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Cereal Grains Food Science Professor Receives Grant to Bring Corn Co-product to Market

South Dakota State University food science professor Padmanaban Krishnan received a four-year grant geared toward getting corn co-products to the food market. 

by South Dakota State University
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Class watching cookie machinePadu Krishnan and students in his new food product development class test run the new cookie depositing unit to demonstrate how new ingredients perform in mass production. New ingredients like food-grade dried distiller's grain will need to perform well in conventional food processing equipment. Pictured from left to right are Lisa Purcell, nutrition and food science exchange student from the University of Western Sydney; Gatlin Miller, nutrition and food science student from Mitchell; Jigyasha Mishra, graduate research assistant from Nepal; observer and food science professor C.Y. Wang; and food science professor Krishnan.South Dakota State UniversityWith a $576,000 project budget for the Minnesota Corn Growers Association grant, Krishnan will work with the food and ethanol industries with the goal of bringing food-grade dried distiller’s grain (DDG) to the commercial marketplace. 

Both industries will need research data on food ingredient quality standards, commercial processing steps, scale-up production and cost-effectiveness.

Regulatory aspects of such an ingredient will also be pursed. Much of the research will focus on providing answers to research questions posed by the industry.

Krishnan’s work over the past 20 years laid the pathway for the grant when the concept of DDG use in food received national attention in 2012 and 2013. Following that, the Minnesota Corn Growers Association board of directors invited Krishnan to make a presentation at their meeting. They then invited a proposal from Krishnan.

“There is intrinsic nutritional value in something that is 38 percent protein and 40 percent dietary fiber,” said Krishnan. “Everywhere in the world someone needs protein for nutrition and someone needs dietary fiber for health and disease prevention.”

According to Krishnan, other grant outcomes will include gaining new knowledge on developing low-glycemic index ingredients in diabetic diets, isolation and recovery of high-value nutraceutical substances from corn pigments, high protein supplements for international feeding programs and gluten-free products.

Krishnan’s work is not only in adding health value to baked foods, but also in increasing corn’s economic value to farmers and the marketplace.

DDG comes from the ethanol-making process. Currently, one third of the corn bushel, which is 56 pounds, is made into distiller’s grain, one third is made into ethanol, and the other third is released into the air as carbon dioxide. This co-product, CO2, can be trapped and used as a solvent in the processing steps for DDG. Under certain conditions of pressure and temperature, CO2 becomes a powerful solvent. This phenomenon is called supercritical fluid extraction. “Not different than using spritzer or club soda to remove stains from linen,” Krishnan said. 

Jigyasha Mishra holds a bag of semi-processed dried distiller's grain and Padu Krishnan, right, holds a bag of food-grade DDGJigyasha Mishra, graduate food science student, left, holds a bag of semi-processed dried distiller's grain and Padu Krishnan, right, holds a bag of food-grade DDG, ready for food formulation.South Dakota State UniversityKrishnan wants to create a food-grade product for use in baked food items and ready to eat cereals. Krishnan then grinds the DDG into flour and sterilizes it. The DDG is then food-grade and ready for use in the test kitchen. “There isn’t afood item yet on the market containing DDG, but the research is geared toward getting us there,” said Krishnan.

DDG can then be substituted for flour or added into baked goods, tortillas, pizza crust, noodles and more to increase fiber and protein content, while reducing calories. 

“The trick is to add modest amounts in a whole range of foods as opposed to large amounts being added to select foods,” said Krishnan. Flat breads, for example, can easily handle up to 20 percent DDG, while cookies and bread can handle 6 to 10 percent. 

When substituting DDG in baked goods, taste is a crucial, along with shelf-stability and sensory characteristics.

Two DDG vials of unprocessed and processed grainUnprocessed dried distiller's grain is shown on the left, and processed DDG is on the right.South Dakota State UniversityKrishnan has baked many different food items using DDG, and the taste-test results almost always come out favorably. He has faith in the science behind it, and plans to produce a nutritional food product that consumers trust and enjoy.

“DDG is currently priced at $95 per ton. It used to be sold at $269 per pound not too long ago,” Krishnan said. “At the current cost of 5 cents per pound for the raw material, it represents a product that shows immense potential for economic improvement. 

“We are sitting on gold mines. DDG could be used to solve the world’s food problems as well as increase farmer profitability.”