a b s t r a c t
In this work the supercritical fluid extraction (SFE) with carbon dioxide (CO2) and with ethyl acetate (EtAc)
and ethanol (EtOH) as co-solvents was applied to obtain the phenolic fraction from guava seeds (Psidium
guajava L.). The extraction was explored at various operating conditions, using 10, 20 and 30MPa and 40,
50 and 60 ◦C. The use of EtAc and EtOH as co-solvents in SFE was also studied. The supercritical process
was compared with traditional techniques such as Soxhlet extraction using EtAc and EtOH as solvents.
The quality of the different extracts, obtained using SFE and Soxhlet methods and different solvents, was
evaluated through the antioxidant activity, obtained by the collection methods of scavenging DPPH and
bleaching of -carotene, and also through the total phenolic content (TPC) of the samples, by the Folin-
Ciocalteu method. The antioxidant potential indicates the use of ethanol as co-solvent as the best modifier
in SFE, used in concentration of 10% (w/w) at 50 ◦C and 30 MPa. The quality of the extracts obtained by SFE
with EtOH varied with the operating conditions of temperature and pressure, with higher values obtained
at 10 and 20MPa for TPC results and also antioxidant methods. The process yield of the phenolic fraction
was also evaluated for all the extraction procedures studied (SFE and Soxhlet), with results varying from
0.380 to 1.738% (w/w