Carotene (Carotene) refers to several related unsaturated hydrocarbons of the formula C40Hx, synthesized by plants, but the animal can not be manufactured. Carotene is an orange photosynthetic pigments. For the human visual system,

Chemically, carotene molecule containing more than 40 carbon atoms, an unsaturated hydrocarbon, the number of hydrogen atoms contained with the carotenoids differ, does not contain other chemical elements. One or both ends of certain types of carotene molecule is a hydrocarbon ring. Carotene for both for human visual color, which is due to the molecule to form a broad conjugated double bond system. Carotene on four terpene structure, which means that from 4 10 carbon terpene carotene biosynthesis, or 5 carbon carotene from 8 isoprene units formed.

The two most common plants carotene, by the Greek letter designation, is α- carotene and β- carotene. γ, δ, ε, and ζ- carotenoids also present. Since they are hydrocarbons, oxygen-atom and thus is fat soluble, water-insoluble. Other carotenoids, such as lutein, molecules containing oxygen atoms, thus less hydrophobic