Nevertheless, in a sustainable perspective, it is possible to attain
a compromise between the extraction conditions and the richness
of the extract in antioxidants. Using a hydroalcoholic solvent
(50%w:50%e), at 40 ◦C during 60 min, it is possible to obtain an
extract rich in phenolic compounds, containing an average concentration
of 302.5
±
7.1 mg GAE/L total phenolics, 83.0
±
1.4 mg ECE/L
flavonoids and 0.43
±
0.06 mg TAE/L tannins, and exhibiting high
antioxidant capacity, saving simultaneously time and energy, compared
with other conditions analyzed. Two other aspects of the
extraction process studied that deserve to be highlighted are the
fact that the recovery of the solvents used is relatively straightforward,
which represents a plus in terms of sustainability, and that
it is not necessary to separate silverskin batches according to the
variety of coffee bean, since the composition of the extracts is not
significantly affected by the composition of the samples (data not
shown). This can make the extraction process more expedite.