A photochemiluminescence assay was conducted in order to
evaluate the antioxidant activity of the carotenoid extracts. This
assay involves the photochemical generation of superoxide ðO
2$
Þ
free radical combined with chemiluminescence detection of luminol,
which acts as a photosensitizer and also as an oxygen radical
detection reagent. This reaction takes place in the PHOTOCHEM®
(Analytik Jena AG). The ACL and ACW kits provided by the manufacturer
were used to measure lipophilic and hydrophilic antioxidant
capacity, using Trolox or ascorbic acid as the calibration
reagents, respectively. The results were expressed as mg Trolox or
ascorbic acid equivalents/mg carotenoids in the extracts. All samples
were measured in duplicate.