| July 2007 |
Fruits' Antioxidant Strength Revisited
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New details about the antioxidant power of more than a half-dozen fruits have emerged from studies led by an antioxidants expert based at the ARS Arkansas Children's Nutrition Center, Little Rock, Ark. (Journal of the American College of Nutrition, volume 26, pages 170 to 181).
Antioxidants—color-imparting compounds in fruits and veggies—are thought to stall aging, ward off disease and reduce the harmful effects of molecules known as oxygen free radicals.
Researchers measured blood (plasma) antioxidant capacity, or AOC, of volunteers shortly after these healthy women, age 18 to 70, had eaten blueberries, cherries or dried plums, or had downed 10.6 ounces of dried-plum juice. Analysis of the samples confirmed that antioxidants in some foods apparently are easier to absorb and use than others. Dried plums, for instance, did not raise volunteers' plasma AOC levels, perhaps because one of plums' most plentiful antioxidants—chlorogenic acid—isn't readily absorbed, or is readily degraded, by our bodies.
Though grapes and kiwi both led to noticeable spikes in plasma AOC, scientists haven't yet pinpointed which antioxidants were responsible for the increases.
Further research may help establish national guidelines that indicate the kinds and amounts of antioxidants we need for optimal health.
For details contact Ronald L. Prior, (501) 364-2747; USDA-ARS Arkansas Children's Nutrition Center, Little Rock, Ark.
What's in Foods Marketed to Kids?
When buying foods for kids, it's reasonable to reach for those that feature extra nutrition information on the front of the package. But foods in packaging that highlights, for example, "good source of nutrient x, y or z" may also be high in saturated fat, sodium or added sugar.
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That was the case with more than half of the kids' foods that ARS researchers based at the agency's Grand Forks (N.D.) Human Nutrition Research Center noted when checking the shelves in six major supermarkets in the area. In all, the researchers examined the packaging of nearly 57,000 food items.
Some 60 percent of the 9,105 kid-oriented foods that were packaged with nutrition information—not just the nutrient-content label—were also high in one or more ingredients that can contribute to health problems such as childhood obesity.
Those ingredients included saturated fat, sodium or added sugar. Levels were compared to those recommended in the 2005 Dietary Guidelines for Americans.
Wise shopping decisions might help combat childhood obesity. Almost nine million American children age six years or older are obese.
For details contact Gerald F. Combs, Jr., (701) 795-8456; USDA-ARS Grand Forks Human Nutrition Research Center, Grand Forks, N.D.
Low-Fat Dairy Foods Help Some Battle Belly Fat
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Eating calcium-rich foods, including low-fat dairy products, may have helped some young white males in the Bogalusa (La.) Heart Study to form less abdominal fat than their study counterparts.
ARS-funded scientists at the Children's Nutrition Research Center, Houston, Texas, and co-researchers from Tulane University, New Orleans, La., analyzed foods and beverages consumed by—and various body-fat measurements of—1,306 young adult male and female blacks and whites age 19 to 38.
The intent? To determine if there was an association between calcium, dairy foods, overweight and obesity.
Results showed that, for young white males only, eating higher amounts of calcium-rich foods—including low-fat dairy foods—was inversely associated with waist-to-hip ratio, a measure of abdominal adiposity (Journal of the American College of Nutrition, volume 25, pages 523 to 532).
Additional research may reveal why weight-control benefits, attributed to calcium and low-fat dairy foods in other studies, didn't occur in more of the Bogalusa volunteers. That information could help the nearly two-thirds of American adults who are considered overweight or obese.
For details contact Theresa A. Nicklas, (713) 798-7087; USDA-ARS Children's Nutrition Research Center, Houston, Texas.
Want Citrulline? Try Watermelon!
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Here's another reason to enjoy watermelon before summer ends: This delicious fruit is unusually high in an amino acid known as citrulline. Our bodies use citrulline to make yet another amino acid, arginine, which helps cells divide, wounds heal, and ammonia to be removed from the body.
Watermelon's citrulline seems readily available for the body to take up and use. That's suggested in studies by scientists currently or formerly at the ARS South Central Agricultural Research Laboratory, Lane, Okla.
They did the work with co-investigators from the ARS Henry A. Wallace Beltsville (Md.) Human Nutrition Research Center; the ARS Citrus and Subtropical Products Research Laboratory, Winter Haven, Fla.; and several universities, documenting their work in the journal Nutrition (volume 23, pages 261 to 266).
Volunteers in the study completed one three-week stint during which they drank about three eight-ounce glasses of watermelon juice every day, and one three-week period of drinking about twice that much of the juice daily.
For comparison, other volunteers neither drank the juice nor ate watermelon or certain other foods that would skew study results.
Blood levels of arginine, synthesized in the body from the citrulline provided by the watermelon juice, were 11 percent higher in volunteers tested after three weeks on the three-glasses-a-day regimen (24 ounces), and 18 percent higher following the six-daily-glasses regimen (48 ounces), when compared to levels in samples from volunteers who didn't drink the melon juice.
Now, the scientists want to determine the best way to extract citrulline from watermelon. Preliminary results of medical research—done elsewhere—suggest that arginine might help treat high blood pressure, unhealthy blood sugar levels and vascular disorders associated with sickle-cell disease.
For details contact Penelope M. Perkins-Veazie, (580) 889-7395, ext. 267; USDA-ARS South Central Agricultural Research Laboratory, Lane, Okla.
Top-notch Iceberg Lettuces Foil Microbial Foes
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Fresh, crunchy iceberg lettuces that boast new resistance to some of their worst disease enemies may show up in supermarket produce sections of the future.
Lettuce breeders at ARS' Crop Improvement and Protection Research Unit, Salinas, Calif., lead the research, often collaborating with university specialists.
More than a half-dozen vegetable seed companies have requested seed of parent iceberg lettuce plants that the scientists developed as the first-ever to resist attack by the microbe that causes verticillium wilt. A lettuce lacking this resistance may collapse, like a deflated playground ball, before it has a chance to form the familiar firm, nicely rounded head (Plant Disease, volume 91, pages 439 to 445).
Lettuce is one of America's top-five most popular vegetables. Iceberg lettuce outsells all other kinds of this versatile leafy green.
The new parent plants join a long list of other superb iceberg lettuces developed at the Salinas laboratory. That list includes plants with resistance to the microbes that cause diseases named for the symptoms they trigger, including lettuce mosaic, big vein and corky root (HortScience, volume 42, pages 701 to 703).
For details contact Ryan J. Hayes or Beiquan Mou, (831) 755-2800; USDA-ARS Crop Improvement and Protection Research Unit, Salinas, Calif.
New Bean Blunts Bacterial Blight
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Great northern beans—plump, nutritious and faster to cook than many other bean types—make a hearty baked-bean entree as well as tasty chili, soups, salads and more. Now, a new great northern bean named ABC-Weihing offers growers a special advantage: It resists the microbe that causes common bacterial blight.
ABC-Weihing is among the first great northern beans with that prized trait, according to the scientists who developed this legume. They are based at ARS' Vegetable and Forage Crops Production Research Unit, Prosser, Wash., the ARS Henry A. Wallace Beltsville (Md.) Agricultural Research Center, Beltsville, and at the University of Nebraska.
Severe outbreaks of common bacterial blight can cause yield losses of up to 40 percent.
Great northern beans are high in fiber and protein, and are an important source of antioxidants and minerals, plus folate and other B vitamins.
To accelerate the breeding of ABC-Weihing, the researchers used marker-assisted selection, a technique that detects key genes faster than most conventional plant-breeding tactics. An article in a forthcoming issue of Crop Science tells more.
ARS scientists and university colleagues have already boosted common bacterial blight resistance in several other popular kinds of beans, including pinto and both white and dark-red kidney beans.
For details contact Phillip N. Miklas (509) 786-9258; USDA-ARS Vegetable and Forage Crops Production Research Unit, Prosser, Wash.
Bread—and Bioenergy, Too? Yes!
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Breads, pastas, cookies and other foods might tomorrow be made with a perhaps-surprising ingredient—flour milled from distillers' dried grains, or DDGs. Right now, DDGs—left over after ethanol is distilled from corn—are accumulating in unprecedented amounts, a result of the surge in U.S. ethanol production.
ARS scientists with the North Central Agricultural Research Laboratory, Brookings, S.D., and co-researchers are taking a new look at the old idea of using DDGs flour in place of some or all of the wheat flour in familiar recipes. An array of foods low in calories and carbs—but high in protein and fiber—could result.
However, scientists must first discover a way to prevent or remove the odors and off-flavors that develop in DDGs during conventional ethanol production (Cereal Foods World, volume 51, pages 52 to 60).
Today's DDGs are used primarily as livestock feed ingredients.
For details contact Kurt A. Rosentrater, (605) 693-5248; USDA-ARS North Central Agricultural Research Laboratory, Brookings, S.D.
Freezer-Friendly Wraps—From Fish—Fight Sogginess
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Clear, shiny, invisible coatings that you can eat might provide a new way to make sure unwanted water vapor or oxygen can't ruin the taste or texture of your favorite frozen foods.
Perhaps surprisingly, these wraps, which look something like conventional plastic wraps for kitchen use, might be derived from gelatin extracted from the silvery skins of seagoing fish such as Alaskan pollock (Journal of Food Science, volume 71, pages E202 to E207).
In Alaska, skins left over after pollock and other fish are processed into fillets are typically ground up and dumped into the sea or processed into low-value fishmeal. Fish gelatin coatings may provide a profitable and environmentally friendly alternative to dumping
The thin, pliable coatings that ARS food technologists at the Western Regional Research Center, Albany, Calif., and Subarctic Agricultural Research Unit, Fairbanks, Alaska, and their university colleagues have developed and tested have no seafood taste or odor, despite their marine origin.
Films made from fish gelatins aren't new. But the ARS studies apparently are the first to establish the effectiveness of Alaskan pollock gelatin as a barrier to unwanted moisture and oxygen. In fact, the fish gelatin proved a more effective barrier than films made from the traditional sources—cow and pig hides.
Another plus: The fish gelatin would be acceptable in kosher and halal cuisines, while today's cow and pig gelatins are not.
For details contact Peter J. Bechtel, (907) 474-2708; USDA-ARS Subarctic Agricultural Research Unit, Fairbanks, Alaska.
Best Ways To Clean Your Kitchen Sponge
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Heating your used kitchen sponges in your microwave for one minute, or washing them in your dishwasher and leaving them there through a drying cycle, are the most effective household ways to inactivate harmful bacteria, yeasts and molds.
ARS food safety experts who specialize in research on foodborne pathogens, like E. coli O157:H7, looked at several simple, convenient and often-recommended ways of cleaning reusable kitchen sponges. Techniques included soaking sponges for three minutes in a 10-percent chlorine bleach solution, soaking in lemon juice or sterile water for one minute, heating in a microwave at full power for one minute, or washing in a dishwasher—including through a drying cycle.
At the outset of the experiment, they soaked all the sponges for 48 hours at room temperature in a slurry of ground beef and laboratory compounds which allow bacteria, yeasts and molds naturally present in the beef to grow on the sponges.
Microwaving and dishwashing each killed nearly 100 percent of the bacteria, with dishwashing being only slightly (0.0001 percent) less effective.
And, microwaving and dishwashing each killed nearly all yeasts and molds; less than 1 percent (only 0.00001 percent) survived.
For details contact Manan Sharma or Cheryl L. Mudd, (301) 504-8400; USDA-ARS Henry A. Wallace Beltsville Agricultural Research Center, Beltsville, Md.
Peppers! Fun, Factual Exhibit in D.C.
Love peppers?
There's still time to visit "A Pepper for Every Pot," a special exhibit about the beauty, flavors and nutrients in these fascinating plants.
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Allow at least a half-hour to view the displays at the U.S. Botanic Garden's Conservatory, 100 Maryland Ave., S.W., in Washington, D.C., now through November 12, 2007.
ARS is cosponsor of the exhibit, with agency scientists from the Henry A. Wallace Beltsville (Md.) Agricultural Research Center contributing pepper plants that they have developed. Superior peppers from their research include Tangerine Dream, a sweet, edible ornamental pepper that produces small, orange fruit on a flat, low-growing plant (HortScience, volume 39, pages 448 to 449) and All-America Selection award winner Black Pearl, which forms black leaves and small, hot, shiny black fruit that ripen to a bright scarlet (HortScience, volume 40, pages 1571 to 1573).
For details contact John R. Stommel (301) 504-5583 or Robert J. Griesbach (301) 504-6574; USDA-ARS Henry A. Wallace Beltsville Agricultural Research Center, Beltsville, Md.
