Extraction of rice brain oil using supercritical carbon dioxide and propane

Extraction of rice bran lipids was performed using supercritical carbon dioxide (SC−CO₂) and liquid propane. To provide a basis for extraction efficiency, accelerated solvent extraction with hexane was performed at 100°C and 10.34 MPa. Extraction pressure was varied for propane and SC−CO₂ extractions. Also, the role of temperature in SC−CO₂ extraction efficiency was investigated at 45,65, and 85°C. For the SC−CO₂ experiments, extraction efficiencies were proportional to pressure and inversely proportional to temperature, and the maximal yield of oil achieved using SC−CO₂ was 0.222±0.013 kg of oil extracted per kg of rice bran for conditions of 45°C and 35 MPa. The maximal yield achieved with propane was 0.224±0.016 kg of oil per kg of rice bran at 0.76 MPa and ambient temperature. The maximum extraction efficiencies of both SC−CO₂ and propane were found to be significantly different from the hexane extraction baseline yield, which was 0.261±0.005 kg oil extracted per kg of rice bran. A simulated economic analysis was performed on the possibility of using SC−CO₂ and propane extraction technologies to remove oil from rice bran generated in Mississippi. Although the economic analysis was based on the maximal extraction efficiency for each technology, neither process resulted in a positive rate of return on investment.     

Supercritical carbon dioxide extraction of cottonseed with co-solvents

Extraction of cottonseed lipids with supercritical carbon dioxide (SC-CO₂) was conducted with and without a cosolvent, ethanol or 2-propanol (IPA). At 7000 psi and 80°C, the reduced pressure, temperature and density of SC-CO₂ was at 6.5, 1.17 and 1.85, respectively; the specific gravity was 0.87. Under these conditions, CO₂ is denser than most liquid extraction agents such as hexane, ethanol and IPA. The extraction of cottonseed with SC-CO₂ gave a yield of more than 30% (moisture-free basis). This is comparable to yields obtained by the more commonly used solvent, hexane. The crude cottonseed oil extracted by SC-CO₂ was visually lighter than refined cottonseed oil. This was substantiated by colorimetric measurements. No gossypol was detected in the crude oil. However, crude oil extracted by SC-CO₂, to which less than 5% of ethanol or IPA as co-solvent was added, containedca. 200 ppm of gossypol, resulting in the typical dark color of cottonseed crude oil with gossypol. CO₂ extracted a small amount of cottonseed phosphatides, about one-third of that extracted by pure ethanol, IPA or hexane. A second extraction with 100% ethanol or IPA after the initial SC-CO₂ extraction produced a water-soluble lipid fraction that contained a significant amount of gossypol, ranging between 1500 and 5000 ppm. Because pure gossypol is practically insoluble in water, this fraction is believed to be made up of gossypol complexed with polysaccharides and phosphatides. Partially presented at the AOCS 1993 Annual Meeting & Expo in Anaheim, California.     

Characterization of wheat bran oil obtained by supercritical carbon dioxide and hexane extraction

Supercritical carbon dioxide (SC-CO₂) and soxhlet extraction using was carried out to extract oil from wheat bran oil. For SC-CO₂, the pressure and temperature were ranging from 10 to 30 MPa and 313.15–333.15 K. The extraction was performed in a semi batch process with a CO₂ flow rate of 26.81 g/min for 2 h. Wheat bran oil was characterized to investigate the quality. Acid value (AV) and peroxide value (POV) were higher in hexane extracted oil compared to SC-CO₂ extracted oil. Induction period was measured by rancimat test. The oil obtained by SC-CO₂ extraction had higher capability to delay the oxidation by surrounding environment. The DPPH radical scavenging activity was also measured. The SC-CO₂ extracted oil showed higher radical scavenging activity compared to hexane extracted oil.     

Supercritical carbon dioxide extraction of oil from Thunnus tonggol head by optimization of process parameters using response surface methodology

Total oil was extracted from ground fish head of Longtail tuna (Thunnus tonggol) using supercritical carbon dioxide (SC-CO₂) at 20 to 40 MPa, 45 to 65 °C and 1 to 3 ml min^?1. Response surface methodology (RSM) was employed to optimize the operating conditions of the SC-CO₂ technique where the highest oil yield was obtained (35.6% on dry weight basis) at 40 MPa, 65 °C, and 3 ml min^?1. The solubility of the oil in SC-CO₂ increased from 2.9 to 14.2 g oil/100 g of CO₂ with increasing pressure and temperature. The total saturated, monounsaturated and polyunsaturated fatty acids obtained were 41.6, 24.7 and 26.8%, respectively, where the omega-3 fatty acids were found to be 22.3%. A correlation was developed determining the coefficients of the second-order polynomial equation where the extraction parameters of SC-CO₂ method to extract fish oil from fish sample were successfully optimized using response surface methodology.     

Characterization of purified phospholipids from krill (Euphausia superba) residues deoiled by supercritical carbon dioxide

Purification of phospholipids (PL) from the Antarctic krill (Euphausia superba) using a two-step extraction process has been investigated. Using supercritical carbon dioxide (SC-CO₂) extraction with optimal extractions conditions of 45 °C, 25MPa, and CO₂ flow rate of 22 g/min, most of the neutral lipids were extracted. PC, PE and PI were then extracted in a second step conducted with modified existing method using ethanol, hexane and acetone as solvents. The major PL of krill residues was quantified by high performance liquid chromatography (HPLC-ELSD). The fatty acid compositions of total PL, PC, PE and PI were analyzed by gas chromatography (GC). A significant amount of polyunsaturated fatty acids (PUFA) was present in both total and PLs fractions. The purified PLs were characterized by their acid value, peroxide value, and the oxidative stability. The purity of PL ranged between 93 and 97% and was evaluated by spectrophotometry.     

Supercritical CO2 extraction of flaxseed

Extraction of flaxseed oil was performed with supercritical carbon dioxide (SC-CO₂). To investigate the effects of pressure and temperature on the solubility of oil and oil yield, three isobaric (21, 35, and 55 MPa) and two isothermal (50 and 70°C) extraction conditions were selected. Although the maximal solubility of flaxseed oil, 11.3 mg oil/g CO₂, was obtained at 70°C/55 MPa, the oil yield obtained after 3 h of extraction at this condition was only 25% (g oil/g seed×100), which represented 66% of the total available oil of the flaxseed. Lipid composition and FFA and tocol (tocopherol and tocotrienol) contents of the oils obtained by both SC-CO₂ and petroleum ether extraction were determined. The α-linolenic acid content of the SC-CO₂-extracted oil was higher than that obtained by solvent extraction.     

Supercritical CO2 extraction of rice bran

Extraction of rice bran lipids with supercritical carbon dioxide (SC-CO₂) was performed. To investigate the pressure effect on extraction yield, two isobaric conditions, 7000 and 9000 psi, were selected. A Soxhlet extraction with hexane (modified AOCS method Aa 4–38; 4 h at 69°C) was also conducted and used as the comparison basis. Rice bran with a moisture content of 6%, 90% passable through a sieve with 0.297 mm opening, was used for extraction. A maximum rice bran oil (RBO) yield of 20.5%, which represents 99+% lipid recovery, was obtained with hexane. RBO yield with SC-CO₂ ranged between 19.2 and 20.4%. RBO yield increased with temperature at isobaric conditions. At the 80°C isotherm, an increase in RBO yield was obtained with an increase in pressure. The pressure effect may be attributed to the increase in SC-CO₂ density, which is closely related to the value of the Hildebrand solubility parameter. RBO extracted with SC-CO₂ had a far superior color quality when compared with hexane-extracted RBO. The level of sterols in SC-CO₂-extracted RBO increased with pressure and temperature.     

Supercritical carbon dioxide extraction,purification, and characterization of wax from sorghum and sorghum by-products as an alternative natural wax

The objective of this work was to obtain high purity natural wax from sorghum and by-products of sorghum processing (sorghum dried distillers grains with solubles [DDGS] and sorghum bran) using a green process based on supercritical carbon dioxide (SC-CO₂). SC-CO₂ extractions were carried out at varying temperatures (50, 70°C) and pressures (30, 40 MPa) at a CO₂ flow rate 1 L/min for 120 min. Significantly higher wax yield (4.9%) from DDGS was obtained by SC-CO₂ at 40 MPa/70°C compared with whole kernel (0.6%) and bran (3.3%) (p < 0.05). The yield of the extracts obtained by SC-CO₂ extraction was higher than that of the conventional hexane extraction for all three sorghum sources. The highest fraction of wax in the SC-CO₂ extracts was obtained from whole kernel extracts (89%), whereas it was 53.3% from the DDGS and 26.8% from the bran at the same extraction conditions. SC-CO₂ and hexane extracts from sorghum whole kernel shared a similar melting peak temperature of 76.3–77.9 and 79.7°C, respectively, while DDGS and bran extracts by SC-CO₂ showed a much lower melting temperature in the range of 50.7–61.9°C, indicating the presence of lower melting point components such as triacylglycerols. However, the melting points of the DDGS and bran extracts after ethanol purification were significantly increased with the observed peak temperature of 80.8 and 82.0°C, respectively. While the wax yield from DDGS and bran was higher than that of whole kernel, the sorghum whole kernel feedstock was found to be a more feasible feedstock to obtain higher purity wax.     

Supercritical Carbon Dioxide Extraction and Characterization of Argentinean Chia Seed Oil

Extraction of chia seed oil was performed with supercritical carbon dioxide (SC-CO₂). To investigate the effects of pressure and temperature on the oil solubility and yield, two isobaric (250 and 450 bar) and two isothermal (40 and 60 °C) extraction conditions were selected. The global extraction yield of chia oil increased with pressure enhancement, but temperature had a little influence on it. The maximum oil recovery using SC-CO₂ at a mass flow rate of 8 kg/h was 97%, which was obtained at 60 °C, 450 bar for a 138-min extraction. The results showed that solubility changed from 4.8 g oil/kg CO₂ at 60 °C–250 bar to 28.8 g oil/kg CO₂ at 60 °C–450 bar. The final extract obtained by SC-CO₂ under different conditions and Soxhlet extraction contained mainly α-linolenic (64.9–65.6%) and linoleic (19.8–20.3%) acids. SC-CO₂ extraction is an interesting alternative methodology because it is possible to achieve a chia oil yield close to that obtained by conventional extraction with a similar fatty acid composition using an environmentally friendly process.     

Supercritical Carbon Dioxide Extraction of Sorghum Bug (<Emphasis Type="Italic">Agonoscelis pubescens</Emphasis>) Oil Using Response Surface Methodology

Supercritical fluid extraction (SFE) of sorghum bug oil (SBO) with carbon dioxide was performed and compared with Soxhlet extraction using hexane. Response surface methodology (RSM) was used to determine the effects of pressure (200–400 bar) and temperature (50–70 °C) on the sorghum bug oil yield in SC-CO₂. The high extraction yield (more than 45.0%) was obtained at 300 bar and 60 °C followed by 400 bar and 70 °C, while the lower yield was obtained at 159 bar and 60 °C. At low pressure levels (159 and 200 bar), the oil yield decreased due to the reduced density of CO₂ at higher temperatures. Gas chromatography was used to characterize the fatty acids of the oils obtained while α-tocopherol was quantified by HPLC. No differences were found in the fatty acid compositions of the various extracts, while the α-tocopherol extracted from sorghum bug oil by the conventional solvent method was less than that extracted by the SFE process using CO_2. It can be observed that the conventional solvent extraction method exhibited notable DPPH radical-scavenging activity, with an efficacy slightly lower (IC₅₀ 7.45 ± 0.3) than that of the SFE extracts.     

Supercritical fluid extraction of daphne (Laurus nobilis L.) seed oil

Laurus nobilis L., commonly known as daphne tree, is an evergreen that belongs to the Lauraceae family. Daphne trees produce grape-sized shiny purplish berries having three parts: flesh, skin, and an inner kernel (single seed). This study examines supercritical CO₂ (SC-CO₂) extraction of oil from daphne seeds. The oil yield of ground seeds varied from 14 to 28% depending on the method and particle size used for oil recovery. Yields were similar for both petroleum ether and SC-CO₂ extraction. The extraction yield decreased significantly with increasing particle size. The amount of extract collected increased exponentially with increasing SC-CO₂ pressure. The highest extraction yield was obtained at the highest temperature studied, 75°C. More than 45% of the oil was lauric acid. SC-CO₂ is a viable technique to obtain high-purity L. nobilis L. seed oil, which is a potential ingredient for the cosmetic industry.     

Optimization of the Extraction of <Emphasis Type="Italic">Alpinia oxyphylla</Emphasis> Essence Oil in Supercritical Carbon Dioxide

The essence oil of the Alpinia oxyphylla seed has been used as a vasodilatatory and analgesic agent in pharmacology. The extraction of the essence oil in supercritical carbon dioxide (SC-CO₂) from Alpinia oxyphylla seeds was investigated. Small particles were obtained after breaking open, sieving, and drying from the Alpinia oxyphylla seeds. The small particles were placed in a 5-L extraction tank in a temperature-controlled system. The CO₂ flow rate of the system was set at 1 L/min in this study. Response surface methodology with a three-factor and three-level Box-Behnken experimental design was used to evaluate the effects of the reaction parameters such as extraction time (1, 2, 3 h), temperature (45, 55, 65 °C), and pressure (20, 30, 40 MPa), on the extraction yield of the essence oil from Alpinia oxyphylla seeds. The results indicate that the extraction pressure was the most important parameter affecting the yield of the essence oil. A model for the estimation of the yield was developed. Based on the analysis of ridge max, the optimal extraction conditions were established as an extraction time of 2.8 h, a temperature of 67.5 °C, and a pressure of 28.5 MPa, with an expected yield of 2.78%. Extraction of Alpinia oxyphylla essence oil in SC-CO₂ under these optimal conditions was conducted, and a yield of 2.77 ± 0.19% was obtained.     

Supercritical fluid extraction of oil from millet bran

Proso millet bran [Panicum miliaceum (L.)], variety Dakota White, was extracted with supercritical carbon dioxide (SC-CO₂) to yield crude oil. The effects of operating parameters (pressure, temperature, and specific solvent flow) and of features of the raw material (moisture content and particle size) on oil extraction were investigated. Complete de-oiling of ground millet bran pellets was achieved under 300 bar at 40°C with a specific solvent flow of 2–10 h⁻¹ within 200 to 500 min. Solvent requirements were 20–30 kg CO₂/kg raw material. Composition of crude SC-CO₂ oil extracted under optimal conditions, i.e., fatty acid profile, amount of unsaponifiables, tocopherols, free fatty acids, sterols, sterol esters, waxes, hydrocarbons, and phospholipids, was compared to that of crude oil obtained by petroleum ether extraction. These two oils were similar in terms of fatty acid profile and amount of free fatty acids, unsaponifiables, peroxides, and tocopherols. They differed in respect to phospholipids (present in petroleum etherextracted oil and absent in SC-CO₂ extracted oil), metals, and waxes (lower levels in SC-CO₂ extracted oil). The effects of extraction procedures on oxidative stability of crude SC-CO₂ oil were studied. Ensuring that all pieces of the extractor in contact with the oil were in stainless steel; cleaning the separator, i.e., washing with KOH, rinsing, purging with N₂ and CO₂, and heating; performing a couple of extractions before the main extraction; and achieving the extraction without interruption all positively influenced the oxidative stability of the oil. Conversely, increasing CO₂ purity above 99.5% had no effect. Oxidative stability of the SC-CO₂ oil extracted under these conditions was only slightly lower than that of the oil extracted with petroleum ether.     

Comparison of supercritical CO2 and hexane extraction of lipids from sorghum distillers grains

Total yields and compositions of sorghum dried distillers grains with solubles (DDGS) lipids obtained by supercritical CO₂ (SC‐CO₂) extraction were compared with those obtained by recirculated solvent extraction (RSE) with hexane. The total yield of lipids obtained by SC‐CO₂ extraction at 27.5 MPa and 70 °C was 150 g lipids/kg DDGS, while the yield obtained by RSE with hexane at 69 °C was only 85 g lipids/kg DDGS. The contents of four high‐value compounds, i.e., policosanols, phytosterols, free fatty acids (FFA) and tocols, in the lipids obtained by SC‐CO₂ extraction were 31.2, 15.6, 155.3 and 0.50 mg/g at 27.5 MPa and 70 °C, compared to 26.6, 9.6, 57.3 and 0.03 mg/g for RSE with hexane at 69 °C. The profiles of phytosterols and FFA in the sorghum DDGS lipids were relatively independent of the extraction methods and operating conditions.     

Response surface optimization of Smyrnium cordifolium Boiss (SCB) oil extraction via supercritical carbon dioxide

In this study, the essential oil of aerial parts of a species of a plant called Smyrnium cordifolium Boiss (SCB) was extracted by supercritical CO₂. The essence was analyzed by the method of GC/MS. Design of experiments was carried out with response surface methodology by Minitab 16 software to optimize four operating variables of supercritical carbon dioxide (SC-CO₂) extraction (pressure, temperature, CO₂ flow rate and extraction dynamic time). This is the first report announcing optimization of the operation of supercritical extraction of SCB in laboratorial conditions. Optimizing process was done to achieve maximum yield extraction. Independent variables were dynamic time (t_d), pressure (P), temperature (T) and flow rate of SC-CO₂ (Q) in the range of 30–150 min, 10–30 MPa, 40–60 °C and 0.5–1.7 ml/min, respectively. The experimental optimal recovery of essential oil (0.8431, w/w%) was obtained at 13.43 MPa, 40 °C, 150 min (dynamic) and 1.7 ml/min (CO₂ flow rate).     

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.     

Trigonella foenum-graecum L. Seed Oil Obtained by Supercritical CO2 Extraction

Supercritical CO₂ extraction (SC-CO₂) of fenugreek (Trigonella foenum-graecum L.) seed oil and its chemical composition and antioxidant activity were investigated. A central composite design combined with response surface methodology was used to study extraction conditions including pressure, temperature, and time. The optimum extraction conditions were 28.5?MPa extraction pressure, 41?°C extraction temperature, and 118?min extraction time, where 3.78?% yield was predicted. Fenugreek seed oil extracted under optimum conditions by SC-CO₂ was mainly composed of 28.3?% C18:3, 33.45?% C18:2, 9.89?% C16, 8.1?% C18:1, 3.7?% C18, 0.71?% C20, and 0.61?% C22. The fenugreek oil was rich in unsaturated fatty acids (nearly 70?% of the total fatty acids), and polyunsaturated fatty acids accounted for 61.42?% (mass percentage) of the total amount. The 2,2-diphenyl-1-picrylhydrazyl radical-scavenging activity increased from 12.5 to 88.4?% when the concentration was increased from 1 to 12?mg/ml. The reducing power of the seed oil was concentration-dependent. The antioxidant activity of the supercritical fluid extraction extract was superior to those obtained by Soxhlet extraction.     

Fatty acid composition,cytotoxicity and anti-inflammatory evaluation of melon (Cucumis melo L. Inodorus) seed oil extracted by supercritical carbon dioxide

ABSTRACT

Melon seed oil has been extracted by Soxhlet (hexane) and by supercritical CO₂ operating to various pressures and temperatures. Linoleic acid (67.06–68.22%) was the most abundant followed by oleic acid (21.63–22.45%), palmitic acid (5.57–6.23%) and stearic acid (2.98–3.67%). The highest inhibition of inflammation was 18.8% at 50 µg/mL for hexane and SC-CO₂ extracts obtained under 55 MPa and 70°C. The largest inhibition of IGROV and OVAR tumor cell lines were 29.9% and 21.6%, respectively, at 50 µg/mL for the ethanol extract. These results of biological activities indicate that melon seed oils can be dedicated to nutrition.     

Time Fractionation of Minor Lipids from Cold-Pressed Rapeseed Cake Using Supercritical CO<Subscript>2</Subscript>

This work explored the possibility of using supercritical carbon dioxide (SC-CO₂) to achieve fractionation of pre-pressed rapeseed (Brassica napus) cake oil at 30–50 MPa, at 40 or 80 °C, and increase the concentration of minor lipids (sterols, tocopherols, carotenoids) in the oil. Minor lipids are partially responsible for desirable antioxidant effects that protect against degradation and impart functional value to the oil. The weight and concentration of minor lipids in oil fractions collected during the first 60 min were analyzed. Cumulative oil yield increased with pressure, and with temperature at ≥40 MPa, but was lower at 80 °C than at 40 °C when working at pressure ≤35 MPa. Differences in solubility between the oil and minor lipids explained fractionation effects that were small for tocopherols. Unlike tocopherols, which are more soluble in SC-CO₂ than the oil, sterols and carotenoids are less soluble than the oil, and their concentration increased in the later stages of extraction, particularly at ≥40 MPa, when there was not enough oil to saturate the CO₂ phase. Because of the fractionating effects on rapeseed oil composition, there was an increase in the antioxidant activity of the oil in the second half as compared to the first half of the extraction. Consequently, this study suggests that SC-CO₂ extraction could be used to isolate vegetable oil fractions with increased functional value.     

Effects of supercritical CO2 extraction parameters on chemical composition and free radical-scavenging activity of pomegranate (Punica granatum L.) seed oil

Pomegranate (Punica granatum L.) seed oil (PSO) was prepared by supercritical CO₂ (SC-CO₂) extraction technology. Changes in the yield, chemical composition and free radical-scavenging activity of PSO under different extraction parameters were investigated. The results of SC-CO₂ extraction revealed that extraction pressure was the dominant factor to affect the oil yield. PSO was characterized by a high content of punicic acid (approximately 60%) and γ-tocopherol (more than 300 mg/100 g oil). A slight increase in the contents of punicic acid, arachidic acid and gadoleic acid was observed under higher extraction pressure and temperature. At lower pressure or shorter extraction time, PSO with high amount of total tocopherols was obtained. PSO extracted by SC-CO₂ showed strong free radical-scavenging activity towards 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azinobis-(3-ethylbenz-thiazoline-6-sulfonic) diammonium salt (ABTS) radicals and its scavenging ability was correlated with the level of tocopherols in extracted oils.