Oregano (Origanum vulgare / Onites)

Oregano is a condicio sine qua non in Italian cuisine, where it is used for tomato sauces, fried vegetables and grilled meat. Together with basil, it makes up for the character of Italian dishes; see parsley on Italian variants of bouquet garni.
The dish most associated with oregano is pizza, a kind of open pie: Bread dough topped with tasty stuff and baked. Bread of this kind was probably eaten in Southen Italy since centuries; according to the legend, pizza came into existence in 1889, when King Umberto and his wife Margherita sojourned in Napoli (Naples). Pizza, at this time not more than white bread flavoured with tomato paste, was then a popular food for the poor masses. To honour the Queen, a local baker devised a richer kind of pizza: In addition to the red tomato paste, white mozzarella cheese and green basil leaves were employed, thus reflecting the colours of the Italian flag. This invention became known as pizza Margherita and spread all over Italy and, with some delay, over the rest of the world.
Oregano can effectively combined with pickled olives and capers or lovage leaves; other than most Italian herbs, oregano harmonizes even with hot and spicy food, as is popular in Southern Italy. The cuisines of other Mediterranean countries make less use of it, but it is of some importance for Spanish, French and Greek cooking.

Used plant part
Leaves. The dried herb is often more flavourful than the fresh (see also thyme on this phenomenon).

Plant family
Lamiaceae (mint family).

Sensoric quality
Aromatic, warm and slightly bitter. Oregano largely varies in intensity: Good quality is so strong that it almost numbs the tongue, but the cultivars adapted to colder climate have often insatisfactory flavour.

Main constituents
The essential oil (max. 4%) may contain variable amounts of the two phenoles carvacrol and thymol (see also thyme and savory); furthermore, a variety of monoterpene hydrocarbons (limonene, terpinene, ocimene, caryophyllene, ß-bisabolene and p-cymene) and monoterpene alcohols (linalool, 4-terpineol) are reported.

Origin
Several species of genus Origanum are native to the Mediterranean, all of which are traded as a spice. The influence of climate, season and soil on the composition of the essential oil is greater than the difference between the various species.
The most important species are O. vulgare (pan-European), O. onites (Greece, Asia Minor) and O. heracleoticum (Italy, Balkan peninsular, West Asia). A closely related plant is marjoram from Asia Minor, which, however, differs significantly in taste, because phenolic compounds are missing in its essential oil. Some breeds show an flavour intermediate between oregano and marjoram (gold marjoram = gold oregano).