Among the oil applications hardest hit by the war on trans fats, frying comes pretty close to the top of the list. In eliminating partial hydrogenation from their frying oils, snack food manufacturers and food service operators now had to contend with unstable oils that had to be changed out more frequently than their previous oils.

"The standard oils, canola oil and soybean oil, can be used, but they degrade very rapidly," said Gerald McNeill, vice-president, R&D, Loders Croklaan, Channahon, IL. "They have a significant amount of polyunsaturates, and that gives you this polymerized sludge at the bottom of the fryer, off flavors, dark color."

Expected to be available in the marketplace within the next few years, high-oleic soybean oils such as Plenish from Pioneer Hi-Bred, a DuPont business, Wilmington, DE, could be an answer. The stability of the oil enables it to have two to three times the fry life as that of conventional soybean oil.

"When you've got an oil like Plenish, it does not develop that polymeric material to any great extent," said Susan Knowlton, senior research manager, Pioneer. "It offers food manufacturers less maintenance of all of their equipment because of that problem that's essentially being eradicated."

The image above shows a side-by-side comparison of frying with commodity soy at left and Plenish at right. Both photographs were taken after 13 days of frying at 176 degrees for 8 hours a day.

In initial testing in food service operations, Plenish proved to be a basic switch from conventional oils. Its basis in soybeans also gives it an advantage over other oils because most American consumers grew up on the taste of soy, according to Ms. Knowlton, so they prefer it to other oils.

"It's not just the flavor — flavor is obviously a huge component of it — but the base cost of soy oil versus some of the other crop oils is lower, so for a food manufacturer, they can anticipate more competitive pricing for a specialty oil like this," Ms. Knowlton said.