Fatty acids in seed oil

Hamilton JTG, Harper DB (1997) Fluoro Fatty Acids in Seed Oil of Dichapetalum toxicarium. Phytochemistry 44 1129... 

In this category, fatty acids with a terminal cyclopentenyl ring are best known (Sebedio and Grandgirard, 1989). There are three main types hydnocarpic (ll-cyclopent-2-enyl-undecanoic) acid (structure IVa, Fig. 5.1), chaulmoogric (13-cyclopent-2-enyl-tridecanoic) acid (structure IVb) and gorlic (13-cyclopent-2-enyl-tridec-6-enoic) acid (structure IVc) and its positional isomers (13-cyclopent-2-enyl-tridec-4-enoate and 13-cyclopent-2-enyl-tridec-9-enoate). They usually occur in varying proportions as major components (up to 90% of total fatty acids) in seed oils along with smaller amounts of saturated, oleic and linoleic acids. 

It appears that cyclopropanoid fatty acids occur mainly esterified in position 2 of the various glycerolipids (Christie, 1970 Hofmann, 1963), the position usually occupied by a polyunsaturated acyl moiety. Phospholipids, in which either a cyclopropanoid fatty acid or a polyunsaturated fatty acid is esterified in position 2, exhibit similar physical properties (Christie, 1970 Hofmann, 1963). Although a systematic study of the distribution of the cy-clopropenoid fatty acids in the various positions of glycerolipids is yet to be carried out, it seems that these unusual fatty acids in seed oils are also predominantly esterified in position 2 (Christie, 1970). 

Species with Long-Chain Fatty Acids in Seed Oil... 

The application of 13C NMR for the rapid analysis of the oil composition of oil seeds is well known [16], 13C NMR has recently been applied to the quantitative analysis of the most abundant fatty acids in olive oil [17]. The values obtained by this method differed by only up to 5% compared with GLC analysis. The quantitative analysis was applied to the olefmic region of the high resolution 13C NMR spectrum of virgin olive oil to detect adulteration by other oils which differed significantly in their fatty acid composition. The application of the methodology for the detection of adulteration of olive oil by hazelnut oil is more challenging as both oils have similar chemical profiles and further experiments are in progress. 

Rapeseed methyl ester (RME) is another alternative biofuel that can be used in diesel engines. RME has the advantages that it is renewable compared to diesel, non-toxic and less flammable compared with many other fuels, like ethanol. RME has the same cetane number, viscosity and density as diesel, contains no aromatic compounds and is biologically degradable with minor contamination in soil. RME can be produced from vegetable oils, but is mostly produced from rapeseed oil by pressing of the seeds or by extraction. Up to 3 tons of rapeseed can be produced from one hectare. The fatty acids in rapeseed oil are mostly oleic acid, linoleic acid and linolenic acid. The oil is pressed from the plant and after some purification allowed to react with methanol in the presence of potassium hydroxide as a catalyst, to produce a methyl ester, see Figure 6.6. 

Watermelon seed oil was prepared and evaluated for its physicochemical properties (22, 23). The seed oil consisted of 59.6% linoleic acid (18 2n-6) and 78.4% total unsaturated fatty acids (Table 4). The predominant fatty acid in the oil was linoleic acid, which was followed by oleic, palmitic, and stearic acids. Linolenic, palmitoleic, and myristic acids were minor constituents. The refractive index, acid value, peroxide value, and free fatty acids of watermelon seed oil were determined to be 1.4696 (25°C), 2.82 (mg KOH/g oil), 3.40 (mequiv oxygen/kg oil), and 1.41 (% as oleic acid), respectively. The saponification value of watermelon seed oil was 201 (mg KOH/g oil), and its iodine value was 115 (g iodine/100-g oil), which was significantly higher than pumpkin at 109 (g iodine/lOO-g oil) (22, 23). 

Perhaps because of such exceptional nutrient content, especially vitamin E and omega-3, -6, and -7 fatty acids, seaberry seed oils have been well studied in Finnish, Chinese, and Russian medical research. These studies address a variety of disease models inflammation, skin injuries, vision disorders, cancer, thrombosis, and bacterial and fungal infections. 

Cyclopropane fatty acids occur frequently in bacterial membrane phospholipids. Also, they generally accompany the cyclopropene acids in seed oils (see following paragraph). Though other chain lengths have been reported, the most common cyclopropane acids are Cu and C19 (lactobacillic acid) compounds. They are probably formed from appropriate olefinic acids (16 1 9c and 18 111c) which are widely distributed in bacterial lipids. The cyclopropane acids have cis configuration but it is not clear whether they are individual enantiomers or racemic mixtures. 

However, despite the fact that the catalytic hydrogenation of double or triple bonds is a well-known and widely used reaction, several authors reported that when deuteration of unsaturated fatty acids or seed oils is earried out with deuterium instead of hydrogen, deuterium scrambling along the aliphatic chain and incorporation of a number of deuterium atoms higher than those required by the saturation of the double bonds can sometimes occur. [37] This extensive incorporation of deuterium atoms was explained in terms of... 

Schuch, R., Ahmad, F. and Mukherjee, K. D. (1986) Composition of triacylglycerols containing cyclopropene fatty acids in seed lipids of Munguba Bombax munguba Mart.). J. Am. Oil Chem. Soc., 63 (6), 778-83. 

The oil content of four Egyptian citrus seeds revealed levels ranging from 40.2 to 45.4% for orange, mandarin, lime and grapefruit. Palmitic, oleic and linoleic acids were the major fatty acids in all oils. The lime oil content, however, showed unusually high levels of linolenic acid (42.2%) (Habib etal, 1986). 

This paper will review progress toward the production of (o-3 fatty acid-emiched seed oils for aquaculture feeds, their efficacy as aquafeed ingredients, and the role of processing technologies in maximizing the potential of oilseeds for aquaculture applications. 

In the triglyceride, the carbon chains represented by RS R and R may be identical but usually they are not. Saturated and unsaturated fatty acids are found in the triglycerides. The saturated acids [CH3(CH2)n COOH] all contain an even number of carbon atoms, n usually being between 4 and 24. Palmitic acid (n = 14) is the most common saturated fatty acid of seed oils some others are caproic (n = 4), caprylic (n = 6) capric (n = 8) lauric (n=10) and myristic acid (n=12) all of which occur in the Palmae, and arachidic (n= 18), behenic (n = 20) and lignoceric acid (n = 22), present in some leguminous seeds. The predominant fatty acids are, however, the unsaturated ones and two of these —oleic and linoleic—are estimated to account for over 60% by weight of all the oils in oil-seed crops. With only a few exceptions, the unsaturated... 

Figure 1 Accumulation of oil in developing seeds of Guile at 15°C. A Accumulation of total triglycerides and of the monounsaturated fatty acids 18 1, 20 1 and 22 1. B Proportion of the monounsaturated fatty acids in the oil (mol%).

Whole sunflower seeds contain about 40% oil and 25% protein. Small black sunflower seeds may contain up to 55% oil. In the 1980s sunflower became a major oilseed crop after the introduction of high yielding varieties. Linoleic (66-72%) and oleic acids (16-20%) are the major fatty acids in oil extracted from regular sunflower oil seeds. Saturated fatty acids, mainly palmitic and stearic acids, comprise less than 15% of the total fatty acids in the oil. 

Plant-species characteristic stable carbon isotope ratios in fatty acids of seed oils basis for a new tool in rnminant nntrition research ... 

---