Use
Carotenoids are a large class of pigments usually located
in the thylakoid membranes of the grana in chloroplasts,
in the form of carotenoprotein complexes.
The general structure of carotenoids is that of
aliphatic and aliphatic-alicyclic polyenes with a few
aromatic-polyenes. They are widely distributed in plants
and act as photosynthetic pigments in cells that lack
chlorophyll. They have the same basic structure as
vitamin A, and are converted into vitamin A in animal
livers. More than 300 carotenoids are known and this
number is on the rise.
There are several biochemical functions in which
carotenoids play a role, apart from their well-known role
as photosynthetic pigments. Carotenoids act as blue light
harvesting pigments, protect biological systems from
photodynamic damage and are safe food colorants.