Neem een oranje tomaat.*
Onderzoekers van de Ohio State universiteit hebben geconstateerd dat de bioactieve stof lycopeen veel beter in het lichaam wordt opgenomen uit oranje dan rode tomaten.
De antioxidant lycopeen zit in tomaten en andere wat rood gekleurde groenten en fruit en staat bekend als bestrijder van kanker, diabetes, osteoporose en hart- en vaatziektes. Lycopeen kan in twee bepaalde vormen voorkomen, als tetra-cis en als all-trans. In rode tomaten zit bijna volledig de all-trans vorm die moeilijk van de vezels is los te weken waardoor voor een hogere effectiviteit, tomaten geruime tijd verwarmd moeten worden. In oranje gekleurde tomaten nu zitten bijna volledig de tetra-cis vorm van lycopeen die wel 2,5 keer makkelijker vrijkomt en daardoor veel makkelijker opgenomen kan worden in het lichaam. Het beste is trouwens lycopeen samen met wat vet op te lossen omdat lycopeen zich niet aan water maar aan vet bindt waardoor de opname nog beter geschiedt.
New
research suggests that the human body absorbs lycopene better from
orange-colored tomatoes than from the more popular red varieties.
Lycopene
is an antioxidant commonly found in tomatoes and other red- or pink-colored
foods, including watermelon, papaya, rosehips, and pink grapefruit or guava.
Evidence suggests that lycopene reduces the risk of cancer, diabetes,
osteoporosis and cardiovascular disease, and possibly even male infertility.
Researchers
from Ohio State University prepared a sauce from tangerine tomatoes
and measured how much lycopene
was absorbed over the next 10 hours by those who ate it. Their findings were
published in the Journal of Agricultural and Food Science.
They
noted that lycopene occurs in two distinct geometric forms — tetra-cis and
all-trans. Approximately 95 percent of the lycopene in red tomatoes is of the
all-trans variety, whereas tangerine tomatoes contain almost entirely the
tetra-cis form. The researchers found that the tetra-cis variety was absorbed
2.5 times more efficiently than the all-trans form.
But
the lycopene in tangerine tomatoes may be more fragile than that in other
varieties. Because lycopene cannot bind to water
molecules, it is hard for the body to separate it from the indigestible fiber in
vegetables. This means that absorption of the compound is normally improved by
processing, including cooking. The scientists found, however, that tetra-cis
lycopene was more likely to break down when heated, as opposed to all-trans,
which was unaffected.
Like
all-trans lycopene, tetra-cis is also absorbed better by the human
body when mixed with
oil. Lycopene is a lipophilic compound, meaning that it binds to fats easily.
The
benefits of less common varieties of tomatoes are only just beginning to be
explored. It is known that the purple coloring in tomatoes comes from anthocyanins,
which also create the coloring in various berries and grapes. Anthocyanins are
also known to be antioxidants,
which protect the body from cell-damaging "free radicals" and decrease
the risk of cardiovascular
disease and cancer.