3.3. Subcritical Water Extraction
Inspite ofthe strong antioxidant activity ofthe extracts obtained
from mango leaves of the variety Osteen using CO2 + 20% of ethanol
at 10 MPa and 55 ◦C (1.23 ± 0.01 DPPH g/g dry extract), such
activity is still far from that AAI obtained for the antioxidant
(+)--
-tocopherol (3.84 DPPH g/g dry extract). Moreover, the
extraction yields obtained with this solvent system were also not
too high and are susceptible to be improved. In this way, SWE was
explored using mango leaves as raw material so this technique is
considered highly efficient to extract polar or slightly polar com-
pounds from different natural matters [19–22].
The global yield of the process obtained with SWE
(24.24 ± 1.17%) from mango leaves of the variety Osteen was
significantly superior to those obtained with SC-CO2 and even
with CO2 plus co-solvents (see Fig. 2A). As well, the high efficiency