Supercritical carbon dioxide extraction of pelletized Jalapeño peppers

The effects of process pressure (220–500 bar) and temperature (35–65 °C) on yield and extract quality of pelletized Jalapeño peppers (Capsicum annuum L) treated with supercritical carbon dioxide (ScCO₂) were studied. Compaction was inadequate when using whole air‐dried pepper flakes conditioned to high moisture as raw material, which resulted in high porosity pellets and low bed densities. Thus, reference pellet samples were produced from Jalapeño pepper flakes that were finely ground and conditioned to low moisture. Pressures ≥290 bar did not affect cumulative extraction of reference pellet samples at 45 °C. On the other hand, the extraction rate of reference pellet samples at 360 bar increased with process temperature, as a result of increments in solubility, improvements in mass transfer properties, and/or improvements in solute desorption from the solid matrix. With regard to pretreatment, finely ground pepper samples were extracted in half the time of reference pellets (120 versus 270 min) at 360 bar and 45 °C; increasing sample moisture prior to pelletization increased extraction yield; and decreasing particle size prior to pelletization increased extraction rate slightly. These results suggest that sample moisture is partially co‐extracted by ScCO₂, and that the extraction rate of pelletized Jalapeño peppers is controlled by internal mass transfer mechanisms. Chlorophyllian pigments were removed in the final stages of the extraction process. Furthermore, pigment extraction increased with process pressure at 45 °C, and it increased slightly with process temperature at 360 bar. On the other hand, the concentration of capsaicinoids in extract samples remained constant during ScCO₂ extraction. Copyright © 2003 Society of Chemical Industry     

A Direct Hexane Extraction Process for Glanded Cottonseed

A modified filter funnel apparatus was used to determine mass flow velocities for extraction of uncooked glanded cottonseed flakes, and the results were compared with a continuous pilot-plant-scale extractor. A mass velocity of 2,000 lb/hr/ft² or higher (considered adequate for oilseed extraction) was obtained in all cases. Both the initial meat moisture before flaking and the flake moisture during extraction were found to affect the mass velocity. A meat moisture before flaking of less than 9% decreased the mass velocity, probably as a result of increased fines and thus smaller flake size. A high flake moisture (about 9%) during heated-hexane extraction caused a decrease in mass velocity compared to that of lower-moisture flakes. The correlation of filter-funnel mass velocity data to a continuous pilot-plant extractor confirmed that uncooked flakes can be satisfactorily extracted to yield low residual lipids by using a low solvent-to-flake ratio and ambient-temperature hexane solvent.     

Influence of experimental conditions on the extraction of phenolic compounds from parsley (Petroselinum crispum) flakes using a pressurized liquid extractor

The influence of six pressurized liquid extraction parameters (temperature, pressure, particle size, flush volume, static time, and solid-to-solvent ratio) on the extraction of phenolic compounds from parsley flakes was examined. Parsley extracts were analyzed for their phenolic content by high performance liquid chromatography and Folin–Ciocalteu assay. The two major phenolic compounds extracted from parsley flakes were identified as apiin and malonyl-apiin. Particle size, solid-to-solvent ratio, and temperature influenced the amount of phenolic compounds extracted from parsley flakes. Higher extraction yields of phenolic compounds were obtained when extractions were performed with the smallest particle size (<0.425 mm) fraction. Temperature also showed a significant impact on the phenolic profile of the parsley extracts. The yield of malonyl-apiin decreased, while the amount of acetyl-apiin improved with the increase in extraction temperature. The latter compound (acetyl-apiin) is formed by decarboxylation of malonyl-apiin. The yield of the phenolic compounds did not increase proportionately with the increase in sample size, thereby suggesting that it is essential to have optimum solid-to-solvent ratio for accurate estimation of bioactive phytochemicals in foods. Flush volume did not show any major influence on phenolic yields, but it can be manipulated to reduce usage of extraction solvents, which in turn decreases solvent waste disposal costs generated after extraction. Similarly, changes in the static time (extraction time per cycle) and pressure did not result in any significant change in the yield of phenolic compounds extracted from parsley samples. However, sample throughput can be increased significantly by reducing static time.     

Supercritical Carbon Dioxide Extraction of Eugenol from Clove Buds

Isolation of eugenol from dried clove buds (Syzygium aromaticum Linn) of Indian origin was carried out using supercritical carbon dioxide (SC-CO₂) extraction. Optimization of its process parameters such as temperature, pressure and time of extraction has been conducted using response surface methodology. The optimized conditions that provided the optimum yield of eugenol were a sample size of 20 g of clove powder of particle diameter 0.5 mm at a temperature of 60°C and pressure of 250 bar for 90 min extracting time at a flow rate of 2 l?min^?1 of CO₂. Statistical analyses conducted on the extraction parameters concluded that extraction temperature have significant effect on the yield of eugenol, whereas extraction pressure and time do not. The results obtained are in accordance to the basic principle of supercritical fluid phase equilibrium behavior. Solubility of eugenol in SC-CO₂ under different temperature and pressure regimes have been determined experimentally and values were used to construct a correlated Chrastil equation in linear form to allow the prediction of solubility of eugenol in SC-CO₂ under different extraction conditions. Using dimensionless numbers, an empirical correlation was also deduced for characterization of the extraction process of eugenol in SC-CO₂ considering overall fixed bed behavior for clove matrix and mass transfer coefficients in supercritical phases.     

Supercritical carbon dioxide extraction of oil and α‐tocopherol from almond seeds

The objective of this study was to extract oil and tocopherols from almond seeds using supercritical carbon dioxide and to compare this extraction with a traditional solvent method. Oil and tocopherol extraction rates were determined as functions of the pressure (350–550 bar), temperature (35–50 °C) and CO₂ flow rate (10–30 kg h⁻¹), using a 10‐l vessel. The effects of matrix particle size on extraction yield were also studied and it was demonstrated that extraction yield is greatly influenced by particle size. Maximum recovery was obtained in the first 2–3 h of extraction at a pressure of 420 bar, a temperature of 50 °C and a flow rate of 30 kg h⁻¹ CO₂. These results suggest that the elevated initial oil and tochopherol solubility is related to the increased proportion of fatty acids in the initial extract. The results were compared with those obtained when hexane/methanol was used as a solvent. Copyright © 2005 Society of Chemical Industry     

Thermo-Physical Properties of Distillers’ Spent Grain Pellets at Different Moisture Contents and Condensed Distillers’ Soluble Concentrations

The thermo-physical properties of distillers’ spent grain (DSG) pellets are the key input parameters for the heat and mass transfer modeling of the drying process and for the design of the suitable drying and storage systems. The main thermo-physical properties like particle density, thermal conductivity, and specific heat capacity of DSG pellets were determined using standard laboratory methods. The effects of moisture content, percentage of condensed distillers’ solubles (also called solubles), and temperature on these selected properties were determined. The average particle density of the DSG pellets with 0, 10, 30, and 50 % solubles was found to be in the range of 898.8–1136.7 kg/m³. It was observed that the particle density of DSG pellets increased with an increase in condensed distillers’ soluble concentration and decreased with an increase in moisture content. Thermal conductivity (0.17–0.42 W/(mK)) and specific heat (1.76–3.47 kJ/(kgK)) of the DSG pellets increase linearly with an increase in moisture content, soluble concentration of the sample, and temperature of the drying medium. Three multiple linear regression equations were developed for predicting these properties as a function of moisture content, soluble concentration, and temperature with R ² value ≥0.86.     

Supercritical CO2 extraction of oilseeds: review of kinetic and equilibrium models

Mass transfer models on supercritical carbon dioxide (SC-CO2) extraction of vegetable oils are reviewed, that may facilitate the scale-up of laboratory data for industrial design purposes. Reviewed mechanisms of oil transport within the solid matrix include the desorption from the solid, the formation of a shrinking core of condensed oil in a non-adsorbing porous matrix, and diffusion in a homogenous medium. Analyzed simplificat ions of a general mass transfer model include external control of mass transfer rates, internal control of mass transfer rates, consideration of a linear driving force, and steady state approximations, among others. More complex two-stage models, and critical comparisons of some of the proposed models are also included. Trends for the external mass transfer coefficient and effective diffusivity in the solid matrix from studies on SC-CO2 extraction of oil from vegetable substrates are thoroughly discussed and contrasted with those obtained using simpler model systems. The possible effect of the axial dispersion on the rate of extraction is also discussed. Finally, the high-pressure vegetable oil-CO2 phase equilibrium is discussed in connection with its influence on the mass transfer process. Special emphasis is given to the role of the solid matrix on high-pressure phase equilibrium.     

Extraction of alkylresorcinols from wheat bran with supercritical CO2

The supercritical fluid extraction (SFE) of wheat bran alkylresorcinols has been studied. Extractions were carried out at 40.0 MPa. The effect of particle size, static extraction pretreatment with supercritical CO₂ (SC-CO₂) and extraction temperature on the extraction kinetics was investigated. The extraction yield increased as the particle size decreased and with temperature. Extraction curves present a faster and linear initial extraction period followed by a slower extraction period. Based on these results the approximate mathematical model of Sovová was successfully applied to describe the extraction curves. The total content of alkylresorcinols was determined and compared with the alkylresorcinol content obtained by conventional organic solvent extraction. Due to the amphiphilic nature of these resorcinolic lipids, the extraction yield was higher for polar organic solvents than for SC-CO₂. Characterization of supercritical extracts was also performed by determining the fatty acid composition and antioxidant activity.     

万寿菊干花颗粒中叶黄素酯的超临界CO2萃取初探

从万寿菊花中萃取叶黄素酯是制备叶黄素过程中的重要技术。本项研究对叶黄素酯的超临界CO2萃取进行了初步探索。实验结果表明,提高萃取压力、减小样品颗粒粒径以及减小萃取介质的极性均可增加叶黄素酯的萃取率。今后如果能在破坏叶黄素酯与花瓣组织介质的关联程度和降低萃取介质极性两个方面取得进展,超临界流体萃取有可能成为一种可应用于叶黄素酯萃取的技术。     

Extraction of sesame seed oil using supercritical CO2 and mathematical modeling

In this work, extraction of sesame oil from sesame seeds using supercritical CO₂ was carried out. The effect of operating parameters such as pressure, temperature, and supercritical CO₂ flow rate and particle size on extraction yield were investigated. An increase in the pressure and the supercritical CO₂ flow rate improved the extraction yield and also shortened the extraction time. The extraction yield increased as the particle size decreased depending on decreasing intraparticle diffusion resistance. The maximum extraction yield obtained was about 85% (relative to Soxhlet extraction by hexane) at 50 °C, 350 bar, 2 mL CO₂/min, 300–600 μm of particle size. Some extraction curves were modeled with two mathematical approaches as shrinking core model and broken and intact core model. The evaluation of model parameters showed that shrinking core model, however, is better than broken and intact cell model.     

Comparison of yields and quality of nutmeg butter obtained by extraction of nutmeg rind by soxhlet and supercritical carbon dioxide (SC-CO2)

Nutmeg is a native South East Asian plant which has medicinal properties. In this work, supercritical extraction was studied in order to obtain experimental data of the influence of pressure, temperature and particle size and in comparison to soxhlet extraction. Supercritical extraction was conducted at operating temperatures of 40, 50 and 60 °C, operating pressures of 20.7, 27.6, 34.5 and 41.4 MPa and dynamic extraction time was 90 min. The effect of three different sieved particle sizes ?0.500, ?1 mm and ?2 mm on the extraction yield was examined. The results show that the highest yield was 38.8 g oil/100 g sample obtained under extraction temperature of 60 °C, pressure 41.4 MPa using particle size of ?0.5 mm. Soxhlet extraction yields 34 g oil/100 g sample for 6 h of extraction time. The GCTOFMS shows that the supercritical extracts exhibited significantly higher aromatic ether group comparable to those obtained by soxhlet.     

Supercritical carbon dioxide extraction of volatile oil from Italian coriander seeds

Supercritical CO₂ fluid extraction of the volatile oil from Italian coriander seeds was carried out under different conditions of temperature (40 and 50 °C), pressure (90, 100 and 150 bar), mean particle size (0.4, 0.6 and 0.8 mm) and CO₂ flow rate (0.79, 1.10 and 1.56kg/h) in order to evaluate their influence on the yield and composition of the volatile oil. Hydrodistillation with the same mean particle sizes was performed and used as a comparative method. The best supercritical fluid extraction conditions were found to be 90 bar, 40 °C, 1.10 kg/h and 0.6 mm. The chemical composition of each supercritical fluid extraction sample was analysed by GC and GC–MS and the global composition was compared with that obtained by hydrodistillation. The dominant components were linalool (65–79%), γ-terpinene (4–7%), camphor (3%), geranyl acetate (2–4%), α-pinene (1–3%), geraniol (1–3%) and limonene (1–2%). Moreover, supercritical fluid extraction samples were collected at specific intervals of amount of CO₂ consumed, during each extraction, and the contribution of the main volatile components from each sample, for the global volatile compositions, was evaluated. In general, the first sample of each extraction contained up to 50% of the mass of each component.     

磁力搅拌辅助超临界CO2萃取五味子中的木脂素类化合物

本研究建立了一种磁力搅拌辅助的超临界CO2萃取法,用于提取五味子中的8种木脂素类化合物,采用高效液相色谱对目标分析物进行分离和测定。本研究以超临界CO2作为萃取溶剂,采用乙醇溶液预先浸渍样品,通过磁力搅拌促进样品与超临界CO2的充分接触,以提高传质效率。本研究对影响木脂素类化合物提取率的各个因素进行了优化,并与传统方法进行了比较。实验结果表明,各目标分析物在线性范围内具有良好的线性关系(r>0.9998),检出限和定量限为21.30~990.20 ng/mL和60.80~2992.80 ng/mL,加标样品回收率在75.00%~97.78%之间,分析结果令人满意。与其他方法相比,虽然本法在提取时间和实验成本上并不占优势,但本法所获得的提取率明显高于微波提取法和热回流提取法,并与药典方法相似,尽管本法在萃取过程中使用了少量的有机溶剂,但料液比仅为1:2,是其他方法的1/25~1/50。本法具有样品处理量大、操作简单、绿色环保、萃取效率高等优点,在工业化生产应用方面具有一定潜质,可用于中药中木脂素类化合物的提取分离。     

超临界CO2萃取红花籽油的实验研究

以萃取优质红花籽油为目的，以红花籽为原料，考察了各操作参数对红花籽油萃取率的影响。结果表明：萃取压力、CO2流量和原料粒径对红花籽油萃取率产生较大影响，其他因素影响较小。在萃取压力28MPa、萃取温度40℃、CO2流量3．55k/gh、粒径0．4mm，含水量0．5％，时间120min的条件下，萃取率可达90％。经气相色谱分析红花籽油的组成，亚油酸含量高达85％，不饱和脂肪酸的含量约92％。萃取物分析表明：超临界红花籽油的品质优于传统方法得到的红花籽油。     

不同预处理方式对超临界流体萃取葡萄皮精油影响的研究

针对葡萄皮渣综合利用问题,研究了超临界流体萃取技 术提取葡萄皮精油过程中不同预处理方式对萃取率的影 响。结果表明,不同含水量条件下,粉碎粒度由0.9mm降 低到0.2mm,萃取率均有明显提高;含水量越低萃取率越 高,含水量7.26％时的萃取率相应低于含水量5.53％的处 理组;葡萄皮的真空冷冻干燥预处理方式最适于超临界 流体萃取葡萄皮精油,萜烯类化合物得率为78.16％。     

Supercritical carbon dioxide extraction of lycopene: A review

Lycopene is a powerful antioxidant and potential high-value compound for the nutraceutical and pharmaceutical sectors. Its low solubility in water and high solubility in toxic organic solvents has led to a number of studies being carried out on using supercritical carbon dioxide to extract lycopene, with a majority of the studies focusing on extraction from tomatoes or tomato-derived preparations. Parameters such as temperature, pressure, flow rate, extraction time, sample moisture content and sample particle size influence the yield of lycopene via the exertion of different mechanisms. The use of co-solvents and modifiers can greatly enhance the lycopene yield beyond optimization of the parameters previously mentioned, while the co-extraction method offers a new way of enhancing lycopene yields. The scope of this review covers the effects of various parameters on lycopene extraction by supercritical carbon dioxide.     

Supercritical Carbon Dioxide Extraction of Squalene from <Emphasis Type="Italic">Amaranthus paniculatus</Emphasis>: Experiments and Process Characterization

Separation of squalene from Amaranthus paniculatus using supercritical carbon dioxide extraction (SC-CO₂) technology and optimization of its process parameters such as temperature, pressure, time of extraction, flow rate of carbon dioxide, and batch size have been conducted. The optimized conditions that provided the best yield of squalene were a sample size of 40 g of amaranth grains of particle diameter of 0.75 mm at a temperature of 100°C and pressure of 550 bar for 1.5 h extracting time at a flow rate of 0.2 L min⁻¹ of carbon dioxide. Solubility of squalene in SC-CO₂ under different operating conditions has also been evaluated using Chrastil equation which showed good agreement with the experimentally obtained yields. Various statistical analyses (regression equations, t test, and analysis of variance) conducted on the extraction parameters concluded that extraction pressure, time and sample batch size have significant effect on the yield of the squalene whereas extraction temperature and particle diameter do not. The results obtained are in accordance to the basic principle of supercritical fluid-phase equilibrium behavior and the solubility isobar and isotherm obtained showed similar trends with those reported for squalene. Using dimensionless numbers, an empirical correlation was also deduced for characterization of the extraction process of squalene in SC-CO₂.     

Supercritical CO2 extraction of nimbin from neem seeds––a modelling study

The extraction of nimbin from neem seeds using supercritical carbon dioxide is investigated in this paper. A model that accounts for intraparticle diffusion (D_e) and external mass transfer of nimbin (k_f) is presented for the supercritical extraction process. Mass transfer is based on local equilibrium adsorption between solute (nimbin) and solid (neem solid). The external mass transfer coefficient was determined by fitting the theoretical extraction curve to experimental data. The following range of conditions: 0.24–1.24 cm³/min of CO₂, 10–26 MPa, 308–333 K, 1.0–2.5 g of neem kernel powder and 0.0575–0.185 cm of particle size of neem kernel powder, were considered. In addition, a new correlation for Sherwood number (Sh) was developed in terms of the dimensionless groups; Reynolds number (Re) and Schmidt number (Sc) from optimisation results. This correlation was compared to previous correlations and was found to give superior results when compared to experimental data.     

Supercritical CO2 extraction of trans-lycopene from Portuguese tomato industrial waste

Supercritical CO₂ extraction of trans-lycopene from Portuguese tomato industrial wastes (skins and seeds) was carried out in a flow apparatus. The effects of moisture content, feed initial composition, particle size, solvent flow-rate, pressure and temperature on the extraction yield and recovery were evaluated.     

Pecan Kernel Breakage and Oil Extracted by Supercritical CO2 as Affected by Moisture Content

During supercritical CO₂ extraction of oil from pecans, kernel breakage frequently occurs when the depressurization time is short. The purpose of this study was to investigate the effects of initial moisture content of pecan kernels and moisture equilibration time on pecan breakage and oil recovery when extracting with supercritical CO₂. Initial pecan moisture content, adjusted to 3.5% to 11.0%, had a significant effect on breakage when using a short depressurization time. With higher pecan moisture, less kernel breakage occurred. Increasing moisture equilibration time from 1 to 48 h reduced kernel breakage and produced an average of 30% more oil during extraction. Moisture content did not significantly affect the amount of oil extracted.