NEWS for North Dakotans
Agriculture Communication, North Dakota State University
7 Morrill Hall, Fargo, ND 58105-5665

January 28, 1999

NDSU Researchers See Food Preservative, Other Products in Potato Peels

Potato processors see red, as in red ink, when they look at all the potato peels that go to waste every day. Profitable commercial solutions for utilizing potato peels remain on the horizon, but a group of food scientists at North Dakota State University believe they're moving in the right direction.

The researchers have begun focusing on a specific extract in potato peels that initial tests show has potential as a food preservative. In addition, they think the extract might work as a browning agent in microwave products.

"Part of our mission is to find value-added uses for things like this," says Mary Hadley, an associate professor of food and nutrition at NDSU.

The researchers isolated the extract by blending the peels with water, putting the slurry into a centrifuge and then freeze-drying the insoluble material. They have added the extract directly to mayonnaise, cookies and pastries to compare for taste against commercially available preservatives.

"What we've found is that nobody can taste the difference," says Hadley.

The researchers initially selected light-colored foods to see if the potato peel extract discolors from heat. The extract belongs to a class of preservatives call phenolics, some of which can turn black under heat, explains Hadley.

Although the potato peel extract did not discolor, Hadley says the extract's color might be something researchers could manipulate, and if so, it could become an ingredient in microwave products where an oven-browned appearance is desirable.

To determine shelf life, researchers have also used chemical analyses to measure peroxide levels. They compared the potato peel extract to the synthetic preservatives BHT (butylated hydroxytoluene) and BHA (butylated hydroxyanisole) and to an oily resin extracted from the rosemary plant. Hadley says the potato peel extract performed equal to BHT and better than either BHA or the rosemary extract.

Now, the researchers are preparing to use sunflower oil preserved with the potato peel extract for making mayonnaise, cookies and pastries. Hadley says they'll extensively test these products this spring for taste and shelf life.

"After we take the extract out of the potato peel, we're left with a lot of material," Hadley adds. So, the researchers will also be looking at ways to utilize the fiber, starch and minerals that remain. At this point, the products they're considering include a filler for animal feed and perhaps a cat litter, derived from drying and extruding the components.

Moving the extract and other products into commercial channels remains the challenge, Hadley says. She plans to consult NDSU researchers from other disciplines after the taste and shelf-life tests conclude.

And there may be yet-another potential use for the potato peel extract. Hadley says researchers at other universities have reported success in controlling blood glucose in type II diabetics with a phenolic preservative similar to the potato peel extract. Based on extremely preliminary results, NDSU researchers think they have generated a similar response after administering the potato peel extract to genetically obese laboratory rats suffering from diabetes.

"It looks promising," Hadley concludes. "It's something that needs to be looked at in much greater depth."

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Source: Mary Hadley (701) 231-7476

Editor: Dean Hulse (701) 231-6136