Fig. 3 shows the antioxidant capacity, measured by the DPPH
quenching assay, of the Torrefacto roasted coffees in comparison
with conventional roasted coffees of different origins (Colombia,
Brazil, Kenya, Guatemala, and Vietnam) and different roasting degrees
(Dark, Medium and Light). Commercial conventional roasted
coffees showed lower DPPH results than lab-roasted torrefacto
roasted coffees. This might be explained by a longer storage (from
roasting to purchase) under less controlled conditions (room
temperature) in commercial samples, because during storage the
antioxidant capacity decreases due to the presence of residual oxygen,
and other radicals or pro-oxidant compounds formed during
the roasting process