Major fatty acids

By way of a specific example let us consider erucic acid. The main commercial source of erucic acid is a specially bred form of rape seed (HEAR) as pointed out above. With European consumption being around 60 000 tpa almost 40 000 ha of land are used to grow rapeseed for erucic acid production in Europe. The high level of erucic found in this type of rape seed oil make it unsuitable for human consumption, owing to the indigestibility of such large amounts of this acid. Erucic acid is also the major fatty acid to be found in nasturtium and crambe seeds (up to 75% and 56% respectively), and it is also found in the salad herb, rocket. 

The major fatty acids present in plant-derived fatty substances are oleic acid (9-octadecenoic, C18 l), linoleic acid (9,12-octadecadienoic, C18 2) and the conjugated isomers thereof and linolenic acid (9,12,15-octadecatrienoic, C18 3) (Scheme 31.1). Their rates of oxygen absorption are 100 40 1, respectively, hence partial hydrogenation with consequent lowering of the iodine number would lead to a significant increase in oxidative stabihty, particularly when C18 3 is reduced. 

Each phospholipid class in a given tissue has a characteristic fatty acid composition. Though the same fatty acid may be present in a number of lipids, the quantitative fatty acid composition is different for each class of lipids and remains fairly constant during the growth and development of the brain. A typical distribution profile of the major fatty acids in rat brain phospholipids is given in Table 3.1. Not only do the phosphoglycerides differ in the structure of the polar head groups, or phospholipid... 

Table 11.4 Averaged composition of the major fatty acids in bovine milk fat (adapted from Jensen, 2000 297).

TABLE 1.3 The major fatty acids in the wax esters of escolar and oilfish muscle... 

Feeley, R. M., Criner, P. E. and Slover, H. T. 1975. Major fatty acids and proximate composition of dairy products. J. Am. Diet. Assn. 66, 140-146. 

In addition to the major fatty acids, milk also contains many minor polyunsaturated acids (Kurtz 1974) hence the autoxidation of dairy products can lead to a multitude of saturated and unsaturated aldehydes. 

Lactobacillic acid A major fatty acid of lactobacilli... 

From the sea anemone M. senile was isolated j3-glucopyranosyl-( 1 - l)-ceramide, the structure of which was determined by mass spectrometry, H-n.m.r. spectroscopy, and chemical splitting. The major sphingosine in the cerebroside is a new base containing two double bonds and branching at one double bond, namely, 2-amino-D-eryf/jro-l,3-dihydroxy-9-methyl-( , E)-octadeca-4,8-diene. The major fatty acids are Ci6 0 and C20 o a-hydroxy acids.133... 

From the muscle tissue of the bivalve Barnea dilatata japonica, a galac-tocerebroside has also been isolated, but here, the major fatty acid component is hexadecanoic acid (92.3%), and the major sphingosine base is C,8 2 sphingosine.130... 

The lipid composition in all of these oligosylceramides is similar. The major fatty acids are hexadecanoic and octadecanoic acid, and the major sphingosine base is octadeca-4-sphingenine. 

The major, fatty acid component in these glycolipids is the C22 , acid, and no hydroxy acids were found. The sphingosine bases are represented by dihydroxy bases, among which, the preponderant one is the C,8 sphin-... 

Table 2 compares the major fatty acids of vegetable and fish oils and animal fats. Vegetable oils differ among themselves in the percentage of C16-C18 fatty acids, with the exception of coconut oil. In animal fats, fatty acid chain lengths extend from C10 to C20. 

Despite the large variety of potential fatty acid components in natural-occurring phosphodiglycerides, only three major fatty acid derivatives of synthetic phospholipids are commonly used in liposome preparation (1) myristic acid (w-tetradecanoic acid containing 14 carbons), (2) palmitic acid (w-hexadecanoic acid containing 16 carbons), and (3) stearic acid (w-octadccanoic acid containing 18 carbons) (Fig. 334). 

Fatty acids and sphingosines. The lipid composition of the four monosialogangliosides is shown in Table II. The major fatty acids are palmitic, stearic and oleic acids. The long chain base is composed mainly of C-18 sphingosine with less than 20% of dihydrosphingosine. 

Palmitic acid was present in all thymus gangliosides as a major fatty acid, which is also in contrast to the fatty acid compositions of the various organs. 

Ricinoleic acid (Figure 3.8) is the major fatty acid found in castor oil from seeds of the castor oil plant (Ricinus communis Euphorbiaceae), and is the 12-hydroxy derivative of oleic acid. It is formed by direct hydroxylation of oleic acid (usually esterified as part of a phospholipid) by the action of an 02- and NADPH-dependent mixed function oxidase, but this is not of the cytochrome P-450 type. Castor oil has a long history of use as a domestic purgative, but it is now mainly employed as a cream base. Undecenoic acid (A9-undecenoic acid) can be obtained from ricinoleic acid by thermal degradation, and as the zinc salt or in ester form is used in fungistatic preparations. 

Fig. 16. Mutants derived from an arachidonic acid-producing fungus, M. alpina 1S-4 Desaturases missing are shown in parentheses. Major fatty acids produced are shown in brackets...

Table II lists the increases for the four major fatty acids in the free fatty acid fraction. Collectively, palmitic (C. q), oleic (Cig.), linoleic (C g an< lin°lenic comprise greater...

Figure 9.17 Distribution of major fatty acids ( xg fatty acids L-1 and xg fatty acid mg-1 OC) in particulate organic matter (POM), very high molecular mass dissolved organic matter (VHDOM) (30 kDa-0.02 xm), and high molecular mass DOM (HDOM) (1-30 xm) in Delaware Bay estuary. Bacterial fatty acids (FA) included branched and normal saturated acids and 15 1A4 and PUFA = polyunsaturated fatty acids. (Modified from Mannino and Harvey, 1999.)...

The extraction of seed with ether yields a dark green, fatty oil. The major fatty acid is oleic acid, which is followed by pet-roselinic acid. The fatty acid composition is indicated in Table 18.1. 

Analytical methods for determining the authenticity of vegetable fats have classically been based on comparison of the composition of some major and minor components. For the most important traded oils, tables of the composition (i.e. profiles) of the major fatty acids and sterols have been of importance and have in some cases been supported by data describing other components such as triacylglycerols, sterol esters, volatiles, waxes and fatty alcohols. 

Milk fat does have a very characteristic fatty acid composition, and contains about 15 major fatty acids and several hundred minor fatty acids (Gunstone etal., 1994 Hettinga, 1996). One might think that this would mean that authentication would be relatively easy from just the fatty acid composition. However the fatty acid composition is not just complicated, it is also very variable. Early surveys showed this variability (Hilditch and Williams, 1964 Hallabo and El-Nikeety, 1987) and some of the reasons for this variability were soon evaluated (Hilditch and Williams, 1964). 

A summary of the ranges of major fatty acids (>1%) that have been found in bovine milk fats is given in Table 5.3. This includes values obtained from... 

Table 5.3 Range of major fatty acids reported in bovine milk fat...

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