Asparagus is the name a genus of plants within the flowering plant family Asparagaceae, as well as a type of vegetable obtained from one species within the genus Asparagus, specifically the young shoots of Asparagus officinalis. This vegetable has been used from very early times for culinary purposes, owing to its delicate flavor and diuretic properties (elevates the rate of bodily urine excretion). There is a recipe for cooking asparagus in the oldest surviving book of recipes, Apicius's third century C.E. De re coquinaria, Book III.
As a vegetable, the tender, succulent shoots of asparagus not only touches upon people's senses of taste, touch, smell, and vision, but also provides excellent nutrition, providing folic acid, iron, rutin, various vitamins, and other beneficial elements.
Asparagus is a genus of plants in the family Asparagaceae, an angiosperm family that is not universally recognized, as often the plants involved are treated as belonging to the family Liliaceae (Lily family).
There are up to 300 species in Asparagus, all from the Old World. They have been introduced in many countries in both hemispheres and throughout temperate and tropical regions. Many species from Africa are now included in the genera Protasparagus and Myrsiphyllum. However, recent studies have shown that the taxonomic level genera may not be appropriate; instead, division into subgenera or no division at all may be more appropriate.
Members of Asparagus range from herbs to somewhat woody climbers. Most species have flattened stems (phylloclades), that serve the function of leaves. Three species (Asparagus officinalis, Asparagus schoberioides, and Asparagus cochinchinensis) are dioecious species, in other words, with male and female flowers on separate plants. The others may or may not be hermaphroditic.
The best known member of the genus is the vegetable asparagus (Asparagus officinalis). Other species of Asparagus are grown as ornamental plants. Some species such as Asparagus setaceus have branches that resemble "ferns"' hence they are often called "Asparagus fern" (though they are not true ferns). They are often used for foliage display, and as houseplants. Commonly-grown ornamental species are Asparagus plumosus, Asparagus densiflorus, and 'Asparagus sprengeri.
Asparagus includes the following species, including the garden vegetable officinilas
- Asparagus aethiopicus - Sprenger's Asparagus Fern
- Asparagus africanus - African Asparagus
- Asparagus asparagoides - Smilax, African Asparagus Fern, (Australia) Bridal Creeper
- Asparagus cochinchinensis - Chinese Asparagus
- Asparagus declinatus - Foxtail Asparagus Fern, (Austr.) Bridal vein
- Asparagus densiflorus - Ground Asparagus, Asparagus Fern, (South Africa) Emerald Fern, Basket Asparagus
- Asparagus densiflorus - Sprenger's Asparagus
- Asparagus falcatus - Sicklethorn
- Asparagus macowanii - Ming Fern
- Asparagus officinalis - Asparagus
- Asparagus officinalis officinalis - Garden Asparagus
- Asparagus officinalis prostratus - The Garden Asparagus was adapted from this wild European version
- endemic to the coasts of Belgium, Britain, the Channel Islands, France, Germany, Ireland, Spain and The Netherlands.
- Asparagus plumosus - Asparagus Fern, Florist's Fern, (Austr.) Climbing Asparagus
- Asparagus Plumosus Nanus - is a greenhouse variety, bearing fern-like foliage.
- Asparagus racemosus - Wild Asparagus
- Asparagus scandens - Climbing Asparagus
- Asparagus setaceus - Fern Asparagus, Lace Fern
- Asparagus sprengeri - Emerald Fern
- Asparagus umbellatus - Green Asparagus
- Asparagus virgatus - Broom Fern
Varieties and cultivation
The garden vegetable variety of asparagus officinalis is cultivated in three basic varieties; green, white, and purple. Asparagus can be grown from seeds, but is more commonly grown by purchasing three to four year old roots or "rhizomes." The rhizomes are also commonly referred to as "crowns." The edible stalks are harvested in the early spring and then allowed to continue their growing cycle through out the summer and fall. They produce a delicate, fern-like appearance, similar to their decorative species. Being a perennial plant, asparagus, if cared for, can produce yields for 12-15 years (VRIC 2006).
The green or common garden asparagus ranges from pencil thin to three fourths of an inch thick stalks and is most commonly grown in the United States.
White asparagus is cultivated by denying the plants light and increasing the amount of ultraviolet light exposed to the plants while they are being grown. The edible stalks are considered to be milder in taste, more tender than the green varieties, and less woody in texture. White asparagus is preferred and more common in Europe.
Purple asparagus is different from its green and white counterparts, mainly as it is characterized by high sugar and low fiber levels. Purple asparagus was originally developed in Italy and was commercialized under the variety name "Violetto d'Albenga." Since then, breeding work has continued in countries such as United States and New Zealand.
The English word "asparagus" derives from classical Latin, but the plant was once known in English (prior to 1400) as "asperages" or "aspergy," and then later (sixteenth and seventeenth centuries) as sperage, sparage, or sperach, from the Medieval Latin sparagus. This term itself derives from the Greek aspharagos or asparagos, although some believe the Greek term originated from foreign sources, likely from the Persian asparag, meaning "sprout" or "shoot." The original Latin name has now supplanted the English word.
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.
Widely cultivated for its tender, succulent, edible shoots, asparagus cultivation began more than 2,000 years ago in the eastern Mediterranean region. Greeks and Romans prized asparagus for its unique flavor, texture, and alleged medicinal qualities. They ate it fresh when in season and dried the vegetable for use in winter.
Unlike most vegetables, where the smaller and thinner are the more tender, thick asparagus stalks have more tender volume to the proportion of skin. When asparagus has been too long in the market, the cut ends will have dried and gone slightly concave. When selecting asparagus, care must be taken to choose stalks that are not too long, more than 6" in length, nor too woody. Woody stems are not pliable and indicate that the stalk was not harvested when it was young and tender.
Meticulous cooks scrape asparagus stalks with a vegetable peeler, stroking away from the head, and refresh them in ice-cold water before steaming them; the peel is often added back to the cooking water and removed only after the asparagus is done, this is supposed to prevent diluting the flavor. Small or full-sized stalks can be made into asparagus soup. Cantonese restaurants in the United States often serve asparagus stir-fried with chicken, shrimp, or beef. Asparagus may also be quickly grilled over charcoal or hardwood embers, for an infusion of smoke flavor. Asparagus is one of few foods that is considered acceptable to eat with the hands in polite company, although this is more common in Europe.
In their simplest form, the shoots are boiled or steamed until tender and served with a light sauce like hollandaise or melted butter or a drizzle of olive oil with a dusting of Parmesan cheese. A refinement is to tie the shoots into sheaves and stand them so that the lower part of the stalks are boiled, while the more tender heads are steamed. Tall cylindrical asparagus cooking pots have liners with handles and perforated bases to make this process foolproof.
Some of the constituents of asparagus are metabolized and excreted in the urine, giving it a distinctive, mildly unpleasant odor. The smell is caused by various sulfur-containing degradation products (e.g. thiols and thioesters). Studies showed that about 40 percent of the test subjects displayed this characteristic smell; and a similar percentage of people are able to smell the odor once it is produced. There does not seem to be any correlation between peoples' production and detection of the smell (Stevens 2000). The speed of onset of urine smell is rapid, and has been estimated to occur within 15-30 minutes from ingestion (Somer 2000).
Asparagus is one of the most nutritionally valuable vegetables.
It is the best vegetable provider of folic acid. Folic acid is necessary for blood cell formation and growth, as well as liver disease prevention. Folic acid is also important for pregnant women as it aids in the prevention of neural tube defects, such as spina bifida, in the developing fetus.
Asparagus is very low in calories, contains no fat or cholesterol, and is very low in sodium. Asparagus is a great source of potassium, fiber, and rutin, a compound that strengthens the walls of capillaries. It also provides balanced amounts of vitamins C, A, B6, riboflavin, and thiamine, as well as iron (VRIC 2006). The amino acid asparagine gets its name from asparagus, the asparagus plant being rich in this compound. Asparagus rhizomes and roots are used ethnomedically to treat urinary tract infections, as well as kidney and bladder stones.
Production, imports, and exports
Worldwide, according to the Food and Agriculture Organization (FAO) of the United Nations, 6,764,000 metric tons of asparagus were produced in 2005, with top producers being China (5,906,000 metric tons) and Peru (206,000 metric tons) (FAO 2006). U.S. production was third (99,580 metric tons), with concentrations in California, Michigan, and Washington, and Germany (82,758 metric tons) was the fourth.
However, the United States Department of Agriculture (USDA), Foreign Agriculture Service, believes the FAO data greatly exaggerates the production of asparagus in China. The USDA reported for 2004 that the top producers were China (with only 587,500 metric tons), Peru (186,000 metric tons), United States (102,780 metric tons), and Mexico (67,247) (USDA 2005).
The top asparagus importers in 2004 were the United States (92,405 metric tons), followed by the European Union (18,565 metric tons) and Japan (17,148 metric tons). The United States imports both green fresh asparagus and white fresh asparagus from Peru. While both types are imported and marketed in the United States, the color requirements of the current U.S. grading standards only provide for the grading of green asparagus (USDA 2005).
White asparagus is very popular in Germany there where it is known as "spargel." Its production, however, is only enough to meet 61 percent of its consumption demands (Spence 2006).
Other plants called asparagus
Many related and unrelated plants may be called "asparagus" or said to be "used as asparagus" when eaten for their shoots. In particular, the shoots of a distantly related plant, Ornithogalum pyrenaicum, may be called "Prussian asparagus." This could be because Asparagus derived its name from the ancient Greeks, who used the word to refer to all tender shoots picked and savored while very young.
- Fellingham, A. C., and N. L. Meyer. 1995. New combinations and a complete list of Asparagus species in southern Africa (Asparagaceae). Bothalia 25: 205-209.
- Food and Agricultural Organization. 2006. ProdSTAT: Crops. FAOSTAT. Retreived March 25, 2007.
- Somer, E. 2000. Eau D'Asparagus. WEBMD. Retrieved Aug. 31, 2006.
- Spence, M. 2006. Asparagus: The king of vegetables. German Agricultural Marketing Board. Retrieved Feb. 26, 2007.
- Stevens, Roger, J. G. 2000. Why does urine smell odd after eating asparagus? Why Does Urine Smell Odd After Eating Asparagus?. British Medical Journal. Retrieved Aug. 31, 2006.
- United States Department of Agriculture (USDA). 2005. World asparagus situation and outlook. USDA, World Horticultural Trade & U.S. Export Opportunities. Retrieved Feb. 27, 2007.
- Vegetable Research and Info Center (VRIC), University of Californina, Davis. 2006. Asparagus. Vegetable Research and Info Center. Retrieved March 25, 2007.
- Watson, L., and M. J. Dallwitz. 2006. The families of flowering plants. Delta (DEscription Language for TAxonomy). Retrieved Feb. 28, 2007.
All links retrieved November 15, 2012.
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