similar. The ethanol Soxhlet extraction gave the highest yield, but the concentrations of β‐sitosterol and tocopherols in this extract were lower than in the supercritical fluid extraction product. The fatty acid profiles of the extracts were determined, and a high unsaturated/saturated ratio was observed. The fatty acid compositions were only slightly different for oils obtained by the different extraction methods. Copyright © 2005 Society of Chemical Industry     

YIELD AND QUALITY OF ONION FLAVOR OIL OBTAINED BY SUPERCRITICAL FLUID EXTRACTION AND OTHER METHODS

Methods of extraction of onion flavor oil were studied including supercritical fluid extraction using carbon dioxide (CO₂), liquid CO₂ extraction and steam distillation-solvent extraction. The effect of using entrainers with supercritical fluid extraction was also studied. The yield and the quality of onion extracts obtained from the different methods were compared. The maximum yield of 0.0324% was obtained by supercritical CO₂ extraction at 3600psi (24.5 MPa), 37C at a CO₂ flow rate of 0.5 L/min. Ethyl alcohol used as entrainer enhanced the yield of onion oil over that obtained by supercritical CO₂ experiment without entrainer at the CO2flow rate of 1.0 L/min. Gas chromatography and combined gas chromatography-mass spectrometry of the extracts indicated that the flavor profiles were different for extracts obtained by different methods. Supercritical and liquid CO₂ extracts had fresh onion-like flavor as opposed to a cooked flavor of the extract obtained by steam distillation-solvent extraction.     

超临界CO2密度对全反式番茄红素吸光系数的影响

目的:通过在超临界CO2色谱上测定CO2流动相密度与全反式番茄红素组分峰面积的相关性,推算二氧化碳密度变化对全反式番茄红素的吸光系数(A1cm)的影响。方法:超临界色谱条件:色谱柱:Diamonsil C8(250mm×4.6m m,5μm);检测波长:4 5 3 n m;压力变化范围:1 1.5～1 7.5 M P a;温度变化范围:3 5～5 5℃;流速:2mL/min;进样量:20μL。结果:全反式番茄红素组分在超临界CO2中最大吸收波长处的峰面积是可变的,与CO2密度呈线性正相关。结论:可推断全反式番茄红素吸光系数与超临界CO2流体密度变化呈正相关。     

Determination of Volatile and Semivolatile Contaminants in Meat by Supercritical Fluid Extraction/Gas Chromatography/Mass Spectrometry

Meat products that were exposed to a warehouse fire were collected and examined to identify contaminants present in the samples. An extraction method using supercritical carbon dioxide at 100 atm and 60°C was developed to analyse and characterise volatile and semi-volatile compounds from the samples. The major volatile compounds were lipid oxidation products, such as hexanal and nonanal. Volatiles concentrations from fire-exposed meat products were compared to control samples to determine compositional differences. Aromatic and polycyclic aromatic hydrocarbons were identified, and naphthalene was measured in suspected fire-damaged meat products. Direct supercritical extraction from the meat samples proved to be a rapid and reproducible method to assess contamination in commercial meat products.     

Studies on proteins and amino acids exposed to supercritical carbon dioxide extraction conditions

Lysozyme was treated with humid supercritical carbon dioxide and nitrogen (300 bar, 80°C and room temperature, 6 and 2h). No alterations could be demonstrated by amino acid analysis and assays of TNBS-reactive lysine. Independent of the gas used, digestion experiments and SDS-PAGE indicated an unfolding, a partial oligomerization and some fragmentation of the protein molecules in samples treated at 80°C. Such alterations are caused by heating proteins in the presence of water as shown elsewhere.Furthermore, l-glutamic acid, l-glutamine, l-methionine, l-leucine, l-alanine, β-alanine and l-lysine were treated with humid supercritical carbon dioxide (300 bar, 80°C, 6h). Automated amino acid analysis demonstrated a loss of 15–23% only with glutamine and a loss of 10% with glutamine exposed to nitrogen under the same reaction conditions, while glutamine treated at room temperature remained unaltered. This loss was caused by conversion of glutamine to 2-pyrrolidinone 5-carboxylic acid, identified by ion-exchange and thin-layer chromatography and hydrolysis to glutamic acid.Protein alterations to the extent observed here, as well as the formation of pyrrolidinone carboxylic acid, do not negatively influence food quality under the reaction conditions used in supercritical carbon dioxide extraction of foods.     

Biological activity of Boswellia serrata Roxb. oleo gum resin essential oil: effects of extraction by supercritical carbon dioxide and traditional methods

The findings of this study suggests that chemical composition, essential oil yield, antioxidant and antimicrobial activity of Boswellia serrata oleo gum resin essential oils extracted by hydro distillation, steam distillation and supercritical fluid carbon dioxide methods vary greatly from each other. The optimum essential oil yield was obtained using hydro distillation method (8.18 ± 0.15 %). The essential oils isolated through different extraction methods contained remarkable amounts of total phenolics and total flavonoids. Essential oil isolated through supercritical fluid carbon dioxide extraction exhibited better antioxidant activity with highest free radical scavenging potential (96.16 ± 1.57 %), inhibition of linoleic acid oxidation (94.18 ± 1.47 %) and hydrogen peroxide free radical scavenging potential (68.25 ± 1.02 %). Moreover, the antimicrobial activity of essential oils was performed through well diffusion, resazurin microtiter plate and micro dilution broth assay assays. The essential oil isolated through steam distillation method revealed highest antimicrobial activity with maximum inhibition zone (24.21 ± 0.34 to12.08 ± 0.30 mm) and least MIC values (35.18 ± 0.77 to 281.46 ± 7.03 µg/mL). The comparison of chemical composition of essential oils isolated at different extraction methods have shown that the concentration of α-thujene, camphene, β-pinene, myrcene, limonene, m-cymene and cis-verbenol was higher in steam distilled essential oil as compared to hydro and supercritical fluid carbon dioxide extracted essential oils. These compounds may be responsible for the higher antimicrobial activity of Boswellia serrata oleo gum resin steam distilled essential oil.     

Extraction of canola seed (Brassica napus) oil using compressed propane and supercritical carbon dioxide

This study aimed to investigate the extraction of canola seed (Brassica napus) oil using supercritical carbon dioxide and compressed propane as solvents. The extractions were performed in a laboratory scale unit at temperatures and pressures of 40, 50 and 60 °C and 20, 22.5 and 25 MPa for carbon dioxide and 30, 45 and 60 °C and 8, 10 and 12 MPa for propane extractions, respectively. The results indicated that pressure and temperature were important variables for the CO₂ extraction, while temperature is the most important variable for the extraction yield with propane. The extraction with propane was much faster than that with carbon dioxide. The characteristics of the extracted oil, that is, the oxidative stability determined by DSC and the chemical profile of fatty acids determined by gas chromatography, were similar for the two solvents. The overall extraction curves were well described by the Sovová model.     

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.     

Inactivation and reactivation of horseradish peroxidase treated with supercritical carbon dioxide

Effects of supercritical carbon dioxide (SCCO₂) on the activity of horseradish peroxidase (HRP) in pH 5.6 acetate buffer solution were investigated. SCCO₂ treatment could effectively inactivate HRP. Higher pressure, higher temperature, and longer treatment time caused more inactivation. The maximum reduction of HRP activity reached nearly 90% at 30 MPa and 55 °C for 60 min. Analysis of first-order reaction kinetic data (characterized by a rate constant k and by a decimal reduction time D) showed that D value was closely related to the pressure and temperature of SCCO₂ treatment. Higher pressures or higher temperatures resulted in lower D values (higher k), the D value of HRP was minimized to 64.52 min treated by the combination of 30 MPa and 55 °C. The Z _p, representing the range of applied pressure between which the D values change by a factor of 10, was 114.81 MPa. The activity of HRP treated by SCCO₂ was reactivated significantly after initial 7-day storage at 4 °C apart from the samples at 30 MPa for 60 min, indicating the HRP inactivation may be reversible and the reactivation of HRP is dependent on the pressure level and treatment time.     

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.