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Phenolic Profiles of Portuguese Olives: Cultivar and Geographics
Rosa M. Seabra1, Paula B. Andrade1, Patrícia Valentão1, Miguel Faria2, Alistair G. Paice3 and Maria Beatriz P. P. Oliveira2
1REQUIMTE Serviço de Farmacognosia, Faculdade de Farmácia, Universidade do Porto, Portugal2REQUIMTE Serviço de Bromatologia, Faculdade de Farmácia, Universidade do Porto, Portugal3REQUIMTE Department of Clinical Biochemistry and Nutrition and Dietetics, King’s College School of Medicine, London, United Kingdom
Chapter 20
7
1Olives and Olive Oil in Health and Disease Prevention.ISBN: 978-0-12-374420-320.1 IntroductIon
According to FAO, olive is the most extensively cultivated fruit crop in the world. This can be attributed to the high nutritional value of its products, its tolerance to drought and salinity, and to its minimal maintenance require-ments. Although it can be found in the USA, Argentina and Mexico, it is in countries from the Mediterranean basin that olive groves have their main impact. Therefore, table olives and olive oil are characteristic components of the Mediterranean diet and are considered one of the fac-tors responsible for the low incidence of coronary heart disease and prostate, breast and colon cancers in this area (Covas, 2007).
The aforementioned health benefits of olives are par-tially attributed to their characteristic fatty acid composition but also micronutrients such as the tocopherol antioxidants and, above all, phenolic compounds. In fact, studies have shown that diets containing olive oil achieve better results than other diets containing equivalent amounts of oleic acid but lower amounts of phenolic compounds (Medeiros, 2001). Aside from its recognized role as a health promoter, the phenolic composition of olive oil has also been assayed as a tool to indicate the oil’s quality and to differentiate olive cultivars.
Portugal, although possessing a large Atlantic coast, is still considered a Mediterranean country; especially its eastern region, which is characterized by a climate and soil very similar to those observed in Spain, and where olive groves are a characteristic feature of the landscape. Although its oil production is much less than that of some other EU countries, it is comparable to that of Algeria and double that of Palestine (http:// www.internationaloliveoil.org).
7Copyright © 2010 Elsevier Inc.
All rights of reproduction in any form reserved.2010
This chapter intends to give an overview of Portuguese olive production and cultivars and to evaluate the role of phenolic profiles as possible markers.
20.2 Olea eurOpaea cultIvars and theIr dIfferentIatIon
Olea europaea is a highly variable species with a total of 1250 cultivars dispersed over 54 countries as referred to in the OLEA DATABASE (http://www.oleadb.it/). This large number of olive cultivars is partially explained by the fact that olive plants can survive for a long time, thus retain-ing their genetic characteristics for thousands of years. Furthermore, open crossing between individuals, environ-mental pressure and its long history as a crop have resulted in numerous cultivars (Hatzopoulos et al., 2002).
Traditionally, cultivars have been distinguished by their phenotypical characteristics. These include countless traits from the size, weight, shape and color of fruit to the preco-city of maturation, the pulp/stone ratio, size of leaves, yield of oil, resistance to disease, etc. (Pinheiro and Silva, 2005). Notwithstanding their major role and usefulness in char-acterizing cultivars, these markers can be affected by the environment, which may present a problem if they are to be used for identification. With the advent of specific chemical methodologies, the chemical composition of leaves, olives and olive oil began to be used as possible markers. Chemical constituents that have been used for this purpose include tocopherols, sterols, fatty acids (Matos et al., 2007), vola-tile compounds (Tura et al., 2004) and phenolic compounds (Vinha et al., 2005). Possible correlations between cultivar and biochemical (Briante et al., 2002) and physiological (Bacelar et al., 2007) behavior have also been studied.
sectIon | I Lipids, Phenolics and Other Organics and Volatiles178
In the search for new differentiation methodologies, researchers have over the last two decades begun to use molecular markers in olive characterization. Subsequently practically all the available molecular markers for plants have been applied in olive trees (Owen et al., 2005; Sarri et al., 2006).
20.3 PhenolIcs In olIve fruIts
In olives, phenolics may represent simple substances dis-tributed into several subgroups such as benzoic or cinnamic acids, glycosylated or free flavonoids (mainly luteolin, quer-cetin or apigenin based) or phenolic alcohols represented by tyrosol and hydroxytyrosol (and their glycosides and derivatives like cornoside and halleridone). Verbascoside is a slightly more complex molecule synthesized by grouping caffeic acid with rutinose and hydroxytyrosol. However, the phenolic profile of olives is predominantly characterized by the presence of a group of compounds with a mixed bio-synthetic origin (shikimate/mevalonate) where tyrosol or hydroxytyrosol are linked to an iridoid moiety giving rise to the so-called secoiridoid phenolics. Oleuropein and demeth-yloleuropein are the main examples of this. Olives and olive oil also characteristically contain the iridoidic component of the latter class of compounds but, as they are devoid of phe-nolic character, these will not be referred to in this chapter.
20.4 olIves In Portugal: cultIvars and ProductIon
A database organized by FAO (http://apps3.fao.org/wiews/olive/intro.jsp) includes 21 cultivars of Portuguese origin (data collected from the Portuguese Agronomical Stations). Table 20.1 displays those cultivars together with their main synonyms. The geographic distribution indicated refers to the provinces where the cultivars are grown which, as men-tioned above, are located in the inner part of Portugal (see Figure 20.1). However, reference to other Portuguese culti-vars such as Roupuda (Vinha et al., 2005) or Douro (Bianco and Uccella, 2000) can also be found in the literature.
As can be seen in Table 20.2, Portuguese olive groves are mainly located in Alentejo. In Portugal, olives are grown in small parcels, which represent a hindrance to high productivity but favor the creation of small, high-quality niches. Consumers wish for variety; products considered as safe, more palatable and produced by traditional meth-ods (regarded as ‘natural’) are now more desirable. In spite of its relatively small production, Portugal has seven olive oils registered as PDO (Protected Denomination of Origin) spread within the main producing areas (Figure 20.1).
According to data from EUROSTAT (2005) (http://www.oliveoil.eu), only 2% of the Portuguese olive production is devoted to the generation of table olives. As can be seen in
Table 20.3 the Portuguese eat more table olives than they produce. During the 1990s the average annual consumption was in the order of 15 200 tons, which equates to 1.5 kg/inhabitant/year (http://www.internationaloliveoil.org).
Table olives can be prepared from almost all the cul-tivars growing in Portugal but some cultivars are almost exclusively devoted to table olive. Negrinha is one example, with a low amount of oil production but very good charac-teristics for table olive. This cultivar is the only one used to produce ‘Negrinha do Freixo Table Olives’ PDO. The only other Portuguese table olive PDO is ‘Axeitona e Elvas e Campo Maior’. The Azeiteira, Carrasquenha, Conserva de Elvas and Redondil cultivars can be used for this.
Although olives as a fruit crop are probably the oldest cultivated fruit trees, the maintenance of their intraspecific diversity is a concern. Several factors threaten the existence of certain cultivars. Undoubtedly one of them is the substi-tution of rustic cultivars with more productive ones.
Portugal is no exception. In 2005 80% of the total acre-age of Portuguese olive groves was planted with Galega, a cultivar spread throughout the country. This cultivar is characterized by great productivity. However, when com-pared to Picual, a Spanish cultivar that is being introduced in Portugal, it has considerably lighter fruits (1.48 g com-pared to 4.20 g for Picual), a lower resistance to ‘Gafa’ (infection by Gloeosporium olivarum) and a smaller fat content (about 17% compared to 23% for Picual). Although the oil obtained from Galega is thought to be more accept-able to the public, there are obvious disadvantages for the Portuguese olive growers using it. Picual is not the only Spanish cultivar that can be found in Portuguese olive groves; other cultivars include Santulhana, Blanqueta, Cornicabra and probably others in small quantities.
20.5 characterIzatIon of cultIvars by theIr PhenolIc ProfIle
If, as we believe, cultivars have slight variations in their genomes, then the factor ‘cultivar’ must be the main source of variation in the composition in Olea europaea. However, we also know that external factors such as the climate, soil composition or agricultural practices can modulate gene expression (Romero et al., 2002; Morelló et al., 2003). Apart from genetic factors, one of the most influential intrinsic factors on the set of compounds found in a given cultivar is the degree of ripening. During the development of olives a large set of biochemical reactions takes place (Amiot et al., 1986; Vinha et al, 2005). Most reports point to a decrease of total phenolic content as ripening occurs (Gimeno et al., 2002; Beltrán et al., 2005; Morelló et al., 2005). This decrease does not occur at the same rate for all compounds and in the same way in different cultivars (Morelló et al., 2005). Some authors believe these differ-ences could even be used to differentiate cultivars.
chaPter | 20 Phenolic Profiles of Portuguese Olives: Cultivar and Geographics 179
Table 20.1 Olea europaea Portuguese cultivars.
Cultivar Main synonyms Distribution Uses
Azeitoneira Azeiteira Alentejo Table/oil
Bical* BicudaBical de castelo BrancoLongalCordovil-bical
Beira AltaAlentejoAlgarve
Table/oil
Branquita BlanquetaBlanqueta de Elvas
RibatejoAlto e Baixo Alentejo
Table/oil
Carrasquenha CarrascaCarrasquinhaRedondaSalola
BeirasAlto AlentejoBaixo Alentejo
Table/oil
Cobrançosa* CoutiniaQuebrançosaVerdeal cobrançosa
Trás-os-MontesAlentejo
Oil
Conserva de Elvas Alto e Baixo Alentejo
Table/oil
Cordovesa* CordovilCordovil de ElvasVermelhalBico de corvoCordovil de Serpa
AlgarveAlto AlentejoBaixo Alentejo
Table/oil
Cordovil* Cordovil de Castelo BrancoCordovil GrossoCordovil Nocal
Trás-os-MontesBeira AltaBeira Baixa
Table/oil
Galega* Galega vulgarGalega comumMolarMolarinhaNegra molar
Trás-os-MontesBeiraRibatejoAlentejo
Table/oil
Galega grada de Serpa Galega grossa redondaGalega grada
AlentejoAlgarve
Table/oil
Golosinha GlozinhaGolosinha mançanicaPele de sapo
Alentejo Table/oil
Lentisca* BorreiraBorrentaBrunhentaCarrasca BicalCarrasca NegralCorlideiraZambulha
Trás-os MontesEstremaduraRibatejoAlto AlentejoBaixo Alentejo
Oil
Madural* ComumCornicabra de Trás-os-MontesMadural finaMadural grossaNegra volumosa
Trás-os-MontesBeira-Alta
Table/oil
(Continued)
sectIon | I Lipids, Phenolics and Other Organics and Volatiles180
Table 20.1 (Continued)
Cultivar Main synonyms Distribution Uses
Mançanilha algarvia Mançanilha acuminada AlentejoAlgarve
Table/oil
Mançanilha carrasquenha Maçanilha carrasca Alto Alentejo Table/oil
Negrinha* Galego negrãoNegruxa
Trás-os-Montes Table
Redondal RedondaRedondil GrossoRoupudo
Trás-os-Montes Table/oil
Redondil Mançanilha meuda Alto e Baixo AlentejoRibatejo
Table/oil
Tentilheira AmendoeiraTentilheira acuminata
Alto Alentejo Table/oil
Verdeal transmontana* Verdeal Trás-os-MontesBeira Alta
Table/oil
Verdeal alentejana VerdealVerdeal de SerpaVerdeal tintoVerdeais
AlentejoAlgarve
Table/oil
*Cultivars that were subjected to phenolic analysis (Vinha et al., 2005).
Given that all these potential influences exist, extreme care must be taken when choosing and/or collecting the samples to be analyzed if a ‘chemical fingerprint’ (in this case a phenolic fingerprint) is to be generated. A hetero-geneous sampling requires wide sampling and the use of substantial statistical analysis of any results produced.
A ‘chemical fingerprint’ (or a ‘chromatographic fin-gerprint’ as chromatography is the usual technique used) represents a qualitative and quantitative chromatographic pattern of characteristic compounds within a sample. According to Gong and co-workers (Gong et al., 2003) this chromatographic profile should feature the fundamental attributes of ‘integrity’ and ‘fuzziness’ or ‘sameness’ and ‘differences’. These attributes suggest that, with the help of a constructed chromatographic fingerprint, the authentica-tion and identification of a natural (complex) product can be accurately conducted (‘integrity’) even if the number and/or concentration of chemically characteristic constitu-ents are dissimilar from sample to sample (‘fuzziness’) or, chromatographic fingerprints could demonstrate both the ‘sameness’ and ‘differences’ between samples. Given what is summarized above with respect to the variability of natu-ral products, the construction of a reliable chromatographic fingerprint is no trivial undertaking. Too much analysis and
mathematical work are required! From the extensive litera-ture on this subject the nature of the phenolic compounds present in olives is very important. However, as far as we know there is no work defining a general quantitative profile for Olea europaea fruits or for their numerous cultivars.
The main factor preventing further understanding in this field is the differing methodologies used in its analy-sis. Different experimental procedures have been used to extract, separate and detect different compounds and this is the main reason why, in any given work, the authors cannot find the complete set of phenolics described in the review papers (Table 20.4).
Bearing in mind all these limitations it is likely that col-lating data from different papers to try to compare cultivars will be met with very limited success.
20.6 PhenolIc ProfIles of Portuguese cultIvars
As far as we know, there is only one paper reporting the phenolic profiles of Portuguese cultivars (Vinha et al., 2005). Using a simple methodology previously developed
chaPter | 20 Phenolic Profiles of Portuguese Olives: Cultivar and Geographics 181
A: Trás-os-Montes;B: Beira Alta;C: Beira Baixa;D: Ribatejo;E: Alto Alentejo;F: Baixo Alentejo;G: Algarve;
1: Trás-os-Montes olive oil;2: Beira Alta olive oil;3: Beira Baixa olive oil;4: Ribatejo olive oil;5: Norte Alentejano olive oil;6. Alentejo-Interior olive oil;7: Moura olive oil.
Capital letters refer to provinces (areas surrounded by full lines);numbers refer to locations of PDO olive oils (areas surrounded bydashed lines).
F
76
E
5D
4
3C
B 2
A 1
SPAIN
SPA
IN
G
fIgure 20.1 Distribution of olive groves and PDO olive oils in Portugal. The figure illustrates the provinces where olive groves are pre-dominantly located together with the regions where PDO olive oil produc-tion occurs.
for this (Vinha et al., 2002), the authors analyzed samples from nine of the 21 cultivars listed in Table 20.1 plus three cultivars of Spanish origin cultivated in Portugal. Picual, Cornicabra and Santulhana and Roupuda were labeled as Portuguese but not registered by FAO (Table 20.1). The dry weight results obtained indicated an overall profile characterized by high levels of hydroxytyrosol and oleuro-pein (Table 20.5 and Figure 20.2) with very low amounts of chlorogenic acid (below 12 mg kg1) and low amounts of verbascoside (usually below 0.02% of total pheno-lics). The colored phenolics were those usually described, namely cyanidin 3-glucoside and cyanidin 3-rutinoside,
Table 20.2 Data for Portuguese olive groves.
Region Area (ha) Area (%)
Trás-os-Montes (A*) 70 000 21
Beira Alta (B*) and Beira Baixa (C*) 60 000 18
Ribatejo (D*) 40 000 12
Alto Alentejo (E*) and Baixo Alentejo (F*)
150 000 44
Remaining 20 000 6
total 340 000 100
Capital letters in brackets refer to provinces listed in legend of Figure 20.1.
Table 20.3 Data for Portuguese table olives.
Tonnes % in EU
Production 1995/6–2000/12001/2–2006/7
950010 700
2.01.5
Imports 1995/6–2000/12001/2–2006/7
300300
0.50.4
Exports 1995/6–2000/12001/2–2006/7
48005100
3.12.2
Consumption 1995/6–2000/12001/2–2006/7
11 80013 100
3.12.3
with the latter always in higher amounts than the former. As expected, there was a good (but not strict) correlation between the amounts of these compounds and the matura-tion indices. Five non-colored flavonoids were also found: luteolin 7-glucoside, rutin, apigenin 7-glucoside, quer-cetin 3-rhamnonise and luteolin. In 25 out of 29 samples analyzed, luteolin 7-glucoside and rutin were the pre-dominant flavonoids and, in general, rutin was present in higher amounts than the luteolin derivative. This seems to be a characteristic of the general olive profile since these two compounds are always reported in cultivars from other countries, even when other flavonoids are not found (Table 20.4).
Although it is generally reported that the phenolic con-tent of cultivars decreases during ripening, we did not find that this was true for the cultivars under discussion. For example, the theory that hydroxytyrosol is a degradation
sectIon | I Lipids, Phenolics and Other Organics and Volatiles182
Table 20.4 Non-colored phenolic profiles of olives.
Reference Number of cultivars
Geographic origin
Extractive method
Identified phenolics
Phenolic alcohols (glucosides, esters and derivatives)
Flavonoids Phenolic acids and derivatives
Amiot et al. (1986)
11 France 80% ethanol; cleaning of water phase by petroleum ether; LLE with ethyl acetate
Oleuropein Lut 7-GluRutin
Verbascoside
Esti et al. (1998)
6 Italy As in Amiot et al. (1986) HydroxytyrosolDemethyloleuropeinOleuropein
Lut 7-GluRutin
Romani et al. (1999)
5 Italy 80% ethanol; cleaning of water phase by n-hexane;cleaning by SPE and recover of compounds by ethyl acetate
TyrosolHydroxytyrosolDemethyloleuropeinOleuropein
Lut 7-GluRutinApi 7-Rut and Api 7-RutQuer 3-RutLuteolinHomoorientin
VerbascosideVanillic acidp-Coumaric acidvanillin
Vinha et al. (2005)
10 3
PortugalSpain
Methanol; cleaning of methanolic extract by SPE and recover of compounds by methanol
TyrosolHydroxytyrosolOleuropein
Lut 7-GluRutinApi 7-GluQuer 3-RhamLuteolin
5-CaffeoylQuiVerbascoside
Bianco and Ucella (2000)
1 1 1
PortugalGreeceSpain
Simple biophenols (BP)(ext by 6 N HCl)
HydroxytyrosolTyrosol
Caffeic acidp-Coumaric acidHydroxycaffeic acid
Alkali hydrolysable biophenols (extracted by 2N NaOH)
HydroxytyrosolTyrosol
Caffeic acidp-Coumaric acidHydroxycaffeic acid
Cytoplasmic biophenols (extracted by CH2Cl2 and study of the aqueous fraction)
HydroxytyrosolTyrosolDemethyloleuropeinOleuropeinOleuropein derivativesThree Hydroxytyrosol GlucosidesTyrosol-1-glucosideCornosideHalleridone
Soluble BP soluble esterified BP insoluble-bound BP fraction (extracted by methanol:acetone 1:1)
HydroxytyrosolTyrosolOleuropeinDemethyloleuropein
Protocatechuic acid3,4-diOH-phenylacetic acidp-OH-benzoic acid
Vanillic and homovanillic acidsCinnammic and caffeic acidsSyringic acido-, m- and p-Coumaric acidsFerulic and sinapic acids
chaPter | 20 Phenolic Profiles of Portuguese Olives: Cultivar and Geographics 183
Table 20.5 Characteristics of Portuguese samples under discussion.
Cultivars Geographical origin Maturation index Sum of identified phenolics (mg kg1)
Hydroxytyrosol oleuropein
Flavonoids
Bical Macedo de Cavaleiros (A)Mogadouro (A)Fundão (B)Castelo Branco (C)
3.42.52.53.3
20 53910 357
96848264
468773859386
Cobrançosa Valpaços (A)Mirandela (A)Mogadouro (A)Fundão (C)
4.03.92.43.1
422867439426
16 166
13671461383
1224
Cordovesa Macedo de Cavaleiros (A) 3.6 7422 1532
Cordovil Fundão (C)Castelo Branco (C)
3.83.3
15 8023487
13301380
Galega Fundão (C)Castelo Branco (C)
4.14.2
42552791
4721537
Lentisca Valpaços (A)Valpaços (A)Mirandela (A)Mogadouro (A)
2.83.83.33.3
49 35480873169
14 774
16271152574
2399
Madural Valpaços (A)Mirandela (A)Mogadouro (A)
3.34.33.3
11 68667033093
161920911016
Madural fina Mogadouro (A) 3.2 73 467 1673
Negrinha Figueira de Castelo Rodrigo (A)
6.2 12 764 1452
Roupuda* Mogadouro 1.5 13 712 1937
Verdeal Transmontana
Mirandela (A)Valpaços (A)Macedo de Cavaleiros (A)
4.12.24.6
59604276
29 406
364443
1172
Capital letters in brackets refer to provinces where samples were collected.*Cultivar not listed by FAO in Table 20.1.
product of oleuropein and, therefore, hydroxytyrosol increases as oleuropein decreases, was not observed in this study. In fact, samples with higher maturation indices did not show any increase in the hydroxytyrosol/oleuropein ratio and no correlation was found between maturation index and hydroxytyrosol content, even for the same culti-var. The same can be said for the content of luteolin, since no correlation was found between the maturation index and the content of luteolin. It is generally accepted that free fla-vonoids appear at the end of the maturation process as a consequence of hydrolytic phenomena.
The differentiation of cultivars was only possible at the quantitative level. Some trends were seen but, as found in other matrices (Dopico-García et al., 2008), the influence of geographical origin often surpassed that of the cultivar. Different cultivars with the same geographical origin showed very similar profiles. Of course, this may indicate that extrinsic factors had a strong influence on the expression of the genome. Alternatively, these cultivars may have had very similar genomes, or they may have been mislabeled.
The heterogeneity of the sampling (Table 20.5) ensures that this work must be considered as preliminary. As such
sectIon | I Lipids, Phenolics and Other Organics and Volatiles184
80000A
C
E F
D
B1200
800
400
0
1200
800
400
0
1200
800
400
0
1200
800
400
04.3 3.3
2.5/Bical 2.5/Madural
3.2 3.3*
1200
800
400
0
4.6
4.0/Valpaços 3.9/Mirandela
3.1/Fundão 3.3/Castelo Branco
3.1/Fundão 2.4/Mogadouro
4.1 2.2
60000
40000
20000
0Madural fina
Cultivars
Madural
Mogadouro
MI/cultivar
MI
MI
MI/origin
MI/origin
Hydroxytyrosol and Oleuropein Verdeal
Cobrançosa
Cobrançosa/Cordovil
Lentisca Average
mg
kg−1
mg
kg−1
mg
kg−1
mg
kg−1
mg
kg−1
mg
kg−1
Hydroxytyrosol Luteolin 7-glucoside Rutin Quercetin 3-rhamnosideLuteolinApigenin 7-glucoside Oleuropein
fIgure 20.2 Selected data for phenolics in Portuguese samples. This figure depicts the major components of the non-flavonoid (A) or the flavonoid (B–F) profile for Portuguese cultivars exhibiting intracultivar or intrageographical similarities.
one cannot draw any sound conclusions about the individ-ual profiles of each cultivar, but this approach does raise possibilities that might be confirmed by further studies. For example, with respect to hydroxytyrosol and oleuro-pein, the samples (and therefore cultivars) are very homo-geneous, with the notable exceptions of Madural Fina and Lentisca (Figure 20.2A). In these cultivars the levels are very high. Two notes of caution must be added. Madural Fina is not recorded as a synonym of Madural (Table 20.1). This may indicate that it is an independent cultivar. We must also add that we analyzed samples of Lentisca (Table 20.5); however, three of these reached the labora-tory labeled as Borrenta or Borreira (Table 20.1) and only one as Lentisca (Valpaços, MI 2.8). As can be seen from Table 20.5 it is unlikely that this difference in the level of hydroxytyrosol and oleuropein can be attributed to differ-ent maturation index or geographical origin. Again we pro-pose that this cultivar deserves further attention, and that it may be heterogeneous. From the analysis of oleuropein and hydrxytyrosol content no other conclusions can be drawn.
Flavonoids may be more useful in cultivar differentia-tion. In Verdeal Transmontana, three of the four samples analyzed had characteristically low amounts of flavonoids (Figure 20.2B). The observed exception may reflect a higher maturation index or a differing geographical origin. The cultivar Bical had slightly more flavonoids and seems to be reasonably homogeneous with respect to the quanti-ties of flavonoids. Madural and Cordovil have consistently higher flavonoid contents. Madural is the only cultivar where luteolin-7-glucoside content resembles that of rutin (Figure 20.2C). Cobrançosa (n 4) (Figure 20.2D), Galega (n 2) and Lentisca (n 4) were more heteroge-neous with respect to the proportion of flavonoids.
To evaluate the influence of geographical origin on the characteristics of the phenolic profile, the pair of sam-ples collected in Mogadouro but from different cultivars is noteworthy (Figure 20.2E). Of course, similarities are observable among samples from different cultivars with different geographical origins (Figure 20.2F), but these are exceptions.
chaPter | 20 Phenolic Profiles of Portuguese Olives: Cultivar and Geographics 185
20.7 conclusIon
In conclusion, the phenolic composition of olives is an important concept. However, although a lot of knowledge has already been gained in this area, the many factors influ-encing phenolic profile have thus far prevented the estab-lishment of a general ‘phenolic profile of olive fruits’. Of course, the phenolic profiles for each cultivar area are not yet fully characterized. There are a large number of regis-tered cultivars and the number of cultivars analyzed in the literature is always very small. To study the effect of the cultivar’s character on the phenolic profile in isolation it is necessary to correct for all the other main variables that may influence this. Examples of these confounding variables might include geographical origin, maturation index and the analytical methodology. Since it is also known that climatic factors can affect the composition of organisms, it is also necessary to monitor compositional changes over several years to monitor the effect of differing weather conditions. This would be a Herculean task, involving a huge number of samples – discouraging for a single laboratory to under-take. Overall, despite the considerable number of techniques applied and the large amount of published literature on the subject, olive cultivars are far from being fully characterized and continuing efforts will have to be made in order to solve problems such as mislabeling, homonyms and synonyms.
summary PoInts
l Portugal, although having only an Atlantic coast, is still a Mediterranean country and is responsible for 2% of olives produced in the EU.
l Twenty-one cultivars are registered in Agronomical Stations as having Portuguese origin.
l Chemical profiles have revealed themselves as a some-what useful tool for species and cultivar differentiation.
l Since phenolics are recognized as health promoter com-pounds, it would be doubly useful to use the phenolic profile as a differentiation tool for olive cultivars.
l At a qualitative level, the phenolic compounds identi-fied so far in olive fruits have revealed some constancy, in spite of the numerous factors that can affect them.
l However, little information is still available for depict-ing olive fruit quantitative phenolic profile, exactly because those factors exert influence on the levels of compounds.
l The possibility of using the phenolic profile as a marker for olive cultivars is still under study and many studies are still needed to attain such a goal.
references
Amiot, M.-J., Fleuriet, A., Macheix, J.-J., 1986. Importance and evolu-tion of phenolic compounds in olive during growth and maturation. J. Agric. Food Chem. 34, 823–826.
Bacelar, E., Moutinho-Pereira, J.M., Gonçalves, B.C., Ferreira, H., Correia, C.M., 2007. Changes in growth, gas exchange, xylem hydraulic properties and water use efficiency of three olive cultivars under contrasting water availability regimes. Environ. Exper. Bot. 60, 183–192.
Beltrán, G., Aguilera, M.P., Del Rio, C., Sanchez, S., Martinez, L., 2005. Influence of fruit ripening process on the natural antioxi-dant content of Hojiblanca virgen olive oils. Food Chem. 89, 207–215.
Bianco, A., Uccella, N., 2000. Biophenolic components of olives. Food Res. Inter. 33, 475–485.
Briante, R., Patumi, M., Limongelli, S., Febbraio, F., Vaccaro, C., Di Salle, A., La Cara, F., Nucci, R., 2002. Changes in phenolic and enzy-matic activities content during fruit ripening in two Italian cultivars of Olea europaea L. Plant Sci 162, 791–798.
Covas, M.-I., 2007. Olive oil and the cardiovascular system. Pharmacol. Res. 55, 175–186.
Dopico-García, M.S., Fique, A., Guerra, L., Afonso, J.M., Pereira, O., Valentão, P., Andrade, P.B., Seabra, R.M., 2008. Principal compo-nents of phenolics to characterize red Vinho Verde grapes: anthocy-anins or non coloured compounds? Talanta 75, 1190–1202.
Esti, M., Cinquant, L., La Notte, E., 1998. Phenolic compounds in differ-ent olive varieties. J. Agric. Food Chem. 46, 32–35.
Gimeno, E., Castellote, A.I., Lamuela-Raventós, R.M., De La Torre, M.C., López-Sabater, M.C., 2002. The effect of harvest and extraction methods on the antioxidant content (phenolics, -tocopherol and -carotene) in virgin olive oil. Food Chem. 78, 207–211.
Gong, F., Liang, Y.-Z., Xie, P., Chau, F.-T., 2003. Information theory applied to chromatographic fingerprint of herbal medicine for quality control. J. Chromat. A 1002, 25–40.
Hatzopoulos, P., Banilas, G., Giannoulia, K., Gazis, F., Nikoloudakis, N., Milioni, D., Haralampidis, K., 2002. Breeding, molecular markers and molecular biology of the olive tree. Eur. J. Lipid Sci. Technol. 104, 574–586.
Matos, L.C., Cunha, S.C., Amaral, J.S., Pereira, J.A., Andrade, P.B., Seabra, R.M., Oliveira, B.P.P., 2007. Chemometric characterization of three varietal olive oils (Cvs Cobrançosa, Madural and Verdeal Transmontana) extracted from olives with different maturation indi-ces. Food Chem. 102, 406–414.
Medeiros, D.M., 2001. Olive oil and health benefits. In: Wildman, R.E.C. (ed.), Handbook of Nutraceuticals and Functional Foods. CRC Press, London, pp. 261–266.
Morelló, J.-R., Romero, M.-P., Ramo, T., Motilva, M.-J., 2005. Evaluation of L-phenilalanine ammonia-lyase activity and phenolic profile in olive drupe (Olea europaea L.) from fruit setting period to harvesting time. Plant Sci. 168, 65–72.
Morelló, J.-R., Motilva, M.-J., Ramo, T., Romero, M.-P., 2003. Effect of freeze injuries in olive fruit on virgin olive oil composition. Food Chem 84, 547–553.
Owen, C.A., Bita, E.-C., Banilas, G., Hajjar, S.E., Sellianakis, V., Aksoy, U., Hepaksoy, S., Chamoun, R., Talhook, S.N., Metzidakis, I., Hatzopoulos, P., Kalaitzis, P., 2005. AFLP reveals structural details of genetic diversity within cultivated olive germplasm from the Eastern Mediterranean. Theor. Appl. Genet. 110, 1169–1176.
Pinheiro, P.B.M., Silva, E., 2005. Chemometric classification of olives from three Portuguese cultivars of Olea europaea L. Analyt. Chim. Acta 544, 229–235.
Romani, A., Mulinacci, N., Pinelli, P., Vincieri, F., Cimato, A., 1999. Polyphenolic content in five Tuscany cultivars of Olea europaea L. J. Agric. Food Chem. 47, 964–967.
sectIon | I Lipids, Phenolics and Other Organics and Volatiles186
Romero, M.P., Tovar, M.J., Girona, J., Motilva, M.J., 2002. Changes in the HPLC phenolic profile of virgin olive oil from young trees (Olea europeae L. Cv Arbequina) grown under different deficit irrigation strategies. J. Agric. Food Chem. 50, 5349–5354.
Sarri, V., Baldoni, L., Porceddu, A., Cultrera, N.G.M., Contento, A., Frediani, M., Belaj, A., Trujillo, I., Cionini, P.G., 2006. Microsatellite markers are powerful tools for discriminating among olive cultivars and assigning them to geographically defined populations. Genome 49, 1615–1616.
Tura Jr., D., Prenzler, P.D., Bedgood, D.R., Antolovich, M., Robards, K., 2004. Varietal and processing effects on the volatile profile of Australian olive oils. Food Chem. 84, 341–349.
Vinha, A., Silva, B., Andrade, P., Seabra, R., Pereira, J.A., Oliveira, M.B.P.P., 2002. Development and evaluation of a HPLC/DAD method for the analysis of phenolic compounds from olive fruits. J. Liq. Chrom. & Rel. Technol. 25, 151–160.
Vinha, A.F., Ferreres, F., Silva, B.M., Valentão, P., Gonçalves, A., Pereira, J.A., Oliveira, M.B., Seabra, R.M., Andrade, P.B., 2005. Phenolic profiles of Portuguese olive fruits (Olea europaea L.): influence of cultivar and geographical origin. Food Chem. 89, 561–568.
