Cracking The Kernel For Higher Value Products

by Susanne Retka Schill (Ethanol Producer Magazine) Researchers hope phytate replicates the corn oil extraction success story, but the history of zein shows it can be a slow and difficult road to success.

Diversification of coproducts is increasingly important to the ethanol industry, as the widespread adoption of corn oil extraction has demonstrated so well. Penetrating markets with a new coproduct is no easy task, though. Zein, for instance, has shown promise for decades, but has gained little traction. Now, a team from the University of Minnesota is working on a new coproduct—phytate. In addition to providing a new coproduct with multiple uses, the remaining distillers grains could be considered enhanced with distinct market advantages.

Plants hold on to phosphorus in their seeds in the form of phytate, explains Doug Tiffany, a University of Minnesota extension economist. “It’s useful. If you think about the grain, it’s the source of phosphorus for germination.” However, it’s not always so useful in feed, he continues. “There’s little problem for cattle to utilize the phosphorus, but the poor digestibility of phytate is an issue with monogastrics. That’s what leads to overfeeding and more of it ends up in manure.” For Southeast poultry producers or North Carolina pork producers, phosphorus leaching out of the soils is a growing environmental issue.

There would be other benefits for low-phosphorus distillers besides reducing an environmental concern, Tiffany says. “Lower phytate levels make other nutrients more available and useful to the animal, such as the protein and the vitamins.” The new DDGS would be attractive in feed rations for monogastrics like poultry and swine, as well as for fish, a new and potentially big market for distillers.

The goal is to design a bolt-on process that will divert a portion of the whole stillage stream for chemical extraction of phytate. In addition to working out the integration with the ethanol process, the pilot facility will aid in predicting costs and efficiencies and provide more material for further testing.

Zein has multiple uses. The protein has been the subject in more than 3,400 patents since 1976 and has the potential to become many things such as biodegradable plastic, food and paper coatings, chewing gum base, biodegradable textile fiber, pharmaceutical encapsulation for time release medicines and much more.

Nearing completion, the 15,000 square foot facility will produce a high-quality, food- and pharmaceutical-grade zein protein. The first-of-its-kind plant will process about 600,000 bushels of corn per year, extracting zein at the front end of the plant after the corn is ground, and recycling the ethanol solvent into the plant while returning the starch component to the ethanol process. In early May, the plant was on track to come online this summer and begin its shakedown and start-up period. READ MORE