Olive fatty acid distribution

The chromatogram-like structure of the carbonyl region shows separation of a mixture from different mono-, di- and triglycerides and free fatty acids (Fig. 4.7). This method is used for quality control of olive oils (Sacchi et al, 1990). Integrals of the respective intensities are directly proportional to the molar amount of the component, with one restriction comparison is only allowed between atoms in the same chemical environment, for example carbonyls only with carbonyls, methyls only with methyls and so on. There is no need for a standard to evaluate the fatty acid distribution, and no calibration and no quality control samples are needed. No chemical modification such as saponification or derivatization is necessary, so degradation of the chemically sensitive polyunsaturated acids is avoided. The material can be recovered unchanged after the measurement. In addition to the general fatty acid distribution a determination of individual distributions is possible. ... 

As an example of the conclusions that can be drawn from the combined application of chromatographic and enzymatic techniques, see Table IV, where data are reported on the fatty acid distribution in olive and tea-seed oils (Fedeli and Jacini, 1967). 

Fatty Acids Distribution in Olive and Tea-Seed Oils Glycerides" ... 

Royer, A., Naulet, N., Mabon, F., Lees, M. and Martin, G.J. (1999b) Stable isotope characterisation of olive oils. 2. Deuterium distribution in fatty acids studied by nuclear magnetic resonance. J. Am. 

It is well known that in a naturally occurring oil the fatty acids are not distributed randomly on the glycerol skeleton. Similarly, in olive oil, the fatty acid pattern conforms to the l,3-random-2-random distribution pattern. The saturated fatty acids are almost exclusively found at the 1,3-positions, whilst the 2-position is occupied almost entirely by the unsaturated Po and O, L, Ln acids. 

This method permits a clear distinction between a natural olive oil and an olive oil that has undergone esterification or inter-esterification processes, by determining the distribution of fatty acids on the three positions of glycerol. Lipases catalyse the following reactions ... 

Identity and quality characteristics of the above types of olive oil are given in Tables 9.3 and9.4. Theoretical ECN42 values inTable 9.4 are calculated from the fatty acid composition and the 1,3-random, 2-random distribution theory using an appropriate computer programme. The difference between this theoretical value and a real value obtained by HPLC replaced trilinolein content. K232 and K270 are specific UV extinctions of 1% solution of the fat in a specified solvent,... 

Oleic acid, the most widely distributed of all the natural fatty acids, is present in practically all lipids and is a significant component in sources such as those listed below. Many of these are commercially available and are discussed in more detail in Section 3.3. The least familiar is Jessenia bataua which is a native Amazonian palm. Its oil is considered as a potential replacement for olive oil. The octa-decenoic acids of plant origin are likely to be wholly oleic acid but those of animal origin may contain other isomers. 

Olive oil is unusual because it contains such a high proportion of oleic acid, 65-85%. The compositions of oils from various origins are given in Table 3.74. The triglyceride composition of a typical olive oil is given in Table 3.141 and 3.143 and the positional distribution of fatty acids in Table 3.144. Numerous minor components in olive oil have been characterized (Table 3.75). 

Palmitic acid n-hexadecanoic acid, CH3-(CH2)i4-COOH, a fatty acid, M, 256.4, m.p. 63 °C, b.p.igo 271.5 °C, b.p.i5 215 °C. Together with stearic acid. Pa. is one of Ae most widely distributed natural fatty acids, and is present in practically all natural fat e.g. 36% in palm oil 29% in bovine carcass fat, 15 % in olive oil it is also found in phosphatides and waxes. Pa. is the taw material for the manufacture of candles, soap, wetting agents and antifoams. 

Ester oils are produced by esterification of glycerol with purified fatty acids obtained from olive oil residues. In this case the saturated acyl groups are equally distributed between all three positions of the glycerol molecule, whereas... 

One could believe that 18 1 was desaturated on DAG molecule before galacto-sylation and formation of DGG as it was proposed by KESRI-BEN HASSAINE(5) on Carthamus cotyledons, but the distribution of the radioactive precursor into DAG fatty acids in olive plant leaves (data not shown) indicated that only palmitic and oleic acids were labelled at any time of incubation. This lead us to think that the two desaturation steps of oleic acid could take place on DGG molecule (see the following scheme). However in the absence of a direct evidence this must remain merely as a hypothesis. 

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