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This is a list of antioxidants naturally occurring in food. Vitamin C and vitamin E – which are ubiquitous among raw plant foods – are confirmed as dietary antioxidants, whereas vitamin A becomes an antioxidant following metabolism of provitamin A beta-carotene and cryptoxanthin.
Canthaxanthin biosynthesis proceeds from beta-carotene via the action of a single protein, known as a beta-carotene ketolase, that is able to add a carbonyl group to carbon 4 and 4' of the beta carotene molecule. Although functionally identical, several distinct beta-carotene ketolase proteins are known.
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 ...
High doses of some antioxidants may have harmful long-term effects. The Beta-Carotene and Retinol Efficacy Trial (CARET) study of lung cancer patients found that smokers given supplements containing beta-carotene and vitamin A had increased rates of lung cancer. [141] Subsequent studies confirmed these adverse effects. [142]
Zeaxanthin is one of the most common carotenoids in nature, and is used in the xanthophyll cycle.Synthesized in plants and some micro-organisms, it is the pigment that gives paprika (made from bell peppers), corn, saffron, goji (wolfberries), and many other plants and microbes their characteristic color.
[29] Beta-carotene is found and consumed in many nutritious foods eaten around the world, including fruits and vegetables. Beta-carotene in food is a safe source of vitamin A. [30] A 2012 study showed that the beta-carotene produced by golden rice is as effective as beta-carotene in oil at providing vitamin A to children. [31]
9-cis-beta-carotene 9',10'-cleaving dioxygenase (EC 1.13.11.68, CCD7 (gene), MAX3 (gene), NCED7 (gene)) is an enzyme with systematic name 9-cis-beta-carotene:O 2 oxidoreductase (9',10'-cleaving). [ 1 ] [ 2 ] This enzyme catalyses the following chemical reaction