Various novel techniques including ultrasound-assisted extraction, microwave-assisted extraction, supercritical fluid extraction, and accelerated solvent extraction have been developed for the extraction of nutraceuticals from plants in order to shorten the extraction time, decrease the solvent consumption, increase the extraction yield, and enhance the quality of extracts. A critical review was conducted to introduce and compare the conventional Soxhlet extraction and the new alternative methods used for the extraction of nutraceuticals from plants. The practical issues of each extraction method were discussed. Potential uses of those methods for the extraction of nutraceuticals from plant materials was finally summarized.

Recent advances in extraction of nutraceuticals from plants

Post-combustion CO2 capture from the flue gas is one of the key technology options to reduce greenhouse gases, because this can be potentially retrofitted to the existing fleet of coal-fired power stations. Adsorption processes using solid sorbents capable of capturing CO2 from flue gas streams have shown many potential advantages, compared to other conventional CO2 capture using aqueous amine solvents. In view of this, in the past few years, several research groups have been involved in the development of new solid sorbents for CO2 capture from flue gas with superior performance and desired economics. A variety of promising sorbents such as activated carbonaceous materials, microporous/mesoporous silica or zeolites, carbonates, and polymeric resins loaded with or without nitrogen functionality for the removal of CO2 from the flue gas streams have been reviewed. Different methods of impregnating functional groups, including grafting techniques and modifying the support materials, have been discussed to en...

Post-Combustion CO2 Capture Using Solid Sorbents: A Review

There is currently much interest in biological active compounds derived from natural resources, especially compounds that can efficiently act on molecular targets, which are involved in various diseases. Astaxanthin (3,3'-dihydroxy-β, β'-carotene-4,4'-dione) is a xanthophyll carotenoid, contained in Haematococcus pluvialis, Chlorella zofingiensis, Chlorococcum, and Phaffia rhodozyma. It accumulates up to 3.8% on the dry weight basis in H. pluvialis. Our recent published data on astaxanthin extraction, analysis, stability studies, and its biological activities results were added to this review paper. Based on our results and current literature, astaxanthin showed potential biological activity in in vitro and in vivo models. These studies emphasize the influence of astaxanthin and its beneficial effects on the metabolism in animals and humans. Bioavailability of astaxanthin in animals was enhanced after feeding Haematococcus biomass as a source of astaxanthin. Astaxanthin, used as a nutritional supplement, antioxidant and anticancer agent, prevents diabetes, cardiovascular diseases, and neurodegenerative disorders, and also stimulates immunization. Astaxanthin products are used for commercial applications in the dosage forms as tablets, capsules, syrups, oils, soft gels, creams, biomass and granulated powders. Astaxanthin patent applications are available in food, feed and nutraceutical applications.

https://www.mdpi.com/1660-3397/12/1/128/pdf

Astaxanthin: Sources, Extraction, Stability, Biological Activities and Its Commercial Applications—A Review

Water near or above its critical point (374 C, 218 atm) is attracting increased attention as a medium for organic chemistry. Most of this new attention is driven by the search for more green or environmentally benign chemical processes. Using near-critical or supercritical water (SCW) instead of organic solvents in chemical processes offers environmental advantages and may lead to pollution prevention. Interest in doing chemistry in SCW is not entirely new, however. There has been much previous research in this area with applications in synthetic fuels production, biomass processing, waste treatment, materials synthesis, and geochemistry. Water near its critical point possesses properties very different from those of ambient liquid water. The dielectric constant is much lower, and the number and persistence of hydrogen bonds are both diminished. As a result, high-temperature water behaves like many organic solvents in that organic compounds enjoy high solubilities in near-critical water and complete miscibility with SCW. Moreover, gases are also miscible in SCW so employing a SCW reaction environment provides an opportunity to conduct chemistry in a single fluid phase that would otherwise occur in a multiphase system under more conventional conditions. The paper discusses the use of supercritical water in the following reactions:more » hydrogenation/dehydrogenation; C-C bond formation; rearrangements; hydration/dehydration; elimination; hydrolysis; partial oxidation; H-D exchange; decomposition; and oxidation.« less

Organic Chemical Reactions in Supercritical Water.

There is a rapidly growing body of literature covering the role of plant secondary metabolites in food and their potential effects on human health. Furthermore, consumers are increasingly aware of diet related health problems, therefore demanding natural ingredients which are expected to be safe and health-promoting. By-products of plant food processing represent a major disposal problem for the industry concerned, but they are also promising sources of compounds which may be used because of their favourable technological or nutritional properties. The purpose of this review is to highlight the potential of selected by-products as a source of functional compounds.

By-products of plant food processing as a source of functional compounds — recent developments

The extraction rate of oil from freeze-dried ginger root with supercritical carbon dioxide was measured as a function of CO2 flow rate, particle size, temperature, and pressure. The extraction curv...

Extraction of Ginger Oil with Supercritical Carbon Dioxide: Experiments and Modeling

This study deals with supercritical CO2 extraction of astaxanthin from Haematococcus pluvialis with ethanol as an entrainer. The effects of pressure, temperature, CO2 flow rate, and the existence of the entrainer concentration on the amount of total extract, the amount of astaxanthin extracted, and the astaxanthin content in the extract were studied. Extractions were carried out at the pressures of 20−55 MPa, temperatures of 313−353 K, CO2 flow rates of 2−4 mL/min, and the ethanol entrainer concentrations of 1.67−7.5% (v/v). The amount of the total extract, astaxanthin extracted, and astaxanthin content in the extract increased with increasing temperature and pressure. With higher CO2 flow rate, the amount of the total extract could be increased while the amount of astaxanthin extracted and the astaxanthin content in the extract almost did not change. By using ethanol as an entrainer, a higher amount of astaxanthin extracted (80.6%) could be obtained at moderate pressure and temperature, and with the same...

Extraction of astaxanthin from Haematococcus pluvialis using supercritical CO2 and ethanol as entrainer

Hydrothermal conversion of municipal organic waste into resources.

Extraction or leaching of a solute from a solid material is a process involving mass transfer in the solid matrix. When the solute content in the solid material is sufficiently large as compared to the solubility in fluid phase, the process is similar to that of irreversible desorption. The shrinking-core model was applied to the modeling of the extraction process. The model including axial dispersion in the extraction column was solved numerically. Quasi-steady-state solution without axial dispersion was derived, and the accuracy was discussed in comparison with the numerical solutions. The model calculations gave a good agreement with the experimental extraction curve reported in literature.

Shrinking-core leaching model for supercritical-fluid extraction

The kinetics of poly(ethylene terephthalate) (PET) depolymerization in supercritical methanol was investigated to develop a chemical recycling process for postconsumer PET bottles PET with a high 

Tsutomu Hirose

Papers

Extraction of Ginger Oil with Supercritical Carbon Dioxide: Experiments and Modeling

Extraction of astaxanthin from Haematococcus pluvialis using supercritical CO2 and ethanol as entrainer

Hydrothermal conversion of municipal organic waste into resources.

Shrinking-core leaching model for supercritical-fluid extraction

Depolymerization Mechanism of Poly(ethylene terephthalate) in Supercritical Methanol