High Oleic Soybean

• Conventional soy oil requires hydrogenation to increase its stability for many food uses. This results in formation of trans-fatty acids, which have known coronary health risks.
• By modifying the fatty acid profiles of oilseeds through breeding, researchers have developed healthier oils. Their goal is to replace hydrogenated oils with oils that remain stable but do not include trans-fats.
• Pioneer researchers developed a high oleic soybean oil trait using biotechnology tools. The resulting soybean oil has one of the highest oleic contents among oilseed crops, and lower total saturated fats than conventional soybeans.
• Application testing has shown that high oleic soybean oil can replace regular canola, soy, and partially hydrogenated canola and soy oils in edible applications where increased stability is required. The oil also has industrial uses.
• This new oil trait is on track for 2009 commercialization in the U.S., pending regulatory approvals. It has also been submitted to key importing countries, including the EU.
• The oil will be marketed as TREUS™ brand High Oleic Soybean Oil through the Bunge DuPont Biotech Alliance. Pioneer is advancing varieties with this trait for 2009 com-mercial introduction, pending regulatory approvals.

Soybean oil is the most abundant vegetable oil in the world. In the U.S., more soybean oil is used than all other sources of vegetable oil combined, comprising about two-thirds of the edible oil usage (Figure 1). Common soybean varieties produce an oil high in polyunsaturated fatty acids. Although this property has known health benefits, it makes the oil unstable, easily oxidized and subject to becoming rancid. When heated, soybean oil develops objectionable flavors and odors, making it unsuitable for many applications.

The traditional solution to soybean oil instability has been to partially hydrogenate the oil. Hydrogenation is the addition of hydrogen atoms across the double bonds in unsaturated fatty acids. However, this chemical process adds to the cost of the oil and also introduces side reactions including conversion of double bonds from the cis to the trans molecular configuration, resulting in trans-fatty acids.

Because trans-fats have been associated with coronary health risks, the U.S. Food and Drug Administration (FDA) has mandated the labeling of foods containing these fats. As a consequence, food manufacturers are now trying to eliminate trans-fats from their ingredient lists. This is a tall order, given that the food industry had been using over 7.5 billion pounds of partially hydrogenated soybean oil per year, all of which contained trans-fats.

Figure 1. Total U.S. vegetable oil and animal fat consumption (33.0 billion lbs/year) by source (Bureau of Census, USDA-ERS).

One solution to meeting food processor and industrial needs for more stable vegetable oils has been to change the oil composition of crop plants through breeding. Researchers have worked successfully to increase the proportion of oleic acid vs. linoleic and linolenic acids in several oilseeds. This results in an overall reduction of double bonds in the oil, which mimics the process of hydrogenation and results in higher oxidative stability similar to partially hydrogenated oils. A list of the major vegetable oils currently or soon-to-be available to food processors and other manufacturers is shown in Table 1.

Table 1. Oil profiles of vegetable oils.

High oleic soybean at about 80% oleic acid has one of the highest oleic contents among the oilseed crops. To develop this product, scientists "silenced" a gene in the endogenous fatty acid pathway of soybean seeds using biotechnology tools. Suppression of this gene prevents the addition of a second double bond to oleic acid to form linoleic acid. The end result is greatly increased levels of oleic acid, and decreased levels of linoleic and linolenic acid in the seeds. High oleic soybean also has a lower saturated fatty acid content than commodity soybean oil, making it attractive from a nutritional standpoint.

High oleic soybean variety plot. Extensive studies found that high oleic varieties yield similarly to conventional varieties.

Because high oleic soybean was developed using biotech-nology tools, it is subject to a registration process by the FDA and USDA. In addition, it is being submitted for registration in the key soybean-importing countries. Rigorous testing of the product was required during the registration process to document efficacy and safety.

In this testing, high oleic soybean was found to be no different than conventional soybean for

• Nutrient content (other than oil profile), including proteins and isoflavones
• Allergenicity
• Yield
• Agronomic and other relevant characteristics

High oleic soybean variety plot. Extensive studies found that high oleic varieties yield similarly to conventional varieties.

This new oil type developed by Pioneer researchers will be marketed as TREUSTM brand High Oleic Soybean Oil through the Bunge DuPont Biotech Alliance. This alliance also markets another type of oil - TREUS Low Linolenic Soybean Oil. While many uses will overlap, there are differences in the performance of the two oils for some applications. For example, the high oleic oil performs better for heavy-duty frying (e.g., deep fryers) and has potential for industrial uses

Product application testing is critical to the success of new trans-fat alternative oils. So far, extensive testing conducted at both university and commercial pilot facilities has shown that:

• Low linolenic soy oil, high oleic soy oil and blends are attractive alternatives to partially hydrogenated oils.
  • Test foods included french fries, fried chicken, potato chips, tortilla chips, and salad oil.
• High oleic soy typically equaled or outperformed partially hydrogenated soy in standard oil quality measurements.
  • Polars, polymers, p-anisidine, free fatty acids, and peroxide value were measured.
• High oleic soy generated less objectionable room odor compared to partially hydrogenated oil during frying studies.
  

Product application testing continues to open up new uses for high oleic oils. Research has shown that they can replace regular canola, soy, and partially hydrogenated canola and soy oils in edible applications where increased stability is required. For example, oxidative stability testing of high oleic soybean oil has demonstrated that it is two to three times as stable as regular soybean oil and at least as stable as commonly used partially hydrogenated oils.

High oleic vegetable oil has been used successfully in snack food preparation for frying or spraying to enhance mouth feel and palatability. As a pan release oil, high oleic oil forms a barrier in pans that allows for a clean release of the cooked product without flavor contribution. The increased oxidative stability of high oleic oil results in lower polymerization and less gummy build-up on equipment. Products such as breads, cakes, muffins and pizza can also benefit from this oil.

In addition to food uses, high oleic oils also have industrial applications. The industrial oleochemicals business is investigating the use of high oleic vegetable oils to act as feedstock for the production of numerous products. These products not only have the ecological benefit of being biodegradeable and derived from a renewable resource, but they also lend different and increased functionality.

High oleic vegetable oil is being tested and utilized in the cosmetics business and as a machine lubricant (e.g., high temperature engine, transmission, hydraulic, gear and grease applications). Independent testing has shown that these new oils may actually perform better than petroleum-based products in some uses.

Long-term projections indicate that continued advancement in industrial applications research could result in an even greater volume requirement for high oleic oils in industrial applications than in edible applications.

United States: The high oleic soybean oil trait is on track for 2009 commercial introduction in the U.S., pending regulatory approvals.

Importing Countries: Following U.S. submission (December 2006) and other submissions globally, Pioneer submitted the high oleic soybean oil trait for EU import, food and feed use, and processing approval. This submission was officially received by the European Food Safety Authority (EFSA) in June of 2007.

The Pioneer Product Development Group is rapidly advancing varieties with the high oleic soybean oil trait in anticipation of commercial introduction in 2009, pending regulatory approvals. Several experimental varieties that contain key defensive traits (soybean cyst nematode, Phytophthora, and brown stem rot resistance) in relative maturities ranging from early Group II to mid-Group III were nominated for winter production increase in Chile. Breeding efforts will be expanded at five soybean research centers in 2008 and 2009 and the number of experimental lines in yield trials will triple in 2008, achieving a broader range of maturity groups and more varieties with combined traits.

The authors gratefully acknowledge John Hibbard, Pioneer Business Manager - Biotech Alliance, Johnston, IA and Susan Knowlton, Research Scientist, Wilmington, DE for their contributions to this article.