http://www.ipb.pt/~htgomes/FCT115275/Ref23.pdf

Sub- and supercritical fluid extraction of functional ingredients from different natural sources: Plants, food-by-products, algae and microalgae: A review

Supercritical extraction and fractionation of natural matter is one of the early and most studied applications in the field of supercritical fluids In the last 10 years, studies on the extraction of classical compounds like essential and seed oils from various sources: seeds, fruits, leaves, flowers, rhizomes, etc, with or without the addition of a co-solvent have been published Supercritical extraction of antioxidants, pharmaceuticals, colouring matters, and pesticides has also been studied The separation of liquid mixtures and the antisolvent extraction are other processes that can perform very interesting separations Mathematical modelling has also been developed and refined for some of these processes The objective of this review is to critically analyze traditional and new directions in the research on natural matter separation by supercritical fluids extraction and fractionation

Supercritical fluid extraction and fractionation of natural matter

Supercritical fluid extraction in plant essential and volatile oil analysis.

Along more than a decade, R&D on supercritical fluid extraction (SFE) of vegetable matrices has been increasingly reported in the literature. Aiming at portraying the current state of this field and its evolution in terms of raw materials, products, modes of operation, optimization, modeling techniques, and closeness to industrial application, a large compilation of almost 600 essays from 2000 to 2013 has been deeply analyzed in order to unveil those indicators and their trends. Furthermore, strengths and weaknesses are identified, and some remarks that may drive upcoming research are provided. Globally, more than 300 species are reported in the literature, with prevalence of the extraction of seeds (28% of works) and leaves (17%). The main families of extracted compounds, cosolvents and operating conditions adopted are critically examined, being possible to conclude that researchers investigate many times working regions far from the optimum due to practical limitations or absence of experimental optimization. Current phenomenological, statistical and semi-empirical approaches are reviewed, along with scale-up studies, and economic analysis. In the whole, the most comprehensive picture over SFE of vegetable matrices is provided in this review, highlighting pertinent aspects and opportunities that may further consolidate the convincing route of this technology for the next years.

Supercritical fluid extraction of vegetable matrices: Applications, trends and future perspectives of a convincing green technology

Supercritical fluid extraction (SCFE), based on the utilization of a fluid under supercritical conditions, is a technology suitable for extraction and purification of a variety of compounds, particularly those that have low volatility and/or are susceptible to thermal degradation. The interest in SCFE is promoted by legal limitations of conventional solvents for food and pharmaceutical uses. The physicochemical properties of supercritical CO2 (higher diffusivity, lower viscosity, and lower surface tension than conventional solvents) facilitate mass transfer and allow an environmentally friendly operation. This article presents a comprehensive compilation of data on the supercritical CO2 extraction of antioxidant compounds from vegetal materials, with particular attention to those of a phenolic nature. Aspects concerning the supercritical operation for extraction and fractionation of antioxidants compounds are considered, including equilibrium solubility of pure compounds and effects of the operational con...

Supercritical CO2 extraction and purification of compounds with antioxidant activity.

The effects of temperature, pressure and the addition of co-solvent (ethanol (EtOH) and isopropyl alcohol (IsoC3), both at 1.17% (mass)) on the kinetics of extraction of ginger oleoresin were studied. The design used was a 2×2×3 factorial (pressure 200 and 250 bar; temperature: 25 and 35 °C; solvent: CO2, CO2+EtOH, CO2+IsoC3). The experimental setup used was a fixed bed extractor with diameter of 2.76×10−2 m and length of 0.387 m. The assays were carried out at a mean solvent flow rate of 5.86×10−5 kg/s and with a bed apparent density of 350 kg/m3. The identification of the substances present in the oleoresin was performed by GC-MS; GC-FID was used to determine the ginger extract compositions. The antioxidant activity of the extract fractions was determined using the coupled oxidation of linolenic acid and β-carotene. The results show that the temperature and the interaction of the pressure and the solvent significantly affected the total yield. For the mass transfer rate, the effect of the interaction of the pressure and the solvent was significant; the mass transfer rate increased with the pressure in the absence of the co-solvent and decreased when ethanol and isopropyl alcohol were used. The major substances present in the ginger extracts were α-zingiberene, gingerols and shogaols; the amounts of these compounds were significantly affected by temperature, pressure and solvent. Nonetheless, the antioxidant activity of the ginger extracts remained constant at ≈80% and decreased to ≈60% in the absence of gingerols and shogaols. The Sovova's model quantitatively described the overall extraction curves.

Extraction of ginger (Zingiber officinale Roscoe) oleoresin with CO2 and co-solvents: a study of the antioxidant action of the extracts

o gengibre e seus produtos tais como o oleo essencial e oleoresina sao internacionalmente comercializados para uso nas industrias de alimentose farmaceuticas.O oleo essencial possui os compostos mais volateis responsaveis pelo aroma caracteristico do gengibre e a oleoresina contem alem destes, substâncias classificadas como pungentes. Algumas destas substâncias pungentes agem como importantes antioxidantes. Atualmente, antioxidante obtidos a partir de fontes naturais sao associados a beneficios para saude humana, uma vez que os radicais livres estao relacionados com doencas do coracao, malaria, AIDS, câncer, neurodegenerativas entre outras. Devido a isso toma-se muito importante o estudo de novos antioxidantes. O uso da extracao supercritica tem crescido
muito nos ultimos anos, entretanto ainda e necessaria a obtencao de um numero consideravel de informacoes experimentais para que a construcao de plantas industriais deste tipo de processo aconteca. Neste trabalho os efeitos da temperatura (25 e 35°C), pressao (200 e 250 bar) e o uso de co-solventes (etanol e isopropanol, ambos ai, 17% (mim)) sobre o rendimento total e a cinetica de extracao da oleoresina de gengibre foram estudados. O equipamento utilizado consistiu de um extrator de leito fixo com diâmetro de
2,83x10.2m e comprimento de 0,375 m. Os ensaios foram realizados com vazao media de CO2de 5,83xlO-5kg/s. Os experimentos tiveram 7 horas de duracao. A duracao do periodo de taxa constante de extracao variou de 1,3 a 2,7 horas e os rendimentos ficaram na faixa de 1,93% a 2,65%. A identificacao das substâncias presentes na oleoresina foi feita atraves de
CGIEM. Os extratos de gengibre analisados mostraram-se antioxidantes eficazes, possuiram acao anticancerigenas para algumas linhagens de câncer e inibiram o crescimento de algumas bacterias aqui estudadas. A espectrofotometria mostrou-se inadequada para a quantificacao dos gingerois e shogaois. Os extratos do periodo de taxa
constante e de taxa decrescente de extracao apresentaram monoterpenos, sesquiterpenos, gingerois e shogaois em sua composicao, enquanto o periodo difusional mostrou principalmente gingerois e shogaois 
Abstract

Obtenção de extrato de gengibre (Zingiber officinale Roscoe) com dioxido de carbono supercritico e co-solventes : um estudo da atividade biologica dos extratos

Kelly Cristine Zancan

Papers

Extraction of ginger (Zingiber officinale Roscoe) oleoresin with CO2 and co-solvents: a study of the antioxidant action of the extracts

Obtenção de extrato de gengibre (Zingiber officinale Roscoe) com dioxido de carbono supercritico e co-solventes : um estudo da atividade biologica dos extratos