Crops, fatty acid composition

Katengam S, Crane JM, Slabaugh MB, Knapp SJ (200J) Genetic mapping of a macromutation and quantitative trait loci underlying fatty acid composition differences in meadowfoam oil. Crop Sci 41 1927-1930... 

There is much controversy, at least in Europe, concerning genetic modification of plants. The three major crops affected so far are maize, soyabean and rapeseed. All of these, in addition to their other uses, are sources of oil. The reasons for modification in all these cases are related to herbicide tolerance and resistance to insects. For the varieties generally available at present, there is no known difference from non-modified strains with respect to fatty acid composition, oil yield, tocopherol level, or the level of any other minor oil constituent. 

Most commodity oils contain fatty acids with chain lengths between Cie and C22, with Cig fatty acids dominating in most plant oils. Palm kernel and coconut, sources of medium-chain fatty acids, are referred to as lauric oils. Animal fats have a wider range of chain length, and high erucic varieties of rape are rich in this C22 monoene acid. Potential new oil crops with unusual unsaturation or additional functionahty are under development. Compilations of the fatty acid composition of oils and fats (6, 9, 11, 12) and less-common fatty acids (13) are available. 

Finally, genes required for particular aspects of fatty acid and triacylglycerol biosynthesis can be identified in appropriate sources, cloned, and transferred to other plants. Rapeseed has proved to be particularly flexible in this respect, and its fatty acid composition has been modified in several ways, some of which have now reached or are very close to commercial application (Section 9.4). Genetic modification procedures are also applied to soybean and other oilseed crops. 

The fatty acid composition of the new crop has been modified, and the level of linolenic acid has been reduced from over 50% to 2% (6). This greatly improves oxidative stability of the oil, which by fatty acid composition is very close to sunflower and soybean oils (Table 2). Linola has been found to be more resistant to oxidation than regular flax oil, and its stability is comparable with soybean, canola, and sunflower oils (Przybylski, unpublished data). 

Most transgenic oilseeds with altered fatty acid composition remain research subjects, with commercial introduction limited to two crops, neither of which have yet achieved success in the marketplace. The expected benefits from transgenic crops with altered fatty acid composition include improved stability properties enhanced nutritive value expanded use of renewable resources to replace petroleum derived materials replacement of chemical processes, such as epoxidation of fatty acid double bonds and gradual expansion of agriculture as a chemical industry, a concept long ago known as chemurgy. It is possible to predict some issues that... 

Gunstone, F.D. (2001) Oilseed crops with modified fatty acid composition. J. Oleo Set, 50, 269-279. 

Brar, G.S. (1977) Variability in the fatty acid composition of sesame seed (Sesamum indicum, L.) due to the capsule position on the plant and the seed position in the capsule. Crop Improvement, 4, 1-10. 

Lee, J.I. and Kang, C.W. (1980) Breeding of sesame (Sesamum indicum, L.) for oil quality improvement. 1. Study of the evaluation of oil quality and differences in fatty acid composition between cultivars in sesame. J. Korean Soc. Crop Sci., 25, 54—65. 

Fatty Acid Composition of CNfferent Oibeed Crops of Lallenantia H>enca vs. Linseed Oil... 

Fatty Acid Composition of High and Low Erucic Acid Oilseed Brassica Crops and Common Edible Vegetable Oils... 

Murphy (1995, p. 302) notes that over the next decade and beyond, we face the prospect of being able to engineer most major oil crops to produce the fatty acid composition of our choice . So, if monounsaturates in olive oils were the only reason for the health benefits claimed, this selling point might not have much of a future. 

Canvin, D. 1965. The effect of temperature on the oil content and fatty acid composition of the oils of several oil seed crops. Canadian Journal of Experimental Botany 43 63-69. 

Izquierdo, N. and Aguirrezabal, L. A. N. 2008. Genetic variability in the response of fatty acid composition to minimum temperature during grain filling in sunflower. Field Crops Research 106 116-125. 

Izquierdo, N., Aguirrezabal, L., Andrade, F. and Pereyra, V. 2002. Night temperature affects fatty acid composition in sunflower oil depending on the hybrid and the phenological stage. Field Crops Research 77 115-126. 

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