Beta Carotene Beadlets
Carotene is a strongly-coloured red-orange pigment abundant in plants and fruits. It is an organic compound and chemically is classified as a hydrocarbon and specifically as a terpenoid (isoprenoid), reflecting its derivation from isoprene units. Î²-Carotene is biosynthesized from geranylgeranyl pyrophosphate.
It is a member of the carotenes, which are tetraterpenes, synthesized biochemically from eight isoprene units and thus having 40 carbons. Among this general class of carotenes, Î²-Carotene is distinquished by having beta-rings at both ends of the molecule. Carotene is the substance in carrots that colours them orange and is the most common form of carotene in plants. When used as a food colouring, it has the E number E160a.p119
The structure was deduced by Karrer et al. in 1930. In nature, Î²-carotene is a precursor (inactive form) to vitamin A via the action of beta-carotene 15,15'-monooxygenase.
Isolation of Î²-carotene from fruits abundant in carotenoids is commonly done using column chromatography. The separation of carotene from the mixture of other carotenoids is based on the polarity of a compound. Î²-Carotene is a non-polar compound, so it is separated with a non-polar solvent such as hexane. Being highly conjugated, it is deeply colored, and as a hydrocarbon lacking functional groups, it is very lipophilic.