Esters polyunsaturated

The intermediate m hydrogenation formed by reaction of the unsaturated ester with the hydrogenated surface of the metal catalyst not only can proceed to the saturated fatty acid ester but also can dissociate to the original ester having a cis double bond or to its trans stereoisomer Unlike polyunsaturated vegetable oils which tend to reduce serum cholesterol levels the trans fats produced by partial hydrogenation have cholesterol raising effects similar to those of saturated fats... 

Polyunsaturated fatty acids in vegetable oils, particularly finolenic esters in soybean oil, are especially sensitive to oxidation. Even a slight degree of oxidation, commonly referred to as flavor reversion, results in undesirable flavors, eg, beany, grassy, painty, or fishy. Oxidation is controlled by the exclusion of metal contaminants, eg, iron and copper addition of metal inactivators such as citric acid minimum exposure to air, protection from light, and selective hydrogenation to decrease the finolenate content to ca 3% (74). Careful quality control is essential for the production of acceptable edible soybean oil products (75). 

Sulfated Natural Oils and Fats. Sulfated natural triglycerides were the first nonsoap commercial surfactants introduced in the middle of the nineteenth century. Since then sulfates of many vegetable, animal, and fish oils have been investigated (see also Fats AND FATTY oils). With its hydroxyl group and a double bond, ricinoleic acid (12-hydroxy-9,10-octadecenoic acid) is an oil constituent particularly suited for sulfation. Its sulfate is known as turkey-red oil. Oleic acid is also suited for sulfation. Esters of these acids can be sulfated with a minimum of hydrolysis of the glyceride group. Polyunsaturated acids, with several double bonds, lead to dark-colored sulfation products. The reaction with sulfuric acid proceeds through either the hydroxyl or the double bond. The sulfuric acid half ester thus formed is neutralized with caustic soda ... 

Dahle, L.K., Hill, E.G. and HoUman, RT. (1962). The TBA reaction and the autoxidation of polyunsaturated fatty acid methyl esters. Arch. Biochem. 98, 253-259. 

The lipase-catalyzed fatty acid ester hydrolysis and the lipoxygenation of free polyunsaturated fatty acids are involved in the same lipid degradation pathway. They are respectively the first and second reaction in the lipoxygenase pathway (Fig. 3) [87-91]. The pathway produces volatile products of considerable importance in food technology including Cg[92, 93] or Cg- 94—96 aldehydes and alcohols from polyunsaturated fatty... 

Boronate esters have been used for the preparation of polyunsaturated systems such as retinoic acid esters. 

Linoleic acid is a polyunsaturated fatty acid (compound containing two or more double bonds) occurs as an ester in polyunsaturated fats. 

Keough, T. Mihelich, E.D. Eickhoff, D.J. Differentiation of Monoepoxide Isomers of Polyunsaturated Fatty Acids and Fatty Acid Esters by Low-Energy CE-MS. Anal. Chem. 1984,56, 1849-1852. 

Water-soluble mthenium vinyUdene and aUenylidene complexes were also synthetized in the reaction of [ RuCl2(TPPMS)2 2] and phenylacetylene or diphenylpropargyl alcohol [29]. The mononuclear Ru-vinylidene complex [RuCl2 C=C(H)Ph)(TPPMS)2] and the dinuclear Ru-aUylidene derivative [ RuCl(p,-Cl)(C=C=CPh2)(TPPMS)2 2] both catalyzed the cross-olefin metathesis of cyclopentene with methyl acrylate to give polyunsaturated esters under mild conditions (Scheme 7.10). 

These processes are shown for the CoA ester of linoleic acid, the most common of the polyunsaturated acids. 

Gorreta, F., Bernasconi, R., Galliani, G., Salmona, M., Tacconi, M. T., and Bianchi, R. (2002). Wax esters of co-3 polyunsaturated fatty acids A new formulation as a potential food supplement—Digestion and absorption in rats. Lebensmittel-Wissenschaft und Technologie 35,458-465. 

Another example is afforded by fibrate drugs and phthalate esters, which bind to the PPAR, in mimicry of polyunsaturated fatty acids. 

Lipoxygenase (EC 1.13.11.12) is an enzyme that catalyzes the hydroperoxidation of polyunsaturated fatty acids and esters containing a cis-cis-l, 4-pentadiene system (Table 6). In 1947, Theorell et al. obtained the enzyme in a crystalline form from soybeans and reported that the enzyme neither contained nor required a metal cofactor192. Subsequent studies from three groups of investigators have demonstrated that the enzyme purified from soybeans in an iron-containing dioxygenase74-76 ... 

Deman and Deman (1983) have investigated the determination of trans unsaturation in milk fat by infrared analysis and found values of 7.4% (winter) to 9.9%(summer) when the TGs were analyzed. These are higher than the quantities found by infrared analysis of methyl esters of the fatty acids. These quantities are isolated total trans bonds and do not give an estimate of the positional and polyunsaturated isomers which are present. The trans contents obtained by Deman and Deman are higher than the 4% found by Smith et al. (1978). 

Hydrocarboxylation of Polyunsaturated Fatty Acids and Esters with a Palladium Chloride— Triphenylphosphine Complex Catalyst... 

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