Processing Hot Peppers Like Cotton:
Ed Eaton, New Mexico State
University (NMSU) engineer
(back) and ARS agricultural
engineer Ed Hughs (front)
examine trash removed from
machine-harvested red chilis
by this experimental chili-
Ed Hughs is determined to save chili peppers and cotton for New Mexico
growers. Hughs is an agricultural engineer with ARS's
Southwestern Cotton Ginning Research Laboratory near Las Cruces. Heavily
grown in southern New Mexico, cotton and chili crops are important to
both the state's economy and psyche.
The chili pepper (also spelled "chile" in many parts of the
country) is the state's cultural icon. Chili peppers are to New Mexico
what wine is to France. But New Mexicans had to think the unthinkable
in the late 1990s as they watched global tradefreed by the North
American Free Trade Agreement (NAFTA)threaten to completely steal
their chili pepper market. That market for red chili, green chili, jalapeño,
and cayenne peppers still generates more than $400 million in economic
activity in the state each year.
New Mexico, eastern Arizona, and far-west Texas produce 90 percent of U.S. chilis and about a third of the country's cotton.
Stephanie Walker, NMSU
extension vegetable specialist,
and Ed Hughs, agricultural
engineer, inspect chilis
cleaned by an experimental
cleaner before sending them
to a processing plant.
Chili Task Force to the Rescue
Rather than complain about NAFTA, New Mexico agriculturalists decided
they would instead seek improved technologymainly automationto
lower costs. Hand labor is limited and expensive and not fast enough
to keep up with food-processing plants at peak times. They formed the
New Mexico Chile Task Force to coordinate efforts of the chili industry
with researchers at New Mexico State University, ARS, and the U.S. Department
of Energy's Sandia National Laboratories.
Hughs serves on the task force, sometimes holding meetings at the ARS
lab. Research and extension specialists, producers, processors, and
plant breeders from the three major chili-growing states also participate.
The members have identified as the highest priority the need for an
in-the-field cleaner to remove "trash"sticks and leavesfrom
It may seem strange for a cotton ginning research facility to be working with chili peppers. But it's not as odd as it seems because chili peppers are one of the main crops rotated with cotton in the area. Both crops also face fierce global competition, and both crops have to be harvested and processed with as little trash mixed in as possible.
At NMSU's Plant Science
Research Center, electronics
technician Fermin Alvarado
(driving) and sheet metal
mechanic James Melendrez
(riding) pilot a thermal
defoliator through cotton
test plots. Agricultural
engineer Paul Funk (on
the ground) observes and
records the machine's
Chili pepper harvesting is at about the same stage that cotton harvesting
was 50 years agomostly hand-picked. That proved too costly for
cotton, and it's proving too costly for chili peppers. Though growers
increasingly use mechanical harvesters, they still don't have any mechanical
cleaners in the fields and have only limited ones in processing plants.
Hughs and colleagues at the ginning laboratory worked with the chili
pepper task force to invent a pepper-cleaning machine. They used their
experience with automated cotton ginning for the initial design. It
consists of a roller table that conveys harvested chilis and trash through
a series of rotating cylinders. Small sticks and leaves fall out in
the first stage, the peppers exit through gaps in a later cylinder stage,
and larger trash is carried away in the last cylinder stage.
"Leaves and stems lower the market quality of peppers if there's more than 5 percent trash," says Hughs. "And trash degrades the color that gives red chili peppers their chief economic value as a source of a safe, natural dye.
Textile technologist Carlos Armijo
monitors the performance of a roller
gin stand operating at four to
six times the standard ginning rate.
|"In the past, hand labor
had the advantage of removing all this trash, giving you pure peppers.
But things have changed, and the pressures of today's fast pace mean that
hand labor is not only time-inefficient and very expensive, it's also
no guarantee of a trash-free harvest. Machines often do a better job today."
The new mechanical cleaner might be used in the field before peppers
are boxed for shipment or at the processing plant, but field cleaning
would eliminate transporting of trash, and applying sticks and leaves
to the soil would return nutrients.
Field cleaning would replace the minimal mechanical cleaning that now occurs before the peppers move onto a grading table where they're sorted by hand, further separating them from any remaining trash. The automated cleaner underwent its second test with the 2004 chili pepper harvest.
Hot Air, Faster Ginning
Another invention at Hughs's lab, a two-row prototype thermal defoliator,
offers hot air as an alternative to chemicals for removing cotton leaves
before harvest. As the device is driven through a field, its propane
heaters blast cotton leaves with heat, killing them. It was successfully
tested in fall 2003, with more extensive testing in 2004.
"This defoliation method may be of particular interest to organic
farmers," Hughs says. "We have to determine its effects on
cotton quality, costs, and labor requirements, but we think it will
be competitive with airplane spraying of a chemical defoliant."
This research has been financially supported by a cooperative agreement
with the Propane Education and Research Council.
Moving indoors to the cotton ginsand to a research project financially
supported by the cotton industry through Cotton Incorporatedscientists
at Hughs's lab have found a way to modify roller gin stands to quadruple
the processing speed for upland cotton. Upland cotton makes up most
of the U.S. cotton harvest each fallabout 18 million bales.
As roller stands separate seeds from fiber, they leave longer fibers
than do the saw-gin stands that trace back to Eli Whitney's first patent
in 1794. And longer fibers bring a higher price. But until the recent
innovations, the slow ginning rate for upland cotton made it economically
infeasible to use anything but saw-gin stands.
Just a few simple changes enabled ARS scientists to speed up the ginning
of upland cotton from one bale to four bales per hour. "Now we
can put more of it through the roller stand ginning stage and get a
higher quality product," he says.
Hughs says that because cotton and chili peppers are so commonly grown
in rotation in his area, devising machinery for processing both crops
is a natural way to make the whole local farming system more efficient
and economically viable and therefore more globally competitive.By
Agricultural Research Service Information Staff.
This research is part of Quality and Utilization of Agricultural
Products, an ARS National Program (#306) described on the World Wide
Web at www.nps.ars.usda.gov.
"Processing Hot Peppers Like Cotton" was published in the February 2005 issue of Agricultural Research magazine.