Oleic acid Constitution

The most widespread unsaturated fatty acid is oleic acid (3-4), which occurs, at least in a small amount, in virtually all animal and plant lipids. Oleic acid constitutes 30 0% of the total fatty acids in adipose tissue of animals and 20 80% of the total fatty adds in vegetable fats and oils. For example, ohve oil contains up to 78% oleic add. 

SCDs are a family of microsomal Fe-based metalloenzymes. They act on long-chain saturated acyl CoAs and introduce a ds-double bond at the C-9 or C-10 position. For example, SCDs convert stearic acid into oleic acid, and palmitic acid into palmitoleic acid. Monounsaturated FAs constitute a major component of TGs, cholesteryl esters, and phospholipids. The reaction requires molecular 02 and NADH and generates H20 in the process [3,4]. 

Analytical studies of the tergal secretions of male B. germanica have identified a number of volatile compounds, none of which has so far been subjected to behavioral assays on females. Brossut et al. (1975) found p-hydroxybenzyl alcohol, o-hydroxybenzyl alcohol, di- and tri-methylnaphthalene, benzothiazole, two isomers of nonyl phenol, and myristic, palmitic, and oleic acids. The fatty acids constituted > 92% of the volatile fraction given their abundance in feces and frass, and their role as putative aggregation pheromones (Wileyto and Boush, 1983 Fuchs et al., 1985 Wendler and Vlatten, 1993 Scherkenbeck et al., 1999),... 

The saponifiable portion of the fatty oil accounts for about 90% of the total fixed oil and is characterized by a very high content of octadecenoic acids. Petroselinic and oleic acid occur at similar levels and jointly comprise 74-85%, linoleic 7-16% and palmitic 4-8%, of the constituent fatty acids. During prolonged storage of the spice, the free fatty acid content gradually increases and this is a good indicator of the age of the material. The contents of fatty acids, sterols and total tocopherols in a deodorized oil derived from coriander seeds (yield up to 28%) are compared with those in sunflower oil and tests on the biological effects of coriander oil are reported by Mironova et al. (1991). Of the fatty acids present, total C18 1 acids (petroselinic acid + oleinic acids) constituted 80—82% and petroselinic acid alone 50—60%, and the food value was lower than that of sunflower oif. Kim et al. (1996) found the production of petroselinic acid from cell suspension cultures of C. Sativum. 

Studies on the chemical structure of olive wax esters have shown that the homologues present in olive-pomace oil are almost entirely esters of oleic acid with long chain alkanol constituting the homologous series C40, C42, C44, C46. Odd-chain esters identified in the oil were esters of oleic acid with C23, C25, C27 alcohols. Gas chromatography and mass spectrometry analysis has shown that each carbon chain of the esters in made up of a single isomer in which the acyl moiety is that of oleic acid (Bianchi el al., 1994). Thus, for example, ester C44 was found to be made up of the couple acid-alcohol Cl8 1 and C26, whereas other possible isomers such as C16 l-C28 were not detected. This is unusual if it is compared with the composition of epicuticular ester fractions of oil seeds for which, in cases studied, each ester chain was composed of several positional isomers of the ester group. 

Sesame oil belongs to the oleic-linoleic acid group. It has less than 20% saturated fatty acid, mainly palmitic (7.9 12%) and stearic (4.8 6.1%) acids. Oleic acid and linoleic acid constitute more than 80% of the total fatty acids in sesame oil. Unlike other vegetable oils in this group, the percentages of oleic acid (35.9-42.3%) and linoleic acid (41.5 7.9%) in the total fatty acids of sesame oil are close (Table 5). 

The fatty acid composition of hazelnut oil is as follows 78-83% oleic acid, 9-10% linoleic acid, 4—5% palmitic acid, and 2-3% stearic acid as well as other minor fatty acids (Table 3) (1, 22). Parcerisa et al. (23) examined lipid class composition of hazelnut oil, showing that triacylglycerols constituted 98.4% of total lipids, glycolipids comprised 1.4% of total hpids, and trace amounts (<0.2%) of phosphatidylcholine and phosphatidylinositol were also present. Hazelnut oil contains 1.2-1.14 g/kg of phytosterols primarily in the form of p-sitosterol and is a very good source of a-tocopherol (382-472 mg/kg) (1, 22). The main odorant in... 

Walnuts contain about 65% lipids, however, considerable differences exist among varieties (range 52-70%, w/w) (1,40). Walnuts also contain 15.8% protein, 13.7% carbohydrate, 4.1% water, and 1.8% ash (w/w) (1). The fatty acid composition of walnut oil is unique compared with other tree nut oils for two reasons walnut oil contains predominantly linoleic acid (49-63%) and a considerable amount of ot-linolenic acid (8-15.5%). Other fatty acids present include oleic acid (13.8-26.1%), palmitic acid (6.7-8.7%), and stearic acid (1.4—2.5%) (Table 5) (40). The tocopherol content of walnut oil varies among different cultivars and extraction procedures and ranges between 268 mg/kg and 436 mg/kg. The predominant tocol isomer is y-tocopherol (>90%), followed by a-tocopherol (6%), and then (3- and 8-tocopherols (41). Nonpolar lipids have been shown to constitute 96.9% of total lipids in walnut oil, whereas polar lipids account for 3.1%. The polar lipid fraction consisted of 73.4% sphingolipids (ceramides and galactosylcera-mides) and 26.6% phospholipids (predominantly phosphatidylethanolamine) (42). Walnut oil contains approximately 1.8g/kg phytosterols (1), primarily p-sitosterol (85%), followed by A-5-avenasterol (7.3%), campesterol (4.6%), and, finally, cholesterol (1.1%) (42). 

Position of Double Bond.—The position of the double bond and the full constitution of oleic acid and elaidic acid has been established by means of the products obtained by careful oxidation. It has been shown that when compounds containing a double bond are thus oxidized the effect is to split the compound at the double bond with the oxidation of each doubly linked carbon group to carboxyl. Now both oleic acid and elaidic acid on oxidation yield two acids, each containing nine carbon atoms. One is a mono-basic acid known as pelargonic acid, CsHit—COOH and the other is a di-basic acid, azelaic acid, HOOC—C7H14—COOH. The reaction is... 

Cholesterol is formed in the liver (85%) and intestine (12%) - this constitutes 97% of the body s cholesterol synthesis of 3.2 mmol/day (= 1.25 g/day). Serum cholesterol is esterized to an extent of 70-80% with fatty acids (ca. 53% linolic acid, ca 23% oleic acid, ca 12% palmitic acid). The cholesterol pool (distributed in the liver, plasma and erythrocytes) is 5.16 mmol/day (= 2.0 g/day). Homocysteine stimulates the production of cholesterol in the liver cells as well as its subsequent secretion. Cholesterol may be removed from the pool by being channelled into the bile or, as VLDL and HDL particles, into the plasma. The key enzyme in the synthesis of cholesterol is hydroxy-methyl-glutaryl-CoA reductase (HGM-CoA reductase), which has a half-life of only 3 hours. Cholesterol is produced via the intermediate stages of mevalonate, squalene and lanosterol. Cholesterol esters are formed in the plasma by the linking of a lecithin fatty acid to free cholesterol (by means of LCAT) with the simultaneous release of lysolecithin. (s. figs. 3.8, 3.9) (s. tab. 3.8)... 

Large supply of naturally derived lipids can be obtained from plants in which many oils and fatty acids can be readily extracted and purified. Animal sources (e.g., eggs or milkfats) are used to derive complex lipids such as phospholipids and cholesterol. Yield from natural sources is dependent on the weight-percent composition and the efficiency of the extraction procedure. The constitution of fatty acids in vegetable oils varies widely from different sources. For example, oleic acid is present at 64.6% by weight in olive oil but is present at only 0.7% in palm kernel oil. Similarly, castor oil triglyceride is comprised of almost entirely ricinoleic chains. There are numerous raw material suppliers of oils and oil fractions worldwide. As such, the relative cost of bulk purified... 

Lissapol LS, Ci,H33.C0.NH.CjH3(0.CH3)(S03Na), is made by the condensation of oleic acid chloride with para-anisidine sulphonic acid, and Aerosol MA, derived from succinic acid, has the constitution shown below C,H,3.0.0C.CH.S0,Na... 

At temperatures above 97.5°, a mixture of sodium metal and a saturated hydrocarbon constitutes a binary system of mutually insoluble liquids that can be emulsified in much the same manner as oil and water. When this sodium-in-oil emulsion is permitted to cool below this temperature, the sodium solidifies as microscopic spheres suspended in the hydrocarbon. Addition of certain surface-active agents1 such as oleic acid, prior to cooling, assists in keeping the sodium in suspension. Such a formulation is known as a sodium dispersion. 

It has been now recognised that die phenolic profile of the foods, along with high intakes of the monounsaturated fatty acids, as oleic acid mainly, confers its health-promoting properties to die Mediterranean diet. In fact, olive oil is the main source of unsaturated acids and polyphenols that constitute a complex mixture in olive fruits and in its derived products. In addition, in O. europaea fruits, phenolic profile and content are important factors to consider in order to evaluate virgin olive oil quality. To remain that they are also partly responsible for autoxidation stability and organoleptic characteristics of olive oil. 

Lecithins are derived from glycerol by the replacement of the hydrogen atoms of the hydroxyl groups by certain acid radicals, one of which is the radical of phosphoric acid. When a lecithin is treated with barium hydroxide partial saponification takes place. Choline and palmitic, stearic or oleic acid are obtained, together with glycerophosphoric acid which has the constitution —... 

Ans. The three triacylglycerols are constitutional isomers. A mixture of the three triacylglycerols is formed by the reaction of 1 mol of glycerol with 1 mol each of palmitic, stearic, and oleic acids. Many textbooks gloss over this point and show only one of the isomers. Now that we understand the situation, we will do the same unless the problem specifically asks otherwise. Any one of the three constitutional isomers is acceptable as the answer to Problem 19.8. 

The average monoenoic acid content of milk fat is around 30%. Oleic acid (cis-9-18 1) is the predominant monoenoic acid. It constitutes 95.8% of the positional cis isomers of octadecenoic acid. Monoenoic FA also comprise trans isomers, mainly trani-octadecenoic acids. Cow s milk fat contains 1.3 to 7.3% tra y-18 l acids, with an average of 3.7%. The relative proportions of trans-l8 l positional isomers in milk fat are given in Table 13.4. Trans-I6 l isomers occur in amounts of approximately 0.13% (Precht and Molkentin, 2000). 

Fats can be solid or liquid. This physical property is a direct effect of the fatty acid substituents that are present in them. When fats are in their liquid state they are commonly called oils. Broadly we can generalize that solid fats mainly contain saturated fatty acids, and liquid fats mainly contain unsaturated fatty acids. We should not confuse this generalization with the fact that the naturally occurring fats and oils contain many different types of fatty acids, both saturated and unsaturated. The physical properties of fats are mostly a function of the fatty acids that are present in them. For example, human stored fat contains predominantly oleic acid (a saturated fatty acid) which constitutes about 47 % of the total fatty acid content. It also contains palmitic acid, linoleic acid, stearic acid, myristic acid, and other fatty acids in decreasing amounts respectively. 

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