Extraction of fucoxanthin from raw macroalgae excluding drying and cell wall disruption by liquefied dimethyl ether.

Macroalgae are one of potential sources for carotenoids, such as fucoxanthin, which are consumed by humans and animals. This carotenoid has been applied in both the pharmaceutical and food industries. In this study, extraction of fucoxanthin from wet brown seaweed Undaria pinnatifida (water content was 93.2%) was carried out with a simple method using liquefied dimethyl ether (DME) as an extractant in semi-continuous flow-type system. The extraction temperature and absolute pressure were 25 °C and 0.59 MPa, respectively. The liquefied DME was passed through the extractor that filled by U. pinnatifida at different time intervals. The time of experiment was only 43 min. The amount of fucoxanthin could approach to 390 µg/g dry of wet U. pinnatifida when the amount of DME used was 286 g. Compared with ethanol Soxhlet and supercritical CO2 extraction, which includes drying and cell disruption, the result was quite high. Thus, DME extraction process appears to be a good method for fucoxanthin recovery from U. pinnatifida with improved yields.

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.

Controlled crushing device-intensified direct biodiesel production of Black Soldier Fly larvae.

Insect larvae contain sufficient oil comparable with oleaginous biomass, and hence have potency as alternative biodiesel resources. The direct transesterification of Black Soldier Fly (BSF) larvae have conducted using a controllable crushing device (CCD) and a homogeneous base as a catalyst. The effect of catalyst concentration (wt.%), ratio BSF larvae to methanol (wt./v), reaction time (min) and rotational speed (rpm) on biodiesel conversion was determined. The maximum conversion of 93.8% was achieved at room temperature after 20 min of reaction time and ratio larvae to methanol of 1:2 (wt./v), catalyst concentration of 7 wt% and rotational speed of 3000 rpm. In addition, the green metrics calculation showed that this method produces less waste and uses less solvent. Some of the BSF-biodiesel properties meet the biodiesel standard. The CCD-intensified the DT of BSF larvae is a promising alternative for green and energy-saved biodiesel production.

Reduced-Pressure Process for Fabricating Tea Tree Oil-Polyvinylpyrrolidone Electrospun Fibers.

Electrospun fibers containing tea tree oil (TTO) can be explored for practical applications due to the antimicrobial and anti-inflammatory activities of TTO. Considering that there are potentially toxic components in TTO, it is necessary to eliminate or reduce its content in the preparation process of TTO-doped electrospun fibers. In this work, electrospun TTO-PVP (polyvinylpyrrolidone) fibers containing an 18.18 wt.% decreased content of 1,8-Cineole were successfully fabricated by intense evaporation of a self-made reduced-pressure electrospinning (RP-ES) setup (as low as 94.4 kPa). In addition, such intense evaporation led to a morphology change, where a typical average fiber diameter increased from 0.831 to 1.148 µm, fewer and smaller beads in fibers, along with a rougher and grooves fiber surface. These morphology changes allowed Terpinen-4-ol to remain in the fiber for a more extended period. In addition, RP-ES proved the possibility for intense evaporation and continuous vapor removal by continuously environmental vacuum pumping of electrospinning.

Curcumin-Loaded Liposome Preparation in Ultrasound Environment under Pressurized Carbon Dioxide.

Curcumin-loaded liposomes were prepared using a supercritical carbon dioxide (SCCO2)−ultrasound environment system. The experiments were performed at temperatures of 40−70 °C and pressures of 10−25 MPa in a batch system with ultrasonication for 60 min. Transmission electron microscopy (TEM) images revealed liposome products with spherical morphologies and diameters of <100 nm. Dynamic light scattering (DLS) analysis indicated that the curcumin-loaded liposome nanosuspension exhibited good stability. Changing the operating conditions influenced the amount of liposome-encapsulated curcumin; as the operating temperature or pressure increased, the diameter of the liposome products and the amount of liposome-encapsulated curcumin increased and decreased, respectively. Herein, we described an innovative and practical organic-solvent-free method for generating liposomes from phospholipids.

Enhancement of Curcuma xanthorrhiza Roxb Phytochemical Dissolution via Micronization Using a Supercritical Antisolvent Technique.

Fine particles comprising Curcuma xanthorrhiza Roxb (C. xanthorrhiza) rhizome extract were successfully generated using a supercritical carbon dioxide (SCCO2) antisolvent technique. The SCCO2 antisolvent process was performed at 40 °C with 8-16 MPa operating pressures. The CO2 and feed solution flow rates were 15 and 0.25 mL min-1, respectively. The mixture of C. xanthorrhiza rhizome extract and a polyvinylpyrrolidone (PVP) polymer in acetone-ethanol was used as a feed solution. The collected particle products seemed to possess spherical and spherical-like morphologies with a diameter of less than 500 nm. The infrared spectroscopy analysis showed that the structural properties of C. xanthorrhiza rhizome extract did not change after treatment with the SCCO2 antisolvent. Furthermore, the addition of the PVP polymer in the C. xanthorrhiza rhizome extract particle products may improve their dissolution significantly in an aqueous solution medium.

Extraction of Functional Components from Freeze-Dried Angelica furcijuga Leaves Using Supercritical Carbon Dioxide.

Angelica furcijuga (A. furcijuga), as a material for traditional Chinese medicine, has been widely used in Asian countries, such as China, Korea, and Japan, for several centuries owing to its therapeutic effects. In this study, A. furcijuga leaves were used as starting materials to extract functional substances using supercritical carbon dioxide (SC-CO2) at pressure and temperature ranges of 20-40 MPa and 40-80 °C, respectively. The extraction process was performed in a semibatch-type system with extraction times of 15-120 min. The high-performance liquid chromatography analysis indicated that kaempferol, ferulic acid, ligustilide, and butylidenephthalide as selected functional substances were successfully extracted under these operating conditions. An operating pressure of 30 MPa with an extraction time of 60 min seems to be an appropriate pressure to extract functional components from A. furcijuga leaves. The Hansen solubility parameter values and statistical analysis showed that SC-CO2 with 10% ethanol addition is a feasible tool to isolate these selected functional substances from the A. furcijuga matrix.

PVP/Highly Dispersed AgNPs Nanofibers Using Ultrasonic-Assisted Electrospinning.

Silver nanoparticles (AgNPs) are novel materials with antibacterial, antifungal, and antiviral activities over a wide range. This study aimed to prepare polyvinylpyrrolidone (PVP) electrospinning composites with uniformly distributed AgNPs. In this study, starch-capped ~2 nm primary AgNPs were first synthesized using Atmospheric pressure Pulsed Discharge Plasma (APDP) at AC 10 kV and 10 kHz. Then, 0.6 wt.% AgNPs were mixed into a 10 wt.% PVP ethanol-based polymer solution and coiled through an Ultrasonic-assisted Electrospinning device (US-ES) with a 50 W and 50 kHz ultrasonic generator. At 12 kV and a distance of 10 cm, this work successfully fabricated AgNPs-PVP electrospun fibers. The electrospun products were characterized using Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), High-Resolution TEM (HR-TEM), Fourier Transform Infrared Spectroscopy (FT-IR), X-ray Diffraction (XRD), Thermogravimetric (TG), and X-ray Photoelectron Spectroscopy (XPS) methods.

Oil removal from spent bleaching earth of vegetable oil refinery plant using supercritical carbon dioxide.

The oil in the spent bleaching earth (SBE) matrix was successfully removed by applying the supercritical carbon dioxide (SCCO2) extraction technique in a semi-continuous flow-type system. The SCCO2 extraction process was conducted at 40-80 °C and 20-30 MPa with extraction time of ∼180 min. The color of SBE matrix changes from the dark to dark-pale color after the SCCO2 extraction treatment exhibiting the substances including oil in the SBE matrix were successfully removed. The extracted oil yield was around 95% when the SCCO2 extraction process was performed at 40 °C and 30 MPa with 10% ethanol addition as a co-solvent. The GC analysis showed that the prominent fatty acid constituents in the extracted oil are palmitic and oleic acids, furthermore it can be fed as a feedstock to produce biodiesel fuel. Next, it can be proposed that SCCO2 extraction system is a viable way to extract oil from the SBE matrix.

Synthesis of Hollow PVP/Ag Nanoparticle Composite Fibers via Electrospinning under a Dense CO2 Environment.

Polyvinylpyrrolidone (PVP) is used in a wide variety of applications because of its unique chemical and physical features, including its biocompatibility and low toxicity. In this study, hollow PVP/silver nanoparticle (PVP/Ag NP) composite fibers were synthesized. Stable, spherical Ag NPs, with an average size of 14.4 nm, were produced through a facile sonochemical reduction method. A small amount of starch as a potent reducing and stabilizing agent was used during the reduction of Ag ions to Ag NPs. The fabricated Ag NPs were then added to a 10 wt% PVP-dichloromethane (DCM) solution, which was utilized as an electrospinning feed solution under a dense carbon dioxide (CO2) environment at 313 K and 5 MPa and an applied voltage of 15 kV. The dense CO2 enabled rapid extraction of DCM from the PVP-Ag NPs-DCM solution, which was then dissolved into PVP/Ag NPs, resulting in a hollow structure. Scanning electron microscopy, Fourier-transform infrared (FT-iR) spectroscopy, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses, and thermogravimetric analysis (TGA), were used to characterize the electrospinning products.

Direct Extraction of Lutein from Wet Macroalgae by Liquefied Dimethyl Ether without Any Pretreatment.

Extraction of lutein from raw macroalgae Monostroma nitidum was conducted using a simple method employing dimethyl ether (DME) as a solvent. DME extraction enabled omission of conventional drying and cell wall disruption steps, yielding 0.30 mg/g dry lutein from wet M. nitidum. The yield of extracted lutein was higher than that by chloroform-methanol extraction from freeze-dried and cell-disrupted M. nitidum. DME extraction provides a safe, eco-friendly approach that combines high yields of lutein with unheated drying of wet macroalgae in a single step.

Formation of Fine Particles from Curcumin/PVP by the Supercritical Antisolvent Process with a Coaxial Nozzle.

The production of fine particles via the supercritical carbon dioxide (SC-CO2) antisolvent process was carried out. The experiments were conducted at temperatures of 40-60 °C and pressures of 8-12 MPa with a 15 mL min-1 carbon dioxide (CO2) and 0.5 mL min-1 feed solution flow rate. As a feed solution, the curcumin and the polyvinylpyrrolidone (PVP) powder were dissolved in acetone and ethanol at concentrations of 1.0 mg mL-1 and 2.0-4.0% in weight, respectively. Scanning electron microscopy (SEM) images described that most of the precipitated particle products have spherical morphologies with a size of less than 1 µm. The Fourier transform infrared spectroscopy (FT-IR) spectra exhibited that the curcumin structural properties did not shift after the SC-CO2 antisolvent process. Moreover, the PVP addition in the curcumin particle products can enhance the curcumin dissolution in distilled water significantly.

Atmospheric-Pressure Pulsed Discharge Plasma in a Slug Flow Reactor System for the Synthesis of Gold Nanoparticles.

Gold nanoparticle (AuNP) formation by applying pulsed discharge plasma in the slug flow reactor system was demonstrated. Experiments were carried out continuously at room temperature. The argon gas as a gas phase and the hydrogen tetrachloroaurate(III) tetra hydrate solution containing lysine as a liquid phase simultaneously flowed in the slug flow reactor system. The flow rates of the feed solution and argon gas were kept at 1.5 and 0.2 mL/min, respectively. To generate discharge plasma, the AC power supply with a bipolar pulsed output at 10 kV was applied. The purple color solution product was obtained, and the ultraviolet-visible (UV-vis) spectrophotometer showed that this possessed the absorption light from 510 to 550 nm associated with the existence of gold nanoparticles in each collected sample. Transmission electron microscopy (TEM) revealed that the lysine-capped AuNPs were produced in a spherical morphology and dispersed in aqueous solution products with a diameter of less than 20 nm.

DC-Plasma over Aqueous Solution for the Synthesis of Titanium Dioxide Nanoparticles under Pressurized Argon.

Nanomaterials that comprise titanium dioxide (TiO2) nanoparticles have received much attention owing to their wide applications; presently, the green synthesis of TiO2 nanoparticles is a developing research area. In this study, the TiO2 nanoparticles were synthesized through a DC-pulsed discharge plasma over an aqueous solution surface under a high-pressure argon environment. The titanium-rod electrode was utilized as the material source for the TiO2 nanoparticle generation. Experiments were performed at room temperature with pressurized argon at 1-4 MPa. To generate a pulse electrical discharge plasma, a DC power supply of 18.6 kV was applied. The Raman spectroscopy showed that the TiO2 nanoparticle with a brookite structure was formed dominantly. The scanning transmission electron microscopy equipped with energy dispersion spectroscopy (STEM coupled with EDS) indicated that TiO2 coated with carbon and that without carbon coating were successfully produced at the nanoscale. The process presented here is an innovative process and can update the existing information regarding the synthesis of metal-based nanoparticles using pulsed discharge plasma under an argon environment.

Response surface methodology to supercritical carbon dioxide extraction of astaxanthin from Haematococcus pluvialis.

Experimental design was used to investigate the effect of operating temperature (40-80 degrees C), operating pressure (30-50 MPa), and extraction time (1-4h) of supercritical carbon dioxide (SC-CO2) extraction on astaxanthin yields and the extract antioxidant activity (IC50). The ranges of the factors investigated were 40-80 degrees C for the operating temperature (X1), 30-50 MPa for the operating pressure (X2), and 1-4h for the extraction time (X3). The statistical analysis of the experiment indicated that pressure, extraction time, and the interaction between temperature and pressure (X1X2) had significant effect on astaxanthin yields. The central composite design showed that polynomial regression models were in good agreement with the experimental results with the coefficients of determination of 0.924 and 0.846 for astaxanthin yield and antioxidant activity, respectively. The optimal condition for astaxanthin yield within the experimental range of the variables studied was at 70 degrees C, 50 MPa, and 4h. At this condition, the predicted amount of astaxanthin extracted was 23.04 mg/g (2.3 wt% or 83.78% recovery). For the effect of experimental extraction conditions on antioxidant activity, IC50 was used as an index, which is the concentration that gives a 50% reduction in the absorbance of the ABTS free radical. The analysis of the results showed that the interaction between the operating temperature and operating pressure (X1X2) was the only significant factor affecting the extract antioxidant activity. The statistical model gave the minimum point for antioxidant activity at 67 degrees C, 40.3 MPa, and 1.86 h of extraction, at which the value for 1/IC50 was 0.39 l/mg (or IC50 was 2.57 mg/l).

Degradation of glycerol using hydrothermal process.

Sub-critical or supercritical water was utilized for the degradation of glycerol in an environmentally benign reaction. The reaction was carried out in a batch reactor in the temperature range of 473-673 K, pressure of 30 MPa, and reaction time of 20-60 min. The effects of temperature and reaction time were observed. The degradation of glycerol produced acetaldehyde, acrolein, allyl alcohol and un-identified products. The highest yield of acrolein, acetaldehyde and allyl alcohol were 0.20, 7.17, 96.69 mol%, respectively. Glycerol conversion was 99.92 mol%. While acetaldehyde was formed only in sub-critical water and allyl alcohol only in supercritical water, acrolein was formed in both. The kinetics of the global reaction displayed a pseudo-first-order. The activation energy at subcritical water was 39.6 kJ/mol. Based on the results, this method could be an efficient method for glycerol degradation because the high conversion of glycerol was obtained.