(09/28/18) BATON ROUGE, La. — Looking at ways to develop vinegar, liquid sweeteners, alcoholic beverages and other food-grade products is the goal of a $30,000 grant recently awarded to the LSU AgCenter Audubon Sugar Institute from the United Sorghum Checkoff Program.

Gillian Eggleston, director of the Audubon Sugar Institute and principal investigator, as well as Giovanna Aita, associate professor and co-investigator on the grant, will be working with Hekemeyer Biorefinery in Sikeston, Missouri, to help improve the company’s products.

Eggleston said she has been working with the father-and-son owners of the refinery, Anthony and Matthew Heckemeyer, for the past five years.

“The Heckemeyer Mill is the largest commercial-scale sweet sorghum processing plant in the country that became operational in 2016,” she said.

Sweet sorghum has been used for the rich source of soluble sugars found in its stalk, which can be refined into a number of food-grade products.

Eggleston said the goals of the project include the production of food-grade syrup as well as non-food-grade potable alcohols and food-grade vinegars.

Other products to be developed from the sorghum include the non-processed fiber that will be dedicated for large-scale cattle feed.

“Sweet sorghum, originally from Africa, is not a new crop to the U.S.,” she said. “It was first introduced to the U.S. in the 1850s, when its potential as a liquid food sweetener was quickly recognized.”

Using the stalk to make syrup became popular during the Civil War, when it was discovered that it grew well in the North, thereby allowing the North to not be dependent on sugar from sugarcane grown in the South, she said.

“By the 1890s, over 25 million gallons of syrup were being produced in 44 states,” she said. “Sweet sorghum became the dominate table sweetener of early America, ultimately being displaced by refined white sugar around 1900.”

As consumer taste and expectations for sweeteners have changed, the stage has been set for the re-introduction of sweet sorghum syrup as a commercial liquid sweetener produced in large volume, she said.

“Consumers are requesting healthful, minimally processed sweeteners that are not genetically modified, have no or limited environmental impacts and have high nutritional and dietary values,” she said.

The production process has not been without some issues, though.

“One of the major obstacles that the personnel of Heckemyer Mill encountered in developing the large-scale manufacture of sweet sorghum syrup was the high concentration of starch in the sweet sorghum juice,” she said.

At that point, the Heckemyers contacted Eggleston, who was then a research chemist at the Southern Regional Research Center of the U.S. Department of Agriculture Agricultural Research Service in New Orleans.

That strategic partnership allowed the development of two physical separation solutions to solve the starch problem, Eggleston said.

Matthew Heckemeyer said his current goal is making vinegar and whiskey from his 120-acre crop.

“When we started, the goal was to make fuel from the crop,” Heckemeyer said. “But after that proved too expensive, we turned to vinegar and whiskey.”

Heckemeyer currently has more than 33,000 gallons of his product in the fermentation process.

“The syrup is not so much in demand, but the whiskey is,” he said.

Ultimately, the USDA sweet sorghum juice clarification method was successfully used at the mill to reduce the amount of starch in the syrup.

LSU AgCenter researcher Giovanna Aita discusses the sorghum operation with Matthew Heckemeyer, owner of the Hekemeyer Biorefinery in Sikeston, Missouri, during a recent meeting. Heckemeyer is producing vinegar and whiskey from his sorghum crop. Photo by Gillian Eggleston/LSU AgCenter

Gillian Eggleston, director of the LSU AgCenter Audubon Sugar Institute, visits with Matthew Heckemeyer, owner of the Hekemeyer Biorefinery in Sikeston, Missouri, during a recent visit to his operation. Heckemeyer is producing vinegar and whiskey from his sorghum crop. Photo by Giovanna Aita/LSU AgCenter