Virgin olive oil

Figure 12.1 Analysis of Tinuvin 1577 in 30% virgin olive oil (in hexane), showing (a) the gas cliromatogram comparing the pure oil with a sample at the Tinuvin 1577 detection limit concentration, and (b) the coixesponding liquid chromatogram. Reprinted from Journal of High Resolution Chromatography, 20, A. L. Baner and A. Guggenberger, Analysis of Tinuvin 1577 polymer additive in edible oils using on-line coupled HPLC-GC , pp. 669-673, 1997, with pennission from Wiley-VCH.

MEDINA I, SATUE-GRACIA M T, GERMAN J B and FRANKEL E N (1999) Comparison of natural polyphenol antioxidants from extra virgin olive oil with synthetic antioxidants in tuna lipids during thermal oxidation, JAgric Food Chem, 47, 4873-9. 

Gallardo-Guerreiro, L. et al., Effect of storage on the original pigment profile of Spanish virgin olive oil, J. Am. Oil Chem. Soc., 82, 33, 2005. 

C. Peri, A. Garrido and A. Lopez, eds.. The sensory and nutritional quality of virgin olive oil. Grasas y Aceitas, 45, (Symposium Issue) (1994) 1-81. 

The application of 13C NMR for the rapid analysis of the oil composition of oil seeds is well known [16], 13C NMR has recently been applied to the quantitative analysis of the most abundant fatty acids in olive oil [17]. The values obtained by this method differed by only up to 5% compared with GLC analysis. The quantitative analysis was applied to the olefmic region of the high resolution 13C NMR spectrum of virgin olive oil to detect adulteration by other oils which differed significantly in their fatty acid composition. The application of the methodology for the detection of adulteration of olive oil by hazelnut oil is more challenging as both oils have similar chemical profiles and further experiments are in progress. 

The first application of ANNs to pyrolysis mass spectra from biological samples was by Goodacre, Kell, and Bianchi.96,97 This study permitted the rapid and exquisitely sensitive assessment of the adulteration of extra-virgin olive oils with various seed oils, a task that previously was labor intensive and difficult. Since this study other laboratories have increasingly sought to apply ANNs to the deconvolution and interpretation of pyrolysis mass spectra, the aim being to expand the application of the PyMS technique from microbial characterisation to the rapid and quantitative analysis of the chemical constituents of microbial and other biological samples. 

Goodacre, R. Kell, D. B. Bianchi, G. Rapid assessment of the adulteration of virgin olive oils by other seed oils using pyrolysis mass spectrometry and artificial neural networks. J. Sci. Food Agric. 1993, 63, 297-307. 

TABLE 13.1 Classification of Virgin Olive Oils by Composition1 1... 

By the nature of the process by which olive oil is extracted from the olive, the oil is susceptible to contamination. The high price associated with olive oil of the highest purity— extra virgin olive oil — also leads to falsification by unscrupulous vendors who blend with less costly oils such as com, peanut, and soybean oil. Various analytical techniques have been devised to authenticate the purity of olive oil by detecting certain oil components. 

Virgin olive oil contains considerable amounts of simple phenols that have a great effect on the stability/sensory and nutritional characteristics of the product. Some of the most representative are hydroxytyrosol (3,4-dihydroxyphenylethanol) and tyrosol (4-hydroxyphenylethanol) however, phenolic compounds are removed when the oil is refined (Tovar and others 2001). The phenolic content of virgin olive oil is influenced by the variety, location, degree of ripeness, and type of oil extraction procedure used, and that is why hydroxytyrosol can be considered as an indicator of maturation for olives (Esti and others 1998). Hydroxytyrosol concentrations are correlated with the stability of the oil, whereas those of tyrosol are not (Visioli and Galli 1998). 

Montedoro G, Servili M, Baldioli M and Miniati E. 1992a. Simple and hydrolyzable phenolic compounds in virgin olive oil. 1. Their extraction, separation, and quantitative and semiquantitative evaluation by HPLC. J Agric Food Chem 40 1571-1576. 

Fig. 2.137. Left electrophoregram of chlorophyll pigments in fresh extra virgin olive oil, added with copper chlorophyllin (1) chlorophyllin B (2) pheophytin B (3) pheophytin B(4) chlorophyllin A (5) pheophytin A (6) pheophytin A (7) copper chlorophyllin. Right electrophoregram of chlorophyll pigments in extra virgin olive oil, with a long shelf-life, added with copper chlorophyllin (1) chlorophyllin B (2) chlorophyllin derivatives (3) chlorophyllin A (4) copper chlorophyllin. Reprinted with permission from L. Del Giovine et al. [308].

A. Cichelli and G.P. Pertesana, High-performance liquid chromatographic analysis of chlorophylls, pheophytins and carotenoids in virgin olive oils chemometric approach to variety classification. J. Chromatogr.A 1046 (2004) 141-146. 

Lai YW, Kemsley EK, Wilson RH. 1995. Quantitative analysis of potential adulterants of extra virgin olive oil using infrared spectroscopy. Food Chem 53 95-98. 

E. Bertran, M. Blanco, J. Coello, H. Iturriaga, S. Maspoch and I. Montoliu, Near infrared spectrometry and pattern recognition as screening methods for the authentication of virgin olive oils of very close geographical origins, J. Near Infrared Spectrosc., 8, 45-52 (2000). 

FIGURE 19.3 HPLC (SEC) traces of an extra virgin olive oil (A) sample containing TGP and (B) without TGP. 

Virgin olive oil/ Wax and stigmastadienes Virgin olive oil/ Volatile carbonyls... 

Virgin olive oil/TGP Virgin olive oil/ Triterphenic adds Virgin olive oil/ TAGs... 

The importance of the Mediterranean diet led to increased research activity on olive oils, which mainly focused, among other issnes, on phenolic substances becanse of their biological activities and of the fact that virgin olive oils are the only vegetable oils that contain them, while tocopherols are widely distributed in such foods. Phenolic substances are responsible for the typical taste of olive oils, characterized by fruity, bitter, and pungent flavors. 

The phenolic componnds content of virgin olive oils is not a composition parameter enclosed among those listed by the normative (EC Regulations, International Olive Oil Trade standard. Codex Alimentarins Standard), probably because of the widespread distribution of valnes... 

Determination of vitamin E different matrices Determination of all-rac-a-tocopherol in virgin olive oil... 

A widespread method for determining the induction period for autoxidation of oils and fats consists of passing a continuous stream of air through the heated sample and collecting the volatile acids evolved in a water trap, where they are determined on a real time basis. The time plot usually presents a flat appearance for a certain period and then takes off in an accelerated manner. This test is the basis of several national and international standards (e.g. AOCS Cd 12b-92—oil stability index" ISO 6886—accelerated oxidation test for oxidative stability of fats and oils ) and the design of the Rancimat equipment, where the end determination is based on conductivity measurements . In addition to oxidation stability as determined by the Rancimat method and POV, which negatively affects virgin olive oil stability, other nonstandard properties were proposed for better assessment of the quality of this oil, namely LC determination of Vitamin E (21), colorimetric determination of total polar phenols and UVD of total chlorophyll. ... 

Lo Scalzo, R., and M. L. Scarpati. A new secoiridoid from olive wastewaters. J Nat Prod 1993 56(4) 621-623. Montedoro, G., M. Servilli, M. Baldioli, R. Selvaggini, E. Miniati, and A. Macchioni. Simple and hydrolyzable compounds in virgin olive oil. 3. Spectroscopic characterizations of the secoiridoid derivatives. J Agr Food Chem 1993 41(11) 2226-2234. 

Perri, E., A. Raffaelli, and G. Sindona. OE067 Quantitation of oleuropein in virgin olive oil by ionspray mass spectrometry-selected reaction monitoring. J OE068 Agr Food Chem 1999 47(10) 4156-4160. 

OE212 Perona, J. S., J. Canizares, E. Montero, J. M. Sanchez-Dominguez, and V. Ruiz-Gutierrez. Plasma lipid modifications in elderly people after administration of two virgin olive oils of the same variety (Olea europaea var. hojiblanca) with different triacylgly-cerol composition. Br J Nutr 2003 89(6) 819-826. 

Oleuropein, a conjugate of hydroxytyrosol (3,4-dihydroxybenzyl alcohol), is a characteristic but very variable component of olives and olive oil. After consumption of 25 ml virgin olive oil, hydroxytyrosol, 3-(9-methylhydroxytyrosol (homovanillyl alcohol), and homovanillic acid increase in plasma, as conjugates, predominantly glucuronide ° Oleuropein may be deconjugated by the gut microflora. 

Brenes, M., Garcia, A., Dobarganes, M.C., Velasco, J., and Romero, C., Influence of thermal treatments simulating cooking processes on the polyphenol content in virgin olive oil, J. Agric. Food Chem., 50, 5962, 2002. 

Cosio, M. S., Ballabio, D., Benedetti, S., and Gigliotti, C. (2006). Geographical origin and authentication of extra virgin olive oils by an electronic nose in combination with artificial neural networks. Anal. Chim. Acta 567(2), 202-210. 

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