Huanglongbing
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Oranges from trees infected with Huanglongbing (citrus greening) can be used for orange juice as long as they are mixed with other oranges, according to new ARS research. Click the image for more information about it.
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Fighting Back Against Citrus Greening
U.S.
Department of Agriculture (USDA) scientists in Fort Pierce, Fla. are helping
citrus growers and juice processors address the threat posed by Huanglongbing
(HLB), a disease that is costing the citrus industry millions of dollars each
year.
Citrus trees infected with
HLB, also called citrus greening, usually die within five to 10 years. Fruit on
infected trees often falls to the ground before harvest, and fruit that remains
on trees may become misshapen and sometimes only partially ripen.
Supervisory
horticulturalist Elizabeth
Baldwin with USDA's Agricultural Research Service (ARS) in Fort
Pierce is investigating the effects of HLB on the taste of orange juice
produced from diseased trees. Her goal is to provide help while a permanent
solution is found.
She and her colleagues at
the agency's U.S.
Horticultural Research Laboratory evaluated fruit with or without HLB symptoms—produced
over two growing seasons—for a number of fruit and juice characteristics. They
compared Midsweet, Hamlin, and Valencia oranges, the three principal varieties
harvested for processing, and used gas and liquid chromatography to analyze juice
compounds.
They found that orange
juice from the fruit with HLB symptoms was often higher in limonin and nomilin,
compounds that can give the juice a bitter taste, but that the compounds were
generally below levels that could be detected by human taste panels. Their
results were published in the Journal of Agricultural and Food Chemistry.
In another study, they
investigated how HLB infection affects juice quality in the same three
varieties of orange with respect to cultivar, maturity, and processing methods.
The results showed tremendous variability, depending on the harvest date and
variety of orange. In general, the researchers found more of a problem with
off-flavored juice from diseased Hamlin orange trees than with diseased trees
of the Valencia and Midsweet varieties.
But the researchers
concluded that using some fruit that has HLB symptoms would not cause problems
in commercial operations as long as fruit with and without symptoms, harvested
from several varieties, locations, and seasons, was mixed together. Those
results were published in the Journal of
Food Science.
ARS is the USDA's principal intramural scientific research agency, and
this research supports the USDA goal of promoting international food security.