Information about Asparagus

Asparagus officinalis
Wild Asparagus in Austria
Scientific classification
Kingdom: Plantae Division: Magnoliophyta Class: Liliopsida Order: Asparagales Family: Asparagaceae Genus: Asparagus Species: A. officinalis
Binomial name
Asparagus officinalis L.

Asparagus officinalis is a flowering plant species in the genus Asparagus from which the popular vegetable known as asparagus is obtained. It is native to most of Europe, northern Africa and western Asia.^[1][2][3] It is now also widely cultivated as a vegetable crop.^[4]

Biology

It is a herbaceous perennial plant growing to 100-150 cm tall, with stout stems with much-branched feathery foliage. The 'leaves' are in fact needle-like cladodes (modified stems) in the axils of scale leaves; they are 6–32 mm long and 1 mm broad, and clustered 4–15 together. The flowers are bell-shaped, greenish-white to yellowish, 4.5–6.5 mm long, with six tepals partially fused together at the base; they are produced singly or in clusters of 2-3 in the junctions of the branchlets. It is usually dioecious, with male and female flowers on separate plants, but sometimes hermaphrodite flowers are found. The fruit is a small red berry 6–10 mm diameter.^[5]

Plants native to the western coasts of Europe (from northern Spain north to Ireland, Great Britain, and northwest Germany) are treated as Asparagus officinalis subsp. prostratus (Dumort.) Corb., distinguished by its low-growing, often prostrate stems growing to only 30–70 cm high, and shorter cladodes 2–18 mm long.^[1][5] It is treated as a distinct species Asparagus prostratus Dumort. by some authors.^[6][7]

History

Asparagus has been used from very early times as a vegetable and medicine, owing to its delicate flavour and diuretic properties. There is a recipe for cooking asparagus in the oldest surviving book of recipes, Apicius's 3rd century AD De re coquinaria, Book III. It was cultivated by the ancient Egyptians, Greeks and Romans, who ate it fresh when in season and dried the vegetable for use in winter. It lost its popularity in the Middle Ages but returned to favour in the 17th century.^[8]

Uses

Culinary

Only the young shoots of asparagus are eaten. Asparagus is low in calories, contains no fat or cholesterol, and is very low in sodium. It is good source of folic acid, potassium, dietary fibre, and rutin. The amino acid asparagine gets its name from asparagus, the asparagus plant being rich in this compound.

The shoots can be prepared and served in a number of ways, but are usually boiled or steamed and served with hollandaise sauce, melted butter or olive oil and Parmesan cheese. Tall asparagus cooking pots allow the shoots to be steamed gently. Cantonese restaurants in the United States often serve asparagus stir-fried with chicken, shrimp, or beef, also wrapped in bacon. Asparagus may also be quickly grilled over charcoal or hardwood embers. The best asparagus tends to be early growth (first of the season) and is normally simply steamed and served with melted butter.

The bottom portion of asparagus often contains sand, and as such proper preparation is generally advised in cooking asparagus. A case of botulism borne on asparagus was recorded in Australia in 1991.^[9]

Medicinal

Asparagus rhizomes and root is used ethnomedically to treat urinary tract infections, as well as kidney and bladder stones. It is also believed to have aphrodisiac properties.

Asparagus pee

Proust claimed that asparagus "...as in a Shakespeare fairy-story transforms my chamber-pot into a flask of perfume".

Some of the constituents of asparagus are metabolised and excreted in the urine, giving it a distinctive smell. This is due to various sulfur-containing degradation products (e.g. thiols and thioesters) and ammonia. Recent studies suggest that every individual produces the odorous compounds upon eating, but that only about 40% of individuals have the genes required to smell them.^[10][11] The speed of onset of urine smell is rapid, and has been estimated to occur within 15-30 minutes from ingestion.^[12]

Cultivation

Since asparagus often originates in maritime habitats, it thrives in soils that are too saline for normal weeds to grow in. Thus a little salt was traditionally used to suppress weeds in beds intended for asparagus; this has the disadvantage that the soil could not be used for anything else. 'Crowns' are planted in Winter, and the first shoots appear in Spring; the first pickings or 'thinnings' are known as sprue asparagus. Sprue have thin stems.^[13]

White asparagus, known as spargel is cultivated by denying the plants light and increasing the amount of ultraviolet light the plants are exposed to while they are being grown. Less bitter than the green variety, it is very popular in the Netherlands and Germany where 57,000 tonnes (61% of consumer demands) are produced annually.^[14]

Purple asparagus differs from its green and white counterparts, having high sugar and low fibre levels. Purple asparagus was originally developed in Italy and commercialised under the variety name Violetto d'Albenga. Since then, breeding work has continued in countries such as the United States and New Zealand.

Commercial production

Peru is currently the world's leading asparagus exporter, followed by China and Mexico.^[15] The top asparagus importers (2004) were the United States (92,405 tonnes), followed by the European Union (external trade) (18,565 tonnes), and Japan (17,148 tonnes).^[16] The United States' production for 2005 was on 21,850 hectares (54,000 acres) and yielded 90,200 tonnes, making it the world's largest producer and consumer. Production was concentrated in California, Michigan, and Washington.^[17] The crop is significant enough in California's Sacramento-San Joaquin River Delta region that the city of Stockton holds a festival every year to celebrate it.

The Vale of Evesham is the traditional centre of the UK industry; British asparagus has a more delicate flavour than that grown in hotter climates.

Vernacular names and etymology

Asparagus officinalis is widely known simply as "asparagus", and may be confused with unrelated plant species also known as "asparagus", such as Ornithogalum pyrenaicum known as "Prussian asparagus" for its edible shoots.

The English word "asparagus" derives from classical Latin, but the plant was once known in English as sperage, from the Medieval Latin sparagus. This term itself derives from the Greek aspharagos or asparagos, and the Greek term originates from the Persian asparag, meaning "sprout" or "shoot".

Asparagus was also corrupted in some places to "sparrow grass"; indeed, John Walker stated in 1791 that "Sparrow-grass is so general that asparagus has an air of stiffness and pedantry". Another known colloquial variation of the term, most common in parts of Texas, is "aspar grass" or "asper grass". Asparagus is commonly known in fruit retail circles as "Sparrows Guts", etymologically distinct from the old term "sparrow grass", thus showing convergent language evolution.

It is known in French and Dutch as asperge, in Portuguese as espargo hortense, in Spanish as esparrago, and in German Spargel.

References

External links

• PROTAbase on Asparagus officinalis
• Everything About Asparagus - comprehensive information from the Michigan Asparagus Advisory Board
• Asparagus officinalis - Plants for a Future database entry
• World Asparagus Situation and OutlookPDF (55.0 KiB) - 2005 USDA report
• Asparagus Production Management and Marketing - commercial growing (OSU bulletin)
• Asparagus - nutrition data
• Asparagus - pharmacological activity
• The Stockton Asparagus Festival - held annually every April in Stockton, California