A new soybean developed at Iowa State is poised to become the star ingredient in healthier snack foods.

The soybean can be used to make solid vegetable oil free of trans fats. Trans fats add shelf life to food, but also increase the amount of the unhealthy LDL cholesterol, which increases the risk of heart disease.

The soybeans are different from other soybeans because they are low in linolenic acid, an unsaturated fatty acid.

Regular liquid soybean oil contains about 7 to 8 percent linolenic acid, an acid that can cause the oil to become rancid. It must be hydrogenated to keep it from going rancid and create a useable solid oil. Hydrogenation creates trans fat.

The new soybean oil doesn’t contain linolenic acid, so it won’t go rancid. It can be made into a useable, trans-fat-free solid without hydrogenation by adding a small amount of saturated fat.

The new soybeans contain only about one percent linolenic acid.

It took 35 years of conventional breeding in the field to develop the low-linolenic trait, said soybean breeder Walter Fehr, distinguished professor of agriculture.

He began working with Earl Hammond, professor emeritus of food science and human nutrition, in the 1960s.

The trait for linolenic acid is controlled by three genes, and Fehr and Hammond found them one at a time, without biotechnology. They grew soybean crops in the field and tested them in the lab.

“Essentially, it was like building a pyramid,” Fehr said.

The first gene they found made the biggest impact, cutting the linolenic acid down to 3.5 percent. It was harder to find the second and third genes, Fehr said.

Iowa State is distributing 210,000 pounds of the oil to food companies for their own evaluation, he said.

Improving soybean oil, rather than switching to a naturally low-linolenic oil such as corn oil, makes sense, he said.

“When you change from one oil to another it can change the flavor of your product,” Fehr said.

In addition, soybeans are inexpensive and contain more oil than corn, said Pam White, interim dean of the College of Family and Consumer Sciences.

White evaluated the soybean oil between the fall of 2000 and the summer of 2002.

The low-linolenic liquid vegetable oil could be used in crackers and some cookie products, she said.

Tests showed the solid fat created by adding a small amount of saturated fat was as good as traditional frying fats, White said.

This solid fat could be used for any fried food products, such as potato chips, corn chips and other snack foods.

Adding a little bit more saturated fat to the low-linolenic oil could make it solid enough to be used as a substitute for partially hydrogenated soybean oil in cookies, microwave popcorn and cake mixes.

In 2006, laws will require nutrition labels to list trans fats.

“Companies will be likely to substitute ingredients,” White said.