Biblioteca do Café
URI permanente desta comunidadehttps://thoth.dti.ufv.br/handle/123456789/1
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Item Extraction of caffeine, chlorogenic acids and lipids from green coffee beans using supercritical carbon dioxide and co-solvents(Brazilian Society of Chemical Engineering, 2008-09-02) Azevedo, A. B. A.; Mazzafera, Paulo; Mohamed, R. S.; Melo, S. A. B. Vieira de; Kieckbusch, T. G.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.Item Caffeine Formation by Suspension Cultures of Coffea dewevrei(Instituto de Tecnologia do Paraná - Tecpar, 2000-01) Sartor, Rosana Mary; Mazzafera, PauloThe low caffeine content in leaves of C. dewevrei (~ 0.5 mg/g) is due to a low biosynthesis associated with a fast degradation. On the other hand, high biosynthesis and low degradation confer a higher content (~ 8 mg/g) in leaves of C. arabica. In this work it was observed that cell cultures of C. dewevrei recovered the ability to synthesize caffeine almost in similar levels of C. arabica cultures. Tracer experiments with labelled carbon dioxide showed a significant accumulation of radioactivity in caffeine and metabolites, indicating an active biosynthesis. When the cultures were fed with labelled caffeine most of the radioactivity was recovered in caffeine, indicating that although active, degradation was not so efficient as in leaves, and therefore, contributing for the alkaloid accumulation in the cell cultures.