Extraction of antioxidant compounds from blackberry (Rubus sp.) bagasse using supercritical CO2 assisted by ultrasound

Supercritical carbon dioxide extraction (SFE) was performed to recover bioactive components from blackberry (Rubus sp.) industrial residues. Ultrasound was applied during the extractions in order to enhance rate and yield. Moreover, water and ethanol at different proportions were used as cosolvents to improve the extraction of polar compounds from the residues. The extraction global yields were measured at all performed conditions (pressure, temperature, ultrasound power and cosolvent). The extracts were evaluated in terms of their antioxidant activity, measured using two methods, phenolic content, monomeric anthocyanins, and anthocyanin profile. The application of ultrasound in SFE helped increasing the extraction rate at the beginning of the process, which could be observed on the extraction curves at 15 MPa, the lowest pressure applied. Scanning electron microscopy (FESEM) was used to analyze the blackberry bagasse undergoing SFE with and without ultrasounds and showed that ultrasound disturbs the cell walls, enhancing the release of the extractable compounds. The extracts have shown high antioxidant activity and phenolic contents when obtained at higher temperatures. Regarding anthocyanins, the use of water as cosolvent resulted in a significant increase. Four major anthocyanins were identified and quantified by ultra performance liquid chromatography (UPLC).     

Extraction of bioactive compounds from peach palm pulp (Bactris gasipaes) using supercritical CO2

Natural compounds with biological activity have recently attracted special interest in the agro-industry as sources of additives in nutraceutical food production and pharmaceutical industries. Herein, we evaluated extracts obtained from peach palm fruit (Bactris gasipaes) using supercritical carbon dioxide, in terms of yield, total phenolic content, total flavonoids, total carotenoids, and antioxidant activity by β-carotene bleaching method. Extractions were performed at 40, 50, and 60 °C and 100, 200, and 300 bar; additionally, Soxhlet (with petroleum ether) and methanol extraction were conducted. The results showed that supercritical CO₂ allows obtaining extracts rich in carotenoids and, although it presents lower yield than conventional extraction (SOX), supercritical CO₂ represents a technique with greater advantages. The best operation condition for supercritical extraction was 300 bar–40 °C, given that the highest concentration of carotenoids was obtained, without the yield being significantly different from that obtained with 300 bar–60 °C, this extract had antioxidant activity comparable to that of commercial caffeic acid.     

Extraction of curcuminoids from deflavored turmeric (Curcuma longa L.) using pressurized liquids: Process integration and economic evaluation

Pressurized liquid extraction (PLE) of curcuminoids from deflavored turmeric rhizomes was optimized. The rhizomes were initially deflavored by extraction with supercritical CO₂. Immediately after SFE, PLE process was performed using ethanol as the solvent and a static extraction time of 20 min, and the independent variables were the temperature (333–353 K) and pressure (10–35 MPa). The results indicate that the optimum extraction temperature and pressure were 333 K and 10 MPa, respectively. PLE required three and six times less extraction time than low-pressure solvent extraction and Soxhlet extraction, respectively, to produce similar extraction yields. The cost of manufacturing (COM) decreased from US$ 94.92 kg⁻¹ to US$ 88.26 kg⁻¹ when the capacity of the two-extractor system increased from 0.05 m³ to 0.5 m³ and from US$ 94.92 kg⁻¹ to US$ 17.86 kg⁻¹ when the cost of the raw materials decreased from US$ 7.91 kg⁻¹ to US$ 0.85 kg⁻¹ for a two 0.05 m³ extractor system.     

Obtaining phenolic compounds from jatoba (Hymenaea courbaril L.) bark by supercritical fluid extraction

The extraction of polyphenol compounds from jatoba (Hymenaea courbaril L. var stilbocarpa) bark using supercritical fluid extraction (SFE) with CO₂ and cosolvents has been investigated. Among the solvent systems studied, SFE using CO₂ and water (9:1, v/v), at 323 K and 35 MPa, presented the best results, with extract yield of 24%, and with high antioxidant activity (IC₅₀ of 0.2 mg/cm³). This solvent system was used to determine global yield isotherms, which were built at 323 and 333 K, and 15, 25, and 35 MPa, using a second lot of jatoba. The highest yield was 11.5% at 15 MPa and 323 K, with maximum total phenolic compounds (TPC) of 335.00 mg TAE/g extract (d.b.) and total tannins content of 1.8 g/100 g raw material. A kinetic experiment was performed using optimized conditions, yielding 18% extract, and the kinetic parameters were used to scale-up the process from laboratory to pilot scale. Chemical analyses showed high content of phenolic compounds in the extracts of jatoba bark mostly due to the presence of procyanidins.     

Extraction of anthocyanins and luteolin from Arrabidaea chica by sequential extraction in fixed bed using supercritical CO2, ethanol and water as solvents

Phenolic compounds from Arrabidaea chica Verlot leaves, besides conferring staining properties to their extracts, also have various biological activities including anti-inflammatory and wound-healing properties. To evaluate new possibilities for obtaining extracts with differentiated yield and composition, sequential extractions in fixed bed were performed at 40 and 50 °C, and 300 and 400 bar, using as extracting solvents pure supercritical carbon dioxide (scCO₂) in a first step, acidified ethanol in a second step and acidified water in a third extraction step. Four flavonoids of interest were investigated in the extracts, one of them being flavone (luteolin), and three anthocyanin compounds of type 3-desoxyanthocyanidins which were quantified by high performance liquid chromatography (HPLC). The extraction curves, the global yields and the concentration and yield of the compounds under study were evaluated. The results indicated that the cumulative total yields in the three steps ranged from 22% to 27% in all conditions of temperature and pressure, with the highest global yield at 50 °C and 300 bar. Although the lowest extraction yield was obtained using pure scCO₂, this step was highly selective, since only carajurin in its aglycone form was extracted among the compounds of interest and this was confirmed by analysis of MS/MS.     

Extraction of phenolic fraction from guava seeds (Psidium guajava L.) using supercritical carbon dioxide and co-solvents

In this work the supercritical fluid extraction (SFE) with carbon dioxide (CO₂) and with ethyl acetate (EtAc) and ethanol (EtOH) as co-solvents was applied to obtain the phenolic fraction from guava seeds (Psidium guajava L.). The extraction was explored at various operating conditions, using 10, 20 and 30 MPa and 40, 50 and 60 °C. The use of EtAc and EtOH as co-solvents in SFE was also studied. The supercritical process was compared with traditional techniques such as Soxhlet extraction using EtAc and EtOH as solvents. The quality of the different extracts, obtained using SFE and Soxhlet methods and different solvents, was evaluated through the antioxidant activity, obtained by the collection methods of scavenging DPPH and bleaching of β-carotene, and also through the total phenolic content (TPC) of the samples, by the Folin-Ciocalteu method. The antioxidant potential indicates the use of ethanol as co-solvent as the best modifier in SFE, used in concentration of 10% (w/w) at 50 °C and 30 MPa. The quality of the extracts obtained by SFE with EtOH varied with the operating conditions of temperature and pressure, with higher values obtained at 10 and 20 MPa for TPC results and also antioxidant methods. The process yield of the phenolic fraction was also evaluated for all the extraction procedures studied (SFE and Soxhlet), with results varying from 0.380 to 1.738% (w/w).     

Extraction of anthocyanins from Arrabidaea chica in fixed bed using CO2 and CO2/ethanol/water mixtures as solvents

Leaves of Arrabidaea chica (Humb. Bonpl.) Verlot are rich in anthocyanins and have been used as a medicinal plant in the Amazon region. In order to obtain different extracts from this plant, a sequential extraction in fixed bed was carried out at 40 °C and 300 bar, using supercritical carbon dioxide (scCO₂) in a first step, and a mixture containing CO₂/ethanol/water at mass ratios of approximately 80/20/0, 80/14/6 and 80/10/10 in a second extraction step. The residue from the second step was extracted with water at 40 °C and atmospheric pressure. Ethanolic, aqueous and hydroalcoholic (70:30, v:v) extracts were also obtained by conventional extraction methods at atmospheric pressure. All extracts were analyzed for global extraction yield, total phenolic content, total flavonoids, and carajurin content. High performance liquid chromatography (HPLC) was used both to quantify carajurin, which is the main anthocyanin component of A. chica, and to monitor qualitatively two other anthocyanin pigments found in that plant. The extraction yield in the first step was only 0.65% using pure scCO₂, but this extraction was highly selective to extract carajurin from the three main anthocyanins. The accumulated global yield of the two steps ranged from 3% when the solvent ratio (80/20/0) was used in the second step to about 50% when 6 or 10% water was used, showing the highest yield when the extraction was done with water. The highest contents of total phenolic compounds (178 mg GAE/g extract) and total flavonoids (373 mg EC/g extract) were found in the process performed with the extraction mixture (80/20/0), and the highest carajurin content was obtained in the ethanolic extracts.     

Extraction of phenolic compounds from pitanga (Eugenia uniflora L.) leaves by sequential extraction in fixed bed extractor using supercritical CO2, ethanol and water as solvents

With the goal of maximizing the extraction yield of phenolic compounds from pitanga leaves (Eugenia uniflora L.), a sequential extraction in fixed bed was carried out in three steps at 60 °C and 400 bar, using supercritical CO₂ (non-polar) as solvent in a first step, followed by ethanol (polarity: 5.2) and water (polarity: 9.0) in a second and third steps, respectively. All extracts were evaluated for global extraction yield, concentration and yield of both polyphenols and total flavonoids and antioxidant activity by DPPH method (in terms of EC₅₀). The nature of the solvent significantly influenced the process, since the extraction yield increased with solvent polarity. The aqueous extracts presented higher global extraction yield (22%), followed by ethanolic (16%) and supercritical extracts (5%). The study pointed out that the sequential extraction process is the most effective in terms of global extraction yield and yield of polyphenols and total flavonoids, because it produced the more concentrated extracts on phenolic compounds, since the supercritical ethanolic extract presented the highest phenolics content (240.5 mg GAE/g extract) and antioxidant capacity (EC₅₀ = 9.15 μg/mL). The most volatile fraction from the supercritical extract, which is similar to the essential oils obtained by steam distillation or hydrodistillation, presented as major compounds the germacrenos D and B + bicyclogermacrene (40.75%), selina-1,3,7(11)-trien-8-one + selina-1,3,7(11)-trien-8-one epoxide (27.7%) and trans-caryophyllene (14.18%).     

超临界CO_2萃取铁观音茶叶香气成分

分别采用索氏萃取(SE)、同时蒸馏萃取(SDE)和超临界CO2萃取(SFE)方法提取铁观音的香气成分。用GC/MS分析比较了萃取物中香气成分的组成及质量分数。SDE获得了最多的香气组分,而SFE得到的主要香气成分质量分数和萃取率最高。进一步考察了SFE的压力、温度及夹带剂对主要香气成分的萃取率及质量分数的影响,结果表明随着压力升高香气成分的萃取率及质量分数均升高。而当温度和夹带剂中乙醇质量比为45℃和5%时,总香气成分的萃取率最高,且主要香气成分的质量分数比未添加夹带剂时提高达几十倍,与SFE所得萃取物在香烟中品香评吸的结论完全吻合。     

Extraction of Dittany (Origanum dictamnus) using supercritical CO2 and liquid solvent

Different extraction processes of dittany (Origanum dictamnus) for the recovery of extracts enriched with bioactive components were examined in this work. More specifically, hydrodistillation, extraction with a liquid organic solvent, supercritical CO₂ extraction, as well as a combination of supercritical and liquid extraction were applied in order to recover improved extracts with respect to their antioxidant activity. The latter was determined by using a free radical method (DPPH). The antioxidant activities of the extracts obtained were compared with those of carvacrol, a main component of dittany, and BHT, a common synthetic antioxidant. It is shown that the combination of the conventional liquid extraction with supercritical extraction could be a promising alternative process for the recovery of extracts enriched with bioactive compounds.     

Extraction of essential oil from Cyperus articulatus L. var. articulatus (priprioca) with pressurized CO2

The main goal of this study was to assess the yield and the antimicrobial activity of extracts from Cyperus articulatus L. var. articulatus obtained by pressurized carbon dioxide based on their system phase diagram behavior. The extractions were carried out at 313, 323, 333 K temperatures and, 13 and 25 MPa pressures. The extracts were quantified and chemically characterized by using gas chromatography coupled to mass spectrometry technique. The extracts obtained at the following experimental conditions: 333 K and 13 MPa, showed antifungal activity against Cladosporium sphaerospermum ATCC 4464. At 323 K – 25 MPa, and 333 K – 25 MPa, the extracts showed antibacterial activity against Staphylococcus aureus ATCC 25923. To describe the kinetics of extraction with a packed bed, a mathematical model was employed highlighting the transference mechanisms for masses in the pseudo-binary system as follows (1) carbon dioxide and (2) priprioca extract, the monophasic and multiphasic regions.     

Extraction of caffeine from tea stalk and fiber wastes using supercritical carbon dioxide

The purpose of this study was to investigate obtaining of caffeine from tea plant wastes by supercritical carbon dioxide extraction. Experiments were carried out with tea stalk and fiber wastes of Turkish tea plants that has no economical value. Stalk and fiber wastes were supplied from tea factories. These wastes were ground, sieved and dried at 105 °C temperature in an oven. Parameters affecting caffeine leaching from tea wastes were determined to be, extraction time, extraction temperature, carbon dioxide flow rate, process pressure and particle size. The maximum yield of caffeine from tea stalk wastes and fiber wastes were 14.9 mg/g tea stalk and 19.2 mg/g tea fiber, respectively. The yield increase had been recorded as 61.9% and 65.5%, respectively, in comparison with the chloroform extraction of tea stalk and fiber wastes.     

Extraction,purification and application of thermostable and halostable alkaline protease from Bacillus alveayuensis CAS 5 using marine wastes

A marine bacterium Bacillus alveayuensis CAS 5 produced protease when grown at 55 °C for 60 h in 100 ml of basal medium containing 1% SSP (w/v) and purified to 7.77 fold with specific activity of 518.78 U/mg. The optimum temperature, pH and NaCl for enzyme activity were 50 °C, 9 and 35% respectively. The enzyme was highly stable even at 80 °C, pH 12, 35% NaCl and presence of ionic, non-ionic and commercial detergents. The protease was investigated for its application as cleansing additive in blood stain removal. The preset study emphasized that marine wastes can be utilized to generate high value-added products and hidden potential in the production of functional foods.     

Effects of bilberry (Vaccinium myrtillus L.) litter on seed germination and early seedling growth of four boreal tree species

Laboratory and greenhouse bioassays were used to test for inhibitory effects of senescent and decomposed leaves and aqueous extract from bilberry (Vaccinium myrtillus L.) against seed germination and seedling growth of aspen (Populus tremula L.), birch (Betula pendula Roth.), Scots pine (Pinus sylvestris L.), and Norway spruce [Picea abies (L.) Karst.]. Aqueous extracts from bilberry leaves were inhibitory to aspen seed germination and seedling growth and also induced root damage and growth abnormalities. Addition of activated carbon removed the inhibitory effects of extracts. Senescent leaves reduced pine and spruce seed germination, but rinsing of seeds reversed this inhibition. Senescent leaves were more inhibitory than decomposed leaf litter, suggesting that the inhibitory compounds in bilberry leaves are relatively soluble and released at early stages during decomposition. Spruce was generally less negatively affected by litter and aqueous extracts than the other tested species. This study indicates that chemical effects of bilberry litter have the potential to inhibit tree seedling recruitment, but these effects were not consistently strong. Phytotoxicity is unlikely to be of critical importance in determining success for spruce seedling establishment.     

Sub‐and Supercritical CO2‐Extraction of Hypericum perforatum L.

The extraction of Hypericum perforatum L. by liquid carbon dioxide (p = 80 bar, t = 15 °C) gave almost the same extract yield (1 %, w/w) as by supercritical (p = 100 bar, t = 40 °C) carbon dioxide, containing the same percentages of essential oil (about 6.4 %, w/w). The increase of the extract yield at higher pressure (250 to 350 bar) is due to the increase of extragent density, i.e., solubility. By increasing the grinding degree of the drug, a higher extract yield is obtained in the supercritical range under high pressure. GC‐MS analysis of the extract composition showed that the non‐terpene compounds have the highest contribution. The oil content in the drug, determined by steam distillation, was 0.058 %, w/w. The oil content in the extracts, calculated for the drug, was significantly higher (1.2 to 1.9 times).     

Supercritical CO2 Extraction of Essential Oil from Algerian Rosemary (Rosmarinus officinalis L.)

The present study presents experimental results concerning the supercritical CO₂ extraction of essential oil from Algerian rosemary leaves. The effects of key operating parameters such as pressure, temperature, particle size and CO₂ mass flow rate on the extraction yield were investigated. The obtained yields were in the range of 0.95–3.52 g oil/g dry rosemary, and the best value was observed at a pressure of 22 MPa, a temperature of 40 °C, a flow rate of 7 g/min, and a particle size of 1 mm. The performance of the local rosemary used was assessed by comparison of the obtained yields with values reported in the literature for essential oils derived from different rosemary sources. The GC and the GC‐MS analyses showed that the major compound detected in the essential oil was camphor, at 48.89 wt %.     

Extraction of sesame seed (Sesamun indicum L.) oil using compressed propane and supercritical carbon dioxide

This work is aimed to investigate the extraction of sesame seed (Sesamun indicum L.) oil using supercritical carbon dioxide and compressed propane as solvents. The extractions were performed in a laboratory scale unit in a temperature and pressure range of 313-333 K and 19-25 MPa for carbon dioxide and 303-333 K and 8-12 MPa for propane extractions, respectively. A 2² factorial experimental design with three replicates of the central point was adopted to organize the data collection for both solvents. The results indicated that solvent and density 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 due to the fact that propane is a better solvent for vegetable oils compared to carbon dioxide. On the other hand, characteristics of extracted oil, its oxidative stability determined by DSC and chemical profile of constituent fatty acids determined by gas chromatography, were similar to both solvents. The mathematical modeling of the extraction kinetics using a second order kinetic presented good results for the extraction with both solvents.     

Enrichment,in vitro,and quantification study of antidiabetic compounds from neglected weed Mimosa pudica using supercritical CO2 and CO2-Soxhlet

Supercritical fluid extraction (SFE) using carbon dioxide (CO₂) and liquid CO₂ using Soxhlet (CO₂-Soxhlet) extraction were employed to extract three (3) antidiabetic compounds viz. stigmasterol, quercetin, and avicularin from Mimosa pudica. Various extraction parameters were studied. Extracts were analyzed pharmacologically, qualitatively and quantitatively to ascertain enrichment levels. All three antidiabetic compounds were effectively enriched under optimized conditions of temperature 60°C, pressure 40 MPa, co-solvent ratio 30%, and CO₂ flow rate of 5 ml min^?1. SFE was found to be the better method for enrichment of the antidiabetic compounds than the CO₂-Soxhlet method. Extraction conditions were seen to affect the enrichment of desired compounds.     

Extraction of bioactive enriched fractions from Eruca sativa leaves by supercritical CO2 technology using different co-solvents

Supercritical fluid extraction from freeze-dried Eruca sativa leaves is assessed with the aim of studying the feasibility to obtain bioactive enriched fractions containing different classes of valuable compounds. Total extraction yields and compositions using pure CO₂ and CO₂ + selected co-solvents are compared. Overall extraction curves, fitted by the model of broken and intact cells developed by Sovová, are reported and the influence of the main parameters that affect the extraction process is analysed. The extract with the highest content in glucosinolates and phenols was collected at 30 MPa and 75 °C using 8% (w/w) of water with respect to the CO₂ flow rate, whereas the fraction richest in lipids was obtained using 8% (w/w) of ethanol as co-solvent at 45 °C and 30 MPa. A process including a first step with supercritical CO₂ extraction using water as co-solvent followed by a second step, where a fraction rich in lipids is extracted using ethanol as co-solvent, is proposed. SCCO₂ results are compared with Soxhlet and other methods that combine organic solvents with ultrasounds.