The Open Chemical Engineering Journal is publishing a special issue, that is, a Hot Topic entitled “Recent advances in plant
extract stabilization using supercritical fluids”. Six papers are included in this HT focusing in various aspects of applications of
supercritical fluids to extract and stabilize plant extracts: two papers present new experimental data on co-precipitation of betacarotene
and polymer, one gives new data on modelling the system neem seeds/ carbon dioxide using fuzzy logic, an innovation
to the field. The other three articles are review articles dealing with different aspects of plant extract stabilization using
supercritical carbon dioxide applied to essential oils, to carotenoids, and to phenolic compounds.
The special issue provided an opportunity for publication of original peer-reviewed full-length research and review articles
on new research findings and developments in stabilization of plant extracts using supercritical fluids. Bioactive compounds are
used in the cosmetic, food, and pharmaceutical industries. New techniques to obtain these compounds from a variety of sources
are continuously developed. An example of such technique is supercritical fluid extraction (SFE); this technique has proved to
be technically viable for several types of solid substratum. Nonetheless, new experimental data and modelling work are still
needed in order to transfer this technology to industry. Additional equilibrium data are also needed in order to optimize the
separation step in SFE. The article by Giufrida et al. [1] presents new equilibrium data for ternary systems of CO2 + ethanol +
curcumin and CO2 + ethyl acetate + curcumin. Curcuminoids are being acknowledged lately as an important supplement for
preventing and even cure certain types of cancer. Franceschi et al. [2] provide new data for the co-precipitation of beta-carotene
and poly(hydroxybutirate-co-hydroxyvalerate) (PHBV) with dichloromethane as organic solvent; the results are promising in
applying this technique to other systems. Zahedi et al. [3] studied the extraction from neem seeds using supercritical carbon
dioxide with methanol as co-solvent. The authors neuro-fuzzy network to the model the system; gray box model was validated
with experimental data. The article by Martín et al. [4] is a review dedicated to the applications of encapsulation and coprecipitation
of essential oils with supercritical fluids. Essential or volatile oils are a major class of substances responsible for
the aroma and taste of several foods; they are used in cosmetic and pharmaceutical industries due to their innumerable bioactivities
such as, antioxidant, bactericide, among several others. Santos and Meireles [5] dedicated their review to the encapsulation
of carotenoids. Some carotenoids are pro vitamin A, such as beta-carotene while others are not, such as lycopene. These substances
are used in food, cosmetics, and medicinal to impart color as well as a natural antioxidant. Maróstica Junior et al. [6]
reviewed the applications of supercritical fluids in obtaining and stabilizing phenolic compounds; these are compounds associated
with a variety of bioactivity including anti-aging, therefore, are extensively used in cosmetics, foods, and medicines. Bioactive
compounds are also produced by other techniques such as microwave assisted extraction, ultrasound assisted extraction,
solvent extraction using green solvents, steam distillation; these processes are also classified as green or clean technologies.
Nonetheless, one of the big issues after obtaining the extract is the stabilization of such extract. Techniques that use supercritical
solvents to form micro and nano particles can be used to stabilize these extracts. This special issue served to stimulate the
studies on these areas that are extremely important for academia and industry.
REFERENCES
[1] W. M. Giufrida, R. Favareto, V. F. Cabral, M. A. A. Meireles, L. Cardozo-Filho, M. L. Corazza, “High-pressure vapor-liquid equilibrium data for
ternary systems CO2 + organic solvent + curcumin”, Open Chem. Eng. J., vol. 4, pp. 3-10, 2010.
[2] E. Franceschi, A. Cezaro, S. R. S. Ferreira, M. H. Kunita4, E. C. Muniz4, A. F. Rubira, J. V. Oliveira, “ Co-precipitation of beta-carotene and biopolymer
using supercritical carbon dioxide as antisolvent”, Open Chem. Eng. J., vol. 4, pp. 11-20, 2010.
[3] G. Zahedi, S. Azizi, T. Hatami, L. Sheikhattar, “Gray box modeling of supercritical nimbin extraction from neem seeds using methanol as co-solvent”,
Open Chem. Eng. J., vol. 4, pp. 21-30, 2010.
[4] A. Martín, S. Varona, A. Navarrete, M. J. Cocero, “Encapsulation and co-precipitation processes with supercritical fluids: applications with essential
oils”, Open Chem Eng J., vol. 4, pp. 31-41, 2010.
[5] D. T. Santos, M. A. A. Meireles, “Carotenoid pigments encapsulation: fundamentals, techniques and recent trends”, Open Chem. Eng. J., vol. 4, pp.
42-50, 2010.
[6] M. R. Maróstica Junior, A. V. Leite, N. R. V. Dragano, “Supercritical fluid extraction and stabilization of phenolic compounds from natural sources –
review”, Open Chem. Eng. J., vol. 4, pp. 51-60, 2010.
Encapsulation and Co-Precipitation Processes with Supercritical Fluids:
Applications with Essential Oils