What is lycopene?
- Lycopene is a red carotenoid pigment that colours tomatos and many other red, orange, yellow fruits/veg
- Has potential health benefits
Not soluble in water and low solubility in solvents
It consists entirely of carbon and hydrogen so is a non-polar hydro-carbon
Lycopene melting point?
High at 172-173 degrees
Moleculer structure of lycopene?
- Is polyunsaturated and in its natural form all the double bonds are in trans rather then cis form
- Has alternating double bonds
- In lycopene there are 22 carbon atoms in the conjugated
system. This means that the bonding electrons for each of these carbons become “delocalised”. They are shared between all 22 of the carbon
atoms which participate in this system and become a part of a molecular orbital (these factors make it different to most polyunsaturated acids)
Significance of conjugation in lycopene?
- The conjugation makes the molecule linear and infexible with no free rotation
- Only van de waals forces
- Makes it quite insoluble
- Can absorb some wave lengths of light but not red which makes it a bright colour red
- Is stable
- Many possible isomers
Lycopenes in health
- the molecule is an important intermediate in the
biosynthesis of many other carotenoids including -
carotene. It is often referred to as a phytochemical
(simply meaning plant molecule) involved both in
photosynthesis as well as photoprotection through its
ability to minimise oxidative damage to the structure of
the chlorophyll molecule
- powerful antioxidant and consumption is
associated with reduced cancer risks and enhanced
well-being. It is also amongst the phytochemicals
thought to reduce the risks of cancers of the
oesophagus, lungs, prostate and stomach
Lycopene in food?
Low levels are found in
animal foods including chicken liver.
- Green vegetables can be significant sources.
Asparagus, parsley and basil are examples where the
red colour of lycopene is masked by the chlorophyll
Lycopene as a food additive?
Lycopene is sometimes used to colour food and it is an
approved food additive in some but not all countries
Health benefits of antioxidants?
- Antioxidants are responsible for keeping high-energy reactions from damaging essential DNA and proteins.
and other carotenoids operate by a singlet quenching mechanism, which is a well-recognised mechanism of
antioxidant action. They react with singlet oxygen, 1O2,
returning it to the relatively unreactive triplet state
Lycopene may be the most powerful carotenoid
quencher of singlet oxygen . Test tube studies
indicate that it is 100 times more efficient at quenching
singlet oxygen than vitamin E