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What is "altered oil content?"
Which plants have been genetically engineered to have altered oil content?

Vegetable oils have important uses in many aspects of our daily lives. In addition to their direct nutritional benefits in the human diet, plant-based oils are important as food additives (cooking & salad oils, margarine, and in many processed foods) and for industrial applications (in soaps, detergents, cosmetics, paints, and lubricants). Plant oils are usually extracted from the seeds of the plant-- tissues that are very high in oil content. The physical properties of plant oils are determined by the kinds of fatty acids the plant makes. This explains why some plant oils are better for some applications than others-- for example, peanut oil is suitable for cooking, while jojoba is better suited for cosmetics and industrial lubricants. By altering the composition of the fatty acids in a plant via genetic engineering, scientists can tailor a vegetable oil to be more suitable for a specific use.
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High laurate canola
Rapeseed (canola) has been genetically engineered to modify its oil content. Scientists at Calgene (now Monsanto) added a gene encoding a "12:0 thioesterase" (TE) enzyme from the California bay plant (Umbellularia californica) to increase the level of medium length fatty acids-in particular laurate. The bay TE gene is turned on only in the seeds of the plant, the part of the plant from which oil is extracted. Laurate is an important fatty acid in soaps and detergents, and the main source has been from imported coconut and palm oil. High laurate canola provides a new domestic, temperate zone source of the economically important oil. Because the nutritional content of the oil is altered significantly, the FDA requires products from this GE variety to be labeled-- as "high laurate canola"-- although it was developed mainly for industrial and not food uses.

High oleic soybean
This variety of GE soybeans was developed primarily for improved stability of its oils. Soybean oil is high in polyunsaturated fatty acids that make the oil particularly vulnerable to rancidity, making it unsuitable for many food uses. In practice, soybean oil must be partially hydrogenated to increase its stability, but unfortunately this also increases levels of trans-fatty acids, which are associated with atherosclerosis and other nutrition-related chronic diseases.

The soybean gene Fad2-1 encodes a desaturase enzyme that synthesizes some of the polyunsaturated fatty acids responsible for rancidity in soybean seeds. DuPont has utilized a genetic engineering technique called cosuppression to reduce levels of the polyunsaturated fatty acids. When a new copy of the Fad2-1 gene is introduced into the soybean plant, the plant detects an overproduction of the Fad2-1 gene and turns off both copies of the gene-- the original version and the GE copy. The result is that the plant produces less of the unstable polyunsaturated fats and accumulates oleic acid instead (which increases from 20% of oil composition to more than 80%). Like other hydrogenated vegetable oils, the high oleic soybean oil does have lower levels desirable polyunsaturated fatty acids. However, the oil is more stable, does not require chemical hydrogenation, and does not produce the trans-fatty acid byproducts of hydrogenation.

As with high-laurate canola, products based on this soybean variety must be labeled because the nutritional composition has changed.
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