Nutrition: One medium orange contains about 60 calories and 120 percent of the daily vitamin C required by an adult. This fruit also is high in fiber, calcium and vitamin A. It's a good source of thiamin, folate and potassium, too.
Oranges really are good for you, especially during cold and flu season. Vitamin C is a powerful antioxidant that helps the body resist infectious disease. Oranges also contain hesperetin, narigenin, beta-carotene and lutein; these antioxidants act as anti-inflamatories and boost the immune system. Oranges' dietary fiber helps colon health.
Selection: Oranges do not ripen off the tree; they must reach maturity and full ripeness before harvest. Look for firm unblemished fruit with good orange color and finely textured, smooth skin. A juicy orange should feel heavy for its size. Avoid fruit with soft spots, dull or faded coloring or wrinkled, saggy skin.
Storage: Keep fresh oranges unpeeled in the refrigerator. They'll keep for several weeks. Rinse with cool water and pat dry before peeling. When cut, store in a sealed nonmetallic container or zip-locked bag in the refrigerator.
Canning: Peel and separate the oranges into sections. Remove the white pith and any membrane. Pack the sections into sterilized jars and cover the fruit with light syrup (made with equal parts sugar and water, brought to a boil). Allow a half-inch of head space at the top of the jar. Seal and process in a boiling hot-water bath for 10 minutes.
Freezing: Orange sections can be frozen in their own juice. Separate the segments, then cover with fresh juice in a freezer container, allowing a half-inch head space. Frozen segments should keep their quality for six months.
Juice also can be frozen for up to six months.
Freeze the zest, too. Grate the peel and spread onto a cookie sheet. Freeze, then transfer to a plastic bag.
Don't try freezing whole fruit; it will expand and burst.
Store on the tree: If you have an orange tree in your backyard, the best place to "store" oranges is on the tree. They'll keep for months. Pick when ready to use. To test for ripeness before picking, give the fruit a gentle squeeze. If it feels rock-hard and solid, it needs more time. If it has a little give, it's juicy and ripe.
Navel oranges the easy-to-peel seedless fruit beloved for fresh munching is the king of California's citrus. Navel oranges are actually mutant conjoined twin fruit; the undeveloped twin is embedded in the end opposite the stem. That forms the indentation that looks like a navel or bellybutton. That unusual mutation also makes navel oranges sterile. New trees are propagated from cuttings and grafted onto rootstock.
The first and still most popular navel variety is Washington. William Saunders, the USDA's first botanist, developed this variety in 1871 from stock imported from Brazil. He grew his orange trees in greenhouses in Washington, D.C., on what's today the National Mall. Washington's introduction to California in 1873 helped launch the state's citrus industry.
Oranges enjoyed a major boom during the late 1800s with groves planted throughout California and Florida. According to lore, the juice industry was born out of a bumper California crop shortly before World War I. Fresh-squeezed juice stays fresh less than a day, but pasteurization then a new concept stabilized juice for shipment nationwide.
By the 1920s, orange juice was considered an essential part of an American breakfast. Valencia, the world's No. 1 orange and a native of Portugal, is the most popular juice orange. (A navel contains about half the juice of a Valencia.) Juice takes a lot of oranges. Depending on the size of the fruit and variety, each orange yields 2 to 4 ounces of juice. One cup (8 ounces) of juice has 100 calories and 150 milligrams of vitamin C.
Orange juice makes a great marinade; the acidity naturally tenderizes meat, fish or poultry while adding a distinctive flavor. Try substituting orange juice for vinegar in your favorite marinade recipe. Or use equal parts juice and olive oil, seasoned with salt and pepper to taste.
The same goes for vinaigrettes; substitute orange juice for the vinegar.
Oranges can be grilled. Peel, then slice the fruit 1/2-inch thick. Remove any seeds. Grill slices over medium heat until soft but not mushy; about 2 minutes per side.
As for peeling an orange, try this trick. Roll the fruit under your palm on a hard surface. This loosens the skin and makes peeling much easier.
Oranges are native to China and originally were more prized for their fragrant blossoms than fruit. Both flowers and fruit have been used in Asian cooking for more then 4,000 years.
By the 15th century, Arab traders spread orange mania throughout the Middle East and Mediterranean.
Brazil now is the world's orange basket, producing more than half the global crop.
Missionaries brought the first orange to Florida in the 1500s. Spanish missionaries also brought orange seeds to California and planted the first trees here in the 1600s.
Oranges need hot days and cold nights to develop sweetness, which makes California's Central Valley ideal for this crop.
Blood oranges, popular in Spain and Italy, also grow very well in the Valley. Cold nights intensify their red color.