**1. Introduction**

162 Olive Oil – Constituents, Quality, Health Properties and Bioconversions

Taglauer, E A.W. Czanderna & D. M. Hercules (1991). Ion scattering spectroscopy, in Ion

Temime, S.B., Campeol, E., Cioni, P.L., Daoud, D. & Zarrouk, M. (2006). Volatile compounds

Tura, D., Prenzler, P.D., Bedgood, D.R., Antolovich, M. & Robards, K., (2004). Varietal and

Vichi, S. (2010)Extraction Techniques for the Analysis of Virgin Olive Oil Aroma. *Olives and* 

Vichi, S., Castellote, A.I., Pizzale, L., Conte, L.S., Buxaderas, S. & Lopez Tamames, E.( 2003).

Xu, X., and D. A. Willis, 2002, "Non-equilibrium phase change in metal induced by

nanosecond pulsed laser irradiation," *J. Heat Transfer*, 124:293-298.

from Chétoui olive oil and variations induced by growing area. *Food Chem.* 99, 315–

processing effects on the volatile profile of Australian olive oils. *Food Chem.* 84,

Analysis of virgin olive oil volatile compounds by headspace solid-phase microextraction coupled to gas chromatography with mass spectrometric and

Spectroscopies form Surface Analysis, *Plenum Publ. Co., New York*.

*Olive Oil Health and Disease Prevention* ISBN: 978-0-12-374420-3

flame ionization detection. *J. Chromatogr.* A 983, 19–23.

325

341–349.

Olive (*Olea europaea* L.) is one of the oldest agricultural tree crops worldwide and is an important source of oil with beneficial properties for human health. *Olive oil* is produced solely from the fruit of the olive tree (*Olea europaea* L.) and differs from most of the other vegetable oils in the method of extraction, allowing it to be consumed in crude form, hence conserving its vitamins and other natural healthy high-value compounds.

In comparison to commonly used vegetable oils, the cost of *olive oil* is higher. As such, *olive oil* is more prone against adulteration with other cheaper oils in order to increase profits. Several grades of *olive oil* are marketed which also command different prices. There is also the possibility of the addition of cheaper grades of *olive oil* to better graded ones for the same economic reasons. The presence in highly prized *olive oil*s of lower grade material is sometimes revealed by specific analytical methods.

Mixing low-grade sunflower, canola or other oil with olive's industrial chlorophylls, and flavouring it with beta-carotene has been brought to light and sold as *olive oil*. The FDA does not have the resources to test all the imported *olive oil* for adulteration, and some products are difficult to test. One can always expect adulteration and mislabeling *olive oil* products (Mueller, 1991). Christy et al., (2004) used near-infrared (NIR) spectra in the region of 12,000–4000 cm (-1) to detect adulteration of *olive oil* with sunflower oil, corn oil, walnut oil and hazelnut oil. It has reported that adulteration of virgin *olive oil* with hazelnut oil could be detected only at levels of 25% and higher with Fourier transform infrared spectroscopy (Kumar et al., 2011). However, Rabiei (2006) has reported the use of molecular approach in revealing hazelnut-adulterated *olive oil* at level of less than 10% of hazelnut.

Several methods have been proposed for monitoring the adulteration of virgin *olive oil*s with other edible oils. In the last 10 years, technology and knowledge have undergone a great advance in the fight against adulteration; however, in the same way, knowledge of defrauders has also been increased. This enables them to prepare more sophisticated adulterations that make useless the methodologies proposed to detect them. Those oils normally added to virgin *olive oil* can be, either *olive oil*s of lower quality (e.g. olive-pomace *olive oil* or virgin *olive oil* obtained by second centrifugation of the olives), or seed oils (e.g. corn, soybean, palm or sunflower oil, among others) (Peña et al., 2005).

Traceability of Origin and Authenticity of *Olive Oil* 165

Olive (*Olea europaea* L.) is the main cultivated species belonging to the monophyletic *Oleaceae* family that comprises 30 genera and 600 species, within the clade of Asterids, in which the majority of nuclear and organellar genomic sequences are unknown. The Olea genus includes 30 species and has spread to Europe, Asia, Oceania and Africa (Bracci et al., 2011). The wild olive or oleaster (*Olea europaea* subsp. *europaea* var. *sylvestris*) and the cultivated olive (*Olea europaea* subsp. *europaea* var. *europaea*) are two co-existing forms of the subspecies *europaea*  (Green 2002). Other five subspecies constitute the *Olea europaea* complex including *laperrinei*, present in Saharan massifs; *cuspidata*, present from South Africa to southern Egypt and from Arabia to northern India and south-west China; *guanchica* present in the Canary Islands; *maroccana* present in south-western Morocco; and *cerasiformis* present in Madeira (Green 2002). The Mediterranean form (*Olea europaea*, subspecies *europaea*) includes the wild and cultivated olives is a diploid species (2n = 2x = 46) (Kumar et al., 2011). The origin of the olive tree is lost in time, coinciding and mingling with the expansion of the Mediterranean civilisations which for centuries governed the destiny of mankind and left their imprint on Western culture.

The common olive is an evergreen tree that grows up to ∼12m in height with a spread of about 8 m. However, many larger olive trees are found around the world, with huge, spreading trunks. The trees are also tenacious, easily sprouting again even when chopped to the ground. Sometimes it is difficult to recognize which is the primary trunk. The tree can be kept at a height of about 5m with regular pruning. Olives are long-lived, with a life

Most olive-growing areas lie between the latitudes 30◦ and 45◦ north and south of the equator, although in Australia some of the recently established commercial olive orchards are nearer to the equator than to the 30◦ latitude and are producing a good yield; this may be

The olive fruit is termed a *drupe* botanically, which are green in color at the beginning and generally become blackishpurple when fully ripe. A few varieties are green even when ripe, and some turn a shade of copper brown. Olive fruits consist of a carpel, and the wall of the ovary has both fleshy and dry portions. The skin (exocarp) is free of hairs and contains stomata. The flesh (mesocarp) is the tissue that is eaten, and the pit (endocarp) encloses the seed. Olive cultivars vary considerably in size, shape, oil content and flavor. Raw olive fruits contain an alkaloid that makes them bitter and unpalatable. A few varieties are sweet

Olive cultivars are basically classified into "oil olives" and "table olives," and oil cultivars predominate. Olive cultivars are also classified according to the origin of the cultivar – for example, Spanish, Italian, Greek, Syrian, Moroccan, Israeli, etc. The most popular cultivars are: Picual, Arbequina, Cornicabra, Hojiblanca and Empeltre in Spain; Frantoio, Moraiolo, Leccino, Coratina and Pendolino in Italy; Koroneiki in Greece; Chemlali in Tunisia; Ayvalik in Turkey; Nabali, Suori and Barnea in Israel and The West Bank; Picholin in France; Mission in California; and various varieties in Australia. The table olive cultivars include Manzanilla and Gordal from Spain; "Kalamata" from Greece; "Ascolano" from Italy; and

**2. General description of olive plant** 

expectancy of greater than 500 years (Kumar et al., 2011).

because of their altitude or for other geographic reasons.

enough to be eaten after sun-drying (Wiesman, 2009).

"Barouni" from Tunisia (Jacoboni & Fontanazza, 1981; Weissbein, 2006).

It has long been known that the chemical composition of virgin *olive oil* is influenced by genetic (variety) and environmental (climatological and edaphologic conditions) factors. So the olive production area is greatly responsible for the specific characteristics of *olive oil*.

The analytical analyses have their limits. This has promoted a growing interest towards the application of DNA-based markers since it is independent from environmental conditions. Specific protocols for DNA isolation from *olive oil* have been developed (Breton et al., 2004; Busconi et al., 2003; Consolandi et al., 2008; De la Torre et al., 2004). The application of DNAbased methods requests the knowledge on nucleotide sequences of olive. This information for olive is back to 1994, when the first *Olea europaea* L. sequence has deposited in NCBI. Table 1 provides brief information on olive genomics presented on NCBI from 1994 to July 2011 consist of Nucleotides, ESTs and GSS accessions.

T*raceability* in food is a recently developed concept of control of the whole chain of food production and marketing that would trace back to each step of the process. In a narrower sense, *genetic traceability* is performed to find out the genetic identity of the plant material from which the transformed products have originated. The recognition of the genetic background underlying food products aims to prove the authenticity of valuable food and to discourage from the adulteration with extraneous material of lower cost and value. Recently, Rotondi et al., (2011) has performed *olive oil* traceability by means of a combination of the chemical and sensory analyses with SSR biomolecular profiles. Her group demonstrated that the genetic (SSR analysis) component and the selected fatty acids (eicosenoic, linoleic, oleic, stearic, palmitic and linolenic), seems to represent a possible tool for inter- and intra-varietal characterisation and for monovarietal traceability.


\*http://www.ncbi.nlm.nih.gov, \*\*EST: expressed sequence tags, \*\*\*GSS: genome survey sequences Table 1. Olive genomics information present on NCBI database from 1994 to July 2011

It has long been known that the chemical composition of virgin *olive oil* is influenced by genetic (variety) and environmental (climatological and edaphologic conditions) factors. So the olive production area is greatly responsible for the specific characteristics of *olive oil*.

The analytical analyses have their limits. This has promoted a growing interest towards the application of DNA-based markers since it is independent from environmental conditions. Specific protocols for DNA isolation from *olive oil* have been developed (Breton et al., 2004; Busconi et al., 2003; Consolandi et al., 2008; De la Torre et al., 2004). The application of DNAbased methods requests the knowledge on nucleotide sequences of olive. This information for olive is back to 1994, when the first *Olea europaea* L. sequence has deposited in NCBI. Table 1 provides brief information on olive genomics presented on NCBI from 1994 to July

T*raceability* in food is a recently developed concept of control of the whole chain of food production and marketing that would trace back to each step of the process. In a narrower sense, *genetic traceability* is performed to find out the genetic identity of the plant material from which the transformed products have originated. The recognition of the genetic background underlying food products aims to prove the authenticity of valuable food and to discourage from the adulteration with extraneous material of lower cost and value. Recently, Rotondi et al., (2011) has performed *olive oil* traceability by means of a combination of the chemical and sensory analyses with SSR biomolecular profiles. Her group demonstrated that the genetic (SSR analysis) component and the selected fatty acids (eicosenoic, linoleic, oleic, stearic, palmitic and linolenic), seems to represent a possible tool

for inter- and intra-varietal characterisation and for monovarietal traceability.

1994 3 3 1995 1 1 1996 1 1 1997 13 13 1998 1 1 1999 11 11 2000 39 39 2001 57 57 2002 57 57

2004 23 23 2005 213 213 2006 44 44

2008 186 186

07/2011 33

Year Olea europaea accessions on NCBI database\*

2003 88 64 24

2009 4891 55 4,836

Total sequences 7,869 1,793 6,019 24 \*http://www.ncbi.nlm.nih.gov, \*\*EST: expressed sequence tags, \*\*\*GSS: genome survey sequences Table 1. Olive genomics information present on NCBI database from 1994 to July 2011

2007 337 335 2

2010 1871 690 1,159 22

**Total nucleotide sequences Nucleotide EST**\*\* **GSS**\*\*\*

2011 consist of Nucleotides, ESTs and GSS accessions.
