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Tater Treats: Nutritious Sweetpotato Chips and Fries
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Geneticist Janice Bohac and
technician John Fender compare
chips made from USDA sweetpotato
breeding lines.
(K9419-1)
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Imagine a sweetpotato that isn't very
sweet.
For the last 8 years, ARS geneticist
Janice R. Bohac and entomologist D. Michael Jackson of the U.S. Vegetable
Laboratory, in Charleston, South Carolina, pathologist John Mueller of Clemson
University, and cooperators have used conventional breeding and selection to
develop medium-light orange, yellow, or cream-colored sweetpotato breeding
lines for new uses.
"They're bland in flavor and lower in sweetness—perfect for making
great potato chips or french fries," says Bohac. She has been testing them
in the small-scale chip-making kitchen in her laboratory. |
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Entomologist D. Michael Jackson
(left) and John Fender examine
sweetpotato breeding lines for
maintenance of quality during
long-term storage.
(K9421-1)
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"Unlike the sweet,
orange-fleshed varieties of the United States, these sweetpotatoes resemble
those eaten in the Tropics and favored by many Americans originating from Asia,
Africa, the Caribbean, and South America," Bohac says. "Because
they're not as sweet or moist as the traditional American types, they are great
candidates for chips and fries."
Bohac's new sweetpotatoes have several attributes that make them an excellent
ingredient in snack foods. For one, they are highly nutritious. Chips made from
them contain many nutrients—including the orange-pigmented beta-carotene
that's the precursor to vitamin A.
"Just one medium-sized orange or dark-yellow sweetpotato provides more
than the Recommended Dietary Allowance of vitamin A and high levels of fiber,
vitamin C, and folic acid," she says.
In addition, Bohac says her new sweetpotatoes have high dry matter
content—as high as 40 percent. "This means that these chips don't
soak up as much oil as other chips or those made from the leading U.S.
sweetpotato variety. Thus, they're crispy and have less fat."
"I've had people here try them and say, ‘I don't usually like
sweetpotatoes, but I like these,’" says Bohac.
The sweetpotato, Ipomoea batatas, is a member of the morningglory
family. Sweetpotato ranks as the seventh largest food crop in world production.
In 1999, they were a $215-million-plus crop in the United States.
Sweetpotato roots resemble—and are often called—yams, Dioscorea
alata or D. rotundata, but they aren't botanically related to yams.
Yams are not grown commercially in the United States. And while yams are dry
and starchy and can make a good chip, they contain little to no beta-carotene
or vitamin A, and so are less nutritious.
Another good feature of Bohac's and Jackson's new sweetpotato breeding lines is
that they can be grown with fewer pesticides because they are resistant to key
sweetpotato pests like root-knot nematodes, Fusarium wilt, and soil insects.
And they grow and produce well in the South.
"A lot of the starchy sweetpotato varieties grown in tropical countries
don't yield well in the United States because they are not adapted to our
climate," says Bohac. "They also deteriorate quickly in
storage."
Unlike current commercially grown U.S. varieties, "these new sweetpotatoes
are being developed specifically to be grown in the United States for making
chips and fries," she says.
Bohac is hoping that sweetpotato chips will catch on here as they have
elsewhere. Starchy, bland sweetpotato chips and fries are popular in many parts
of the world, including Peru, Japan, China, Bangladesh, Thailand, New Zealand,
and Jamaica and other Caribbean countries.
"In the United States, sweetpotato chips have been marketed only on a
small scale—primarily because current varieties have a strong sweetpotato
flavor," she says. "They also require more processing to remove
sugars, reduce browning during frying, and achieve the right texture."
Bohac and her colleagues have named one of the new dry-fleshed sweetpotatoes
"White Regal." It's being used as a parent to produce improved
dry-fleshed breeding lines with multiple pest resistance. There are several
other dry-fleshed lines in advanced testing that may be superior to current
commercial fresh-market cultivars for making chips and fries.
"We need to do more yield testing—as well as cooking tests with
sweetpotatoes coming out of several months of storage—to determine which
cultivars will be most suitable for processing. This information will determine
which breeding lines will ultimately be released," she says.
Bohac is looking for a commercial cooperator so she can produce and test the
chips on a larger scale. "If these new chips catch on, they could open up
new markets for U.S. farmers and new nutritious products for consumers,"
she says.—By Hank Becker,
Agricultural Research Service Information Staff.
This research is part of Plant, Microbial, and Insect Genetic Resources,
Genomics, and Genetic Improvement, an ARS National Program (#301) described on
the World Wide Web at http://www.nps.ars.usda.gov.
Janice R. Bohac is with the USDA-ARS
U.S.
Vegetable Laboratory, 2875 Savannah Hwy., Charleston, SC 29414; phone (843)
556-0840, fax (843) 763-7013.
Striking Potato Gold
Want nutritionally packed potatoes? Plant geneticist Kathleen G. Haynes, with
ARS' Vegetable Laboratory, and nutritionist Beverly A. Clevidence, head of ARS'
Phytonutrients Laboratory, both in Beltsville, Maryland, are developing
yellow-fleshed potatoes with increased carotenoid content. Some of their potato
lines have more lutein content than commercial potatoes. Lutein is a carotenoid
thought to protect against age-related eye problems and blindness.
"U.S. consumers are increasingly interested in yellow-fleshed potatoes
because the colored variety tastes better," says Haynes.
"Yellow-fleshed potatoes may offer more health benefits with enhanced
carotenoid levels. Also, the quality is better."
The newly developed potatoes can be used for baking or making chips. Their
flesh ranges from white to very dark yellow to almost orange. Haynes has found
that the more intense the yellow, the higher the lutein content.
Clevidence's laboratory is analyzing the carotenoid content in some of the
potato lines. "We're still in the early stages," Haynes notes.
"We don't have a variety that's ready for commercial release. We're
evaluating different lines that could ultimately end up in a new variety."
So far, the promising lines contain 3 to 13 times more carotenoid than Yukon
Gold, the most widely purchased yellow-fleshed potato in the U.S.
marketplace.—By Tara
Weaver-Missick, Agricultural Research Service Information Staff.
Kathleen G. Haynes is with the
USDA-ARS
Vegetable
Laboratory, Building 010-A, Room 312, BARC-West, Beltsville, MD 20705;
phone (301) 504-7405, fax (301) 504-5555.
Beverly A. Clevidence is
with the USDA-ARS Phytonutrients
Laboratory, Building 307, Room 323, BARC-East, Beltsville, MD 20705; phone
(301) 504-8396, fax (301) 504-9456. |
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"Tater Treats: Nutritious Sweetpotato Chips and
Fries" was published in the
May 2001
issue of Agricultural Research magazine.
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