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Cholesterol-Reducing Compounds Found in Citrus
September 7, 2005
An ongoing search for profitable
new uses for food-processing byproducts has led Agricultural Research Service
(ARS) scientists to focus on citrus
waste. They've recently learned that a compound found in orange oil decreases
blood serum levels of the protein responsible for low-density lipoprotein (LDL)
that's a major cholesterol carrier.
Manthey, at the ARS
and Subtropical Products Research Laboratory in Winter Haven, Fla., has
done extensive research on flavonoids in citrus peel byproducts. He has focused
on the polymethoxylated flavones, or PMFs, which typically occur at very high
concentrations in the oil that's in orange peel residue.
In Florida, about 700,000 tons of dried peel solids are left over from
squeezing around 150 million boxes of juice oranges every year, on average.
Most of this processing waste is now sold for livestock feed at little or no
profit to citrus processors.
Manthey's research has shown that the PMFs decrease blood serum levels of
apoprotein B, the structural protein of LDL cholesterol. Too much circulating
LDL cholesterol can slowly lead to atherosclerosis, clogged arteries and
eventual heart attacks and strokes. These problems are accelerated by chronic,
low-grade inflammation in the blood vessels.
For the past eight years, Manthey has collaborated with
KGK Synergize of London, Ontario,
Canada, a company that specializes in research to identify health-promoting
compounds and focuses on nutraceuticals. Sometimes called functional foods,
nutraceuticals are natural, bioactive chemical compounds with
disease-preventing or medicinal properties. Nutraceuticals are being
commercially produced by food, pharmaceutical, and herbal and dietary
The original collaboration between ARS and KGK Synergize involved studies of
the anticancer properties of citrus PMFs, but it subsequently expanded into in
vitro investigations of the abilities of PMFs to lower LDL-cholesterol in
more about the research in the September issue of Agricultural
ARS is the U.S. Department of
Agriculture's chief in-house scientific research agency.