Development of Genetically Engineered Soybean Oils for Food Applications

Abstract

The major use of the ten billion pounds or so of soybean oil produced in the US is for food products such as cooking oils, shortenings and margarines.Refined, bleached and deodorized (RBD) soybean oil used for cooking is usually hydrogenated to increase storage life and stability during frying. RBD soybean oil is also extensively hydrogenated to increase melting point for functionality in shortenings and margarines. Hydrogenation results in oils rich in trans fatty acids, the consumption of which may be associated with coronary heart disease. RBD oils used for salad oils are not hydrogenated but are rich in palmitic acid, the consumption of which has also been associated with coronary heart disease. Therefore, it is nutritionally desirable to produce trans-free soybean oils rich in monounraturated fatty acids with reduced palmitic acid for cooking and soybean oils with no saturated fatty acids for salad oils. It is also desirable to produce trans-free oils rich in stearic and oleic acids for shortenings and margarines. Cloned genes may be introduced into soybeans to create transgenic lines with improved oil traits. The design of transgene constructs has been assisted by the use of soybean somatic embryos in suspension culture as a model system for soybean seed transformation. This system has allowed the selection of the right genes and promoters to achieve the desired phenotypes in transgenic soybeans. Current soybeans in development include lines producing oil with reduced palmitic acid, lines with over 80% oleic acid and lines with up to 30% stearic acid. Commercialization of high oleic acid transgenic soybeans has demonstrated that it is possible to drastically alter the fatty acid composition of a soybean seed without affecting the yield or environmental sensitivity of the soybean plant.

Kloning fragmen gen penyandi β-ketoacyl-ACP synthase II dari dua tipe kelapa sawit dengan kandungan asam oleat yang berbeda Cloning of gene fragment encoding β-ketoacyl-ACP synthase II from two types of oil palm with different oleic acid content

“…Kinney (1996) berhasil meningkatkan kandungan asam oleat dalam kedelai hingga 86%, menurunkan kandungan asam linoleat dari 55% menjadi kurang dari 1% dan asam lemak jenuhnya diturunkan menjadi 10%, dengan cara menekan oleoyl-Δ-12 desaturase. Melalui rekayasa genetika kandungan asam oleat pada kelapa sawit dapat ditingkatkan dengan beberapa pendekatan, diantaranya meningkatkan aktivitas enzim β-ketoacyl-ACP synthase II (KASII) dan menekan aktivitas palmitoyl-ACP thioesterase (PAT) (Cheah et al, 1995).…”

Genetic Improvement: Molecular-Based Strategies

“…The second generation fears put into soybean via biotechnology is increased oleic acid content (Kinney, 1996), increased lysine content (Falco et al, 1995) and achieved resistance to pests from Lepidoptera sp. by Bt (Bacillus thurigiensis) technology (Walker et al, 2002).…”

Strategies for Modifying Fatty Acid Composition in Transgenic Plants

“…However, the high level of polyunsaturation in most vegetable oils used for this purpose leads to decreased shelf-life and instability during cooking. Thus these oils are also partially hydrogenated to reduce the polyunsaturation and minimize these difficulties (Kinney, 1996). Oils with increased levels of oleic acid and decreased levels of polyunsaturated fatty acids would have the desired properties of a cooking oil without the added expense and potential health risks of hydrogenation (Kinney, 1996).…”

“…Thus these oils are also partially hydrogenated to reduce the polyunsaturation and minimize these difficulties (Kinney, 1996). Oils with increased levels of oleic acid and decreased levels of polyunsaturated fatty acids would have the desired properties of a cooking oil without the added expense and potential health risks of hydrogenation (Kinney, 1996). Oils with a high oleic acid content would also be valuable to the chemical industry because oleic acid can be readily converted to azelaic acid, a compound used in the manufacture of a number of products (TOpfer et al, 1995).…”