Avaliação do óleo essencial de Aloysia sellowii (Briquet) moldenke (Verbenaceae) do Sul do Brasil

This work was performed with the aim of evaluating the chemical variability among samples of Aloysia sellowii (Verbenaceae) collected in different geographical regions as well as the application of supercritical CO2 for obtaining essential oil. Thus, samples were collected in different localities and oils were isolated by hydrodistillation and supercritical CO2. Results showed existence of two chimiotypes in the species (cineole and sabinene). The supercritical CO2 extraction process was appropriate for extraction of A. sellowii essential oil at 40 ºC, 110 bar, 2 mL/min of flow and 10 min of extraction time.

Fluidos supercríticos em química analítica. III.: aplicações

The first two papers in this series described the basic theory involved in supercritical fluid chromatography (SFC), how the technique evolved from gas and liquid chromatography and how the instrumentation was developed. Over the last two years, a commercial, dedicated packed-column SFC/MS instrument appeared on the market. The SFC continues to grow in use, with fundamental developments, coupled with a steady rise in the number of industrial users and applications.

Caracterização química de extratos de Ocimum basilicum L. obtidos através de extração com CO2 a altas pressões

This work reports extraction yield and chemical characterization of the extracts obtained by high-pressure CO2 extraction of a cultivar of Ocimum basilicum L. The experiments were performed in the temperature range of 20 to 50 °C, from 100 to 250 atm of pressure. Chemical analyses were carried out by gas chromatography coupled to mass spectrometry, permitting to identify 23 compounds that were grouped into five chemical classes. Results showed that temperature and solvent density influenced positively the extraction yield. At 20 °C and 0.41 g cm-3 occurred a rise in the concentration of monoterpenes, oxygenated monoterpenes, sesquiterpenes and oxygenated sesquiterpenes.

Reator de membrana enzimático e fluidos supercríticos: associação de processos

The aim of this work is to present the new applications of membrane technology in fat and oil processing, with emphasis on development and applications of the enzymatic membrane reactor and its association with extraction and purification technology by supercritical fluids (SCF). Combining the extraction by SCFs and the separation by membranes allows the integration of extractions reactions with selective separation by membranes through filtration of the supercritical mixture (SCF + extracted solutes). This association provides important energy savings regarding the SCF recompression costs.

Avaliação do potencial antioxidante de extratos ativos de plantas obtidos por extração com fluido supercrítico

The aim of this work was to evaluate the antioxidant properties of ginger and rosemary extracts, obtained by supercritical extraction. The extracts were characterized by HPLC, GC-MS, phenolic compounds content and antioxidant activity. The main active compounds were identified and high content of phenolic compounds was observed. The extracts presented high antioxidant activity against the free radicals ABTS•+ (350 and 200 mM Trolox/g, for ginger and rosemary, respectively) and DPPH•+ (145 and 80 mM Trolox/g, for ginger and rosemary, respectively). These results suggested that the attained extracts are potential substitutes of synthetic antioxidants used in chemical, food and pharmaceutical industries.

Biodiesel: visão crítica do status atual e perspectivas na academia e na indústria

This article presents a bibliographic review of research carried out on different alternative processes for biodiesel production. The supercritical and subcritical (non catalytic) reaction conditions, the use of solid basic, solid acid and other heterogeneous catalysts, including the use of immobilized enzymes and whole-cell catalysts are also critically compared with the traditional homogeneous alkaline or acid catalysts that are common on industrial applications. Advantages and limitations of all these processes for the transference from the laboratory to the industry are discussed. A correlation of the chemical composition with the quality parameters of the produced biodiesel is done with aim to stablish adequate procedures for the right selection of the raw-material. Castor bean oil is used as an example of inappropriate oil in order to produce a B100 that fulfill all the international physico-chemical quality standards. In this article are presented research results to adequate the values of viscosity, density and iodine number of the castor and soybean biodiesel to the international standard limits by means blending these both biodiesels at the right ratio.

Variabilidade química de compostos orgânicos voláteis e semivoláteis de populações nativas de Maytenus ilicifolia

This work is focused on the chemical distribution of volatile and semi-volatile compounds of 18 native populations of Maytenus ilicifolia collected all over Brazil. The extracts of bulk samples (30 plants) of each population were obtained by supercritical CO2 extraction technique, and analyzed by GC/MS. The quantification of compounds (phytol, squalene, vitamin E, limonene, stigmasterol, friedelan-3-ol, friedelin, fridelan-3-one, palmitic acid and geranyl acetate) showed significant variations within the different populations, which could be related tom microclimate characteristics.

Floculação de Chlorella sp. produzida em concentrado de dessalinização e estudo de método de extração de lipídeos intracelulares

Chlorella sp. was used to assess algal lipid production with concentrated desalination. In order to investigate the action of the flocculating agent calcium chloride and pH, a Box-Behnken Design and a Central Composite Design (CCD) were carried out. Also, Soxhlet and Supercritical Fluid Extraction (SFE), with and without sonication lipid extraction methods, were examined. The optimal flocculation conditions were pH 10.0 and 2.0 g/L of calcium chloride concentration. The highest lipid content of Chlorella sp. was obtained using the Soxhlet extraction method. The most abundant fatty acid extracted by Soxhlet and SFE, with and without sonication, was palmitic acid, whose proportions were 57.4%, 35.3% and 25.5%, respectively.

Imobilização de lipase por encapsulação em sílica aerogel

Lipase from Burkholderia cepacia was immobilized in a silica matrix and dried in high pressure carbon dioxide media (aerogel). The protic ionic liquid (PIL) was used in the immobilization process by encapsulation. The objective of this work was to evaluate the influence of the drying technique using supercritical carbon dioxide in biocatalysts obtained through the sol-gel technique by evaluating temperature and pressure and, after selecting the best drying conditions, to investigate the application of the technique for the biocatalyst using ionic liquid as an additive in the immobilization process. The results for immobilized biocatalysts showed that the best conditions of pressure and temperature were 100 bar and 25 ºC, respectively, giving a total activity recovery yield of 37.27% without PIL (EN) and 44.23% with PIL (ENLI). The operational stability of the biocatalysts showed a half-life of 11.4 h for ENLI and 6 h for EN. Therefore, solvent extraction using supercritical CO2, besides shortening drying time, offers little resistance to the immobilization of lipases, since their macropores provide ample room for their molecules. The use of the ionic liquid as an additive in the process studied for the immobilization of enzymes produced attractive yields for immobilization and therefore has potential for industrial applications in the hydrolysis of vegetable oils.

Super/subcritical fluid chromatography with packed columns: state of the art and applications

Separations using supercritical fluid chromatography (SFC) with packed columns have been re-discovered and explored in recent years. SFC enables fast and efficient separations and, in some cases, gives better results than high performance liquid chromatography (HPLC). This paper provides an overview of recent advances in SFC separations using packed columns for both achiral and chiral separations. The most important types of stationary phases used in SFC are discussed as well as the most critical parameters involved in the separations and some recent applications.

MÉTODOS DE EXTRAÇÃO DE POLI-HIDROXIALCANOATOS A PARTIR DE BIOMASSA BACTERIANA

Polyhydroxyalkanoates (PHAs) are biodegradable and biocompatible polyesters intracellularly accumulated by many bacteria as an energy reserve material and carbon source. These biopolymers may be extracted from cells after their production phase, and the extraction process involves various individual operations to ensure adequate removal of the biopolymer from the cells. During this process, the following aspects should be considered: reduction of product losses during different stages of the process to obtain a highly pure product, preservation of physical and thermal characteristics, and use of low toxicity chemicals to achieve sustainable production and avoid harming the environment. The impact of the costs of PHA extraction on the total cost of the production process may account for over 50% of the end-value of the product. Within this context, several methods of PHA extraction have been reported in the literature. These methods include the use of solvents, chemical digestion, enzymatic digestion, mechanical extraction with high-pressure homogenization and ultrasound, extraction using supercritical fluids, or a combination of these methods. The present review of the literature shows strategies for extraction processes of PHAs produced by bacteria involving cell destabilization and/or breakage, recovery, and purification of the biopolymer.

HIGH PRESSURE VAPOR-LIQUID EQUILIBRIA OF PALM FATTY ACIDS DISTILLATES-CARBON DIOXIDE SYSTEM

Vapor-Liquid equilibria of palm fatty acids distillates/carbon dioxide system has been investigated experimentally at temperatures of 333, 353, and 373 K and pressures of 20, 23, 26, and 29 MPa using the static method. Experimental data for the quasi-binary system palm fatty acids distillates/carbon dioxide has been correlated with Redlich-Kwong-Aspen equation of state. Modeling shows good agreement with experimental data. Selectivity obtained indicates that supercritical carbon dioxide is a reasonable solvent for separating saturated (palmitic acid) and unsaturated (oleic+linoleic acids) fatty acids from palm fatty acids distillates in a continuous multistage countercurrent column.

THE EFFECTIVE DIFFUSIVITY OF CLOVE(Eugenia caryophyllus) ESSENTIAL OIL IN PRESSURIZED CO2

The effective diffusivity of clove essential oil in subcritical liquid CO2 was estimated. The experimental apparatus employed was a fixed-bed extractor. The fixed bed was formed with grounded (mesh -32 + 65) and compacted clove buds which were considered a solid element. The effective diffusion coefficient was evaluated by fitting the experimental concentration profile to the unsteady state mass balance equation for unidirectional diffusion in a finite solid medium. The diffusion coefficient was related to the concentration of oil in the solid by an exponential function. The estimated values of the effective diffusion coefficient varied from 3.64 to 5.22x10-10 m2/s. The average relative errors were lower than 3.1%.

COMPARISON OF GINGER (Zingiber officiale Roscoe) OLEORESIN OBTAINED WITH ETHANOL AND ISOPROPANOL WITH THAT OBTAINED WITH PRESSURIZED CO2

Ginger (Zingiber officinale Roscoe) belongs to the Zingiberacea family. It is a spice of great commercial importance. In this work ginger oleoresin was obtained with ethanol, isopropanol and liquid carbon dioxide. The chemical compositions of the extract were compared with each other. All oleoresin samples had monoterpenes and sesquiterpenes. Carboxylic acids were found in organic solvent extracts for an extraction time of 2 hours. The component responsible the for pungent characteristic of the oleoresin, gingerois, were detected in samples obtained with organic solvent for extraction times of 6 hours and in samples obtained with CO2 liquid for extraction times of 2 hours.

THE GENERALIZED MAXIMUM LIKELIHOOD METHOD APPLIED TO HIGH PRESSURE PHASE EQUILIBRIUM

The generalized maximum likelihood method was used to determine binary interaction parameters between carbon dioxide and components of orange essential oil. Vapor-liquid equilibrium was modeled with Peng-Robinson and Soave-Redlich-Kwong equations, using a methodology proposed in 1979 by Asselineau, Bogdanic and Vidal. Experimental vapor-liquid equilibrium data on binary mixtures formed with carbon dioxide and compounds usually found in orange essential oil were used to test the model. These systems were chosen to demonstrate that the maximum likelihood method produces binary interaction parameters for cubic equations of state capable of satisfactorily describing phase equilibrium, even for a binary such as ethanol/CO2. Results corroborate that the Peng-Robinson, as well as the Soave-Redlich-Kwong, equation can be used to describe phase equilibrium for the following systems: components of essential oil of orange/CO2.