Fatty acid composition rapeseed

Jorgensen H, Jensen S K and Eggum B O (1996), The influence of rapeseed oil on digestibility, energy metabolism and tissue fatty acid composition in pigs , ActaAgric Scand A Anim Sci, 45, 65-75. 

Figure 13.12 Fatty acid composition of rapeseed oil, (a) before and (b) after industrial partial hydrogenation. (Courtesy of A. Stolyhwo, Transfatty acids in the human diet and the human body. Paper presented at the First International Conference on Advanced Analysis - Exploring Biological Systems in Food. Olsztyn, September 6, 2003.)...

Refined and bleached rapeseed oil were obtained from Onbio Co. Ltd. (Pucheon-Si, Korea). Table 1 presents the fatty acid composition and characteristics of rapeseed oil. Reference standards of FAMES such as palmitic, stearic, linolenic, linoleic, and oleic methyl ester of >99% purity were purchased from Sigma (St. Louis, MO). Methanol and catalysts such as KOH, NaOH, and sodium methoxide were analytical-grade chemicals. 

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. 

If that does occur, then the present system of classification of oils may be impossible to police, and a modified system may become necessary. Perhaps the sale and perceived value of oils will necessarily become dependent on the performance, not the source of the oil. With bulk oils such as palm, peanut, sunflower, safflower, sesame, soya, rapeseed, com, fish, and animal fats and oils, the fatty acid composition will obviously be important for health reasons. If the oil is to be used for frying then the frying properties will be important. In the case of palm products the physical properties and minor components such as carotenoids will be defined. Similarly animal fats will be judged mainly on physical behaviour and effect on the product in which they are used. In all cases the oxidative and stability of the oil will have to be defined. Sesame is a very stable oil, and thus its stability, together with its low level of linolenic acid, would be its major attribute, except for toasted sesame, which would probably be classed as a specialist oil. Already most baking fats sold to the public are blends developed to give the best performance, with no mention on the pack as to the source. If a bulk oil of this type had the desired chemical composition, stability and cooking behaviour, then perhaps the source would not be a matter of concern. 

Labeling Rapeseed Oil products that have been fully hydrogenated should be labeled as Fully Hydrogenated Rapeseed Oil. Label to indicate the 1-Monoglyceride Content as well. Identification Fully Hydrogenated Rapeseed Oil exhibits the following composition profile of fatty acids determined as directed under Fatty Acid Composition, Appendix VII. 

Identification Fully Hydrogenated Rapeseed Oil exhibits the following composition profile of fatty acids as determined under Fatty Acid Composition, Appendix VII. 

Seedfats are characterized by low contents of saturated fatty acids. They contain palmitic, oleic, linoleic, and linolenic acids. Sometimes unusual fatty acids may be present, such as erucic acid in rapeseed oil. Recent developments in plant breeding have made it possible to change the fatty acid composition of seed oils dramatically. Rapeseed oil in which the erucic acid has been replaced by oleic acid is known as canola oil. Low linolenic acid soybean oil can be obtained, as... 

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. 

Sosulski et al. (22) and Smiles et al. (27) examined the fatty acid composition of the individual phospholipids in the LEAR variety from winter rapeseed cultivars (Table 5). 

Canola Rapeseed Oils with Modified Fatty Acid Composition Since the introduction of standard canola, there has been considerable plant breeding efforts to produce canola oils with modified fatty acid compositions. These efforts were primarily to improve oxidative stability, or crystallization properties, or even produce lauric acid-containing oils and, more recently, canola oil containing gamma linolenic acid (11). The following is a list of these developments ... 

Oils from genetically modified rapeseed/canola with a wide range of fatty acid compositions contained 478-677 pg/g of total tocopherols, of which >50% was y- and about 30% was a-tocopherol. There was no relationship between the fatty acid and tocopherol compositions (Abidi et al., 1999). Genetically modified canola oils had similar tocopherol compositions with a range of 504-687 pg/g of total tocopherols (Dolde et al., 1999). 

In the following chapters, examples are cited where fatty acid composition has been modified by biological methods—both traditional and modern. Well-known examples include low-erucic acid rapeseed oil (canola oil) and high-oleic sunflower oil, but attempts to develop oils with modified fatty acid are being actively pursued in many counties—in both academic and industrial laboratories—and substantial developments are likely in the next five to ten years. Some of have been described by the author (Gunstone 2001) and others are cited in the following chapters of this book. 

Kallio, H. and Currie, G. (1993) Analysis of lowerucic acid turnip rapeseed oil by negative ion chemical ionization tandem mass spectrometry. A method giving information on the fatty acid composition in positions sn-2 and sn-lB of triglycerols. Lipids, 28, 207-215. 

Figure 4 shows the peaks of the components in the gas chromatogram. The highest peak was the peak of a-eleostearic acid. Although both eleostearic and linolenic acids have three double bonds, the stmcture and the properties of eleostearic acid are different from linolenic acid which was contained in soybean or rapeseed biodiesel (Fig. 5) [13,17], Table 3 shows the fatty acid composition of tung biodiesel. The saturated fatty acid content of tung biodiesel was 14.1% and the unsaturated fatty acid content was 84.6%. The eontent of...

Table 1 Composition of fatty acids in rapeseed oils.

FIGURE 12.6 Fatty acid composition in herring and rapeseed, before and after frying. 

Experimental Oils. DAG was prepared by esterifying glycerol with fatty acids from soy bean oil using 1,3-specific lipase and purified by silicic acid chromatography (12). Of the total fatty acids in DAG oil emulsion used in this study, 90% existed as the 1,3-DAG and 1,2-DAG isomers in a ratio of 7 3, whereas <10% of total fatty acids were TAG. The TAG oil emulsion was prepared by mixing rapeseed and safflower oils to make the fatty acid composition almost the same as that of the DAG oil (Table 1). The combustion energies of DAG and TAG measured using a bomb calorimeter did not differ (9.1 kcal/g). 

Test Articles and Dosing. The DAG oil (Econa Oil, Kao Corporation, Biological Science Laboratories, Tochigi, JAPAN) used in this study was prepared from rapeseed oil in the presence of lipase, and was 90% DAG (w/w). The ratio of 1,2-DAG to 1,3-DAG was 3 7. Triacylglycerol oil was prepared from a mixmre of rapeseed, soybean, and safflower oils. This mixture was used to match the major fatty acid composition of the DAG and TAG oils as closely as possible. The intended use of the DAG oil product is as a component in cooking, as a substitute for other oils. 

In this study, the PS (a mixture by weight of 47% P-sitos-terol, 27% campesterol, and 25% stigmasterol) was used. The PS/DAG oil was prepared by adding 5.0% of PS into the purified DAG, whereas the PS/TAG was prepared by adding 5.0% of PS to an oil mixture (containing rapeseed, soybean, and safflower oils). The fatty acid composition of the TAG was comparable to that of DAG (Table 1). Packets containing a daily dose of PS (500 mg) dissolved inlO g of DAG or TAG were prepared as the PS/DAG mayonnaise and the PS/TAG mayonnaise, respectively. Packets containing 10-g portions of TAG without PS were prepared as the control mayonnaise. The taste and smell of the mayonnaise were not affected by the addition of PS. 

ALA-DAG was prepared from periUa oil in the presence of immobilized Upase as described by Huge-Jensen et al. (17). The fatty acid compositions of the test oils, i.e., ALA-DAG and safflower/rapeseed oil mixture (SR-oU), are shown in Table 4. SR-oil contained mainly oleic acid (29.1%) and Unoleic acid (57.8%) as its fatty acid components. On the other hand, ALA-DAG contained 60.8% a-hnoleic acid. The DAG and TAG content in the ALA-DAG oil were 85.2 and 14.1%, respectively. The ratio of 1,3-DAG and 1,2-DAG was 70 30. 

On a pilot scale, epoxidation of both rapeseed mefliyl esters (RME) and higholeic sunflower methyl esters (HOSME) generally yields 85-90%. Epoxidized RME have oxirane values ranging from 4.5 to 5.2 and iodine values ranging from 5 to 1.7. Epoxidized HOSME have oxirane values ranging from 4.5 to 5 and iodine values ranging from of 1.7 to 0. The fatty acid compositions of expoxidized methyl esters determined by GC are given in Table 5. 

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