Carotenoid: insoluble in water but soluble in organic solvents. Carotenoids in chloroplasts contain two pigments, namely carotene and lutein. The former is Orange-yellow, the latter is yellow. Its function is to absorb and transmit light energy and protect chlorophyll.

A general term for an important class of natural pigments, which are compounds. They are commonly found in animals, higher plants, fungi, algae and The yellow, orange-red or red pigments in bacteria are mainly β-carotene and γ-carotene, hence the name. Insoluble in water, soluble in fat and fat solvents. Also known as lipochrome. Since its isolation in the early 19th century Nearly 450 natural carotenoids have been discovered so far; new carotenoids are constantly being discovered using new separation and analysis technologies such as thin layer chromatography, high-pressure liquid chromatography and mass spectrometry. Plant carotenoids Exist in various yellow plastids or colored plastids; such as yellow leaves, yellow flowers, yellow and red fruits and yellow roots in autumn. Animal carotenoids are mainly from fat, yolk, feathers and fish scales, as well as the shells of shrimps and crabs. Pigments. Animal carotenoids are generally combined with proteins. For example, astaxanthin contains astaxanthin, and shrimp egg green protein is a complex of astaxanthin and a rich protein. β-carotene is a synthetic vitamin in mammals. The precursor of A is called provitamin A. In addition to chlorophyll, the chlorophyll also contains carotenoids. Carotenoids can transfer the absorbed light energy to chlorophyll a and are essential photosynthetic pigments for photosynthesis.

Carotene, English: carotene; molecular formula: C40H56.

It is widely distributed in biological carotenoid hydrocarbons. The chemical structure has the same polyene chain in the center. There are many isomers such as α, β, γ, δ, ε, etc. depending on the type of aromatic ketone ring or group. These are also called β, ε-carotene, β, β-carotene, β, ψ-carotene, ε, ψ-carotene, ε, ε-carotene. In addition, lycopene is also an isomer of carotene. β-carotene is the most widely distributed and abundant among carotenes. It is the same as chlorophyll in green leaves** * coexists, and is also abundant in carrot roots. The maximum absorption is 497.466 nanometers (in chloroform). It is insoluble in water and alcohol, but soluble in benzene, chloroform, carbon disulfide, etc. α-carotene is found in green leaves and carrot roots. It coexists with β-carotene, and the content is generally less. Optical rotation [α] 18cd = 385° (benzene solution). Maximum absorption is 485, 454 nanometers (in chloroform). γ-carotene is in biological The distribution in the body is limited. The maximum absorption is 508.5, 475, 446 nanometers (in chloroform).