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β-Carotene (beta-carotene) is an organic, strongly colored red-orange pigment abundant in fungi, [7] plants, and fruits. It is a member of the carotenes , which are terpenoids (isoprenoids), synthesized biochemically from eight isoprene units and thus having 40 carbons .
α-Carotene is produced when the all-trans lycopene first undergoes reaction with epsilon-LCY then a second reaction with beta-LCY; whereas β-carotene is produced by two reactions with beta-LCY. α- and β-Carotene are the most common carotenoids in the plant photosystems but they can still be further converted into xanthophylls by using beta ...
The two primary isomers of carotene, α-carotene and β-carotene, differ in the position of a double bond (and thus a hydrogen) in the cyclic group at one end (the right end in the diagram at right). β-Carotene is the more common form and can be found in yellow, orange, and green leafy fruits and vegetables.
Vitamin A occurs as two principal forms in foods: A) retinoids, found in animal-sourced foods, either as retinol or bound to a fatty acid to become a retinyl ester, and B) the carotenoids α-carotene (alpha-carotene), β-carotene, γ-carotene (gamma-carotene), and the xanthophyll beta-cryptoxanthin (all of which contain β-ionone rings) that ...
Astaxanthin / æ s t ə ˈ z æ n θ ɪ n / is a keto-carotenoid within a group of chemical compounds known as carotenoids or terpenes. [3] [4] [5] Astaxanthin is a metabolite of zeaxanthin and canthaxanthin, containing both hydroxyl and ketone functional groups.
Aside from tomatoes or tomato products like ketchup, it is found in watermelons, grapefruits, red guavas, and baked beans. [4] It has no vitamin A activity. [4]In plants, algae, and other photosynthetic organisms, lycopene is an intermediate in the biosynthesis of many carotenoids, including beta-carotene, which is responsible for yellow, orange, or red pigmentation, photosynthesis, and ...
Retinol is synthesized from the breakdown of β-carotene. First, the β-carotene 15,15'-monooxygenase cleaves β-carotene at the central double bond, creating an epoxide. This epoxide is then attacked by water creating two hydroxyl groups in the center of the structure. The cleavage occurs when these alcohols are oxidized to the aldehydes using ...
Beta-carotene 15,15'-monooxygenase (BCO1; EC 1.14.99.36) from animals, which cleaves beta-carotene symmetrically at the central double bond to yield two molecules of retinal. [ 3 ] Beta-carotene-9',10'-dioxygenase (BCO2) from animals, which cleaves beta-carotene asymmetrically to apo-10'-beta-carotenal and beta-ionone, the latter being ...