Rapeseed oil phospholipids

Cmde oils generally contain phospholipids that are removed during the degum-ming stage of refining as a crude mixture (lecithin). This valuable product is the basis of the phospholipid industry, and phospholipids are used extensively in food products, in animal feeds, and in industrial processes. The major members are phosphatidylcholines, phosphatidylethanolamines, and phosphatidylinositols and are accompanied by smaller proportions of other phospholipids. Soybean oil (3.2%), rapeseed oil (2.5%), and sunflower seed oil (1.5%) contain the proportions of total phospholipids indicated in parentheses and are the main sources of commercial lecithins, especially soya lecithin. Palm oil contains little or no phospholipids (7-9). 

Solvent-extracted rapeseed oil has been found to contain the highest level of phosphorus. For this reason, it is common practice to degum solvent-extracted oil or the mixed crude oil from pressing and subsequent solvent-extraction. As the double-zero rapeseed varieties such as canola became available, the applications of rapeseed lecithin have developed positively. Where at first rapeseed lecithin was applied as an emulsifier and energy component in animal feed, the recent concerns about GMO soybean varieties in some parts of the world have increased the market value of the softseed lecithins for food applications (45). The phospholipid composition is similar to soybean lecithin with variations due to crop and processing conditions. The rapeseed phospholipid compositions in Table 12 have been confirmed by recent data, whereas the soybean lecithin composition in... 

Various comparisons of the conventional refining technique versus the ultrafiltration based method using soybean and rapeseed oils are reported, and the results show that there is no difference in the quality of the oils obtained from these two methods. Table 7 compares composition of crude, degummed, superdegummed, and ultrafiltratred oils. The lowest phospholipid, Ca, Mg, and Fe contents were obtained by the ultrafiltration method. Both UF and superdegummed oils were... 

While dietary saturated FA have only a slight effect on the FA in the samples, trans-FA can have a considerable influence. With a diet containing 5.5 g trans-FA daily in the form of hardened fats, after 16 days the trans-FA increased up to 10% at the expense of some proportion of oleic acid in the neutral lipids. Less trans-FA are transferred into the phospholipid fraction than into the TAG fraction (Kaufmann and Mankel, 1967). From rapeseed oil (which contains erucic acid), the erucic acid is transferred into the egg (Biedermann et al., 1971). In addition to the increase in C,82 acid in egg Upids, the physical characteristics change, thus increasing the tendency toward oxidation. 

Other natural products such as rapeseed oil and sunflower oil, whieh are sometimes used, are generally much lower in phospholipid content than soya bean oil. 

Crude soya bean oil contains 3% phospholipids with about 35% of this in the form of lecithin (phosphatidyl choline) (10.47). Rapeseed oil contains 2% and Sunflower seed oil -1.5% total phospholipids. Palm oil, another large tonnage edible oil, usually contains hardly any. Phospholipids are present in margarine where they contribute to its special properties (see above). The small phospholipid content of cereal starch is responsible for its function as a crumb softener when added to bread (see below). 

The artificial phosphorylation of these and other natural products such as rapeseed oil, olive oil, linseed oil, and so on and its consequent effects on their properties, appears to have received limited attention. No very useful phosphorylated products have gained the limelight, but it is known that phosphorylation of soya protein leads to an increase of emulsifying power [33]. For some purposes, phospholipids are deliberately removed from vegetable oils, however, by degumming processes. This is to prevent sedimentation, off-taste development and other undesirable properties from developing. 

Biodiesel (FAME) is a renewable fuel that is made by transesterification of vegetable oils or animal fat with methanol. Several different types of oils could be used, the most common are soybean oil, rapeseed oil, and palm oil [66]. The most widely used transesterification process for commercial biodiesel is alkali-catalyzed [67]. This process typically uses NaOH or KOH as a catalyst. Although the biodiesel is purified, residual amounts of Na or K can remain in the biodiesel [68]. Current standard is Na H- K < 5 ppm for 100 % biodiesel (BlOO). Biodiesel also contains phosphorus that originates from phospholipids. The current standard is P < 4 ppm for BlOO. 

Sosulski et al. (22) examined the polar lipids (PL), phospholipids, and glycolipids in several rapeseed cultivars, including a low erucic acid winter cultivar grown in Poland and found that phospholipids accounted for the major portion (3.6%) of total polar lipids, whereas glycolipids contributed only 0.9%. A more recent study by Przybylski and Eskin (23) reported changes in phospholipids during canola oil processing, as shown in Table 4. 

Phospholipid contents are very similar (about 1 to 2% dry matter) in microbial, plant, and animal tissues. If the content of neutral lipids is low, phospholipids may account for 20 to 40% of lipid extracts (e.g., in marine invertebrates). In egg yolk, 23% of the total lipids are phospholipids and other polar lipids (Kuksis, 1985). On the contfary, in adipose tissue or in oilseeds, the content of phospholipids is between 1 and 3% of total lipids. In oilseeds rich in oil (such as in rapeseed), it is lower than in oilseed with lower oil content (such as soybeans) when the results are expressed in % oil content, but much the same if the content is expressed in terms of total dry matter of the oilseed. Phospholipids are mainly extracted by nonpolar solvents, together with other lipids, and are obtained in the crude oil. However, in the original material, phospholipids are primarily bound to proteins (e.g., in membranes) or may be bound to other tissue components for example, phospholipids interact with chlorophyll pigments, where they may form complexes between the magnesium ion of the chlorophyll molecule and the phospho group of the phospholipids. 

Crude HEAR and LEAR oils inevitably contain some nonglyceride impurities from the biosynthetically active parts of the seed (Carr, 1978). The polar lipids from a HEAR (cv. Sinus) and a LEAR (cv. Janpol) were recently examined by Sosulski et al. (1981). The results (Tables XVII and XVIII) are even more comparable In polar lipid class composition to soybean "lecithin" (Scholfield, 1981 Pardun, 1982) than previously reported by Zajac and Niewiadomski (1975) for HEAR lipids (Ackman, 1977). European HEAR (cv. Norde) phospholipids and fatty acids have been compared to those of LEAR (cv. Oro) by Alter and Gutfinger (1982). The proportion of neutral lipid is a variable that results from the type of processing and would normally be minimized. It is of interest that an alleged soy lecithin evaluated for mink feed closely resembled in fatty acid composition the HEAR lipids (Table XVIII), with 2.0-5.0% of 22 1 (Lund, 1980). If this was in fact rapeseed lecithin the beneficial results of this diet can be added to other nutritional studies (e.g., McCuaig and Bell, 1980, 1981) on HEAR and LEAR gums. 

Antioxidative compounds from oilseeds such as canola/rapeseed, mustard, flax, borage and evening primrose, soybean, cottonseed, peanut and sesame have been investigated. The antioxidative conq)onents present are diverse and may end up in the extracted oil or in their resultant meal after oil extraction. The antioxidative compounds present include tocopherols, sterols, phospholipids, phenolic acids and phenylpropanoids, flavonoids and isoflavonoids, hydrolyzable and condensed tannins, lignans, coumarins, amino acids, peptides and proteins as well as carotenoids (7). 

This processing step is of special importance for rapeseed and soybean oils. Water (2-3%) is added to crude oil, thereby enriching the phospholipids in the oil/water interface. The emulsion thus formed is heated up to 80 °C and then separated or clarified by centrifugation. The crude lecithin (cf. 3.4.1.1) is isolated from... 

We have reported previously that, in developing rapeseed embryos, the oil-bodies appear initially to lack a strongly electron-dense boundary layer (Murphy and Cummins, 1988). These immature oil-bodies contain little or no protein, but do contain some phospholipids. Close to the end of embryogenesis the oil-bodies acquire an osmiophilic layer, and simultaneously are found to contain about 10% w/w protein, most of which is made up of a single hydrophobic polypeptide of 19 kDa. 

Some European countries, such as Hungary, Ukraine and France, and Argentina grow and process sunflower seeds for oil production. Rapeseed lecithin is produced in some Canadian and European crushing plants. In principle it is possible to process lecithin with good phospholipid composition from expelled seed oils only, but the availability is small. 

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