Linoleic acid and linolenic acids

Laurie, myristic, palmitic, and stearic fatty acids make up most of the saturated fatty acids found in fats. Oleic acid, linoleic acid, and linolenic acid are the most abundant unsaturated fatty acids found in oils. 

The biosynthetic origin of the depolymerization-resistant core of cutin (cutan) remains to be established. The early observation that linoleic acid and linolenic acid were preferentially incorporated into the non-depolymerizable core of cutin in apple skin slices suggested that the ether-linked or C-C-linked core might arise preferentially from the czs-l,4-pentadiene system [31]. The insoluble residue, that contained the label from the incorporated polyunsaturated C18 acids, released the label upon treatment with HI, supporting the notion that some of those aliphatic chains were held together by ether bonds. More recently,... 

Linoleic acid and linolenic acid cannot be made in the body and are thus essential. 

Scheme 7.2 Pathway for the enzymatic degradation of linoleic acid and linolenic acid via the lipoxygenase (LOX) pathway to Ce key aroma compounds in fruits and vegetables responsible for green notes. HPL hydroperoxide lyase, ADH alcohol dehydrogenase...

These results indicate that the Fusarium lipoxygenase differs from the soybean lipoxygenase in various respects soybean lipoxygenase is a nonheme iron-containing dioxygenase and has a molecular weight of 102,000, optimum pH of 6.5 to 7,0 and isoelectric point of pH 5.4. The soybean enzyme is not inhibited by cyanide and catalyzes the peroxidation of linoleic acid and linolenic acid at equal rates74-76,193. ... 

Multivitamin Oral Gel with Linoleic Acid and Linolenic Acid... 

Fig. 9 Commonly found unsaturated fatty acids oleic acid, linoleic acid, and linolenic acid...

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. 

For mminant fat to become directly responsive to dietary unsaturated fats, it is necessary to protect the lipids against saturation by rumen microorganisms. The alteration of the lipid content of mutton by the feeding of such protected oil supplements has been described (14). Also, it has been shown that a diet of extruded soybeans increased the linoleic acid and linolenic acid contents of steer adipose tissue (15). 

Linoleic acid and linolenic acid are essential fatty acids that cannot be made by animals and must be obtained by dietary intake from plant sources. When metabolized in animals, these two acids each give rise to a family of Cig, C20, and C22 n-6 and n-3 polyunsaturated fatty acids thus ... 

The detection of triterpenoid compounds in extracts from Bidens pilosa may rationalize the use of this plant in traditional Egyptian medicine in the treatment of wounds and against bacterial infections of the gastrointestinal tract [211,212]. The chloroform extract gave 3-amyrin. Fig. (29), phytosterin B and P-sitosterol glucoside, while the petroleum ether extract afforded P-am5Tin, Fig. (29), phytosterin B, lupeol. Fig. (30), lupeol acetate, linolic acid and linolenic acid. The antimicrobial test was carried out to indicate an evident activity. 

Saturated and unsaturated aldehydes with chain lengths C5-C11 are some of the most problematic and undesirable substances in indoor rooms. Aliphatic aldehydes are very odour-intensive, and the odour is generally described as unpleasantly rancid or greasy . With sensitive persons or in high concentrations the perception of ahphatic aldehydes can cause nausea. Odour thresholds are, for example, 57 and 13 pg m [77] for hexanal and nonanal, and the odour thresholds of the imsaturated aliphatic aldehydes are even a magnitude smaller. Emission sources in indoor rooms are essentially unsaturated fatty acids such as oleic acid, linoleic acid and linolenic acid as components of... 

Recently, Bouh and Espenson reported that MTO supported on niobia catalyzed tlie epoxidation of various fatty oils using UHP as the terminal oxidant (Scheme 12). Oleic acid, linoleic acid and linolenic acid were all epoxidized in high yields (80-100%) within less than 2 h. Moreover, the catalyst could be recycled and reused without any loss of activity. 

Crawford MA, Gale MM, Woodford MH. Linoleic acid and linolenic acid elongase products in muscle tissue... 

The precursors of both n-6 and n-3 polyunsaturated fatty acids (PUFAs), linoleic acid and (/.-linolenic acid, respectively, are essential for mammals as they are required for normal physiological function and cannot be synthesized de novo (Holman, 1968). They can only be accumulated by placental transfer or by dietary intake. Once accretion of these fatty acids has occurred, metabolic, conservation and recycling pathways sustain them (B azan et al., 1994). Unlike mammals, plants can synthesize these precursor PUFAs (linoleic and a-linolenic acids) so they are found in abundance in the chloroplast membranes of plants, in certain vegetable oils, and in the tissues of plant-eating animals (Nettleton, 1991). The best sources of a-linolenic acid are vegetable oils, such as perilla (Yoshida et al., 1993) rapeseed (canola), linseed, walnut, and soybean (Nettleton, 1991). They are also abundant in shellfish, fish, and fish products and can be found in low amounts in green, leafy vegetables and baked beans (Nettleton, 1991 Sinclair, 1993). 

Linoleic acid is an unsaturated fatty acid that is an essential fatty acid in mammals because they cannot synthesize double bonds in fatty acids beyond position 9. Linoleic acid and linolenic acid are thus essential in mammalian diets, since they have double bonds beyond position 9 (at positions 9,12 and at positions 9,12, and 15 for linoleic and linolenic acid, respectively). 

Mammals cannot synthesize unsaturated fatty acids having double bonds further than 9 carbons from the carboxyl group. Thus, mammals can synthesize oleic acid and palmitoleic acid (double bonds at carbon 9), but not linoleic acid (double bons at carbons 9 and 12) or linolenic acid (double bonds at carbons 9,12, and 15). As a result, fatty acids such as linoleic acid and linolenic acid are called essential fatty acids because they must be present in the diet. Figure 18.33 shows how linoleic acid is converted to arachidonic acid, an important precursor to the prostaglandins and thromboxanes. 

Karahdian et al. (1985a,b) demonstrated the production of l-octen-3-ol, 8-nonen-2-one, 3-octanone, 3-octanol and octanoic acid from linoleic acid and linolenic acid. The use of microbially produced fatty acids for characterization of mold fungi has been suggested (Blomquist et al., 1992). Lipolysis of triglycerides or amino acids may lead to the production of compounds such as 2-methylpropanoic acid, butanoic acid, 2-methylbu-tanoic acid, pentanoic acid, hexanoic acid and octanoic acid (Jolivet and Belin, 1993). The presence of different lipids and lipases in different fungi (Ha and Lindsay, 1993) and under different environmental conditions may explain a great deal of the variation in the volatile compounds produced. 

F F compounds are usually not a significant part of plants. Typically they comprise <1%, sometimes much less than 1%, of the plant s total weight. They form from precursors that may constitute a large proportion of the plant. Maltol, a burnt sugar note, has carbohydrates as its precursor, vanillin has lignin as its precursor, beta-ionone, used in berry flavors, has carotenoids as its precursor, and the green notes, hexanal and (E)-2-hexenal, have the fatty acids, linoleic acid and linolenic acid, respectively, as their precursors. 

Problem 23.9. Why are the polyunsaturated fatty acids linoleic acid and linolenic acid considered essential ... 

According to Sim et al. (1972), there is a marked increase of oleic acid content in the egg yolk after supplements of sunflower oil in the feed. The increase of oleic acid is higher than in other feed mixtures with rape oil, soybean oil, or beef tallow. It is remarkable that with other diets low in linoleic acid, a reduction in linoleic acid content in the egg yolk does not conform to the decrease in linoleic acid in the feed. The living organism can produce linoleic acid from certain precursors (e.g., cis-2-octenoic acid), where the synthesis required for chain augmentation must be repeated five times for the production of a double bond. Although linoleic acid and linolenic acid are precursors for the production of arachidonic acid ( 20 4), docosapentaenoic acid ( 22 5), eicosapentaenoic acid ( 20 5) (EPA), and docosahexaenoic acid ( 22 5) (DHA). According to Reiser (1950), hens can produce eicosatrienoic acid ( 20 3). 

Crawford, M.A., Gale, M.M., and Woodford, M.H., Linoleic acid and linolenic acid elongation products in muscle tissue of Syncerus caffer and other ruminant species, Biochem. J., 115, 25, 1969. 

The human body can synthesize all except two of the fatty acids it needs. These two, linoleic acid and linolenic acid, are polyunsaturated fatty acids that contain 18 carbon atoms (Table 8.1). Because they are not synthesized within the body and must be obtained from the diet, they are called essential fatty acids. Both are widely distributed in plant and fish oils. In the body, both acids are used to produce hormonelike substances that regulate a wide range of functions and characteristics, including blood pressure, blood clotting, blood lipid levels, the immune response, and the inflammation response to injury and infection. 

Linoleic acid and linolenic acid are essential fatty acids because they are needed hy the body but are not synthesized within the body. 

That tocopherols are apparently nature s choice of antioxidant is demonstrated in Fig. 4, which is similar to a correlation observed by Hove and Harris (1951). Here the total tocopherol content of oils from babasu (1), beechnut (2), carrot (3), castor bean (4), cacao (5, 6), coconut (7, 8), corn (9, 10), cottonseed (11-13), hazelnut (I4, 15), linseed (16), oat germ (17), okra seed (18, 19), olive (20-25), palm (26-28), peanut (29-33), pecan (34, 35), poppyseed (36), rapeseed (37), rice bran (38), safflower (39), sesame (40, 4I), soybean (42-44), sunflower (45), and wheat germ (46-50), as reported by Lange (1950), have been plotted against their total linoleic plus linolenic acid content as reported by Hilditch (1956). The linoleic, plus linolenic acid content of oils from the same species varies, sometimes threefold. It is unfortunate that the content of tocopherol, linoleic acid, and linolenic acid have seldom been determined on the same sample. If Fig. 4 could have been prepared from such data, the correlation would probably be even more dramatic. 

Modern biobased lubricants are mainly based on rapeseed oil, sunflower oil, soybean oil, and animal fats. These oils easily undergo oxidation due to their content of polyunsaturated fatty acids such as linoleic acid and linolenic acid. Efforts have been made to modify the oils to provide a more stable material and a product more competitive in performance to mineral oil-based lubricants. This modification can involve partial hydrogenation of oil and a shifting of its fatty acids to high oleic acid content [21]. Other reported changes that address the problem of unsaturation include alkylation, acylation, hydroformylation, hydrogenation, oligomerization (polymerization), and epoxidation [20, 22]. 

Definition Oil derived from rose hips, Rosa canina, main components are linoleic acid and linolenic acid... 

In addition to saturated fatty acids with varying chain length, palmitic acid and its derivatives usually occur in the presence of unsaturated fatty acids and their derivatives, in particular those with 18 carbon atoms (oleic acid, linoleic acid and linolenic acid). Figure 34 compares the phase behaviour of various methyl esters of Cis acids in SC CO2. 

The three main precursors for CLA formation in milk were denominated as oleic acid, linoleic acid and linolenic acid (Collomb et al., 2(X)6). There were strong positive correlations between the intake of these fatty acids and the amount of several CLA isomers in milk fat (Collomb, Sieber, Biitikofer, 2004). In part these relationships have been illuminated (Figure 4.1), but the biochemical explanations for many of them have not been completely revealed yet. The explanation of the mechanism of fish oil is also unclear. The direct formation via precursors is unlikely because these oils contain less linoleic and linolenic acids than plant oils, and long-chain PUFAs are not direct precursors of rumenic or vaccenic acid. However, supplementation of the diet with fish oil increased the amount of trans-11 18 1 leaving the rumen (Shingfield et al., 2003). One possible explanation may be the inhibitory effect of docosahexanoic acid (DHA, cis-4,cis-7,cis-10,cis-13,cis-16,cis-l9 22 6), because DHA hampers the reduction of vaccenic acid to stearic acid in vitro (AbuGhazaleh Jenkins, 2004). However, additional experiments are needed to provide an explanation. 

Although most plants appear to have the ability to make linoleic and linoleic acids, animals cannot desaturate positions from C-9 to the methyl terminus of the fatty acid chain, and must obtain unsaturated fatty acids such as linoleic acid and linolenic acid from their diet. The requirement for these acids involves formation of arachidonic acid (61) and, subsequently, prostaglandins. Arachidonic acid, eicosatetra-5,8,11,14-enoic acid, is formed from linoleate by chain extension and by additional desaturation. Prostaglandins (such as 62 and 63) are derived from eicosatrienoic and eicosate-traenoic acids, respectively, although the actual path of biosynthesis is not completely elucidated (Fig. 2.26). These compounds have pronounced hormonal and other effects on mammals and other organisms. 

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