Increasing the dietary fiber from less than
three to more than 10 percent in baked goods and snack foods is now possible.
The best part is that consumers can get the added health benefit without
tasting the difference. Studies suggest fiber can help decrease the risk of
heart disease, some cancers, elevated blood pressure and diabetes. The
recommended fiber intake is 20 to 35 grams daily, but Americans average only
about 15 grams in their diets.
ARS researchers found that by including dairy
proteins such as casein or whey as a binder to hold everything together, they
could also add more dietary fiber to bakery products, such as cookies and
muffins, and to extruded products, such as breakfast cereals, corn puffs,
cheese curls and energy bars. The texture of the higher-fiber foods was
comparable to products currently on the market, researchers reported in Food
Research International, 2001 (vol. 34, pp. 679-687).
Extrusion is the process of forcing corn,
wheat or rye flour and other ingredients through a die under high pressure, and
sometimes heat, essentially cooking the mixture. Until now, it has been
difficult to add cereal fibers during extrusion without causing an undesirable
texture change, which then decreases consumer acceptance. Many extruded food
products have less than one gram of fiber per 50 grams of product. But an
"energy bar" prepared with the new process can contain as many as 15
grams in a 50-gram bar.
In a separate project, the researchers use
milk protein to envelope fiber and keep it from soaking up water when used in
many foods. Reducing the water-holding capacity of the fiber improves food
quality. A patent application has been filed on the process.
For more information, contact
Charles I. Onwulata, (215)
233-6497, Eastern Regional Research
Center, Wyndmoor, PA
Back to
Contents
Dieters who have more of the hormonelike
protein leptin circulating in their bodies may feel less hunger than dieters
whose leptin levels drop while on a weight-loss regimen. That's according to a
15-week study of 12 overweight but otherwise healthy female volunteers age 20
to 40.
Conducted by ARS and University of California-Davis
researchers, the study is among the first long-term analyses of blood leptin in
women who are on a reducing diet. The findings should help obesity researchers
and others determine whether leptin can be used effectively to help people shed
extra pounds.
During the first week of the weight-loss
stint, volunteers' plasma leptin levels dropped by an average of 54 percent.
Then, levels remained low throughout the rest of the study. The incidence of
hunger and the desire to eat doubled in response to the reducing diet. But the
volunteers who reported the greatest increase in hunger and the greatest desire
to eat were those with the largest drop in leptin. The findings were published
in the American Journal of Clinical Nutrition, 1998 (vol. 68, pp.
794-801).
By contrast, volunteers with higher leptin
concentrations and smaller decreases in leptin as the study progressed were
less hungry while dieting. The volunteers responded to a questionnaire once
every two weeks throughout the study, ranking their hunger throughout the day.
For more information, contact
Nancy L. Keim, (530) 752-4163,
Western Human Nutrition Research
Center, Davis, CA
Back to
Contents
There is some evidence that natural,
estrogenlike compounds in soybeans and many other plant foods may reduce hot
flashes and vaginal dryness and increase bone density in women after menopause.
But a careful inspection of the diets of nearly 1,000 older women in
Massachusetts found their average intake of these phytoestrogens to be less
than one milligram (mg) daily.
That's only one to five percent of the
phytoestrogen intake reported for Asian populations. Soybeans and soy protein
products like tofu are concentrated sources of phytoestrogens and are common in
Asian diets. By contrast, foods common in Western diets are far lower in these
compounds.
Epidemiologists at an ARS-supported center in
Boston, Mass., collaborated on the study with researchers in The Netherlands,
Finland and at Boston University School of Medicine. They estimated intakes of
the three classes of phytoestrogensisoflavones, lignans and
coumestansfrom food frequency questionnaires filled out by 964
postmenopausal, Caucasian women participating in the Framingham (Mass.)
Offspring Study.
In contrast to Asian populations, the U.S.
women got the bulk of their phytoestrogensnearly 0.6 mgin the form
of secoisolariciresinol from fruits, such as berries, citrus, apples and melon.
The compound is one of the lignans, and it is most abundant in flaxseed.
The better known isoflavonesgenestein,
daidzein and formononetinprovided about one-fourth of the phytoestrogens
in the women's diets. And these came mostly from beans and peas rather than
from soy products, the researchers reported in the Journal of Nutrition,
2001 (vol. 131, pp. 1826-1832). The third class of phytoestrogens, coumestans,
were barely detectable in the women's diets.
For more information, contact
Paul F. Jacques, (617) 556-3322,
Jean Mayer USDA Human Nutrition Research
Center on Aging at Tufts University, Boston, MA
Back to
Contents
Numerous studies have demonstrated that
taking extra chromium daily in the form of a supplement may improve glucose
tolerance in people whose blood sugar levels range from slightly elevated to
full-blown diabetes. Now, ARS scientists have developed a new chromium
formulation that people absorb into the bloodstream better than anything on the
market.
The new formulation is a complex of chromium
and the amino acid histidine. It is absorbed at least 50 percent better than
chromium picolinatewhich was patented by other ARS scientists nearly
three decades ago and is the best absorbed and most popular chromium supplement
sold today. Histidine (not to be confused with histamine) is one of the
"essential" amino acids because the body doesn't manufacture it. It
is found in all meats and protein-containing foods
Typical Western diets barely supply the new
adequate intake (AI) for chromium--35 micrograms (mcg) daily for men, 25 mcg
for women. And high sugar intakes, trauma and hard exercise can increase
chromium excretion. Because the mineral improves insulin function, a shortfall
can impair the cells' ability to remove excess sugar from the blood stream.
However, chromium supplements won't help people who have high blood sugar in
spite of getting adequate dietary chromium from good sources like liver, whole
grains, nuts and meat.
In tests, men and women absorbed an average
3.1 mcg of chromium from the chromium-histidine complex, compared with 1.8 mcg
from chromium picolinate, 0.4 mcg from chromium chloride and 0.2 mcg from
chromium polynicotinate. The latter two formulations are also popular
supplements. The U.S. Department of Agriculture is seeking a patent on the
chromium-histidine formulation, and the technology is available for
licensing.
In studies worldwide, supplemental chromium
has improved blood sugar levels or other symptoms in people with glucose
intolerance, type 1 and type 2 diabetes, steroid-induced diabetes, and
gestational diabetes.
For more information, contact
Richard A. Anderson, (301)
504-8091, Beltsville Human Nutrition
Research Center, Beltsville, MD
Back to
Contents
Teens who start their day without breakfast
were twice as likely to have diets low in iron, according to a study involving
more than 700 ninth graders in Louisiana. Nineteen percent of the ninth graders
studied skipped breakfast, including 20 percent of white and 36 percent of
non-white girls. What's more, the diets of one in three breakfast-dodgers had a
significant iron shortfalltwice the rate of their breakfast-eating peers.
That's a shortfall that could be hurting
their grades. Iron-deficiency anemia has long been known to have a negative
affect on behavior and learning. And, even marginal iron levels were linked to
poorer math scores among adolescent girls in one recent study. In other
studies, by contrast, eating breakfast has been shown to improve memory,
grades, school attendance and punctuality in children.
Teens who ate breakfast were two to five
times more likely to consume at least two-thirds of the recommended amounts of
most vitamins and minerals, including iron. Intakes of vitamins and minerals,
including zinc, calcium and folic acid, were much higher among the
breakfast-eaters, while fat consumption was lower. The nutrients teens miss
when they skip breakfast are rarely recouped during other meals, according to
the researcher, who published her results in the Journal of Adolescent
Health, 2000 (vol. 27, pp. 314-321).
Girls, in particular, are at risk for low
iron because they have increased needs. And while some teens skip breakfast to
cut calories, this practice is rarely effective. Instead, research suggests
that meal-skippers often eat more high-calorie, salty and low-fiber
snacks.
For more information, contact
Theresa Nicklas, (713) 798-7000,
Children's Nutrition Research Center at
Baylor College of Medicine, Houston, TX
Back to
Contents
An ARS scientist is cooking up a new kind of
french fry for health-conscious consumers who simply can't resist the fast-food
favorite. Because the fries are made from rice flour mixtures, rather than
potatoes, they absorb less fat during cooking. Rice is also hypoallergenic,
nutritious and easily digested, and it stores well.
The fries are made with broken and
immature/thin rice kernels, which fetch a lower price than regular whole rice.
The method, which overcomes technical difficulties experienced by earlier
scientists, processes rice flour mixtures into fries with texture, cooking and
other properties that closely mimic potato fries. Details of the research
leading up to the process appear in the Journal of Food Science, 2001
(vol. 66 (4), pp. 610-613 and vol. 66 (8), pp. 1084-1088).
In tests, the rice fries generally absorbed
25-50 percent less fat from oil during cooking than potato fries. They could
also be made into a "functional food," since they can be fortified
with vitamins, minerals, protein and other nutrients. The U.S. Department of
Agriculture filed for a patent on the process. Now, the ARS researcher and
collaborators with Rishellco, Inc., are consulting with U.S. rice processors on
ways to commercialize the fries.
In related work, the researcher is
experimenting with a whole-rice bread for individuals with celiac disease, an
intolerance to the wheat protein gluten that affects one to two percent of the
U.S. population.
For more information, contact
Ranjit Kadan, (504) 286-4332,
Southern Regional Research
Center, New Orleans, LA
Back to
Contents
Margarine and other foods can be made with a
lower percentage of trans fats with a new hydrogenation process developed by
ARS scientists. Using a hydrogenation process with carbon dioxide makes a
product with less than 10 percent trans fatty acid content that's suitable for
use in margarine and other tablespread formulations. This is good news for
consumers because studies have shown that trans fatty acids may slightly
increase blood cholesterol levels.
Margarine oils are usually prepared using
hydrogenation or by another conventional method, interesterification.
Hydrogenation changes the chemical structure of oils to yield a margarine that
doesn't melt at room temperature. But the product contains 10 to 30 percent
trans fatty acids. The new hydrogenation process also alters the chemical bonds
of vegetable oil, but it produces an oil with a much lower percentage of trans
fatty acids. The researchers are currently seeking an industry partner to
continue this development, which is described in the Journal of the American
Oil Chemists' Society, 2001 (vol. 78, pp. 107-113).
Interesterification rearranges the oil's fat
molecules without adding hydrogen molecules, yielding a product with few trans
fatty acids. Its drawback is that the process is more expensive than
hydrogenation.
For more information, contact
Gary R. List, (309) 681-6388,
National Center for
Agricultural Utilization Research, Peoria, IL
Back to
Contents
The orange and red plant pigments beta
carotene and lycopene score high as antioxidants in the test tube. But their
antioxidant capacity has seemed to disappear in human blood. Not any more. A
new assay that peers into blood lipids shows that these antioxidant nutrients
have been doing their job in our blood all along.
Beta carotene, lycopene and other fat-soluble
antioxidants hang out in the lipid portion of human plasma. But popular assays
measure antioxidant capacity of the water portion only, where vitamin C and
other water-soluble antioxidants settle. Oxidation events generally begin
there, but the chain reactions they set off readily cross over into the lipid
portion of plasma and vice versa.
The new assay, which measures oxidation in
both environments, gives a truer picture of total antioxidant capacity of
biological samples. It was developed by researchers at an ARS-supported center
in Boston, Mass., and the University of Milan, Italy. Ultimately, the assay
will help health professionals better recommend the antioxidants an individual
needs to boost protection against heart disease, cancer and other age-related
diseases. These are believed to evolve, in large part, from cumulative
oxidative damage to cell components.
Named SOLACfor selective oxidizability
of lipid and aqueous compartmentsthe assay appears in the October issue
of Free Radical Biology & Medicine, 2001 (vol. 31, pp. 1043-1050).
The researchers are gearing up to assay plasma samples from two large-scale
population studies to look for correlations between true antioxidant capacity
and heart disease or eye disease. If they find correlations, results from SOLAC
could serve as a biomarker for risk of these diseases.
For more information, contact
Kyung-Jin Yeum, (617) 556-3128,
Jean Mayer USDA Human Nutrition Research
Center on Aging at Tufts University, Boston, MA
Back to
Contents
A fecal detection system, capable of scanning
an entire beef carcass, can help the meatpacking industry supply safe food
products to U.S. and foreign consumers. ARS and Iowa State University
scientists developed and patented the technology that's exclusively licensed by
eMerge Interactive, Inc., Sebastian, Fla.
Under a cooperative research and development
agreement, optical and electronic engineers at eMerge are using the technology
in prototypes that could prove practical for the beef packing industry. Visual
inspection and carcass cleaning are standard tools for reducing the potential
for carcasses to become contaminated with E. coli and other pathogenic bacteria
carried in feces. But the human eye is not sensitive enough to identify all of
the fecal contamination that can occur on carcasses.
In a recent trial of an eMerge prototype,
the new detection system revealed trace levels of fecal contamination that were
invisible to the human eye. The prototype was also successful in evaluating
fecal decontamination of carcasses treated with high-temperature steam, a
common practice.
For more information, contact
Thomas A. Casey, (515) 663-7726,
National Animal Disease Center,
Ames, IA
Back to Contents
ARS scientists are snooping into the secret
tricks that food-poisoning organisms use when they grab onto a surface such as
chicken skin. Their studies may lead to new, safe and effective ways to thwart
pathogenic microorganisms such as Campylobacter, which alone causes an
estimated 2 million illnesses, 10,000 hospitalizations and 100 deaths a year in
this country.
Studies of C. jejuni, the most troublesome of
the Campylobacter species, will help scientists determine how the
microbe's genes interact with molecules known as receptors. Proteins called
proteoglycans and fat-containing compounds called phospholipids likely serve as
receptors, according to preliminary experiments.
In a test with 12 Campylobacter
strains, the scientists found that all of the strains bound to proteoglycans
within about two minutes and, in about 20 minutes, formed large colonies. In
another test, the scientists showed that eight of nine Campylobacter
strains, when exposed to a mixture of chicken-skin phospholipids, bound to a
phospholipid known as sphingomyelin.
Other scientists have already speculated that
proteins or fats in meats may act as receptors. The Albany investigations
provide new evidence that proteoglycans and phospholipids probably play that
role in poultry and show the speed with which the microbe can attach to
receptors that it apparently prefers.
For more information, contact
Robert E. Mandrell, (510) 559-5829,
Western Regional Research Center, Albany,
CA
Back to
Contents
|