*2.6. Color Determination*

Oil samples were filtered, and color was measured using a UV/Vis Jasco V-530 spectrophotometer (Jasco Analytical, Madrid, Spain). Basically, oil samples were placed in quartz cuvettes (1 cm path length) for analysis, using N-hexane as the blank reference. The obtained values were used to calculate CIELAB chromatic coordinates: L\* (brightness), a\* (red–green component), b\* (yellow–blue component) as recommended by the Commission Internationale de l'Eclairage (CIE, Wien, Austria) [25].
