A C T I V E   P R O J E C T S

Genetic Enhancement of the Antioxidant Content of Soybean Oil for Improved Food Processing, Lubricant, and Nutraceutical Properties
Submitted by Edgar B. Cahoon, Plant Genetics Research Unit, USDA/ARS, Donald Danforth Plant Science Center, St. Louis, MO

Cahoon: ecahoon@danforthcenter.org
Background

The oxidative stability of soybean oil is determined by its fatty acid composition and antioxidant content. Oxidative stability is a critical factor for the use of vegetable oils in food processing and industrial lubricant applications.

The primary antioxidants of soybean oil are tocopherols. Tocopherols, together with tocotrienols, comprise the Vitamin E family of compounds in plants. Both classes of vitamin E are potent antioxidants that scavenge free radicals and protect the unsaturated fatty acids of vegetable oils from oxidative breakdown.

Tocotrienols are also produced commercially as nutraceuticals for their demonstrated health-promoting properties.

Recent research by this Principal Investigator have shown that the committed step in tocotrienol biosynthesis is catalyzed by an enzyme designated homogentisate geranylgeranyl transferase (HGGT), which mediates the condensation of homogentistate with geranylgeranyl diphosphate.

Furthermore, the PI and his team, have demonstrated that transgenic expression of an HGGT from barley confers tocotrienol biosynthetic ability to Arabidopis leaves and results in a four- to six-fold increase in total Vitamin E antioxidants in corn seeds.

Purpose

This project will build upon these results to generate soybean seeds with enhanced Vitamin E antioxidant content. Oils from these seeds will have improved oxidative stability and increased food processing applications and lubricant formulations.

Seeds will also be developed that contain novel Vitamin E compositions for nutraceutical applications.

Impact

In line with the mission of IMBA, the proposed project will increase the profitability of soybean by the genetic enhancement of a high-value seed composition trait.

The major focus of this research will be the development of soybean lines with seed oils that have increased oxidative stability. Oxidative stability is central to the use of soybean oil for food processing. About 96% of the 18.3 billion pounds of soybean oil consumed annually in the United States is used for food applications. This represents an annual market of approximately $3.5 billion dollars.

Half of this consumption is for frying and baking applications. And previous research has demonstrated the value of increased levels of tocopherols and tocotrienols for improving the oxidative stability of vegetable oils under conditions of high temperature.