The paper reports on experimental data on the extraction of caffeine, coffee oil and chlorogenic acids from green coffee beans using pure supercritical CO2 and supercritical CO2 modified with ethanol (5% w/w) and isopropyl alcohol (5% w/w) at 50 and 60ºC and 15.2 24.8 e 35.2 MPa. In this study extraction kinetics were obtained for all assays i.e. samples were collected at several time intervals for each solvent and mixed solvent. When pure CO2 and CO2-ethanol mixed solvent were used, an increase in pressure resulted in an increase in the amount of oil extracted. When CO2 was modified with isopropyl alcohol, the amount of coffee oil extracted also increased with pressure. Caffeine extraction initially increased and subsequently decreased with pressure. Chlorogenic acids were only extracted when isopropyl alcohol was used as a co-solvent. An increase in extraction temperature resulted in a decrease of caffeine and oil extraction (retrograde condensation) when only CO2 was used as solvent. With the use of co-solvent this retrograde behavior was no longer observed and the increase in temperature resulted in the increase in the extracted amounts of caffeine, coffee oil and chlorogenic acids
Vieira de Melo, pela orientação e ensinamentos que muito contribuíram para a qualidade deste trabalho.Aos amigos da oficina mecânica da FEQ/Unicamp, pela amizade e presteza.Aos colegas do laboratório: Uiran, Lílian e Ronaldo, pelos anos de agradável convívio.Ao colega Alexandre Tashima pela amizade e colaboração na modelagem matemática.A Érica pelos anos de amizade e companheirismo.Aos amigos de todas as horas: Djou, Bugalu, Leo, Sadan, Urso e Baco.À minha família, pelo amor, carinho e dedicação. Sempre incondicionais e constantes, que muito contribuíram para o meu equilíbrio e, sempre me serviram de referência.Aos amigos recentes pelo apoio e pelas boas horas de conversa e risadas. E a todos aqueles que de forma direta ou indireta contribuíram para a realização deste trabalho.
The caffeine solubility in supercritical CO2 was studied by assessing the effects of pressure and temperature on the extraction of green coffee oil (GCO). The Peng-Robinson¹ equation of state was used to correlate the solubility of caffeine with a thermodynamic model and two mixing rules were evaluated: the classical mixing rule of van der Waals with two adjustable parameters (PR-VDW) and a density dependent one, proposed by Mohamed and Holder² with two (PR-MH, two parameters adjusted to the attractive term) and three (PR-MH3 two parameters adjusted to the attractive and one to the repulsive term) adjustable parameters. The best results were obtained with the mixing rule of Mohamed and Holder² with three parameters
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