The major carotenoids in each sample were quantified by using
calibration curves prepared from standards, and the results were
expressed as lg/g of sample. Standard curves were constructed
with five different concentrations for each carotenoid, each point
in duplicate, with lines passing by origin and coefficients of
co-relation greater than or similar to 0.95. Violaxanthin was quantified
with the standard curve of lutein, and the cis-isomers of bcarotene
with the standard curve of all-trans isomer (Assunção &
Mercadante, 2003). Due to the difficulty of isolating the f-carotene
standard, its quantification was performed through the standard
curve of the all-trans-b-carotene.