More Protein in Snacks
Snack foods are a major dietary component for many U.S. consumers.
Often these crunchy favorites are made from high-starch products such
as corn flour. On average, these between-meal items consist of 3 to
5 percent protein, with the rest mostly carbohydrates, fats, and sweeteners.
Now a way has been found to increase the protein in foods such as breakfast
cereals, corn puffs, cheese curls, and energy bars by up to 35 percent
by adding whey proteins left over from cheesemaking. It wasn't easy
for food technologists to figure out how to add more whey without reducing
the crunchiness of the end product. But through trial and error, they
found the right temperature and moisture at which to blend corn flour
with whey protein isolate so that it would run through a twin-screw
extruder and achieve the desired shape and consistency. This technology
is available for licensing.
Charles I. Onwulata,
USDA-ARS Dairy Processing and
Products Research Unit, Wyndmoor, Pennsylvania; phone (215) 233-6497.
Bacterium Kills Costly Pests
The annual predations of just five plant pests cost U.S. farmers nearly
$3 billion annually in crop losses and control expenses. These "bad
guys" are the Colorado potato beetle, corn rootworm, diamondback
moth, green stinkbug, and silverleaf whitefly. Now, lab tests have shown
that a bacterium called Chromobacterium suttsuga produces multiple
toxins that kill the pests. It can be combined with other compounds
and then applied to soil, plants, or seeds.
Since insect pests often develop resistance to synthetic insecticides,
biological-control alternatives such as this can be an important cmponent
of integrated pest-management programs.
Phyllis A. Martin,
Biocontrol Laboratory, Beltsville, Maryland; phone (301) 504-6331.
Jeffrey R. Aldrich,
USDA-ARS Chemicals Affecting
Insect Behavior Laboratory, Beltsville, Maryland; phone (301) 504-8531.
NitratesA Long Time Draining
A chance finding has shown that unused nitrate applied as fertilizer
during crop production can take a long time to percolate through the
soil to groundwater. This was confirmed during preparations for a new
study on the movement of nitrate through soil. It apparently took nearly
30 years for nitrate applied during an experiment conducted from 1969
to 1974 to move through subsurface soils and reach a water table 60
feet below the soil surface.
In that earlier study, done on a 74-acre research site in western Iowa,
researchers applied fertilizer to soil at 3 times the normal rate and
then tracked its concentration and movement through soil for the next
10 years. Then, in 1996, scientists were preparing to monitor groundwater
for a new experiment when they detected the nitrate 60 feet deep in
the soil. To confirm that it was residue from the nitrate applied in
1969, they examined groundwater flow rates and ages and compared the
depth of the concentration with streamflow records. This finding shows
that it may take several decades to fully know the effects of farm practicesor
improvements made to them.
Mark David Tomer and
Michael R. Burkart, USDA-ARS National
Soil Tilth Laboratory, Ames, Iowa; phone (515) 294-0213 [Tomer],
(515) 294-5809 [Burkart].
Modified Grain Sorter Spots Mycotoxins
Many outside plants can be infested with fungi that produce potentially
harmful compounds called mycotoxins. In favorable conditions, these
fungi can infect crops such as corn, cottonseed, wheat, or peanuts,
producing toxins that can cause serious illness in livestock and may
be carcinogenic to humans. But detecting the fungi on large-volume crops
like grainand removing themis a big challenge
to commodity handlers.
Now an engineer has used near-infrared spectroscopy to transform a
standard grain sorter into a fast, effective tool for detecting two
important mycotoxins that occur in corn: aflatoxin, produced by some
strains of Aspergillus flavus, and fumonisin, produced by Fusarium
fungi. He added a pair of filters that correspond to two bands of infrared
light needed to detect aflatoxin and fumonisin.
One pass through this modified sorter detected and removed 80 percent
or more of corn infected with the two mycotoxins. And the sorter mistakenly
rejected only 5 percent of uncontaminated corn instead of upwards of
Tom C. Pearson,
USDA-ARS Grain Marketing and Production
Research Center, Manhattan, Kansas; phone (785) 776-2729.
Donald T. Wicklow,
Research Unit, Peoria, Illinois; phone (309) 681-6243.
"Science Update" was published in the June
2004 issue of Agricultural Research magazine.