Some of the properties that have been attributed to carotenoids in biological systems are shown in Fig. 2.
In some cases, these properties can be considered to be biological functions, as they appear to be
essential for the life of the organism. Other properties can be demonstrated but may not be essential to
the system, and can be considered to be actions or associations of carotenoids. Many of the biological
properties that have been associated with carotenoids are shown in Fig. 2