Onion certainly is a borderline case between spices and vegetables; we, however, included it to the list of spices as it is an indispensable ingredient to nearly every cuisine of the world, and it is used for large spectrum of different dishes.

Onion is a very famous and used plant all over the world it seems that it is originate from West or Central Asia. It belongs to Alliaceae family (onion family) used plant part is the Bulb (subterranean leaves). Super terranean green leaves display the same aroma, but are slightly less intensive; in their culinary use, they equal chives. In fresh state you find onion, spicy, pungent and lachrymatory. Its use is widely spread in Syria and Syrian used onion in most of their culinary.

Fresh onions contain only traces (0.01%) of essential oil, which mostly consists of sulfur compounds: Ethyl and propyl disulfides, vinyl sulfide and other sulfides and thioles. The lachrymatory principle is variously identified as thiopropanal-S-oxid (CH3-CH2-C(SO)H) or its tautomer propenyl sulfenic acid (CH3-CH=CH-SOH). This substance is released from its precursor S-1-propenyl-L-cysteine sulfoxide as a reaction to cell damage; this mechanism is very similar to that in garlic.

It’s usage all over the world

Pastes prepared by grinding onions together with a variety of spices are known in quite many countries. Indonesia displays a great variety of onion-based spice pastes (bumbu); from the New World, Jamaican jerk is the most famous example. Both concoctions are mostly used to marinate meat or fish. In India, onion is the basis of most sauces and gravies. Nearly every North Indian recipe starts with the same procedure:

Fry chopped onions slowly, add spices and fry until the onion turns golden. The mixture (wet masala) may afterwards be pureed, simmered with tomatoes or yoghurt, or just added to boiling vegetables or meat. It is part of the art of Indian cooking to estimate spice amounts in advance; if you take too much or too little, the error will become manifest only in the last phase of cooking, when corrections are difficult to make. In the Imperial cuisine of Northern India (moghul cuisine), gravies are prepared in a similar way; yet aromatic spices are used more lavishly at the cost of pungent chilies. Gravies based on onion are prepared in another way in Burma, whose unique situation between China, India and Thailand has given rise to a unique cuisine.

Pastes prepared by grinding onions together with a variety of spices are known in quite many countries. Indonesia displays a great variety of onion-based spice pastes (bumbu); from the New World, Jamaican jerk is the most famous example. Both concoctions are mostly used to marinate meat or fish. In India, onion is the basis of most sauces and gravies. Nearly every North Indian recipe starts with the same procedure: Fry chopped onions slowly, add spices and fry until the onion turns golden. The mixture (wet masala) may afterwards be pureed, simmered with tomatoes or yoghurt, or just added to boiling vegetables or meat. It is part of the art of Indian cooking to estimate spice amounts in advance; if you take too much or too little, the error will become manifest only in the last phase of cooking, when corrections are difficult to make. In the Imperial cuisine of Northern India (moghul cuisine), gravies are prepared in a similar way; yet aromatic spices are used more lavishly at the cost of pungent chilies. Gravies based on onion are prepared in another way in Burma, whose unique situation between China, India and Thailand has given rise to a unique cuisine.

By frying, onion changes its taste and turns more sweet and aromatic; the flavour develops best after long frying in comparatively cool fat. Fried onion rings are popular in Central Europe as a decoration, Onions may also be dried, in which case they again change their flavour and turn more garlic-like. Onion powder is a rather popular spice in the South of the US and in México, and forms part of commercially available chile-con-carne spice mixtures .