Destemmer prototype moves industry forward

Green chile peppers have increasingly gained popularity and are a major contributor to the economy of New Mexico. The New Mexico Chile Association estimates the green chile’s contribution to the state’s economy to be about $325 million. Imports have steadily increased as New Mexico’s acreage decreased, and that shift has been linked directly to labor issues. Both labor costs and labor availability are major issues for growers.

Stephanie Walker discusses green chile traits.

Increased mechanization within the agricultural industry has been a driving force toward regaining domestic production and helping assure its profitability for growers. A systems approach is required to achieve mechanized harvesting and regain an economic advantage for the domestic chile industry. The systems approach has required an integrated approach in breeding research, production practices, and harvest and processing equipment.

Several entities are working on developing a destemmer, and New Mexico State University, a key player in all three facets of mechanization, currently has a model that is expected to be a viable force in this process. A destemmer prototype, developed by NMSU’s Manufacturing and Technology Engineering Center (M-Tec), has been in trials and will be used at several commercial locations for this year’s chile and cayenne harvest.

Ryan Herbon, an engineer with NMSU’s M-Tec, headed a team that has worked on the destemmer project since 2007. After developing several preliminary prototypes, work began in earnest in 2010 on the current model.

Challenges to mechanization

Freshly harvested green chile peppers.

Harvest labor costs for hand-harvested chile account for about 50 percent of production costs in the U.S., but that cost decreases to less than 10 percent with mechanical harvesting, according to the USDA Agricultural Research Service (ARS). While about 85 percent of red chile and paprika is harvested mechanically, green chile harvesting mechanization remains a major challenge. Efficient mechanical harvesters now used in red chile harvesting appear to be acceptable for green chile harvesting. Models are available from a number of manufacturers that include Boese, McClendon, Massey, Pik Rite and Oxbo, which features a header built by Yung-Etgar.

Harvesting without breakage or bruising is essential to retain the market value. Green chiles are marketed as fresh produce, canned or frozen. Chile peppers with damage are unacceptable in all three markets, and peppers containing stems or other foreign matter will either have reduced value or be unacceptable. Mechanical harvesting, variety breeding and destemmer development are the primary challenges to moving the industry forward.

The NMSU M-Tec team that completed the destemmer prototype for commercial use in this year’s harvest

Dr. Paul Funk, USDA ARS agricultural engineer said, “A lack of destemming technology has limited acceptance of harvest mechanization.” Funk is with the USDA Southwestern Cotton Ginning Research Lab at NMSU, and the chile industry mechanization process draws on some of the experiences of the cotton industry’s mechanization in the 1950s and 1960s.

While experienced harvesters can easily destem chile peppers in the harvesting process with a slight twisting motion, the continued concerns of labor costs and, perhaps even more important to the grower, labor availability, have spurred work toward mechanization.

Destemmer model evolves

Green chiles are traditionally destemmed in the field and brought into the processing area, but when a commercial destemmer is available, chiles will be mechanically harvested and arrive with stems. NMSU’s destemmer prototype operates in the following manner. After being loaded onto an 8-foot-wide feed conveyor, chiles drop to a shaker table where they are aligned to move on the 10-lane conveyor. They are moved on the conveyor at a pace of about 250 feet per minute. The next step for the chile peppers is to be moved under a computer imaging system to identify the precise location of the stem on each chile for proper cutting. The NMSU M-Tec team developed the imaging software.

Herbon said, “At first we used an actual knife to make the cut, but now we’re using a water stream at 4,000 PSI that is more efficient.” A General 50 hp plunge pump is used. The stems are dropped, and the chile peppers are moved on to bins for preparation for market.

NMSU’s destemmer prototype was scheduled for use during this year’s green chile harvest at several New Mexico sites, beginning with the green chile harvest in August. The destemmer is scheduled to be used for green chiles at Bueno Foods in Albuquerque and Border Foods in Deming. Cayenne peppers are generally harvested following the green chile harvest, and the destemmer is scheduled for use with cayenne at Cervantes Foods in Vado.

A Oxbo harvester with header by Yung-Etgar performed well in recent trials at NMSU.

“Our next step after use in this year’s harvest will be to find a manufacturer,” Herbon said.

Breeding for mechanization

With efficient mechanical harvesters available, destemmer development and variety breeding for mechanical harvesting have continued to progress. Green chile peppers that will work better with mechanical harvesting are moving a step closer with chile breeding that is continuing at NMSU College of Agriculture, Consumer and Environmental Sciences.

Green chile peppers are currently harvested by hand with destemming done in the field. Both green chile and cayenne peppers have a tender flesh that can easily break in the mechanical harvesting process, and the development of varieties that are more resistant to breakage is an important step in mechanizing the complete harvesting process.

Stephanie Walker discusses the Nu Mex Joe E. Parker variety.

Stephanie Walker, NMSU Extension vegetable specialist, said, “We’re looking at resistance to breaking. We’re always keeping in mind resistance to pests and diseases. We don’t select anything that isn’t resistant to those.” Additionally, retaining taste is essential to the market value of the chiles. Development of varieties with fruit set high on the plant to help facilitate mechanical harvesting is a goal. In addition to concern about breakage, the amount of plant material, referred to as trash, that is in the harvested chile peppers is of importance.

Walker and colleagues have looked at a number of breeding lines including those from Texas A&M University and Curry Seed & Chile Co., Pearce, Ariz. Walker said, “We’ve found two varieties that have performed the best to be Nu Mex Joe E. Parker and Despanado. Both of these varieties had less breakage and less trash. We had good results using the Oxbo harvester with the header by Yung-Etgar in our trials.”

Walker said, “We’re trying to straighten out the curved shape of the chile pepper.” The traditional varieties with the curve sometimes result in excessive loss as the straight cut is made to remove the stem. Varieties that are straighter will allow the cut to be made straight across the chile with less loss of the chile, which lowers the value.

Green chile bloom.

Economic impact important

Although interest in chiles has steadily increased, U.S. acreage of chiles has decreased. This decrease is attributed directly to the cost and availability of field labor for the time-sensitive harvest. According to the USDA’s ARS, imports of chile peppers into the U.S. have increased steadily, with a 72 percent increase since 2000.

About 4,000 people are estimated to be employed directly in the chile industry in New Mexico, and the green chile has been a significant crop and a cultural icon of the region for more than 400 years. Increasing the potential for the crop to be produced on more acreage increases the likelihood of its becoming a stronger contributor to the state and national economy.

Funding for the mechanization project is primarily provided by the New Mexico Chile Association, with a membership that is made up of growers and producers of chile and chile products.

Nancy Riggs is a freelance writer. She resides in Mount Zion, Ill.