Iran is a vast region in southwest Asia. One of the most important crops in Iran is onion, used almost daily in cooking by all Iranian families year-round. Onion has numerous advantages due to its vitamins, antioxidant, protein, and minerals. Moreover its fat produces 45 calories/100g fresh weight contributing to its usage in almost all salads and food. Besides nutritional value, onion can create more income compared with other crops for farmers and onion processors like value-added onion products, and onion in Iran also can be exported to other countries, especially the United Arab Emirates. Of the 24 provinces in Iran, nine are important onion production regions including three for onion export.

I. Onion Cultivation in Iran
The geographical environment in Iran is very varied, from the Persian Gulf in the south to the Caspian Sea in the north. Most dry farming is in Gilan, Golastan, and Mazandaran provinces, which are featured with Mediterranean environmental conditions and irrigated cultivation.
Onion is cultivated around the majority of Iran cities, and almost all have city names where they are grown, such as Azarshahar onion, Shahdad onion, Ramhormoz onion, and Bardseer onion. Azerbaijan Sharghi province is the top one for onion cultivation accounting for 24.8% of production, followed by Esfahan, Khorasan, and Khuzestan provinces accounting for 16.7%, 9.3%, and 8.3%, respectively.
Common and popular methods of onion production used in Iran are direct seeding and transplanting. The average cultivated area of onion is 44,241 ha and total production is about 1,125,050 t/year, with an average yield 25.43 t/ha. Because of the single annual production season, onion is often stored in Iran through the rest of the year.

II. Onion Varieties in Iran
Onions in Iran are generally available in three colors: yellow, red, and white. Yellow onions are full-flavored for cooking almost anything and they will turn dark brown when cooked and give sweet flavor. The red onion is better for fresh use or grilling. White onions are conditionally utilized for cuisine due to the golden color and sweet flavor.
In addition, onions can be bred and grown to mature at smaller size like pearl, boiler or pickler onions. Pearl and boiler onions can be cooked as a vegetable rather than an ingredient. Pickler onions are usually pickled.

III. Onion Consumption in Iran
Onion is treated as a vegetable and herbaccous drug of people in central Asia, and it plays an importance role in human health to prevent diseases. Onion in Iran is almost daily used in cooking by all Iranian families year-round and it is utilized in many ways: aroma and taste in the preparation of vegetables, frozen, cooked, pickled, used in factory-made food, dehydration and so on. Onion consumption is estimated to be in the range of 8 to 12 kg per person in Iran while it’s more in urban areas.

IV. Onion Dehydration
Onions can be processed into various types in frozen, canned, caramelized, pickled, powdered, chopped, and dehydrated forms. However, all onions for processing are grown from specific varieties best suited for dehydration. Onion dehydration is the popular form featured with easy operation, versatile functions. Onion dehydration is aimed at producing the concentrated product with a long shelf life, and the onion can be simply reconstituted without substantial loss of flavor, taste, color and aroma. The dehydrated onion products start as 9 pounds of raw onions and after processing are1 pound of dehydrated onions.

1. Onion Processing and Equipment
Onion dehydration involves the use of a continuous operation involving the following basic steps: onion grading, root cutting, peeling, cleaning, slicing, dehydration, milling and packaging.
1.1 The ripe onion should be graded in size by the vegetable grading machine. Then onions with big bulb, small stem, tight structure will be chosen.
1.2 Next, remove onion outer leaves, tops and roots by onion peeling & root cutting machine.
1.3 After removing the tops, roots and outer integuments, onions are cut into slices by slicing machine. The thickness of slices should be 3-5 mm and they need a full washing.
1.4 After cleaning, put onion slices into the dewaterting machine to remove the surface water.
1.5 Preheat the drying machine to a temperature of 60 ℃, and spread the onion slices evenly on the trays of the drying machine for dehydration. The drying temperature should be 55-60 ℃, drying time should be 6-7 hours. When the moisture is reduced to ≦5%, the drying process is finished.
1.6 Take out trays and collect dried onion slices, then pack these onion flakes; or further process these dehydrated onion slices into chopped onion, minced onion, onion granules, or onion powder.

2. Different Forms of Dehydration Onions
Different dried onions are processed from the dehydrated onion by different processing methods. They all come in three colors: white, yellow and red.


♦ Onion flakes (10mm-30mm)
Widely used in varied food preparations wherever along with onion flavor and taste. Onion’s appearance and texture is desired and can be easily used in salads and other preparations or serving after re-dehydration.


♦ Onion Chopped (Size: 3.0 - 5.0 mm)
Utilizde in dry soups, mixes, specialty ethnic food preparations, canned/dried/frozen vegetable mixes, dry casserole mixes, stuffing mixes, food service & fast food and particularly when large onion pieces are desired.


♦ Onion Minced (Size: 1.0 - 3.0 mm)
Mainly used in preparation of soups, sauces, canned/dried/frozen foods, salad dressings, meat products and other food products whenever onion flavor or taste is required.


♦ Onion Granules (Size: 0.1 - 0.5 mm & 0.5 to 1.0 mm)
Particularly applied in Vegetables & Meat preparations, gravies, sauces, seasoning salad dressings, cheese, crackers etc.


♦ Onion Powder
Free flowering powder is made from finely ground, dehydrated onions, used as seasoning in soups, sauces, seasoning, and meat products and suitable for varied food preparations, particularly when strong onion flavor and taste is desired.

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