Talk of corn breeding these days seems to be followed closely by the word “biotech,” but plenty of researchers are still employing traditional plant-breeding methods to develop desirable traits in crops. One case in point: New corn lines, developed by three Iowa-based researchers, could lead to a slew of desirable corn-based products, including cooking oils and margarine that keep blood cholesterol levels down and salad dressings that last longer.
Geneticist Linda Pollak and plant biologist Susan Duvick, both with the USDA's Agricultural Research Service at Ames, IA, have worked with Iowa State University food science professor Pamela White to cross traditional Corn Belt in-bred lines with hybrids cultivated during past independent studies that contain genes from eastern gamagrass, Tripsacum dactyloides. These crosses have produced corn with higher oil content and higher percentages of oleic acid — the monounsaturated fatty acid that may be the key to “heart-friendlier” corn products.
Benefits to consumers, growers
High percentages of oleic acid give corn oil a more stable flavor and longer shelf life and also have been linked to lowering human blood cholesterol levels. High levels of cholesterol in the blood can lead to coronary heart disease, heart attacks and strokes.
These features may be a boon to producers of corn-based cooking oils, who have lost customers to high-oleic alternatives such as olive oil and canola oil. And that could mean potential premiums for growers.
“In typical hybrids, about 20% of the oil is oleic,” Pollak explains. “These new lines contain up to 70% oleic acid. That compares favorably with olive oil, which has about 80%.”
A high-oleic oil contains a lower percentage of the other types of fatty acids, which means they have fewer of the negative effects of either polyunsaturated or saturated fatty acids, while maintaining their many good properties, Pollak says. Scientists think this type of oil also may reduce plasma levels of low-density lipoproteins — or bad cholesterol — without reducing the high-density lipoproteins — or good cholesterol.
Other new lines with higher levels of saturated fatty acid oil provide a good starting material for making margarine, according to the researchers. When the oil from these new hybrids is used to replace currently used corn oils, less processing is needed to create the familiar yellow sticks. The margarine is also healthier.
Oleic acid's stability, which makes for longer storage and refrigerator shelf life, may also prove attractive to makers of salad dressing. Many salad dressings today use very polyunsaturated soybean or canola oils, which don't have high stability and can become rancid fairly quickly.
What remains to be determined, Pollak says, is the optimum level of oleic acid for corn. “We obviously want to achieve as high a level as possible, but we don't want to alter the good flavor or frying qualities of corn oil,” she says.
She adds that, because these lines were developed through traditional plant breeding, they have potential applications in food markets that are resistant to biotechnology. “The market for non-GMO food looks to be growing,” Pollak says.
The researchers are talking with potential industry partners and say that, with proper funding, their work could lead to marketable hybrids in as few as four years. “Because they are traditionally bred, they don't require the lengthy federal approval time that biotech crops do,” Pollak explains.
Some Tripsacum lines have high protein and oil contents that could provide cost-effective alternatives to soybean meal in animal feeds. Pollak states, “They would be an ideal fit for producers who could feed it to their own livestock.”