Evaluation of Bioactive Compounds and Antioxidant and Cytotoxic Effects of Oil and Pulp without Açaí Fat (Euterpe oleracea) Obtained by Supercritical Extraction.

For bioactivity studies, it is necessary to use products with a high degree of purity, which may influence the cytotoxic effects. Supercritical technology presents itself as an alternative to obtain these products. Therefore, the objective of this work was to obtain the bioactive compounds of oil and pulp of açaí fat-free supercritical technology and evaluate the cytotoxicity of products in MRC-5 and VERO cells in vitro. The açaí pulp was subjected to extraction with supercritical CO2 to obtain the oil and pulp without fat, under conditions of 323.15 K at 35 MPa, 333.15 K at 42 MPa, and 343.15 K at 49 MPa. The largest yields (51.74%), carotenoids (277.09 µg/g), DPPH (2.55 µmol TE/g), ABTS (2.60 µmol TE/g), and FRAP (15.25 µm of SF/g) of oil and ABTS (644.23 µmol TE/g) of pulp without fat were found in the condition 343.15 K at 49 MPa. The highest levels of compounds phenolics (150.20 mg GAE/g), DPPH (414.99 µmol TE/g), and FRAP (746.2 µm SF/g) of the pulp without fat were found in the condition of 323.15 K to 35 MPa. The fat-free pulp presented high levels of anthocyanins without significant variation in cytotoxicity. The developed process was efficient in obtaining oil rich in carotenoids, and the supercritical technology elucidated an efficient way to obtain açaí fat-free pulp.

Evaluating sacha inchi (Plukenetia volubilis) oil stability and physicochemical properties: A comparison between conventional extraction and supercritical fluids.

This study aimed to compare the effects of two extraction techniques (conventional n-hexane and supercritical CO2) on the oil extraction yields, fatty acids profile, anti-hyaluronidase activity, oxidative stability, and in vitro bioactivities of oils from Sacha Inchi (Plukenetia volubilis). Higher oil extraction yield (99 %) was achieved using the SC-CO2, although similar fatty acids profiles were depicted between both treatments (p < 0.05). The SC-CO2 oil presented higher anti-hyaluronidase (31 %) activity, but lower oxidative stability (5.05 h) compared to the solvent extraction (10 %, and 5.3 h, respectively). In vitro assays further revealed that the best human normal colon cells (FHC) cell viability (100 %), anti-inflammatory (50 % lower NO production), and antioxidant (20 % ROS reduction) activities were consistently observed in both extraction treatments at concentrations of 50 µg/mL and higher. These findings highlight the potential of supercritical CO2 extraction in yielding Sacha Inchi oil with enhanced bioactive properties without the disadvantages of the use of organic solvents extraction.

Supercritical CO2 Treatment to Modify Techno-Functional Properties of Proteins Extracted from Tomato Seeds.

Tomato seeds are a rich source of protein that can be utilized for various industrial food purposes. This study delves into the effects of using supercritical CO2 (scCO2) on the structure and techno-functional properties of proteins extracted from defatted tomato seeds. The defatted meal was obtained using hexane (TSMH) and scCO2 (TSMC), and proteins were extracted using water (PEWH and PEWC) and saline solution (PESH and PESC). The results showed that scCO2 treatment significantly improved the techno-functional properties of protein extracts, such as oil-holding capacity and foaming capacity (especially for PEWC). Moreover, emulsifying capacity and stability were enhanced for PEWC and PESC, ranging between 4.8 and 46.7% and 11.3 and 96.3%, respectively. This was made possible by the changes in helix structure content induced by scCO2 treatment, which increased for PEWC (5.2%) and decreased for PESC (8.0%). Additionally, 2D electrophoresis revealed that scCO2 hydrolyzed alkaline proteins in the extracts. These findings demonstrate the potential of scCO2 treatment in producing modified proteins for food applications.

Foaming of 3D-Printed PLA/CaCO3 Composites by Supercritical CO2 Process for Sustainable Food Contact Materials.

In the last decade, among the emerging technologies in the area of bioplastics, additive manufacturing (AM), commonly referred to as 3D printing, stands out. This technology has gained great interest in the development of new products, mainly due to its capability to easily produce customized and low-cost plastic products. This work aims to evaluate the effect of supercritical foaming of 3D-printed parts based on a commercial PLA matrix loaded with calcium carbonate, for single-use sustainable food contact materials. 3D-printed PLA/CaCO3 parts were obtained by 3D printing with a 20% and 80% infill, and two infill patterns, rectilinear and triangular, were set for each of the infill percentages selected. Supercritical fluid foaming of PLA/CaCO3 composite printed parts was performed using a pressure of 25 MPa, a temperature of 130 °C for 23 min, with a fast depressurization rate (1 s). Closed-cell foams were achieved and the presence of CaCO3 did not influence the surface of the foams or the cell walls, and no agglomerations were observed. Foam samples with 80% infill showed subtle temperature fluctuations, and thermogravimetric analysis showed that samples were thermally stable up to ~300 °C, while the maximum degradation temperature was around 365 °C. Finally, tensile test analysis showed that for lower infill contents, the foams showed lower mechanical performance, while the 80% infill and triangular pattern produced foams with good mechanical performance. These results emphasize the interest in using the supercritical CO2 process to easily produce foams from 3D-printed parts. These materials represent a sustainable alternative for replacing non-biodegradable materials such as Expanded Polystyrene, and they are a promising option for use in many industrial applications, such as contact materials.

Antidepressant-like effect of Campomanesia xanthocarpa seeds in mice: Involvement of the monoaminergic system.

Background and aim: Campomanesia xanthocarpa Berg. (Myrtaceae) present several pharmacological actions, but there are no reports on its antidepressant-like potential. This study investigated the antidepressant-like effect and mechanism of action of Campomanesia xanthocarpa seeds extract obtained from supercritical CO2 (40 °C, 250 bar). Experimental procedure: Mice were orally treated with the extract 1 h before the TST. To investigate the involvement of the monoaminergic system in the antidepressant-like activity of the extract, pharmacological antagonists were administered prior to the acute oral administration of the extract (60 mg/kg). Also, the interaction of the extract with antidepressants was assessed in the tail suspension test (TST). The in vitro inhibitory potential of C. xanthocarpa seeds extract towards MAO A and MAO B enzymes was tested in vitro. Results and conclusion: Animals treated with Campomanesia xanthocarpa seeds extract showed a significant reduction in the immobility time in the TST. Mice pretreatment with SCH23390, sulpiride, prazosin, yohimbine, and p-chlorophenylalanine prevented the anti-immobility effect of the extract in the TST. The combined administration of sub-effective doses of the extract with imipramine, bupropion and fluoxetine significantly reduced mice immobility time in the TST. The extract showed MAO A inhibitory activity (IC50 = 151.10 ± 5.75 µg/mL), which was greater than that toward MAO B (IC50 > 400 µg/mL).The extract of Campomanesia xanthocarpa seeds obtained by supercritical CO2 shows antidepressant-like activity, which relies on the activation of the monoaminergic neurotransmission (serotoninergic, dopaminergic and noradrenergic), suggesting that this species might represent a resource for developing new antidepressants.

Antimicrobial activity of Annona muricata leaf oleoresin.

Bioactive compounds extracted from plants such as antimicrobials have attracted the attention of consumers and the food industry. This study aimed to determine the antimicrobial activity and chemical composition of Annona muricata leaf oleoresin obtained by supercritical CO2 extraction. The oleoresin was obtained by supercritical CO2 extraction and the chemical identification by gas chromatography coupled to mass spectrometry. Antimicrobial activity was evaluated by broth microdilution method against 14 foodborne fungi and bacteria. The oleoresin major chemical class was phytosterols (22.7%) and the major compounds were γ-sitosterol (15.7%), α-tocopherol (13.7%), phytol (13.1%), and hexadecanoic acid (11.5%). Minimum inhibitory concentration against bacteria ranged from 0.0025 to 0.010 mg mL-1. The oleoresin had high bactericidal activity against all bacteria, mainly Enterobacter cloacae and Pseudomonas aeruginosa with 0.005 mg mL-1 minimum bactericidal concentration. However, it had low fungicidal activity. The leaf oleoresin of A. muricata has promising applications in food, cosmetic, and pharmaceutical industries.

Croton lechleri Extracts as Green Corrosion Inhibitors of Admiralty Brass in Hydrochloric Acid.

Croton lechleri, commonly known as Dragon's blood, is a tree cultivated in the northwest Amazon rainforest of Ecuador and Peru. This tree produces a deep red latex which is composed of different natural products such as phenolic compounds, alkaloids, and others. The chemical structures of these natural products found in C. lechleri latex are promising corrosion inhibitors of admiralty brass (AB), due to the number of heteroatoms and π structures. In this work, three different extracts of C. lechleri latex were obtained, characterized phytochemically, and employed as novel green corrosion inhibitors of AB. The corrosion inhibition efficiency (IE%) was determined in an aqueous 0.5 M HCl solution by potentiodynamic polarization (Tafel plots) and electrochemical impedance spectroscopy, measuring current density and charge transfer resistance, respectively. In addition, surface characterization of AB was performed by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy techniques. Chloroform alkaloid-rich extracts resulted in IE% of 57% at 50 ppm, attributed to the formation of a layer of organic compounds on the AB surface that hindered the dezincification process. The formulation of corrosion inhibitors from C. lechleri latex allows for the valorization of non-edible natural sources and the diversification of the offer of green corrosion inhibitors for the chemical treatment of heat exchangers.

Functional and chemical qualities of Vitis labrusca grape seed oil extracted by supercritical CO 2 / Calidad funcional y química del aceite de semilla de Vitis labrusca extraído mediante CO 2 supercrítico / Qualidade funcional e química do óleo de semente de Vitis labrusca extraído por CO 2 supercrítico

Abstract Grape seed oil, which is usually extracted with highly toxic organic solvents that are harmful to human health, is produced from tons of grape pomace waste, generated during winemaking. Sometimes, this waste is used to make compost or is burnt, which causes environmental contamination. The functional qualities, antioxidant capacity (AC), α-tocopherol and total phenolic compounds content (TPC) of Black Borgoña (Vitis labrusca) grape seed oil, extracted by supercritical CO2, were evaluated. The high content of linoleic acid (ω-6) and monounsaturated fatty acids contributed to the beneficial effect on the functional quality indices, which were 0.20, 0.23, 11.80 for IA, IT and H:H, respectively. In addition, a POV of 6.23 ± 0.08 milliequivalents of peroxide/kg oil and an anisidine index of 2.70 ± 0.05 indicated a good quality oil. Also, a high concentration of a-tocopherol (9.82 ± 0.02 mg/100 g oil) and a high TPC ("4.14 ± 3.24 mg GAE/kg oil) were obtained. This study demonstrated that supercritical CO2 extraction is a suitable method for the delivery of a high-quality grape seed oil.

Resumen El aceite de semilla de uva que generalmente se extrae con disolventes orgánicos altamente tóxicos y perjudiciales para la salud humana, se produce a partir de toneladas de residuos de orujo de uva, generados durante la elaboración del vino. A veces, estos residuos se utilizan para hacer compost o se queman, lo que provoca la contaminación del medio ambiente. Se evaluaron las cualidades funcionales, la capacidad antioxidante (AC), el contenido de a-tocoferol y los compuestos fenólicos totales (TPC) del aceite de semilla de uva Borgoña Negra (Vitis labrusca), extraído mediante CO2 supercrítico. El alto contenido de ácido linoleico (ω-6) y de ácidos grasos monoinsaturados contribuyó al efecto beneficioso sobre los índices de calidad funcional que fueron de 0.20, 0.23, ''.80 para IA, IT y H:H, respectivamente. Además, un POV de 6.23 ± 0.08 miliequivalentes de peróxido/ kg de aceite y un índice de anisidina de 2.70 ± 0.05 indicaban una buena calidad del aceite. También se obtuvo una alta concentración de α-tocoferol (9.82 ± 0.02 mg/100 g de aceite) y un alto TPC ("4.14 ± 3.24 mg de GAE/ kg de aceite). Este estudio demostró que la extracción con CO2 supercrítico es un método adecuado para obtener un aceite de semilla de uva de alta calidad.

Resumo O óleo de semente de uva é geralmente extraído com solventes orgânicos altamente tóxicos que são prejudiciais à saúde humana, é produzido a partir de toneladas de resíduos de bagaço de uva, gerados durante a vinificação. Às vezes, esses resíduos são usados para fazer adubo ou são queimados, o que causa contaminação ambiental. Foram avaliadas as qualidades funcionais, capacidade antioxidante (AC), a-tocoferol e o teor total de compostos fenólicos (TPC) do óleo de semente de uva Borgoña Negra (Vitis labrusca), extraído por CO2 supercrítico. O alto teor de ácido linoleico (ω-6) e ácidos graxos monoinsaturados contribuiu para o efeito benéfico sobre os índices de qualidade funcional que foram 0.20, 0.23, 11.80 para IA, IT e H:H, respectivamente. Além disso, um POV de 6.23 ± 0.08 miliequivalentes de peróxido/ kg de óleo e um índice de anisidina de 2.70 ± 0.05 indicava uma boa qualidade de óleo. Também foi obtida uma alta concentração de α-tocoferol (9.82 ± 0.02 mg/100 g de óleo) e um alto TPC ("4.14 ± 3.24 mg de óleo GAE/ kg). Este estudo mostrou que a extração de CO2 supercrítico é um método adequado para a entrega de um óleo de semente de uva de alta qualidade.

Lippia graveolens HBK oleoresins, extracted by supercritical fluids, showed bactericidal activity against multidrug resistance Enterococcus faecalis and Staphylococcus aureus strains.

OBJECTIVE: The aim of this work was to characterize Lippia graveolens oleoresins, obtained by Supercritical Fluid Extraction (SFE), from crops collected at different locations in Mexico. The antimicrobial effect of oleoresins was tested in reference strains and clinical isolates of susceptible and multidrug-resistant (MDR) strains of Enterococcus faecalis and Staphylococcus aureus. SIGNIFICANCE: The increasing of MDR strains is becoming a global public health problem that has led to the search for new treatments, and essential oils have resurged as a source of compounds with bactericidal functions. Oregano essential oil has attracted attention recently, however, this oil is mainly obtained by hydro-distillation (uses large amounts of water) or solvents extraction (potential contaminant). SFE has gained popularity as it represents an environmentally friendly technology. METHODS: L. graveolens oleoresins were obtained by SFE, total phenol contents were quantified by Folin-Ciocalteu method, the identification of compounds and thymol and carvacrol quantification was carried out by GC-MS. The antimicrobial activity was tested by minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). RESULTS: SFE showed higher yields compared with the hydro-distillation process. L. graveolens grown in different Mexican locations showed differences in oleoresin composition and a slightly different antimicrobial capacity against clinical isolates. CONCLUSIONS: It was demonstrated that SFE is an efficient technology for extracting L. graveolens oleoresins. Additionally, the solvent-free extraction method and the observed antimicrobial effect increase the applications of these oleoresins in fields, such as cosmetics, food industry, medicine, amongst others.

Comparison of different extraction methods of Brazilian "pacová" (Renealmia petasites Gagnep.) oilseeds for the determination of lipid and terpene composition, antioxidant capacity, and inhibitory effect on neurodegenerative enzymes.

Pacová (Renealmia petasites Gagnep.) is a Brazilian native plant, usually cultivated in south regions of the country. Pacová was previously reported concerning their possible health benefits, mostly from folk medicine. However, only few works relates the health benefits with the composition of the fruit parts. In this context, this work aimed to bring, for the first time in literature, the chemical characterization in respect to lipid and terpene composition of R. petasites oilseed, performed by three different extraction methods (supercritical fluid extraction (SFE) with CO2, Soxhlet with petroleum ether (SOX), and maceration with hexane (MAC)). SFE was most selective for MUFAs, PUFAs, sesqui- and diterpenes. The main terpene identified in all extracts was 2-carene. The extracts presented poor AChE inhibition, and SOX presented potential inhibitory effect against lipoxygenase activity. Overall, R. petasites oilseed is a natural source of terpenes and their potential health benefits are highly encouraged to be investigated.

Low-Frequency Ultrasound Coupled with High-Pressure Technologies: Impact of Hybridized Techniques on the Recovery of Phytochemical Compounds.

The coupling of innovative technologies has emerged as a smart alternative for the process intensification of bioactive compound extraction from plant matrices. In this regard, the development of hybridized techniques based on the low-frequency and high-power ultrasound and high-pressure technologies, such as supercritical fluid extraction, pressurized liquids extraction, and gas-expanded liquids extraction, can enhance the recovery yields of phytochemicals due to their different action mechanisms. Therefore, this paper reviewed and discussed the current scenario in this field where ultrasound-related technologies are coupled with high-pressure techniques. The main findings, gaps, challenges, advances in knowledge, innovations, and future perspectives were highlighted.

Valorization of Fermented Shrimp Waste with Supercritical CO2 Conditions: Extraction of Astaxanthin and Effect of Simulated Gastrointestinal Digestion on Its Antioxidant Capacity.

Lactic acid fermentation increases the bioactive properties of shrimp waste. Astaxanthin is the principal carotenoid present in shrimp waste, which can be found esterified in the liquid fraction (liquor) after its lactic acid fermentation. Supercritical CO2 technology has been proposed as a green alternative to obtain astaxanthin from fermented shrimp waste. This study aimed to optimize astaxanthin extraction by supercritical CO2 technology from fermented liquor of shrimp waste and study bioaccessibility using simulated gastrointestinal digestion (GD) of the optimized extract. A Box-Behnken design with three variables (pressure, temperature, and flow rate) was used to optimize the supercritical CO2 extraction. The optimized CO2 extract was obtained at 300 bar, 60 °C, and 6 mL/min, and the estimated characteristics showed a predictive extraction yield of 11.17%, antioxidant capacity of 1.965 mmol of Trolox equivalent (TE)/g, and astaxanthin concentration of 0.6353 µg/g. The experiment with optimal conditions performed to validate the predicted values showed an extraction yield of 12.62%, an antioxidant capacity of 1.784 mmol TE/g, and an astaxanthin concentration of 0.52 µg/g. The astaxanthin concentration decreased, and the antioxidant capacity of the optimized extract increased during gastrointestinal digestion. In conclusion, our optimized supercritical CO2 process is suitable for obtaining astaxanthin from shrimp by-products after lactic acid fermentation.

Aspirin-Loaded Polymeric Films for Drug Delivery Systems: Comparison between Soaking and Supercritical CO2 Impregnation.

Polymeric implants loaded with drugs can overcome the disadvantages of oral or injection drug administration and deliver the drug locally. Several methods can load drugs into polymers. Herein, soaking and supercritical CO2 (scCO2) impregnation methods were employed to load aspirin into poly(l-lactic acid) (PLLA) and linear low-density polyethylene (LLDPE). Higher drug loadings (DL) were achieved with scCO2 impregnation compared to soaking and in a shorter time (3.4 ± 0.8 vs. 1.3 ± 0.4% for PLLA; and 0.4 ± 0.5 vs. 0.6 ± 0.5% for LLDPE), due to the higher swelling capacity of CO2. The higher affinity of aspirin explained the higher DL in PLLA than in LLDPE. Residual solvent was detected in LLDPE prepared by soaking, but within the FDA concentration limits. The solvents used in both methods acted as plasticizers and increased PLLA crystallinity. PLLA impregnated with aspirin exhibited faster hydrolysis in vitro due to the catalytic effect of aspirin. Finally, PLLA impregnated by soaking showed a burst release because of aspirin crystals on the PLLA surface, and released 100% of aspirin within 60 days, whereas the PLLA prepared with scCO2 released 60% after 74 days by diffusion and PLLA erosion. Hence, the scCO2 impregnation method is adequate for higher aspirin loadings and prolonged drug release.

Paraprobiotics obtained by six different inactivation processes: impacts on the biochemical parameters and intestinal microbiota of Wistar male rats.

This study investigated the effects of feeding paraprobiotics obtained by six processes [heat, ultrasound, high pH, low pH, irradiation and supercritical carbon dioxide (CO2)] on biochemical parameters and intestinal microbiota of Wistar male rats. Daily administration of paraprobiotics did not affect (p ≥ 0.05) the food intake, body weight, glucose and triglycerides levels, expression of antioxidant enzymes or thermal shock proteins in comparison to the control. Bifidobacterium lactis inactivated by irradiation and supercritical CO2 decreased the total cholesterol levels in serum (p < 0.05). Bifidobacterium lactis inactivated by supercritical CO2 increased the albumin and creatinine levels, while decreased the HDL-cholesterol levels (p < 0.05). Clostridiales (45.6-56%), Bacteroidales (31.9-44.2%) and Lactobacillales (3.9-7.8%) corresponded to the major orders in paraprobiotic groups. The properties of paraprobiotics are dependent on the method of inactivation, the intensity of the method employed and on the strain used.

Bioactive Compounds and Evaluation of Antioxidant, Cytotoxic and Cytoprotective Effects of Murici Pulp Extracts (Byrsonima crassifolia) Obtained by Supercritical Extraction in HepG2 Cells Treated with H2O2.

The use of clean technologies in the development of bioactive plant extracts has been encouraged, but it is necessary to verify the cytotoxicity and cytoprotection for food and pharmaceutical applications. Therefore, the objective of this work was to obtain the experimental data of the supercritical sequential extraction of murici pulp, to determine the main bioactive compounds obtained and to evaluate the possible cytotoxicity and cytoprotection of the extracts in models of HepG2 cells treated with H2O2. The murici pulp was subjected to sequential extraction with supercritical CO2 and CO2+ethanol, at 343.15 K, and 22, 32, and 49 MPa. Higher extraction yields were obtained at 49 MPa. The oil presented lutein (224.77 µg/g), oleic, palmitic, and linoleic, as the main fatty acids, and POLi (17.63%), POO (15.84%), PPO (13.63%), and LiOO (10.26%), as the main triglycerides. The ethanolic extract presented lutein (242.16 µg/g), phenolic compounds (20.63 mg GAE/g), and flavonoids (0.65 mg QE/g). The ethanolic extract showed greater antioxidant activity (122.61 and 17.14 µmol TE/g) than oil (43.48 and 6.04 µmol TE/g). Both extracts did not show cytotoxicity and only murici oil showed a cytoprotective effect. Despite this, the results qualify both extracts for food/pharmaceutical applications.

A comparative and economic study of the extraction of oil from Baru (Dipteryx alata) seeds by supercritical CO2 with and without mechanical pressing.

The present study evaluated the effect of supercritical fluid extraction (SFE) assisted by cold pressing (SFEAP) on the overall yield, extraction kinetics, composition of baru seed oil and manufacturing cost (COM). The best extraction conditions were determined in extraction assays combining different pressures (150-350 bar) and temperatures (35 and 45 °C). The extraction yield by SFEAP (28.6 g oil/100 g baru seed) was approximately 31% higher than that obtained by SFE (21.9 g oil/100 g baru seed), according to the kinetic study with the best extraction conditions (350 bar and 45 °C). The extraction yield observed under this condition allowed us to obtain a lower COM for both techniques (SFE was US$ 118.32/kg baru oil and SFEAP was US$ 87.03/kg baru oil) compared to lower pressures and temperatures. The oil obtained under all extraction conditions was rich in unsaturated fatty acids and other bioactive compounds. The extraction of baru seed oil by SFEAP resulted in a higher yield and lower manufacturing cost than SFE.

A comparative study of the energy, exergetic and thermo-economic performance of a novelty combined Brayton S-CO2-ORC configurations as bottoming cycles.

This paper presents a comparative study on the energy, exergetic and thermo-economic performance of a novelty thermal power system integrated by a supercritical CO2 Brayton cycle, and a recuperative organic Rankine cycle (RORC) or a simple organic Rankine cycle (SORC). A thermodynamic model was developed applying the mass, energy and exergy balances to all the equipment, allowing to calculate the exergy destruction in the components. In addition, a sensitivity analysis allowed studying the effect of the primary turbine inlet temperature (TIT, PHIGH, rP and TC) on the net power generated, the thermal and exergy efficiency, and some thermo-economic indicators such as the payback period (PBP), the specific investment cost (SIC), and the levelized cost of energy (LCOE), when cyclohexane, acetone and toluene are used as working fluids in the bottoming organic Rankine cycle. The parametric study results show that cyclohexane is the organic fluid that presents the best thermo-economic performance, and the optimization with the PSO method conclude a 2308.91 USD/kWh in the SIC, 0.22 USD/kWh in the LCOE, and 9.89 year in the PBP for the RORC system. Therefore, to obtain technical and economic viability, and increase the industrial applications of these thermal systems, thermo-economic optimizations must be proposed to obtain lower values of the evaluated performance indicators.

A comparative energy and exergy optimization of a supercritical-CO2 Brayton cycle and Organic Rankine Cycle combined system using swarm intelligence algorithms.

This article presents a multivariable optimization of the energy and exergetic performance of a power generation system, which is integrated by a supercritical Brayton Cycle using carbon dioxide, and a Simple Organic Rankine Cycle (SORC) using toluene, with reheater ( S - C O 2 R H - S O R C ), and without reheater ( S - C O 2 N R H - S O R C ) using the PSO algorithm. A thermodynamic model of the integrated system was developed from the application of mass, energy and exergy balances to each component, which allowed the calculation of the exergy destroyed a fraction of each equipment, the power generated, the thermal and exergetic efficiency of the system. In addition, through a sensitivity analysis, the effect of the main operational and design variables on thermal efficiency and total exergy destroyed was studied, which were the objective functions selected in the proposed optimization. The results show that the greatest exergy destruction occurs at the thermal source, with a value of 97 kW for the system without Reheater (NRH), but this is reduced by 92.28% for the system with Reheater (RH). In addition, by optimizing the integrated cycle for a particle number of 25, the maximum thermal efficiency of 55.53% (NRH) was achieved, and 56.95% in the RH system. Likewise, for a particle number of 15 and 20 in the PSO algorithm, exergy destruction was minimized to 60.72 kW (NRH) and 112.06 kW (RH), respectively. Comparative analyses of some swarm intelligence optimization algorithms were conducted for the integrated S-CO2-SORC system, evaluating performance indicators, where the PSO optimization algorithm was favorable in the analyses, guaranteeing that it is the ideal algorithm to solve this case study.

Effect of Experimental Parameters on the Extraction of Grape Seed Oil Obtained by Low Pressure and Supercritical Fluid Extraction.

Grape seeds are an important byproduct from the grape process. The objective of this work was to evaluate the effect of experimental parameters (temperature and time of pretreatment with ultrasound) to obtain grape seed oil using low pressure (Soxhlet-Sox and Bligh Dyer-BD) and high pressure (supercritical carbon dioxide-SFE) methods. The best condition for pretreatment of samples was 30 min of sonication at 30 °C before extraction by Sox or BD. Ultrasound pretreatment was efficient to increase oil extraction yield by 32.10 (Sox), 20.31 (BD) and 12.54% (SFE), depending on the extraction method used as well as, and certainly influenced the total phenolic concentration in 311 (Sox), 234 (BD), and 184 (SFE)%. Ten fatty acids were identified in the oils, the major ones being 18:2ω-6cis (linoleic 52.39%-63.12%), 16:0 (palmitic 20.22%-26.80%) and 18:0 (stearic 8.52%-13.68%). The highest epicatechin concentration was identified in the BD sample: 30-30 (150.49 ± 5.98mg/kg), which presented a concentration of ≥3 times compared to the control (56.68 ± 1.81mg/kg). Ultrasound pretreatment also contributed positively (56% and 99% increase) in the α-tocopherol content of the SFE: 30-30 and BD: 30-30 samples, respectively. The results indicate that the ultrasound pretreatment is a suitable technology to improve the quality of the oil from the grape seed.

Antioxidant compounds extracted from Diaporthe schini using supercritical CO2 plus cosolvent.

Endophytic fungi have been highlight in the production of secondary metabolites with different bioactive properties, such as in the production of the antioxidant compounds. Therefore, the objective of this work was the extraction of the antioxidant compounds from the biomass of Diaporthe schini using supercritical carbon dioxide (CO2) without and with ethanol as cosolvent. The biomass was produced by submerged fermentation and the parameters evaluated in the extraction process were: pressure (150-250 bar), temperature (40-60 ºC) and cosolvent [biomass: cosolvent ratio, 1:0, 1:0.75 and 1:1.5 (w/v)]. Extraction yield, antioxidant activity and chemical composition of the extracts were determined. The highest extraction yield (3.24 wt.%) and the best antioxidant activity against the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical (96.62%) were obtained at 40 ºC, 250 bar and biomass:cosolvent ratio of 1:1.5 (w/v). The chemical compounds 1,4-diaza-2,5-dioxo-3-isobutyl bicyclo[4.3.0]nonane and benzeneethanol identified in GC/MS could be responsible for the antioxidant activity found in this study.