Olive (Olea europaea L.)

The fruit (a drupe), which is pale green when unripe and purple to black when ripe. Most olive fruits are harvested for the extraction of olive oil; only a small fraction goes into the production of pickled olives.

The leaves of the olive tree are used medicinally for their hypotensive qualities.

Oleaceae (olive family).

Raw unripe olives are very bitter; to make them palatable, the bitter constituents are reduced by treatment with lye. Ripe olives, on the other hand, can be directly preserved in salt or brine.

Olives in various stages of ripening homepage.bluewin.ch

Olive oil has a very vari­able flavour. The best oils can have mild or strong flavour that ranges some­where between floral, fruity or fresh. Poor qualities have pungent, acidic, rancid or even no aroma.

In leaves and fruits of the olive tree, a phenolic seco-iridoid called oleuropein is found; it is the hypotensive principle. Before pickling olives, the oleuropein is removed either by treatment with lye or by lactic fermentation; the remaining residues of oleuropein are sometimes said to prevent diseases resulting from high blood pressure.

Olive branch with unripe fruit

Olive oil is ob­tained from the meso­carp (pulp) of special varieties of olives with rather small fruits; the meso­carp contains about 55% of oil.

In the past, olive oil was extracted in hydraulic presses, like most other vegetable oils (see sesame); from that time stems the term cold-pressed for the first fractions with best flavour, which were extracted at low temperature and less than 50 bar pressure (Italian olio extra vergine di oliva, Greek partheno elaiolado [παρθένο ελαιόλαδο]).

Olive branch with unripe fruits

Olive branch with unripe fruit

Today, how­ever, olive oil is almost ex­clusively obtained by centri­fugation, which allows much better yield without applying elevated tem­perature. Con­sequently, almost all olive oil in the food sector is cold-pressed olive oil. The very best quality (dripping oil) is produced without centrifugation, by sedimentation only; it is rare and expensive. The best quality produced in mass scale is called native olive oil extra in the countries of the European Union; native extra loosely corresponds to the more historic term extra vergine. Both native olive oil extra and the next quality class, native olive oil, must be produced without applying heat, and must not be refined. Products called simply olive oil, however, have usually been refined and often contain small amounts of native oils to improve the flavour.

Olive oil is composed, like all vegetable oils (see also sesame), of fatty acids bound to the alcohol glycerol. Typically, the following fatty acids are found in olive oil: 66% oleic acid, 12% linoleic acid, 9% palmitic acid, 5% eicosenoic acid and 5% palmitoleic acid. Olive oil may contain up to 1.5% of an acyclic triterpene hydrocarbon, squalene.

Ripe olive

Flowering olive branch

The most im­portant parameter for the quality of olive oils is the content of free fatty acids, which must be below 0.8% for native olive oil extra, but may be up to 2% for native olive oil. Free fatty acids are formed in the ground olive paste by action of enzymes (lipases) contained in the olive fruits. The only way to control their formation is cooling and quick extraction. Free fatty acids are unwanted because they lower the smoke point and contribute off-flavour.

The desired flavour of olive oil is dominated by aldehydes (hexanal and 2-hexenal). Furthermore, higher aldehydes, primary alcohols (mainly C6 compounds like hexanol, 2-hexene-1-ol, 3-hexene-1-ol) and their acetic acid esters contribute to the characteristic olive oil aroma. Lastly, hemiterpenoid volatiles were found (3-methyl butanal, 4-methoxy-2-methyl-butanethiol, ethyl esters of 2- and 3-methyl butyric acid). The flavour components, however, depend on variety and geographic origin of the oil.

The typical olive oil colour is due to plant pigments of the carotenoid series (β-carotene, phytofluene, ξ-carotene, lutein, auroxanthin, luteoxanthin, violaxanthin, neoxanthin, neochrome), which contribute a yellow hue, and greenish to brown porphyrines (chlorophyll a and b, and pheophytine a and b). Chlorophyll content may be as high as 10 ppm.

Cultivation of the olive tree is known in the Eastern Medi­terranean since five millennia. Whether the plant really stems from these regions or is a native to Central Asia is subject to debate.

Olivenblüten

Olive flowers

Olive is a loan from Latin oliva olive; olive tree, which itself was derived from Greek: elais [ἐλαίς] olive tree and elaia [ἐλαία] (from older elaiva [ἐλαίϝα], Mycenaean elaiwa [𐀁𐀨𐀷, 𐀁𐁉𐀷, 𐂐]) olive; olive tree; furthermore elaion [ἔλαιον] (Mycenaean elaiwon [𐀁𐀨𐀺, 𐀁𐁉𐀺, 𐂕]) olive oil. These words are not Indo–European in origin; it is generally accepted that they were transferred to Greek by some Eastern Mediterranean language, often assumed to be Semitic. Yet as we don’t know the botanical origin of the olive tree, the name could, together with the tree, have travelled from more distant Eastern regions. There is a curious connection to the Dravidian languages which are today spoken in Southern India: Sesame, an important local source of vegetable oil, bears names that are remarkably similar to Greek elaia, e. g., Tamil ellu (pronounced yellu [எள்ளு]). Sometimes, both words are suspected to derive from a common ancestor, e. g., Akkadian ellu flower, fruit, olive.

Olive flowers

Most of the con­tempo­rary Euro­pean lan­guages have a word for olive that derives, directly or in­directly, from Latin oliva. Ex­am­ples are German Olive, Polish oliwka, Slovenian oljka, Frisian oliif, Latvian olīvas and Dutch olijf. In some languages, the name got slightly modified, e. g., Lithuanian alyvos and Albanian ullir.

The medieval German terms for olive were Old High German oliberi (10.th century) and Middle High German ölber oil-berry, which were obviously formed under the influence of Latin oliva (Old High German oli oil is an old Romance loanword from Latin oleum and attested since the 8.th century). Modern German Olive is a much younger loan (16.th century). The Middle High German term has vanished from the language, but was conserved in Yiddish as eylbirt [אײלבירט], which, however, is today also used to denote other oilseed plans, e. g., sunflower.

Only in the languages of the Iberic peninsula, the Latin name was superseded by an Arabic loan: Spanish aceituna and Portuguese azeitona both come from Arabic az-zaytun [الزيتون] the olive; on the other hand, Spanish oliva and Portuguese oliveira refer to the tree, not to the fruit. See also capers for more examples of Arabic loans in Iberic languages.

Olive branch with unripe fruits

Very young olives, shortly after pollination

The Arabic word zaytun [زيتون] is cognate to Hebrew zayith [זית], Aramaic zayta [ܙܝܬܐ] and perhaps also Coptic jeeit [ϫⲉⲉⲓⲧ] olive and might derive from a Common Semitic root signifying to be prominent; on the other side, it might also have been borrowed from a language of Mesopotamia (Sumerian zirdum [𒍢𒅕𒌈], Akkadian serdu). Due to the spread of Islâm, the word was subsequently transferred to many more languages, from the Mediterranean (Portuguese azeitona) to Africa (Swahili zeituni) and Asia, which features related names in a wide area from the Caucasus to the South Asian tropics: Georgian zetis [ზეთის], Armenian jiteni [ձիթենի], Kazakh zäytun [зәйтун], Kurdish zaitun [زةیتوون], Farsi zeitun [زیتون], Punjabi and Hindi jaitun [ਜੈਤੂਨ, ज़ैतून], Tamil saidun [சைதூண்], Dhivehi zaithooni [ޒައިތޫނި] and even Mongolian chidun [чидун]. Another, more distantly related word is Maltese żebbuġ which is suspected to derive from a term for olive in the Berber language, which also belongs to the Semitic language subfamily.

Due to the enormous importance of olives for both the Greek and the Roman cultures, their name entered nearly every European language via Latin oleum oil as generic word for liquid fats, e. g., English oil, French huile, German Öl, Italian olio, Dutch olie, Polish olej and Finnish öljy.

Olive branch with unripe fruits

Similarly, the Iberic names for oil (Spanish aceite, Por­tuguese azeite besides óleo) derive from the local names of olive, aceituna and azeitona, respec­tively.

In other parts of the world, the generic names of cooking fats may also be derived from whatever oilseed dominates local cookery. Examples are provided by coconut and sesame.

Some Slavonic names of olive, e. g., Bulgarian maslina [маслина] olive, have an exactly opposite history: Maslina derives from maslo [масло] oil, fat, which originally meant butter (from a Common Slavonic root MAZ- spread). Words related to Bulgarian maslina made their way into some non-Slavonic languages, e. g., Romanian măslin and Yiddish masline [מאַסלינע].

The term maslo [масло], however, is not used for olive oil in Bulgarian, which is instead known as zehtin [зехтин] (from Turkish zeytin olive). Vegetable oils are often called olio [олио] in Bulgarian.

Occasionally, fruits of botanically unrelated trees may be called olives, often with an epithet referring to distribution. For example, the Bengali olives (or Indian olives) are the aromatic fruits of Elaeocarpus robustus; in West Bengal and Bangladesh, they are often used to prepare a chutney with delicious fruity and acidic taste. A similar case is the Thai olive ma kok [มะกอก] (Spondias mombin, Sp. pinnata, Sp. cytherea and others), which allegedly gave its name to Thailand’s capital, Bangkok. Such designations may sometimes be used to denote true Mediterranean olives in the local language, with or without an epithet foreign.

Nature One Health: Olive Transport Information Service: Olive Oil Pacific Islands Ecosystems at Risk: Olive Olive Trees in Crete Olive Fruit Facts Olive Presses and Mills Tuscany and Italy – Olives and Olive Oil Olive Expert: Through the Mists of Time Composition of Olive Oil Informationsgemeinschaft Olivenöl (olivenoel-info.net) Bilderserie zur Herstellung von extra vergine Olivenöl (Koni Berg) Recipe: Tapenade (www.cliffordawright.com) Recipe: Tapenade (homecooking.about.com) Recipe: Tapenade (appetizerrecipe.com) Recipe: İmam bayıldı (Imam bayildi) (cliffordawright.com) Recipe: İmam bayıldı (Imam bayildi) (recipecottage.com) Recipe: İmam bayıldı (Imam bayildi) (recipehound.com)