Consider the onion. This humble vegetable adds layers of color, texture, nutrition and flavor to many prepared foods, from soups and stews to onion rings and pizzas.
According to Wayne Mininger, executive vice president, National Onion Association, Greeley, CO, "Nearly 20% of U.S. bulb onions are utilized in some sort of value-added, processor-managed food product."
Following is an overview of the humble, yet essential, vegetable.
Onion production
Onions constitute the third largest fresh vegetable industry in the United States and are grown in 20 states from coast to coast. Idaho, eastern Oregon, Washington and California are the leading production areas. The National Onion Association estimates that fewer than 1,000 U.S. farmers plant more than 142,000 acres of onions each year.
Per capita consumption of onions in the United States has more than doubled in the past 25 years, with Americans consuming nearly 20 pounds of onions annually.
Onion types and colors
A domestic supply of onions is available yearround. Their flavor is determined by many factors, including genetics, planting location, soil and temperature.
Onions come in different colors and sizes, but are from the same species. On average, dry bulb onions are 89% water and 8% to 9% soluble sugars (this amount varies based on the time of year). Minerals, proteins and sulfur compounds make up the remaining composition.
The distinctive flavor and aroma of onions and other allium family members (like garlic) come from the sulfur compounds. These compounds are also responsible for the tear response created when cutting an onion. In raw or partially cooked onions, these compounds can mask sugars and dominate the flavor profile.
Fresh onions, available from March to August, have thin, light-colored skins. They have more water content and typically taste mild to sweet. The term “sweet onion” is used to describe fresh onions. Fresh onions have a mild flavor and are ideal for raw and lightly cooked dishes.
Storage onions, available August to April, have multiple layers of thick, dark-colored, papery skin. Being low in water content, storage onions have higher amounts of solids. They are the best choice for soups, stews, and caramelized or roasted applications.
Long cook times will dampen the flavor of all onions, so it is important to use stronger-flavored onions for caramelizing, roasting and in soups or other dishes that have lengthy cook times. Avoid high heat, as this will cause the onion to develop a bitter flavor. Low heat over a long time will diminish an onion’s strong flavor and enhance its natural sweetness.
Both fresh and storage onions are available in yellow, red and white. Yellow onions are all-purpose and popular. In fact, 87% of the U.S. onion crop is comprised of yellow varieties. Most of the sweet varieties that carry a trade name are yellow.