Perspectives Online

A ‘win-win-win’ combination


From left are Van-Den Truong, Michael Drozd, K.P. Sandeep, Ken Swartzel, Josip Simunovic and Gary Cartwright. Not pictured is Pablo Coronel.
Photo by Dave Caldwell

Roughly a decade of work came to fruition for a six-member College of Agriculture and Life Sciences research team in late March with a ribbon cutting at a sweet potato processing plant in Snow Hill.

The plant, owned by a company appropriately named Yamco, will produce sweet potato puree using continuous-flow microwave heating technology developed in the College’s Department of Food, Bioprocessing and Nutrition Sciences.

The technology was developed by a team consisting of Gary Cartwright, pilot plant coordinator; Dr. K.P. Sandeep, associate professor; Dr. Josip Simunovic, senior researcher; Dr. Ken Swartzel, William Neal Reynolds Professor and director of the Food Systems Leadership Institute; Dr. Van-Den Truong, associate professor and USDA Agricultural Research Service research food technologist; and Dr. Pablo Coronel, at the time a graduate student in the department.

All save Coronel were on hand March 26 for the Yamco ribbon cutting in Snow Hill. Yamco was formed by seven sweet potato growers who together account for roughly half of the sweet potatoes grown in North Carolina, according to a Yamco press release. If a sweet potato grower is big in North Carolina, that probably means he or she is big nationally, for North Carolina produces close to half the nation’s sweet potatoes.

Swartzel said the technology, for which a patent is pending, was developed in collaboration with Industrial Microwave Systems of Morrisville. Dr. Michael Drozd, founder of Industrial Microwave Systems and inventor of cylindrical microwave heating devices, also played a key role in developing the continuous-flow process. The heating devices are used in the continuous-flow process.

Industrial Microwave Systems equipped the Snow Hill plant, while Cartwright and Truong played major roles in advising Yamco as the plant was developed and helped design the processing system. Yamco purchased a license to use the technology for exclusive commercial production of sweet potato puree.

The plant is expected to create 63 jobs.

“Let me tell you, in Greene County, that’s a lot,” said Greene County Commission Chairman Jack Edmondson during the ribbon-cutting ceremony, which was attended by approximately 200 people. North Carolina Agriculture Commissioner Steve Troxler and Dean Johnny Wynne of the College of Agriculture and Life Sciences also attended the ceremony and addressed the crowd.

“It’s really a delightful time for us at the university to see technology developed at the university being utilized and commercialized by a home-grown company,” said Wynne. “This is not a company coming to the area. This is a company developed in this area.”

Swartzel, who was also recognized at the ribbon cutting, called the plant a “win-win-win situation,” pointing out that the technology was developed in North Carolina, the processing plant is in North Carolina, and it is using a product produced in North Carolina.

Swartzel said Department of Food, Bioprocessing and Nutrition Sciences faculty began working on continuous-flow microwave technology in 1998. He explained that the technology differs from other processing technologies in that it heats the material being processed more quickly and more uniformly. He said other technologies tend to overprocess to reach required processing temperatures in the center, or coldest part, of the material being processed. As a result, parts of the material tend to be overcooked.

Using continuous-flow microwave technology to process sweet potato puree produces a product that is shelf-stable without refrigeration, Swartzel added. He said sweet potato puree produced using the technology maintains the same bright orange color it had when it was fresh and retains a fresh sweet potato aroma.

Swartzel said the shelf life of sweet potato puree processed using the technology is at least a year and a half.

Truong added that the puree produced by the Snow Hill plant will be used in numerous foods. It will likely be used as baby food as well as an ingredient in processed foods such as soups, baked goods and ice cream, even beverages. Sweet potatoes are prized for their nutritional content. They have a particularly high beta carotene content and also contain vitamins C, B6, dietary fiber and potassium.

Simunovic pointed out that the continuous microwave processing technology is by no means limited to sweet potatoes.

“A wide variety of fruit and vegetable purees, homogenates and pulps can be sterilized rapidly and stored under ambient temperature conditions,” Simunovic said. “Dairy products, meat pieces in a variety of sauces, cheese dips and sauces, salsas, soups and stews have been tested and demonstrated as excellent candidates for continuous flow microwave sterilization and aseptic packaging.”

Simunovic said team members hope the technology will be used to develop other value-added products that originate in North Carolina.

Swartzel said major food companies are already interested in Yamco. Department of Food, Bioprocessing and Nutrition Sciences faculty also helped Yamco secure what is known as a “no-rejection letter” from the U.S. Food and Drug Administration authorizing use of the technology to process sweet potato puree. Swartzel said the no-rejection letter is the equivalent of FDA approval of the processing technology.

In addition, the Yamco plant will give sweet potato growers a market for what now is largely a waste product. Much of North Carolina’s sweet potato production ends up on grocery store shelves, which means these sweet potatoes must be attractive and relatively uniform in size.

Yet Swartzel said perhaps 35 to 40 percent of the sweet potato crop is not attractive enough for the supermarket. These sweet potatoes are misshapen or odd sizes. Yamco represents a market for these sweet potatoes that would otherwise be considered culls.

So perhaps Swartzel needs to add another “win” to his “win-win-win” designation.

—Dave Caldwell