Spain is the leading European producer. Onions are also available in various processed forms. Boiled and pickled onions are packed in cans or jars. Frozen onions are available chopped or whole, and bottled onion juice is sold for use as a flavouring. Dehydrated onion products have been available since the 1930s.
Processing involves elimination of most of the moisture by heat or by freeze-drying.
Such products include granulated, ground, minced, chopped, and sliced forms. Onion powder is made by grinding dehydrated onions and is sometimes packaged in combination with salt. Dried onion products are used in a variety of prepared foods. They are also sold directly to the consumer for use as condiments. The United States is the world's leading producer of dried onion products, and the state of California is a major producer of onions developed and cultivated for this industry.