Caballero B. (ed.) Encyclopaedia of Food Science, Food Technology and Nutrition. Ten-Volume Set

Подождите немного. Документ загружается.

0005 The International Olive Oil Council (IOOC), es-

tablished in 1959, is the intergovernmental organiza-

tion responsible for administering the International

Agreement on Olive Oil and Table Olives. This agree-

ment has been negotiated at the United Nations and

lays down the policy that members should take for

standardization of the market for olive oil, olive-

pomace oil, and table olives. The Agreement is

renewed regularly (for the time being, the 1986 Agree-

ment has been prolonged until 31 December 2000).

Principles and provisions set are compulsory in inter-

national trade, recommended in domestic trade, and

incorporated in the trade standards for olive oil and

olive-pomace oil.

0006 According to recent IOOC reports, the increasing

production of olive oil in Europe, as well as in the rest

of the world, has led to a drop in prices and to a

concomitant rise in consumption. Data concerning

consumption in 1998/1999 and estimated consump-

tion for 1999/2000 are given in Table 2. Similar

trends stand for the year 2001/2002. Olive oil con-

sumption is practically concentrated in the producing

countries. The average annual per-capita consump-

tion of olive oil reflects the economic policy and

culinary traditions of each producing country. Thus,

consumption that is reported for Greek consumers

(19.5 kg) is twofold higher than that in Italy or Tu-

nisia. In France and in the countries of central and

northern Europe, consumption of olive oil is very

low. In the last decade, there has been a significant

increase in olive oil consumption. In countries such

as Germany, Denmark, UK, and Ireland, the esti-

mated per-capita per-year consumption in the last

2 years has been around 0.5–0.6 kg. In the USA and

Canada, similar estimates are approximately 0.8 kg.

The results of the ‘Seven Countries Study’ related the

low rate of coronary heart disease among the Cretan

population to the regular consumption of virgin olive

oil. This was the first scientific evidence for the

nutritional role of this ‘high-in-monounsaturates’

juice. Currently, the interest is focused on the role of

olive oil in the prevention of bone and nervous-system

functions, digestion, antiageing properties at cell and

mitochondrial levels, diabetes, and breast tumors,

and also in the preventive role of some of its minor

constituents in the oxidation of low-density lipopro-

tein (LDL). (See Coronary Heart Disease: Etiology

and Risk Factor; Antioxidant Status; Prevention.)

Commercial Types of Olive Oil

0007Olive oil is marketed in accordance with the designa-

tions of Table 3. Virgin olive oil is obtained by only

mechanical or other physical means under conditions,

particularly thermal, which do not lead to alterations

in the oil. This oil has not undergone treatment other

than washing, decantation, centrifugation, and filtra-

tion. Extra, fine, and ordinary virgin olive oils are

different edible grades of virgin olive oil. Lampante

is a nonedible grade of virgin olive oil suitable for

refining or other technical uses. Refined olive oil is the

oil refined by the methods used for other vegetable

oils. These include neutralization, decolorization with

bleaching earth, and deodorization. Olive oil is an

edible blend of virgin olive oil and refined olive oil.

Olive-pomace oil is obtained by solvent extraction of

the cakes derived from olive milling. The triacylgly-

cerol composition is similar to that of virgin olive oil,

but some of the nonsaponifiable compounds differ

significantly. Due to the high content of waxes, the

oil has to be winterized before refining. Olive-pomace

oil can be used as a mixture with virgin olive under

the designation ‘olive-pomace oil.’ This oil cannot be

called ‘olive oil.’ Virgin olive oils may also be traded

as ‘appelation d’origin’ products in accordance with

the existing legislation (e.g., EC Regulation 2081/92).

(See European Union: European Food Law Harmon-

ization.)

tbl0002 Table 2 World olive oil consumption

Country 1998/1999 (tonnes) Percentage share 1999/2000 (tonnes, estimated) Percentage share

European Union 1 669 000 70 1 679 000 71

USA 157 000 7 160 500 7

Turkey 97 000 4 60 000 2.5

Syria 88 000 4 85 000 3.5

Tunisia 49 000 2 65 000 3

Morocco 55 000 2 50 000 2

Algeria 35 000 1 29 000 1

Other producing countries 142 000 6 139 000 6

Other nonproducing countries 92 500 4 92 500 4

Total 2 385 200 100 2 359 900 100

Data from IOOC (1999) Trade Standards Applying to Olive Oil and Olive Pomace Oil. COI/T. 15/NC, Doc. No. 2; rev. 9. Madrid: International Olive Oil

Council.

4254 OLIVE OIL

Olive-oil Extraction

0008 There are three extraction procedures currently used

to separate the oil from the other phases in the

paste, liquid or solid. These are pressure, centrifuga-

tion, and percolation. Specialized manufacturers

provide suitable machinery for the proper extraction

of olive oil.

Pressure

0009 This is the oldest method but is still in use. In this

system, the paste is pressed to release an oily must

(olive þvegetation water) (Figure 5). The liquid phase

separates from the solid phase with the help of the

drainage effect of the mats and the stone fragments. A

cake is formed between the mats, while the two liquid

phases (oil and vegetation water) are separated by

centrifugation.

Centrifugation or Three-phase Systems

0010 The crushed olives are mixed with water. A horizon-

tal centrifuge (Figure 6) separates the mass into

pomace and must, which is further separated into

oil and vegetation water. In the 1970s and 1980s,

three-phase centrifuges replaced pressure systems to a

great extent to cut processing costs and to reduce olive

storage time. A recent innovation to reduce polyphe-

nol losses is the so-called two-phase system, which is

able to separate the oily phase without the addition of

water. The oily phase is separated from the paste to

give oil and water plus husks.

Percolation

0011A steel plate is plunged into olive oil paste. When it is

withdrawn, it will be coated with oil because of the

different surface tensions of the liquid phases (the

metal phase is coated with a skin of oil). The system

fig0005Figure 5 (see color plate 117) Hydraulic pressure unit (cour-

tesy of ELAIS SA, Piraeus, Greece).

tbl0003 Table 3 Quality criteria for olive oils and olive-pomace oils

Extra

virgin

olive oil

Virgin

olive

oil

Ordinary

virgin

olive oil

Lampante

virgin

olive oil

Refined

olive oil

Olive oil

Crude

olive-pomace

oil

Refined

olive-pomace

oil

Olive -pomace

oil

1. Organoleptic characteristics:

Panel test score

(scale 1–9)

6.5 5.5 3.5 3.5

Odor and taste Acceptable Good Acceptable Good

Color Light yellow Light yellow

to green

Light yellow

to brownish

yellow

Light yellow

to green

Aspect at 20



for 24 h

Limpid Limpid Limpid Limpid

2. Free acidity % m/m

(expressed as oleic

acid)

1.0

2.0 3.3 >3.3 0.3 1.5

No limit 0.3 1.5

3. Peroxide value

(mEq peroxide oxygen

per kg oil)

20 20 20 No limit 5.0 15 No limit 5 15

4. Absorbance in

ultraviolet (K

1cm

)

270 nm 0.25 0.25 0.30

No limit

1.10 0.90 2.00 1.70

D K 0.01 0.01 0.01 0.16 0.15 0.20 0.18

0.8;

Banning of the category agreed in the EC;

After passage of the sample through activated alumina, absorbance at 270 nm shall be equal to or

less than 0.11;

commercial name is discussed;

1 proposed.

Data from IOOC (1999) Trade Standards Applying to Olive Oil and Olive Pomace Oil. COI/T. 15/NC, Doc. No. 2; rev. 9. Madrid: International Olive Oil

Council.

OLIVE OIL 4255

is combined with a continuous horizontal centrifuge

to increase the capacity.

Cold Pressing

0012 Cold pressing is the extraction process of olive oil

from olive paste at a temperature of less than 25



Milling Conditions and Quality of Olive Oil

0013 Traditional pressure-extraction systems yield good-

quality oil when olives are in good condition and

good manufacturing practice is applied. Percolation

(selective filtration) also provides good-quality oil.

Centrifugation plants have a larger hourly processing

capacity and significant practical advantages. In such

systems, however, the paste has to be thinned with

warm water. This lowers the level of polar natural

antioxidants, which have been associated with the

storage stability of the oil and its beneficial health

effects. Depending on the variety and stage of matur-

ity of olives, different crushing systems are necessary

to obtain the optimum polyphenol content and better

aroma characteristics. Stone mills yield oils with a

good aroma and less intense bitter taste than metal-

disk crushers because of a lower polyphenol content.

Hammer crushers usually yield oil with a characteris-

tically high content of polyphenols. The malaxation

time and temperatures are also critical for the aroma

and quality.

0014 Other methods to improve the quality and organo-

leptic scores during milling are based on the use of

pectolytic and cellulolytic enzymes. The International

Olive Oil Council, however, does not accept such

techniques because olive oil is by definition obtained

from the fruits of olive tree only by ‘physical means.’

Olive Oil Composition

0015 The composition of olive oil is primarily triacylgly-

cerols and secondarily free fatty acids, and some

0.5–1.5% of nonglyceridic constituents. The Codex

Alimentarius Commission, the IOOC, and the Com-

mission of the European Union provide identity and

compositional characteristics for olive oil and olive-

pomace oil.

0016EEC Regulation 2568/91 and subsequent amend-

ments (EC 2632/94, EC 656/95, and EC 2472/97) set

the limits for fatty acid composition and content in

sterols, waxes, saturated fatty acids in position-2 of

triacylglycerols, erythrodiol þuvaol, trilinolein and

trans unsaturated fatty acids and also for specific

absorption at various wavelengths. These limits are

very strict and aim at protecting good-quality olive

oil, and especially virgin olive oil, from adulteration.

The same directives also define analytical methods.

(See Fatty Acids: Properties; Analysis.)

0017Extended information for the composition of olive

oil and other aspects of olive oil chemistry and tech-

nology are provided in reviews and books authored

mainly by Spanish, Italian, and Greek authors.

Fatty Acids and Triacylglycerols

0018The fatty acid composition of olive oil ranges from

7.5 to 20.0% palmitic acid, 0.5 to 5.0% stearic acid,

0.3 to 3.5% palmitoleic acid, 55.0 to 83.0% oleic

acid, 3.5 to 21.0% linoleic acid, 0.0 to 1.5% linolenic

acid, 0.0 to 0.8% arachidic acid, 0.0 to 0.2% behe-

nic acid, and 0.0 to 1.0% lignoceric acid. The olive oil

composition may differ from sample to sample,

depending on the zone of production, the latitude,

the climate, the variety, and the stage of maturity of

olives when collected. Olive oil has a fatty acid

composition similar to that of hazelnut, almond and

high-oleic sunflower oils. This composition differs

significantly from any other type of edible oil and

fat. (See Nuts; Sunflower Oil; Vegetable Oils: Types

and Properties.)

0019The triacylglycerol profile of olive oil, as deter-

mined by reversed-phase liquid chromatography, is

also different from the profiles of maize, cottonseed,

sunflower soybean, and rapeseed oil, and resembles

that of hazelnut oil. The main triacylglycerols found

in olive oil are: OOO (40–59%), POO (12–20%),

OOL (12.5–20%), POL (5.5–7%), SOO (3–7%)

(O ¼oleic acid, P ¼palmitic acid, S ¼stearic acid,

L ¼linoleic acid).

Tocopherols

0020The dietary benefits of olive oil are partly attributed

to the presence of a-tocopherol and other natural

antioxidants. a-Tocopherol acts not only as a free

radical trapping agent but also as a singlet oxygen

quencher. This protective effect against photooxida-

tion is enhanced by the presence of b-carotene. The

fig0006 Figure 6 Horizontal centrifuge (decanter): 1, exit of solid

phase. 2, exit of liquid phase (oil and water). From Kiritsakis KA

(1998) Olive Oil: From the Tree to the Table, 2nd edn. Trumbull, CT:

Food and Nutrition Press, with permission.

4256 OLIVE OIL

main homolog of vitamin E forms present in olive

oil is a-tocopherol, which makes up approximately

95% of total tocopherols. The other 5% are b- and g-

tocopherols. Good-quality, fresh virgin olive oils have

a considerable content of a-tocopherol (200–300 mg

1

). Refined, bleached, and deodorized olive oils

have markedly reduced contents because of the losses

of tocopherols during processing. (See Tocopherols:

Properties and Determination.)

Squalene

0021 Squalene (C

), an intermediate in the biosyn-

thesis of sterols in plant and animal world, is the

major olive oil hydrocarbon. Squalene is found in

olive oil at a concentration ranging from 0.7 to 12 g

per kilogram of oil. The squalene content depends on

the olive cultivar and oil-extraction technology, and it

is dramatically reduced during the process of refining.

There are claims that squalene can enhance the qual-

ity of life, if taken continuously, and that its consump-

tion is beneficial for patients with heart disease,

diabetes, arthritis, hepatitis, and other diseases. It

has been claimed that the high squalene content of

olive oil, as compared with that of other human

foods, is a major factor in the cancer-risk-reducing

effect of this oil.

Carotenoids

0022 The main carotenoids present in olive oil are b-carot-

ene and lutein. Trace amounts of neoxanthin, violax-

anthin, cryptoxanthin, and other xanthophyls may be

found. The total carotenoids content may range be-

tween 1 and 20 mg per kilogram of oil; normal values

do not exceed 10 mg kg

1

. Oils have been reported

that have a higher content of lutein than of b-carotene

and vice versa. So far, studies have indicated an in-

verse correlation between b-carotene intake and inci-

dence of cardiovascular disease, but no clear effect on

low-density lipoprotein (LDL) oxidation has been

demonstrated with b-carotene. (See Carotenoids: Oc-

currence, Properties, and Determination.)

Sterols

0023Phytosterols are functional ingredients. They have

an absorption level 20 times lower than that of

cholesterol. Phytosterols inhibit the absorption of

cholesterol in the body during digestion. Four classes

of sterols occur in olive oil, common sterols (4-

desmethylsterols), 4-a-methylsterols, 4,4-dimethyl-

sterols, and triterpene dialcohols (erythrodiol and

uvaol) (Figure 7). The major class is 4-desmethylster-

ols. Usual values reported for these classes are 1000–

2000 mg per kilogram of oil. Part of the total sterols is

present as esters with fatty acids. b-Sitosterol makes

up 60–90% of the total sterol fraction. Other sterols

found in considerable amounts are d

-avenasterol

(Figure 8;5–36% of the total sterol fraction) and

campesterol (approx. 3% of the total sterol fraction).

The rest of the 4-desmethylsterols present in olive oil

are found in trace or very small amounts. Certain

sterols are probably responsible for the resistance of

olive oil to rapid deterioration at elevated tempera-

tures. (See Functional Foods.)

Phenolic Compounds

0024Virgin olive oil contains phenolic substances that

affect its stability and flavor. Tyrosol (4-hydroxyphe-

nethyl alcohol) and hydroxytyrosol (3,4-dihydroxy-

phenethyl alcohol) are usually mentioned as the

major constituents. Other phenolic compounds are

caffeic acid, o-coumaric acid, p-coumaric acid, ferulic

acid, gallic acid, homovanillic acid, p-hydroxybenzoic

acid, p-hydroxyphenylacetic acid, protocatechuic

acid, sinapic acid, syringic acid, tyrosol glucoside,

and vanillic acid. Aglycons of oleuropein and ligstro-

side, the esters of hydroxytyrosol and tyrosol with

Erythrodiol Uvaol

fig0007 Figure 7 Two triterpene dialcohols used to check purity of virgin olive oil.

OLIVE OIL 4257

elenolic acid, diacetoxy and dialdehydic forms of

these aglycons, elenolic acid, and flavonoids have

been also reported to be present in the polar fraction

of virgin olive oil (Figure 9).

0025 The content in phenolic compounds differs from oil

to oil (a few to more than 400 mg per kilogram of oil,

expressed as caffeic acid). When the level exceeds

300 mg kg

1

, the oil may have a bitter taste. How-

ever, a high polyphenol content appears to be benefi-

cial for the shelf-life of the oil, and there is a good

correlation of stability and total phenol or o-diphenol

content. Among the various phenolic compounds

tested for their contribution to the stability, hydroxy-

tyrosol and caffeic acid were found to be the most

potent antioxidants.

0026 Dietary antioxidants present in exra virgin olive oil

were found to increase the resistance of low-density

lipoproteins to in-vitro or in-vivo oxidation experi-

ments. According to a large number of reports,

hydroxytyrosol is the most important biophenol of

olive oil similar to the phenolic compounds encoun-

tered in green tea and in red wine. Oleuropein also

presents valuable functional properties, but it occurs

in olive oil only in trace amounts. It is found in

abundance in olives and olive leaves. (See Phenolic

Compounds.)

Chlorophyls

0027 The color of olive oil is mainly due to pheophytins a

and b. Traces of chlorophyls a and b may be found

only in fresh oils. The chlorophyl content in virgin

olive oil ranges from trace amounts to more than

30 mg kg

1

. The level of chlorophyls (and carote-

noids) depends on genetic factors, degree of fruit

ripening, and extraction technology. The level de-

creases as the fruit ripens. In the absence of light,

chlorophyls probably act as weak antioxidants. In

the presence of light, it is accepted that chlorophyls

act as strong oxidation promoters. Chlorophyls

are responsible for the yellow/green hues of the oil.

(See Chlorophyl.)

Volatile and Aroma Compounds

0028More than 100 constituents have been identified in

virgin olive oil, mainly hydrocarbons, alcohols, alde-

hydes, esters, and ketones. However, only a few of

these compounds contribute significantly to its

aroma. The most important odorants are volatiles

with six carbon atoms, arising from the enzymic oxi-

dation of both linoleic and linolenic acids during olive

crushing and malaxation. Genetic, agronomic, and

technological parameters, such as olive variety,

degree of fruit ripening, crushing, and malaxation

conditions or extraction system affect the enzymic

activity and alter the quality and intensity of the

aroma. Certain compounds were found to be respon-

sible for desirable flavor attributes, e.g., (Z)-3-hexe-

nal for the ‘green, apple-like’ odor, hexanal for the

‘grassy’ odor, (E)-2-hexenal for the ‘green, bitter

almond-like’ odor, ethyl 2-methylbutanoate for the

‘fruity’ odor. Other compounds such as octanal,

nonenals, decadienals, 1-octen-3-one, acetic acid, 3-

methylbutanol, 2-phenylethanol, etc., are responsible

for some negative attributes. (See Flavor (Flavour)

Compounds: Structures and Characteristics.)

Storage and Packing

0029The oxidative stability of virgin olive oil is mainly

related to its characteristic pattern of triacylglycerols

(low unsaturation, iodine value < 90) and also to the

considerable levels of polar phenolic antioxidants and

the presence of a-tocopherol. Since the early 1970s, it

was found that there was a good correlation between

polyphenols and the oxidative stability of the oil, and

3,4-Dihydroxy-

phenethylalcohol

4-Hydroxyphenethylalcohol

(hydroxytyrosol, HYTY)

(tyrosol, TY)

COOMe

Oleuropein

Elenolic acid

COOMe

OGlu

Glu = glucose

fig0009Figure 9 Major phenolic and related compounds in olive fruit

and olive oil.

-Avenasterol

fig0008 Figure 8 Chemical structure of Delta

-Avenasterol.

4258 OLIVE OIL

all the researchers agreed that the level of polyphenols

or of specific phenols, e.g., tyrosol level, coincided

well with the overall oil quality. Thus, oils with a

high initial peroxide value may have an unexpectedly

long shelf-life due to a high content of natural anti-

oxidants. In the last decade, some researchers focused

their interest on the contribution of individual phenols

present in virgin olive oil to its oxidative stability.

Recent publications indicate that there is an interest

in all natural antioxidants of olive oil that are studied

in parallel. The importance of polyphenols for olive

oil stability explains the efforts of investigators to

develop an appropriate technology to recover them

from olive oil wastewater.

0030 Bottled virgin olive oil has a shelf-life of around 18

months. This period is very long for a fat product.

The resistance of the oil to oxidation may be sup-

ported by special storage and packing conditions

(see Figure 10).

0031 Storage in dark places is essential for the keepabil-

ity of the product to prevent the prooxidant activity

of chlorophyls in the presence of light. Storage in cool

places protected from air access is suggested to pre-

vent autoxidation. Therefore, stainless steel contain-

ers are ideal for storage. Glass bottles are resistant to

fat and oxygen permeation, but only colored bottles

offer light protection.

Traditional and Modern Use

0032Olive oil is part of a cuisine that is simple, light, and

placid, with defined tastes and full of harmony, the

so-called Mediterranean cuisine. Olive oil resistance

to the development of rancidity is combined with a

vast array of flavor and color hues and distinct fea-

tures due to differences in cultivars of olives from

which the oil is extracted. A good-quality olive oil

blends perfectly with the greens. The exquisite taste

of olive oil is very often complemented by the sharp

taste of vinegar, lemon, or tomato. In salads or in

cooking, olive oil is usually mixed with herbs and

spices, which are also an important element of the

Mediterranean diet. Olive oil shows a remarkable

resistance during domestic deep-frying of potatoes

or in other uses at frying temperatures due to its

low unsaturation. It is, therefore, recommended not

only as a salad oil but also for cooking and frying.

See also: Carotenoids: Occurrence, Properties, and

Determination; Chlorophyl; Coronary Heart Disease:

Etiology and Risk Factor; Antioxidant Status; Prevention;

European Union: European Food Law Harmonization;

Fatty Acids: Properties; Analysis; Flavor (Flavour)

Compounds: Structures and Characteristics; Functional

Foods; Nuts; Olives; Phenolic Compounds; Sunflower

Oil; Tocopherols: Properties and Determination;

Vegetable Oils: Types and Properties

Further Reading

Boskou D (ed.) (1996) Olive Oil, Chemistry and Technol-

ogy. Champaign, IL: AOCS Press.

Boskou D and Elmadfa I (eds) (1999) Frying of Food.

Lancaster, PA: Technomic Publishing.

Codex Alimentarius Commission (1993) Revised Norm for

Olive Oil, C1 1993/15-FO.

Commission of the European Communities (1991) Regula-

tion No. 2568/91: On the characteristics of olive oil

and olive-residue oil and on the relevant methods of

analysis. Official Journal of the European Commission

No. L248.

Fedeli E (1977) Lipids of olives. Progress in the Chemistry

of Fats and other Lipids 15: 57–74.

Gracian Tous J (1968) The chemistry and analysis of olive

oil. In: Boekenoogen HP (ed.) Analysis and Character-

isation of Oils, Fats and Fat Products, pp. 315–606.

London: Interscience Publishers.

fig0010 Figure 10 (see color plate 118) Pottery from Knossos Palace.

Reproduced from Psillakis N and Kastanas E (1999) The civiliza-

tion of olive: olive oil, 2nd edn. Greek Academy of Taste, Karmanor,

Iraklion, Crete (Greece), with permission.

OLIVE OIL 4259

Harwood J and Aparicio R (eds) (2000) Handbook of Olive

Oil, Analysis and Properties. Gaithersburg, MD: Aspen.

IOOC (1996) International Encyclopedia of Olive Tree,

1st edn. Madrid: International Olive Oil Council.

IOOC (1999) Trade Standards Applying to Olive Oil and

Olive Pomace Oil. COI/T. 15/NC, Doc. No. 2; rev. 9.

Madrid: International Olive Oil Council.

Kiritsakis KA (1998) Olive Oil: From the Tree to the Table,

2nd edn. Trumbull, CT: Food and Nutrition Press.

Kumpulainen JTand Salonen JT (eds) (1996) Natural Anti-

oxidants and Food Quality in Atherosclerosis and

Cancer Prevention. Cambridge: The Royal Society of

Chemistry.

Newmark HL (1997) Squalene, olive oil and cancer risk:

A review and a hypothesis. Cancer Epidemiology, Bio-

markers and Prevention 6: 1101–1103.

Perrin JL (1992) Les composes mineurs et les antioxygenes

naturels de l’olive et de son huile. Mise au point. Revue

Franc¸aise des Corps Gras 39: 25–32.

Ryan D and Robards K (1998) Phenolic compounds in

olives (a review). Analyst 123: 31R–44R.

Tsimidou M (1997) Polyphenols and quality of virgin olive

oil in retrospect (a review). Italian Journal of Food

Science 10: 99–116.

OLIVES

B L Raina,RegionalResearchLaboratory(CSIR),

Jammu,India

Introduction

000 1 Olive (Olea europaea, family Oleaceae) is an ever-

green xerophytic tree grown for its drupes, which

yield oil and are also marketed as table or pickled

olives. The olive seems to have been cultivated

since prehistoric times in the eastern Mediterranean

region, and has been closely associated with human

religious, sociocultural, medicinal, and nutritional

needs. Today, olive cultivation has attained commer-

cial crop status in every country with a Mediterranean

climate. Spain, Italy, and Greece are leading producers

of olives. Other important olive-producing countries

are Turkey, Tunisia, Portugal, France, Morocco, Al-

geria, Syria, Yugoslavia, Jordan, the USA, Cyprus,

Israel, Argentina, and Libya.

Production and Trade

000 2 There are about 800 million olive trees in the world,

covering about 9 million hectares (ha), with the

annual olive fruit production being about 13.7 mil-

lion metric tonnes (t). Approximately 720 000 t of the

production are consumed as table olives, and the

remaining 8 680000 t are used for the extraction of

oil (Table 1). Nearly 2.3 million t of olive oil and

230 000 t of olive residue oil is produced globally.

About 260 000 t of olive oil and 200 000 t of table

olives is traded in international markets. Olive oil is

exported by 35 countries to more than 100 countries

in five continents. Spain is the largest exporter and

Italy buys nearly half of the entire quantity traded in

the international market. Of the 300 000 t of olive oil

produced in Greece, around 65% is consumed on the

domestic market, whilst 100 000 t is exported, mostly

to the European Union (EU). Seventy-five percent of

all the olive oil produced in Greece is edible virgin

olive oil, for which the global market is expanding.

With its 4.2% share of world olive oil production and

8.7% share of world exports. Turkey ranks fourth

and in some years fifth after Tunisia. The annual

increase in olive oil production is 1.4% as compared

to 4% in respect of other edible oils.

0003As the world’s largest producer, Spain produces

between 200 000 and 250 000 t of table olives per

year. This is over 60% of EU production. Half is for

the domestic market and half is for export. Greece is

the second largest producer of table olives and

exports of the typical table varieties are greater than

tbl0001Table 1 Major production of olives and olive oil

Country Fruit production (1000 MT) Oil production (1000 MT)

1996 1997 1998 1996 1997 1998

Spain 4506 5686 3564 1037 1164 777

Italy 2147 3591 2680 420 698 497

Greece 1950 1879 2068 470 457 427

Turkey 1800 520 1550 197 56 56F

Tunisia 1550 500 1000F 329 96 210

Morocco 908 518 650 87 50 66

Syria 648 403 763 140 85 121F

Portugal 284 267 287F 46 43 43

Algeria 313 319 124 50 49 47F

Argentina 92 92F 92F 4 12 12F

World 15 308 14 702 13 757 2848 2770 2316

F, Food and Agriculture Organization estimate.

Source:www.fao.org.

4260 OLIVES

sales on the home market. The production of table

olives in Italy is around 86 397 t per year. Table olives

account for about 3.4% of the annual crop, and

barely 10% of world production. Turkey is one of

the world’s biggest producers and consumers of table

olives, and lies sixth in the export ranking. It is the

world’s top producer of black olives (29%) and their

second biggest exporter (19%).

0004 The crop is very labor-demanding, provides em-

ployment to millions, and accounts in many countries

for a major share of agricultural income. Almost 25%

of the farming income in the Mediterranean basin is

from olive products. The olive products, which have

been consumed by the Mediterranean people for gen-

erations, are increasingly becoming a luxury in coun-

tries with a high standard of living.

Botany

0005 Olive is an evergreen tree 3–12 m or even more in

height and, in some instances, bears fruit for 1000

years or even more; branches are numerous; leaves

are opposite, leathery, lanceolate, dark green above,

silvery beneath; flowers are small, white, dimorphic

(male and perfect), appearing in early spring in loose

axillary clusters. Fruit setting in olive is erratic in

certain areas, especially where irrigation is insuffi-

cient, the plantation is dense, the pests and diseases

are not controlled and, above all, a single cultivar is

planted over a wide area, reducing the chances for

cross-pollination.

0006 The olive fruit is a globular, oblong, or sometimes

crescent-shaped drupe. The pericarp is composed of

epicarp or skin, the mesocarp or pulp, and the endo-

carp or stone (pit) which contains the seed. The fruit

reaches its maximum weight 6–8 months after

flowering late in spring, and passes through succes-

sive shades of straw, pink, and red, before finally

turning purplish-black at full maturity. The ripe fruit

weighs from 1.5 to 13 g. The pit with its hard shell

makes up 13–30% of the fruit weight and the skin

1.5–3.5%. The seed does not exceed 3% of the

weight of the fruit. At full maturity, the mesocarp

contains 6–10% soluble solids and 15–40% or even

more oil, depending on variety. The pericarp contains

96–98% of the total amount of oil, while the

remaining 2–4% of the oil is in the kernel. The char-

acteristic bitter glycoside, oleuropein, is more concen-

trated close to the peel.

Varieties

0007 The principal varieties cultivated for oil have

medium-sized fruits and are harvested when ripe.

More important among these are Arauco, Bouquetier,

Corfolia, Dafnolia, Fratoio, Koroneiki, Lechin,

Manzanillo, Morcal, Nevadillo, Picual, Rozzola, Rou-

gette, Smertolia, Taggiasea, Tsounati, and Zorzalena.

The varieties preferred for table olive production, with

less than 8% oil, include Ascolano, Calamata, Chalk-

idikis, Conservolea, Gordal, Hojiblanca, Manzanillo,

Megariticci, Mission, Sevillano, Throumbolia, Ver-

dale, and Volou.

Physiology and Biochemistry

Fruit Development and Ripening

0008Along with an increase in fruit weight, various

changes in constituents occur during the development

of the fruit. In the cultivar Gordal, there is a continu-

ous increase in the oil content, a brief rise in reducing

sugar content, followed by a decline till maturity, a

sharp initial drop in crude fiber content and a gradual

one afterwards, and a low protein and ash content.

There are no qualitative changes in chlorophyl and

carotenoid pigments in Hojiblanca and Manzanillo

olives during growth and ripening. The pigment con-

tent in the virgin olive oil varies according to the

degree of ripeness of the fruits. Initially the major

component is pheophytin, while in oil obtained at

the end of the season lutein is the most abundant.

The loss of chlorophyl pigments in the fresh fruits

and virgin oil is not due to activation of chlorophyl-

lase during oil processing. The b-carotene content

and its provitamin A value diminish with ripeness

(13.2 mg b-carotene per g oil is reduced to 1.27 mg

1

in Sevillano variety). The considerable range in

the lutein/b-carotene ratio (between 1.3 and 5.1

depending on variety) makes this ratio a differenti-

ator of single-variety oils. The amount of coumaric

acid, syringic acid, and flavonol varies with maturity.

The quantitative differences in the composition of

flavonol and flavone glycosides during ripening may

be useful in the biochemical characterization of

olive cultivars. Cultivar and stage of maturity

influence tocopherol and tocotrienol contents. The

concentrations of the volatile compounds during

three stages of ripeness in four different cultivars are

reported to decline with increasing ripeness, although

hexyl acetate is highest and hexan-1-ol lowest at the

ripe stage. During maturation of the fruit, the size of

oil droplets within the olive increases, raising the

extractability of the oil from about 20% in the early

stage to as much as 90% in fully mature fruit. Fur-

thermore, small fruits are characterized by high oleur-

opein and low verbascoside contents. The gradual

loss of firmness and of anhydrogalacturonic acid

content of the pectic chain is associated with increas-

ing enzyme activities. Pectinesterase activity appears

OLIVES 4261

during ripening and polygalacturonase activity mainly

during storage. The activity of cellulolytic enzymes

increases with ripening of the fruit. (See Colorants

(Colourants): Properties and Determination of Nat-

ural Pigments; Ripening of Fruit.)

Constituents of Olive Fruit

0009 The moisture and oil content form 85–90% of the

weight of pulp, while the rest comprises organic

matter and minerals. The major monosaccharides

in fruit pulp are glucose, mannose, xylose, gala-

ctose, and arabinose, accompanied by mannitol and

rhamnose in certain cultivars. The pulp is rich in

potassium. Small amounts of organic acids, such as

citric, malic, oxalic, malonic, fumaric, tartaric, lactic,

acetic, and tricarballylic (1,2,3 propanetricarboxylic

acid) are present. (See Acids: Natural Acids and

Acidulants; Carbohydrates: Classification and Prop-

erties.)

0010 A variety of phenolic compounds are found in olive

pulp; caffeic and ferulic acids are among the simpler

of them. The major orthodiphenolic compound typ-

ical of olives is oleuropein, which is responsible for

the bitter taste of immature olives. Two linear com-

pounds are reported to be isolated from the ethyl

acetate extract of residues resulting from Spanish

olive oil processing. These compounds are identified

as 3-(1-(hydroxymethyl)-(E)1-propenyl) glutaric acid

and 3-(1-(formyl)-(E)1-propenyl) glutaric acid. These

products are structural components of oleuropein.

Oxidation products of oleuropein and other pheno-

lics impart the black color to the fruit as a result of

complex interactions between diphenol oxidase and

oleuropein. Anthocyanins, specifically the glycosides

of cyanidin and peonidin, are responsible for the

purple and black color of ripe olives. The highest

concentration of anthocyanin pigments has been

observed in the epicarp (0.55 g kg

1

); a complex

mixture of flavonoids is found in the mesocarp;

derivatives of luteolin and apigenin are found in the

endocarp. (See Phenolic Compounds.)

0011 The skin, pulp, and seed contain different lipid

fractions and fatty acids, sterols, triterpene alcohols,

dialcohols, and hydrocarbon fractions. Among the

differences between the parts of the olive drupe are

the presence of erythrodiol and traces of uvaol,

oleanoic acid, traces of ursolic acid, and oleanoic

aldehydes in the skin only. The distribution of

unsaponifiable hydroxy compounds fractions within

the drupe and their concentration in oils from various

parts of Lingurian olives reveal the presence of sterols,

4-methylsterols, triterpene alcohols (TTA), triterpene

dialcohols (TTDA), linear saturated alcohol (LSA),

and phytol. Most of the sterols, 4-methylsterols,

TTA, and phytol are found in the pulp, while LSA

and TTDA are found in the peel. The main hydroxy

components are LSA in the peel, TTA in the pulp, and

sterols in stone and seed. The kernel oil is character-

ized by the presence of estrone ester (8 mg per

100 ml oil).

0012Fifty-six volatile compounds are reported to be pre-

sent in the leaves, flowers, epicarp, and mesocarp of

Lucca and Mission varieties, and 29 compounds,

including 3-vinylpyridine, methylvinylpyridine, and

cis-jasmone, have been identified in these varieties.

Higher concentrations of hexanal and trans-2-hexanal

are found in the Lucca variety, while numerous long-

chain hydrocarbons are found in flowers of both

varieties. The peroxidase activity and lipid peroxida-

tion intensity in leaves may be of potential use in

selecting olive cultivars for yield.

Soil and Climate

0013Olive does well on moderately saline soils not suitable

for most other crops. The soil should be deep and

well-drained, so that the roots penetrate deeply to

take advantage of underground moisture even in

relatively arid areas. The olives can also grow on

calcareous slopes provided the fertility of the soil is

built up.

0014Olive can be grown commercially in warm-temper-

ate and subtropical countries located between

latitudes 30



and 45



N and 30



and 45



S, at 300–

400 m altitude in the north to 1000–1220 m above

sea level in favorable sections of the south. The pro-

duction of olives under dry conditions needs better

resource management. This includes use of special

tools and traditional water conservation measures.

It cannot be grown where the winter temperature

falls below 9



C, as this temperature will kill the

trees. A certain degree of chilling, differing consider-

ably among cultivars, is necessary for floral induc-

tion. The olive blooms relatively late in the spring. A

long, relatively hot growing season is required for the

fruit to develop to the appropriate size. A consistently

clear and dry atmosphere is necessary for maximum

yield of fruit. Adequate soil moisture must be present

throughout the year to produce heavy yields of the

required size of fruit.

Cultural Practices

Propagation

0015Olives are propagated by hardwood cuttings, or by

small softwood cuttings rooted under mist sprays, or

by ‘ovule’ protuberances formed at the base of the

trunk. The treatment with IBAþ putrescine HCl and

4262 OLIVES

placing the cuttings in the polyethylene tunnel im-

prove the rooting ability. Although propagation by

seeds provides a stronger root system and more fruit-

ful trees, the seedlings produced require grafting and

thus a longer time to reach fruiting. The variable

nature of the rootstock may bring about variability

in the growth and size of the trees. The nursery

trees are planted 8–12 m apart in irrigated orchards

or 12–22 m apart in unirrigated groves.

0016 IRTA-i.18, a clone selection of the olive Arbequina,

is superior to the cultivar for fruit color, fruit yield at a

density of 300 trees h

1

, crown volume, fruit weight,

flesh/stone ratio, and oil content, and identified as

suitable for commercialization. The topical pollen

application can be used instead of interplanting of

pollinizer trees to reduce shotberry incidence in

Manzanillo olive groves.

Irrigation and Drainage

0017 For production of a good crop of large fruit size, the

trees should have adequate soil moisture throughout

the year, especially before flowering time in late

winter and early spring and during the summer,

when fruit growth takes place and new fruiting

wood develops. In the Mediterranean region both

oil and pickling olives are largely grown without

irrigation. Under rain-fed conditions the olives re-

quire 40–50 years to reach full productivity, necessi-

tating the use of many intercrops to provide income

during the interim period. The yield of full-bearing

olive trees in Spain is about 825 kg ha

1

, and water is

the main limiting factor for low yield.

0018 In California, the olive groves are grown under

irrigated conditions. To insure adequate tree growth

and profitable yields, supplementary summer irriga-

tion is necessary. Olive is very sensitive to excessive

soil moisture. Poor drainage at any time, if prolonged,

will kill the tree.

Fertilizers

0019 The olive tree can obtain the required amount of

potassium and phosphorus from the soil. However,

nitrogen is utilized by the plants more rapidly, neces-

sitating the application of nitrogenous fertilizers.

Under irrigated conditions in California, the growers

apply 450 g nitrogen per tree per year just before

onset of the winter season. In gravelly, shallow, foot-

hill types of soil, the trees respond well to potassium

and boron. In Greece, a fertilizer mixture containing

nitrogen, phophorus, and potassium is used.

0020 The organic method of cultivation using Hedy-

sarum coronarium cover crop inoculated with a

granular formulation of Rhizobium hedysarii to

supply nitrogen to olive significantly increases the

total and organic nitrogen in the soil and has an

impact on olive productivity.

Pruning and Thinning

0021Pruning methods for the bearing trees vary greatly. In

the Mediterranean region, heavy pruning is practiced.

Heavy pruning under irrigated conditions leads to

reduced yields owing to the removal of potential

fruit-bearing surfaces, and results in fruit bearing in

alternate years. A moderate amount of annual

pruning, involving removal of injured, dead, or ill-

placed branches, is all that is necessary to spread the

fruiting surface uniformly, so that every part of the

bearing wood is adequately exposed to light and air.

The height of plants in regular plantation is generally

maintained at up to 5 m. In some countries, thinning

of fruits is achieved by spraying the young fruits with

150 p.p.m. naphthaleneacetic acid. Spray-thinned

trees may be expected to bear fruit the following

year. The girdling with GA3 plant regulator applica-

tion (50 or 100 p.p.m.) increases the fruit yield.

Pests and Diseases

0022Olives have many pest problems, some of them

affecting the tree or the fruit itself. Olive fruit fly

(Dacus oleae Gmel.), olive kernel borer (Prays oleae

Bern.), olive scale (Parlatoria oleae Colvee.), Olean-

der or ivy scale (Aspidiotus hederae (Vallot), greedy

scale (A. camelliae Signoret), California red scale

(Aonidiella aurantii (Maskell), and black scale (Sais-

setia oleae Bern.) are the important pests of olive.

Two recent reports of beetles injurious to the olive

tree involve Nericonia nigra and Noemia semirufa.

0023The olive fruitfiy (Dacus oleae Gmel.) is a major

pest in the Mediterranean region. The insect attacks

at early fruit maturity, causing fermentation and pre-

mature fruit dropping. Sometimes, owing to adverse

climatic conditions, the production loss due to this

fly can be as high as 30%. The infestation adversely

affects the oil quality by increasing acidity, especially

when infestation exceeds 30%. The pest is best

controlled by proteinaceous attractant sprays. (E)-2-

hexanal emitted by the crushed olives has repellent

property to the fruitfly. Chrysopids are the most

active and effective predators on olive kernel borer

(Prays oleae Bern). The pesticides deltamethrin,

fenthion, and formothion are also used to control

Dacus oleae. The use of green immature olives for

pickling has become popular in Spain as a means of

escape from the olive fly.

0024The principal disease of the olive tree is ‘olive-

knot,’ caused by Bacterium savastanoi Stevens,

which leads to knots or tumors on the leaves, twigs,

branches, and trunk. There is no proper control for

OLIVES 4263