Fatty acids naturally occurring

Ri, R2 and R3 represent the chains of different fatty acids. Naturally occurring fats and oils are mixtures of such mixed triacylglycerols. Soya bean oil has been estimated to contain about 79 per cent of mixed triacylglycerols compared with about 21 per cent of the simple type. Comparable figures for linseed oil are 75 and 25 per cent, respectively. Triacylglycerols with residues of one fatty acid only do occur naturally laurel oil, for example, contains about 31 per cent of the triacylglycerol of lauric acid. 

C27H55COOH. Glistening scales m.p. 89 C. A straight-chain, saturated fatty acid, that occurs in many natural waxes. 

Fatty acids normally occur naturally as esters fats oils phospholipids and waxes all are unique types of fatty acid esters There is however an important class of fatty acid derivatives that exists and carries out its biological role m the form of the free acid This class of fatty acid derivatives is described m the following section... 

Fatty acids occur mainly as esters in natural fats and oils but do occur in the unesterified form as free fatty acids, a transport form found in the plasma. Fatty acids that occur in natural fats are usually straight-chain derivatives containing an even number of carbon atoms. The chain may be saturated (containing no double bonds) or unsaturated (containing one or more double bonds). 

Odd-numbered fatty acids do occur naturally with carbon numbers between 3 and 19. Those with carbon numbers 15 to 19 are present in large amounts in certain species of fish and bacteria. Even-numbered fatty acids, 4 to 10, are mainly found in milk and butter fats. 

Trans fatty acids The phospholipids in the plasma and in membranes of all cells contain long-chain polynnsatnrated fatty acids (PUFA). During periods of growth and development of organs, PUFAs are reqnired for phospholipid synthesis. The PUFAs are, of conrse, obtained from dietary triacylglycerol and phospholipids. The donble bonds in most natural fatty acids are cis not trans Nonetheless trans fatty acids do occur in dietary fats. If the diet contains trans fatty acids, they might be incorporated into the phospholipids along with the cis fatty acids and hence into membranes. The presence of these abnormal fatty acids will modify the stmctnre of the phospholipids which conld impair the fnnction of the membrane. There are two main sonrces of trans fatty acids in the diet foods produced from ruminants contain trans fatty... 

Fatty amines are those containing alkyl groups having more than six carbon atoms. The commercial fatty amines are synthesized from fatty acids that occur in nature and are used as chemical intermediates. Other major uses of fatty amines and their derivatives include textile chemicals (particularly fabric softeners), emulsifiers for petroleum and asphalt, and flotation agents for ores. 

As discussed briefly in the Focus On box titled The Preparation of Soap" in Chapter 19, fats are triesters formed from glycerol and long, linear-chain carboxylic acids, known as fatty acids. The resulting triesters are called triacylglycerols. Stearic, palmitic, and oleic acids are among the many different fatty acids that occur in nature ... 

Bohenin occurs as a white to light tan, waxy solid. It is a triglyceride containing behenic acid at the 1- and 3-positions and oleic acid at the 2-position. Behenic acid is a saturated fatty acid that occurs naturally in peanuts, most seed fats, animal milk fat, and marine oils. It is produced by the interesterification of triolein and ethyl behenate in the presence of a suitable lipase enzyme preparation. It melts at approximately 52°. It is insoluble in water soluble in hexane, in chloroform, and in acetone and slightly soluble in hot ethanol. 

Glyceride. An ester of glycerol and fatty acids in which one or more of the hydroxyl groups of the glycerol have been replaced by acid radir cals. Glycerides occur in nature and can be made synthetically. The most common ones are based on fatty acids and occur in oild and fats. Mono- and triglycerides are of commercial importance... 

CAS 57-10-3. CH3(CH2)14COOH. A saturated fatty acid, it occurs in natural fats and oils, tall oil, and most commercial-grade stearic acid. 

Products and Uses A fatty acid that occurs naturally in meat and dairy products. 

Oxidation of fatty acids can occur in a number of ways, depending on the position of oxidation (i.e. a-, )8- or ft>-oxidation) and the nature of the substrate (e.g. lipoxygenase attack on polyenoic fatty acids). 

Table 23.1 lists some of the most common fatty acids, and Table 23.2 gives the fatty acid composition of a number of common fats and oils. Notice that in the unsaturated fatty acids in Table 23.1 the double bonds are all cis. Many naturally occurring fatty acids contain two or three double bonds. The fats or oils that these come from are called polyunsaturated fats or oils. The first double bond of an unsaturated fatty acid commonly occurs between C9 and C10 the remaining double bonds tend to begin with Cl 2 and C15 (as in linoleic acid and linolenic acid). The double bonds, therefore, are not conjugated. Triple bonds rarely occur in fatty acids. 

Oleic acid is a naturally-occurring fatty acid in animal and vegetable oils. At the present, edible and industrially fatty acids are obtained from seeds of highly oleaginous plants, and oleic acid naturally occurs in greater quantities than any other fatty acid. This characteristic makes it an important compoimd for the diet and for increasing the lipophilicity of bioactive molecules (Lin and Huey, 2009 Aki et al., 2005). 

It is apparent that it is not easy to obtain such separations reproducibly, and the separation of the first two isomers, in particular, is rarely easy. There is little to confuse the analysis in commercial CLA samples in which only Cjg fatty acids are present. However, when CLA is fed in nutritional experiments, other fatty acids may be present in tissues and confuse the picture. The important cis,trans- somexs usually elute in a region of the chromatogram that is free of other fatty acids. On the other hand, 21 0 or 20 2 fatty acids may occur naturally, and they elute in the same part of the chro-... 

In addition to the saturated fatty acids derived from acetate such as dodecanoic acid (lauric acid, Cn, Figure 11.16, n = 10), tetradecanoic acid (myristic acid, C, Figure 11.16, n = 12), hexadecanoic acid (palmitic acid, Qe, Figure 11.16, n = 14), and octadecanoic acid (stearic acid, Cis, Figure 11.16, n = 16) by a pathway such as that in Figure 11.16 (an abbreviated version of Schemes 11.37 and 11.38), many unsaturated fatty acids also occur naturally. 

The fatty acids that occur in greatest amount in natural fats are the saturated 16 0 palmitic acid, the 18 0 stearic acid and the unsaturated 18 1 oleic acid. Branched chain fatty acids and fatty acids containing an uneven number of C atoms are rarely found. 

Table 3.2 compiles the major fatty acids which occur in food. Palmitic, oleic and linoleic acids frequently occur in higher amounts, while the other acids listed, though widely distributed, as a rule occur only in small amounts (major vs minor fatty acids). Percentage data of acid distribution make it obvious that unsaturted fatty acids are the predominant form in nature. 

GC separations of synthetic epoxy fatty acids have been referred to briefly above. Epoxy fatty acids also occur naturally, in seed oils especially, and ECL data for a number of these have been published [191,735,871],... 

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