Beta-Carotene | Wikipedia audio article
Channel: wikipedia tts
Date: 10/12/2018

This is an audio version of the Wikipedia Article:
Beta-Carotene


00:01:19 1 Provitamin A activity
00:02:46 1.1 Symmetric and asymmetric cleavage
00:03:34 1.2 Conversion factors
00:03:52 1.2.1 Retinol activity equivalents (RAEs)
00:04:35 1.2.2 International Units
00:05:18 2 Dietary sources
00:05:27 3 Side effects
00:06:00 3.1 Excessive intakes and vitamin A toxicity
00:06:05 3.2 Drug interactions
00:06:15 3.3 β-Carotene and lung cancer in smokers
00:07:29 4 Research
00:07:39 4.1 Cancer
00:08:13 4.2 Cataract
00:08:25 5 See also
00:08:57 6 References
00:09:07 7 External links
00:09:44 undefined
00:09:55 undefined
00:11:04 undefined
00:11:43 undefined
00:12:35 undefined
00:13:19 undefined



Listening is a more natural way of learning, when compared to reading. Written language only began at around 3200 BC, but spoken language has existed long ago.

Learning by listening is a great way to:
- increases imagination and understanding
- improves your listening skills
- improves your own spoken accent
- learn while on the move
- reduce eye strain

Now learn the vast amount of general knowledge available on Wikipedia through audio (audio article). You could even learn subconsciously by playing the audio while you are sleeping! If you are planning to listen a lot, you could try using a bone conduction headphone, or a standard speaker instead of an earphone.

You can find other Wikipedia audio articles too at:
https://www.youtube.com/channel/UCuKfABj2eGyjH3ntPxp4YeQ

You can upload your own Wikipedia articles through:
https://github.com/nodef/wikipedia-tts



"The only true wisdom is in knowing you know nothing."
- Socrates



SUMMARY
=======
β-Carotene is an organic, strongly colored red-orange pigment abundant in 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. Among the carotenes, β-carotene is distinguished by having beta-rings at both ends of the molecule. β-Carotene is biosynthesized from geranylgeranyl pyrophosphate.β-Carotene is the most common form of carotene in plants. When used as a food coloring, it has the E number E160a. The structure was deduced by Karrer et al. in 1930. In nature, β-carotene is a precursor (inactive form) to vitamin A via the action of beta-carotene 15,15'-monooxygenase.Isolation of β-carotene from fruits abundant in carotenoids is commonly done using column chromatography. It can also be extracted from the beta-carotene rich algae, Dunaliella salina. The separation of β-carotene from the mixture of other carotenoids is based on the polarity of a compound. β-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.