The major commercially exploited betalain crop is red beetroot
which contains two major pigments,
namely betanin (a red betacyanin) and vulgaxanthine I (a
yellow betaxanthin). Red beetroot is mostly cultivated in North
America, Central America and Britain. Amaranthus is a cosmopolitan
genus of short-lived herbs made up of more than 60 species.
Some amaranths are cultivated as leafy vegetables, grains or
ornamental plants, while others are weeds. Grain amaranths such
as Amaranthus cruentus, Amaranthus coudatus and Amaranthus
hybridus contain more betacyanins in their tissues in comparison to
those of Amaranthus tricolor, a vegetable amaranth . The prickly pear (Opuntia spp.) is widely
distributed in Mexico, Latin America, South Africa and the Mediterranean.
The prickly pear exhibits various colors due to the
combination of betacyanins and betaxanthins. The red pitahaya or
red dragon fruit (Hylocereus polyrhizus) is well known for its