Molecular markers facilitate low-linolenic-acid soy oil.

USDA-ARS scientists at the agency's Plant Genetics Research Unit are improving soybean oil's longevity by lowering its linolenic acid content. This, in turn, should improve the oil's marketability.

Most soybeans contain high levels of linolenic acid, which has double chemical bonds that degrade in the presence of air, heat and light. This is a troublesome characteristic for producers and consumers who want durable, shelf-stable food. Soy oil is often partially hydrogenated to reduce its linolenic acid content.

Nine out of 10 consumers are somewhat concerned about the nutritional content of food, according to the United Soybean Board 2004 Consumer Attitudes annual survey. As of Jan. 1, 2006, the FDA is requiring that all food manufacturers include trans fatty acids (trans fats) as a line item on Nutrition Facts panels. Products containing 0.5 grams or more of trans fats are now subject to mandatory labeling.

Hydrogenation increases a product's shelf life and stability, but produces trans fats, which several studies have linked to high cholesterol and heart disease. With growing public awareness and the new law requiring food labels to list trans fats, the food oil industry would welcome an alternative to hydrogenated oils. Could low-linolenic soybeans provide the solution?

With colleagues from ARS and Iowa State University, investigators have developed molecular markers that identify specific mutations in three genes which can be used in plant breeding programs to lower soy oil's linolenic acid content. Oil from the low-linolenic soybeans does not have to be hydrogenated.

The researchers have identified the low-linolenic soybean lines in mutant plants, which they used to identify the mutant genes and develop the molecular markers. Usually, soybean breeders depend on random segregation of the three genes for low-linolenic acid. These new markers will make it possible to better identify soybean genotypes for low-linolenic acid content. Eventually, investigators hope the breeding process will result in stable, nutritious beans for the food oil industry.

The QualiSoy Initiative, under the auspices of the United Soybean Board, is bringing seed companies, processors and food manufacturers together to expand the market for low-linolenic soybean oil. This oil would create a competitive advantage for growers, and allow food manufacturers and vendors to market long-lasting products without compromising their nutritional value.

Further information. Kristin Bilyeu, USDA-ARS Plant Genetics Research Unit, Room 210, Waters Hall, University of Missouri, Columbia, MO 65211; phone: [phone]; fax: [phone]; email: [e-mail].