New Mexico State University engineers are resolving one of the last issues of mechanized chile harvesting – destemming the chile pod.

During traditional hand-harvesting, as the pod is removed from the plant a twist of the wrist leaves the stem’s uneatable pedicle and calyx on the plant. As the traditional labor force decreases, chile farmers are turning to mechanized harvesting. However, the important step of removing the stem is not accomplished by the machinery in the field.

“Automatic harvesting and destemming are critical improvements for the chile industry since workers are very scarce and labor costs are much higher in the U.S. than foreign countries from which more and more chile is coming. If New Mexico wants to keep its chile industry and retain our status of chile capital of the world, our industry must automate. Chile is the heart and soul of New Mexico and NMSU is key to ensuring that we keep our chile,” said Gene Baca, vice president of Bueno Foods in Albuquerque.

“Once chile is harvested automatically, the labor needs will shift to processing plants to remove the stems. This isn’t acceptable since cost will increase for processors,” Baca said. “We would have a difficult time finding workers to do that since, who wants to spend all day taking stems off chile? Plus a mechanized system will be much more cost effective.”

Through the NMSU College of Engineering’s Manufacturing, Technology and Engineering Center (M-TEC) engineers are working with the New Mexico Chile Association, through funding from the New Mexico State Legislature, to develop a machine that will remove the stem. After three prototypes, Ryan Herbon, primary engineer on the project, says they have a process that is 80 percent accurate with green chile and 95 percent with red cayenne peppers.

“We started building this prototype at Christmas. We are gathering data on green chile from tests at Bueno Foods and on red cayenne pepper at the Cervantes Enterprises processing plant in La Mesa. So far this system appears to be simple and a cost efficient way to destem chile,” Herbon said. “We have a two month window to gather data so we can fine-tune the machine to be as efficient as possible without damaging the chile pods.”

The NMSU engineers have developed a system that pulls the stems off of the pods. The process begins with the chiles being spread and aligned on a shaking table and troughs that move the pods perpendicular into the destemming rollers. There, the chile is compressed between rollers that incrementally increase in speed which causes the rollers to pull the stem off of the pod.

“The other system had a lot of promise, but was much more complex and expensive to purchase and operate. This system seems to be highly effective,” Baca said.

The mechanized system will be installed at the processing plants to eliminate the need for additional labor during the harvest season.

“I see the destemming process being placed in our production line between the washing and roasting stage,” said Baca. “This system will not add much time to our present process. It takes about 20 minutes for a chile to be washed, roasted, peeled, inspected, chilled, pack and into the freezer. That’s what keeps the flavor fresh.”

This is just one of many projects NMSU M-TEC engineers are working on. M-TEC supports economic development in New Mexico by providing technical assistance, outreach and training and engineering extension services throughout the state.

email: jmoorman@nmsu.edu