Optimization of periodic static-dynamic supercritical CO 2 extraction of taxifolin from pinus nigra bark with ethanol as entrainer

Extraction and Separation of Natural Products from Microalgae and Other Natural Sources Using Liquefied Dimethyl Ether, a Green Solvent: A Review

Microalgae are a sustainable source for the production of biofuels and bioactive compounds. This review discusses significant research on innovative extraction techniques using dimethyl ether (DME) as a green subcritical fluid. DME, which is characterized by its low boiling point and safety as an organic solvent, exhibits remarkable properties that enable high extraction rates of various active compounds, including lipids and bioactive compounds, from high-water-content microalgae without the need for drying. In this review, the superiority of liquefied DME extraction technology for microalgae over conventional methods is discussed in detail. In addition, we elucidate the extraction mechanism of this technology and address its safety for human health and the environment. This review also covers aspects related to extraction equipment, various applications of different extraction processes, and the estimation and trend analysis of the Hansen solubility parameters. In addition, we anticipate a promising trajectory for the expansion of this technology for the extraction of various resources.

Extraction Process Optimization of Curcumin from Curcuma xanthorrhiza Roxb. with Supercritical Carbon Dioxide Using Ethanol as a Cosolvent

Curcuma xanthorrhiza Roxb., known as temulawak, Javanese ginger, or Javanese turmeric, is a plant species belonging to the ginger family. This plant originated in Indonesia, more specifically on Java Island, and is usually used as medicine. It contains a high amount of a phenolic compound, namely, curcumin. A supercritical carbon dioxide extraction technique was employed to extract curcumin from C. xanthorrhiza. The objective of this work was to investigate the effects of temperature, pressure, and CO2 flow rate on the extraction yield and curcumin recovery from C. xanthorrhiza, which was extracted using supercritical carbon dioxide and ethanol as a cosolvent. The Box-Behnken design (BBD) experimental design and response surface methodology were used to optimize the extraction yield and curcumin recovery. The extraction conditions at a temperature of 40 °C, a pressure of 25 MPa, and a CO2 flow rate of 5.34 mL/min produced the optimum extraction yield of 10.4% and curcumin recovery of 3.2%. From Fourier transform infrared analysis, although the physical-chemical structure in the residue of the starting material was almost similar, the quantity of all functional groups in the residue decreased from the starting material. From scanning electron microscopy analysis, it was confirmed that the cell was broken due to the high-pressure effect, so that the extraction process runs easily.

Basil (Ocimum basilicum L.) Leaves as a Source of Bioactive Compounds

Basil (Ocimum basilicum L.) is an annual spicy plant generally utilized as a flavouring agent for food. Basil leaves also have pharmaceutical properties due to the presence of polyphenols, phenolic acids, and flavonoids. In this work, carbon dioxide was employed to extract bioactive compounds from basil leaves. Extraction with supercritical CO₂ (p = 30 MPa; T = 50 °C) for 2 h using 10% ethanol as a cosolvent was the most efficient method, with a yield similar to that of the control (100% ethanol) and was applied to two basil cultivars: “Italiano Classico” and “Genovese”. Antioxidant activity, phenolic acid content, and volatile organic compounds were determined in the extracts obtained by this method. In both cultivars, the supercritical CO₂ extracts showed antiradical activity (ABTS^●+ assay), caffeic acid (1.69–1.92 mg/g), linalool (35–27%), and bergamotene (11–14%) contents significantly higher than those of the control. The polyphenol content and antiradical activity measured by the three assays were higher in the “Genovese” cultivar than in the “Italiano Classico” cultivar, while the linalool content was higher (35.08%) in the “Italiano Classico” cultivar. Supercritical CO₂ not only allowed us to obtain extracts rich in bioactive compounds in an environmentally friendly way but also reduced ethanol consumption.

Berberis Vulgaris Fruit: Determination of Phenolic Compounds in Extracts Obtained by Supercritical CO2 and Soxhlet Methods Using HPLC

Recently, research studies on nutraceutically important polyphenolic substances have attracted intensive attention. Berberis vulgaris is an important source of polyphenolic compounds and is often used in traditional medicine. In this study, the extraction of rutin and apigenin rich oil from Berberis vulgaris fruits was evaluated by supercritical carbon dioxide (Sc-CO₂) extraction method with and without co-solvent. As valuable antioxidants, rutin and apigenin content of extracts were analyzed by HPLC, and their amounts were maximized via parametric optimization. The rutin compound studied in this research has the potential to be a drug against the COVID-19 virus. The operating conditions were considered in the range of 35–70 °C temperatures, 140–240 bar of pressures, 0.35–1.00 mm of mean particle sizes, 3–7 l/min of CO₂ flow rates, and 0–8% w/w co-solvent. As a result of Sc-CO₂ extractions, the amounts of rutin and apigenin were found as 173 ± 14.97 µg/g and 2.91 ± 0.11 µg/g, respectively, with the 8% (w/w) co-solvent addition. The amounts of rutin and apigenin obtained by Soxhlet extractions were found as 208.81 ± 8.48 µg/g and 6.55 ± 0.21 µg/g, respectively. When the Sc-CO₂ method was compared with the Soxhlet method, it was seen that the fast and eco-friendly Sc-CO₂ method was an ideal extraction method by providing 76.89% rutin and 44.53% apigenin recoveries. As a result of this study, the maximum extraction conditions for rutin and apigenin were obtained as 160 bar, 40 °C, 0.35 mm particle size, 3 l/min CO₂, 8% w/w co-solvent ratio, and 120 min extraction period.

Extraction and quantification of some valuable flavonoids from pinecone of Pinus brutia via Soxhlet and Supercritical CO2 extraction: a comparison study

In this study, the extraction of oil from pinecone of Pinus brutia was evaluated by supercritical CO₂ (Sc-CO₂) and Soxhlet extraction methods. The quercetin, rutin and kaempferol (QRK) contents of oil were analyzed one by one via HPLC. The rutin compound investigated in this study has the potential to be a drug against the COVID 19 virus. SEM and BET analysis were performed to observe the structural change and increase in surface area after Sc-CO₂ extraction. The operating conditions were investigated in the range of 35–65 °C temperatures, 140–220 bar of pressures, 0.30–1.00 mm of mean particle sizes, 3–7 l/min of CO₂ flow rates, 0–8% w/w co-solvent and 30–150 min extraction periods. When the results obtained by the Sc-CO₂ method were compared with the results of Soxhlet extraction method, the maximum recovery of total QRK was found 4.18% in co-solvent-free studies and 30.94% in co-solvent-added Sc-CO₂ studies. Sc-CO₂ extraction results of Q, R, and K were found as 14.75 ± 1.08 µg/g, 14.23 ± 1.27 µg/g, and 15.70 ± 1.13 µg/g pinecone, respectively. Soxhlet extraction results of Q, R, and K were found as 36.43 ± 2.26 μg/g, 57.19 ± 3.81 μg/g, and 50.80 ± 2.79 μg/g pinecone, respectively. The maximum amount of QRK was found as 44.68 ± 2.89 μg/g pinecone by Sc-CO₂ method via adding 8% ethanol by mass and as 144.42 ± 5.39 μg/g pinecone by Soxhlet method. According to the reference Soxhlet method efficiency, the Sc-CO₂ extraction recovery was found as 30.94%.

Recent trends in extraction of plant bioactives using green technologies: A review

Phenolic compounds from plant sources have significant health-promoting properties and are known to be an integral part of folk and herbal medicines. Consumption of phenolics is known to alleviate the risk of various lifestyle diseases including cancer, cardiovascular, diabetes, and Alzheimer's. In this context, numerous plant crops have been explored and characterized based on phenolic compounds for their use as supplements, nutraceutical, and pharmaceuticals. The present review highlights some important source of bioactive phenolic compounds and novel technologies for their efficient extraction. These techniques include the use of microwave, ultrasound, and supercritical methods. Besides, the review will also highlight the use of response surface methodology (RSM) as a statistical tool for optimizing the recoveries of the phenolic bioactives from plant-based matrices.

Selective extraction of polar lipids of mango kernel using Supercritical Carbon dioxide (SC-CO2) extraction: Process optimization of extract yield/phosphorous content and economic evaluation

Lipids are biomolecules extracted from plant sources and plant residues and have a beneficial role in various food, nutrition and medical applications. Supercritical carbon-dioxide as an advanced high-pressure technology which increases the productivity and has negligible environmental impact is employed for the selective extraction of polar lipids from the lipid matrix in mango kernel for the first time. The process parameters affecting the extraction such as pressure, temperature and the flow rate of CO₂ are ranged in the intervals of 30-50 MPa, 40-60 °C and 10-30 g min^-1, respectively. Optimization using Box Behnken design obtained the highest yield of 3.38% at 40 °C, 50 MPa and 30 g min^-1. The phosphorous content was evaluated to understand the behaviour of polar lipids extraction at higher pressures. The study showed the effect of process parameters having significant influence on polarity and solvating capacity of CO₂ which enabled for the extraction of polar lipids adding value to the mango kernel converting waste into valuable industrial products. The economic evaluation estimates the return on investment of a plant processing 3000 tons of mango kernel per year to account net present value (NPV) almost five times higher than the investment expenses and the payback period is under 4 years.

Green and Sustainable Valorization of Bioactive Phenolic Compounds from Pinus By-Products

In Europe, pine forests are one of the most extended forests formations, making pine residues and by-products an important source of compounds with high industrial interest as well as for bioenergy production. Moreover, the valorization of lumber industry residues is desirable from a circular economy perspective. Different extraction methods and solvents have been used, resulting in extracts with different constituents and consequently with different bioactivities. Recently, emerging and green technologies as ultrasounds, microwaves, supercritical fluids, pressurized liquids, and electric fields have appeared as promising tools for bioactive compounds extraction in alignment with the Green Chemistry principles. Pine extracts have attracted the researchers’ attention because of the positive bioproperties, such as anti-inflammatory, antimicrobial, anti-neurodegenerative, antitumoral, cardioprotective, etc., and potential industrial applications as functional foods, food additives as preservatives, nutraceuticals, pharmaceuticals, and cosmetics. Phenolic compounds are responsible for many of these bioactivities. However, there is not much information in the literature about the individual phenolic compounds of extracts from the pine species. The present review is about the reutilization of residues and by-products from the pine species, using ecofriendly technologies to obtain added-value bioactive compounds for industrial applications.

Process optimization for the supercritical carbon dioxide (SC-CO2) extraction of wheat germ oil with respect to yield, and phosphorous and tocol contents using a Box Behnken design

The supercritical carbon dioxide (SC-CO2) extraction technique has emerged as one of the best possible alternatives to organic solvent (hexane) extraction. However, very limited information is available on process optimization for this extraction technique and the lack of available engineering data is causing the slow growth of this technique. In the present investigation, SC-CO2 extraction was carried out to extract the oil from wheat germ under various operating conditions and the oil samples were characterized for properties such as phosphorous and tocol contents (vitamin E). A three-level Box Behnken design from response surface methodology was applied to optimize the SC-CO2 extraction parameters such as pressure, temperature and CO2 flow rate with an objective to obtain high oil yield, rich tocol contents and low phosphorous content. The process parameters were maintained between 30 to 50 MPa, 40 to 60 °C and a flow rate of 10 to 30 g·min-1 in a Box Behnken design matrix. Three different second order polynomial models were obtained for oil yield, phosphorous content and tocol contents with high R2 values. The optimum conditions were found to be 50 M Pa, 60 °C and 30 g·min-1 where the predicted oil yield, phosphorous content and tocol contents were found to be 8.87%, 31.86 mg·Kg-1 and 2059.92 mg·Kg-1 respectively. Under the optimum conditions, the experimental oil yield, phosphorous content and tocol contents obtained were found to be very close to the values predicted by the model.