Broccoli

Broccoli is a plant in the cabbage family, whose large flower head is used as a vegetable.

General
The word broccoli, from the Italian plural of broccolo, refers to "the flowering top of a cabbage".

Broccoli is classified in the Italica cultivar group of the species Brassica oleracea. Broccoli has large flower heads, usually green in color, arranged in a tree-like fashion on branches sprouting from a thick, edible stalk. The mass of flower heads is surrounded by leaves. Broccoli most closely resembles cauliflower, which is a different cultivar group of the same species.

History
Broccoli evolved from a wild cabbage plant on the continent of Europe. Indications point to the vegetable's being known 2,000 years ago. Since the Roman Empire, broccoli has been considered a uniquely valuable food among Italians. Broccoli was grown at Antwerp whence it was taken to England by the sculptor Peter Scheemakers, according to a biographical note by J. T. Smith. Broccoli was first introduced to the United States by Italian immigrants but did not become widely known until the 1920s.

Culinary
Broccoli is usually boiled or steamed, but may be eaten raw and has become popular as a raw vegetable in hors d'œuvre trays.

Nutritional and medicinal
Broccoli is high in vitamin C, as well as dietary fiber; it also contains multiple nutrients with potent anti-cancer properties, such as diindolylmethane and small amounts of selenium. A single serving provides more than 30 mg of Vitamin C and a half-cup provides 52 mg of Vitamin C. The 3,3'-Diindolylmethane found in broccoli is a potent modulator of the innate immune response system with anti-viral, anti-bacterial and anti-cancer activity. Broccoli also contains the compound glucoraphanin, which can be processed into an anti-cancer compound sulforaphane, though the benefits of broccoli are greatly reduced if the vegetable is boiled. Broccoli is also an excellent source of indole-3-carbinol, a chemical which boosts DNA repair in cells and appears to block the growth of cancer cells.

Steaming broccoli for 3–4 minutes is recommended to maximize potential anti-cancer compounds, such as sulforaphane. Boiling reduces the levels of suspected anti-carcinogenic compounds in broccoli, with losses of 20 – 30% after five minutes, 40 – 50% after ten minutes, and 77% after thirty minutes. However, other preparation methods such as steaming, microwaving, and stir frying had no significant effect on the compounds.

Broccoli has the highest levels of carotenoids in the brassica family. It is particularly rich in lutein and also provides a modest amount of beta-carotene.

A high intake of broccoli has been found to reduce the risk of aggressive prostate cancer. Broccoli consumption has also been shown to be beneficial in the prevention of heart disease. Broccoli consumption is also associated with malodorous flatulence, from metabolism of the sulfur-containing compounds it contains.

See also Broccoli sprouts for possible health/medical benefits.

Varieties
There are three commonly grown types of broccoli. The most familiar is a often referred to simply as "broccoli", and sometimes calabrese named after Calabria in Italy. It has large (10 to 20 cm) green heads and thick stalks. It is a cool season annual crop.

Sprouting broccoli has a larger number of heads with many thin stalks. It is planted in May to be harvested during the winter or early the following year in temperate climates.

Romanesco broccoli has a distinctive fractal appearance of its heads, and is yellow-green in colour. It is technically in the Botrytis (cauliflower) cultivar group.

Purple cauliflower is a type of broccoli sold in southern Italy, Spain, and the United Kingdom. It has a head shaped like cauliflower, but consisting of tiny flower buds. It sometimes, but not always, has a purple cast to the tips of the flower buds.

Other cultivar groups of Brassica oleracea include cabbage (Capitata Group), cauliflower (Botrytis Group), kale and collard greens (Acephala Group), kohlrabi (Gongylodes Group), and Brussels sprouts (Gemmifera Group). Chinese broccoli (Alboglabra Group) is also a cultivar group of Brassica oleracea.

Production
In North America, production is primarily in California. The seasonal average f.o.b. shipping-point price for cauliflower in 2004 was $33.00 per 100 pounds ($0.73/kg) according to the National Agricultural Statistics Service, USDA.

Cultivation
Broccoli is a cool-weather crop that does poorly in hot summer weather. Broccoli grows best when exposed to an average daily temperature between 18 and 23 °C. When the cluster of flowers, also referred to as a "head" of broccoli, appear in the center of the plant, the cluster is green. Garden pruners or shears are used to cut the head about an inch from the tip. Broccoli should be harvested before the flowers on the head bloom bright yellow.