Color measurement
The color of the oils was determined in triplicate, using
the Lovibond method. Color was measured using the Lovibond
(Lovibond PFX195, VWR International France). The
equipment was calibrated following the method described
by Windsor and Barlow [18], fixing the color yellow in 30
units and varying the color red. Each sample was taken in
a cube and placed in the space provided in the tintometer.
We proceeded by trial and error to match different combinations
of red and yellow slides with the reflected color of
the oil, until we did.