Results (
Thai) 2:
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Fig. 4 shows the FC results 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). The FolineCiocalteau
method is traditionally used to measure phenolic compounds, but
several authors have reported that this method also evaluates other
reducing nonphenolic compounds, such as melanoidins, proteins
and thiols, and thus should be seen as a measure of total antioxidant
capacity rather than phenolic content (Caemmerer & Kroh,
2006; Everette et al., 2010; Perez-Martinez, Caemmerer, De Pena,
Cid, & Kroh, 2010). A decrease of the antioxidant capacity measured
by FolineCiocalteau technique with the increase of roasting
degree can be observed. A highly significant (p < 0.001) and good
correlation (0.785) with L* values has been found. Moreover, FC
values also contributed to the PC1 in Principal Component Analysis
(Fig. 2) together with the CIELab parameters and, then, to the distribution
of coffees according to the roasting degree. Similar patterns
were reported by other authors in conventional roasted coffees, mainly due to a higher
degradation of chlorogenic acids, the most abundant phenolic
compounds in coffee. Loss of phenolic compounds during roasting
is very well known and losses of 8e10% for every 1% loss of dry
matter up to 95% of the chlorogenic acid
content in green coffee with drastic roasting conditions were reported
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