Asparagus (Asparagus officinalis) orgarden asparagus is aperennialflowering plant species in the genusAsparagus native to Eurasia. Widely cultivated as a vegetable crop, its young shoots are used as a springvegetable.
Asparagus is anherbaceous,perennial plant[3] growing typically to 100–150 centimetres (3–5 feet) tall, with stout stems with much-branched, feathery foliage. It has been known to grow as long as 3.5 metres (11 ft).[4] The 'leaves' are needle-likecladodes (modified stems) in theaxils of scale leaves; they are 6–32 millimetres (1⁄4–1+1⁄4 inches) long and1 mm (1⁄32 in) broad, and clustered in fours, up to 15, together, in a rose-like shape.[5] The root system, often referred to as a 'crown', isadventitious; the root type isfasciculated.
Theflowers are bell-shaped, greenish-white to yellowish,4.5–6.5 mm (3⁄16–1⁄4 in) long, with sixtepals partially fused together at the base; they are produced singly or in clusters of two or three in the junctions of the branchlets. It is usuallydioecious, with male and female flowers on separate plants, but sometimeshermaphrodite flowers are found. Thefruit is a small redberry6–10 mm (1⁄4–13⁄32 in) in diameter, which istoxic to humans.[6]
Asparagus grown natively to the western coasts ofEurope (from northernSpain to northwestGermany, northIreland, andGreat Britain) are treated asA. officinalis subsp.prostratus(Dumort.) Corb., distinguished by its low-growing, often prostrate stems growing to only 30–70 cm (12–28 in) high, and shorter cladodes2–18 mm (3⁄32–23⁄32 in) long.[7][8] Some authors treat it as a distinct species,A. prostratusDumort.[9][10]
The English wordasparagus derives from classicalLatin but the plant was once known in English assperage, from theMedieval Latinsparagus.[Note 1] This term itself derives from theAncient Greek:ἀσπάραγος -aspáragos, a variant ofAncient Greek:ἀσφάραγος -aspháragos. The Greek terms are of uncertain provenance; the former form admits the possibility of a Proto-Indo-European root meaning "to jerk, scatter," directly or via aPersian descendant meaning "twig, branch"; but the Ancient Greek word itself, meaning "gully, chasm," seems to be ofPre-Greek origin instead.
Asparagus wascorrupted by folk etymology in some places to "sparrow grass";[11] indeed,John Walker wrote in 1791 that "Sparrowgrass is so general thatasparagus has an air of stiffness and pedantry".[12]The name 'sparrow grass' was still in common use in rural East Anglia, England well into the twentieth century.[13]
Since asparagus often originates in maritime habitats, it thrives in soils that are too saline for normal weeds to grow. Thus, a little salt was traditionally used to suppress weeds in beds intended for asparagus; this has the disadvantage that the soil cannot be used for anything else. Some regions andgardening zones are better-suited for growing asparagus than others, such as the west coast of North America and other more maritime, "Mediterranean" environments. The fertility of the soil is a large factor. "Crowns" are planted in winter, and the first shoots appear in spring; the first pickings or "thinnings" are known as sprue asparagus. Sprue has thin stems.[17]
A breed of "early-season asparagus" that can be harvested two months earlier than usual was announced by a UK grower in early 2011.[18] This variety does not need to lie dormant and blooms at 7 °C (45 °F), rather than the usual 9 °C (48 °F).
Purple asparagus differs from its green and white counterparts in having high sugar and low fibre levels. Purple asparagus was originally developed in Italy, near the city ofAlbenga and commercialized under the variety name 'Violetto d' Albenga'.[19] Purple asparagus can also turn green while being cooked due to its sensitivity to heat.[20]
Asparagus is said to be a usefulcompanion plant fortomatoes, as the tomato plant repels theasparagus beetle. Asparagus may repel some harmful root nematodes that affect tomato plants.[21]
Only young asparagus shoots ("spears") are commonly eaten: once the buds start to open ("ferning out"), the shoots quickly turn woody.[26] The shape of edible spears can vary according to variety; typical shapes are long thin spears from 8mm to 24mm diameter, no longer than 22cm.[27] The roots contain starch.[28]
The shoots are prepared and served in a number of ways around the world, typically as an appetizer[29] or vegetable side dish. In Asian-style cooking, asparagus is oftenstir-fried.Cantonese restaurants in the United States often serve asparagus stir-fried withchicken,shrimp, orbeef.[30] It may also be quickly grilled over charcoal or hardwood embers, and is also used as an ingredient in some stews and soups.
Asparagus can also bepickled and stored for several years. Some brands label shoots prepared in this way as "marinated".
Stem thickness indicates the age of the plant (and not the age of the stalk), with the thicker stems coming from older plants. Older, thicker stalks can be woody, although peeling the skin at the base removes the tough layer. Peeled asparagus will poach much faster.[31] The bottom portion of asparagus often contains sand and soil, so thorough cleaning is generally advised before cooking.
Male plants tend to produce spears that are smaller and thinner, while female plants tend produce larger and thicker spears.[32] The thickness of stalks is not an indication of their tenderness; they are thick or thin from the moment they sprout from the ground.[32]
Green asparagus is eaten worldwide, and the availability of imports throughout the year has made it less of a delicacy than it once was.[8] In Europe, according to one source, the "asparagus season is a highlight of thefoodie calendar"; in the UK this traditionally begins on 23 April and ends onMidsummer Day.[33][34] In Europe the short growing season and high demand leads to a relatively high price for local produce, although asparagus is also imported.
Only seasonally on the menu, asparagus dishes are advertised outside many restaurants, usually from late April to June. For the French style, asparagus is often boiled or steamed and served withHollandaise sauce,white sauce, melted butter or most recently with olive oil andParmesan cheese.[35] Tall, narrow asparagus cooking pots allow the shoots to be steamed gently, their tips staying out of the water.
In western Himalayan regions, such as Nepal and north-western India,Ornithogalum pyrenaicum, known as "wild asparagus," is harvested as a seasonal vegetable delicacy known askurilo orjhijhirkani.[36]
White asparagus is produced by applying ablanching technique while the asparagus shoots are growing:[37] the shoots are covered with soil as they grow, i.e.earthed up; without exposure to sunlight, there is nophotosynthesis and the shoots remain white. The locally cultivated so-called "white gold" or "edible ivory" asparagus, also referred to as "the royal vegetable",[38] is believed to be less bitter and more tender than unblanched green. Freshness is valued, and the lower ends of white asparagus must be peeled.
During the GermanSpargelsaison orSpargelzeit ("asparagus season" or "asparagus time"), the asparagus season that traditionally finishes on 24 June, roadside stands and open-air markets sell about half of the country's white asparagus consumption.[39]
Asparagus has been used as a vegetable owing to its distinct flavor, and in medicine due to itsdiuretic properties and its purported function as anaphrodisiac. It is pictured as an offering on an Egyptianfrieze dating to 3000 BC. In ancient times, it was also known in Syria and in the Iberian Peninsula. Greeks and Romans ate it fresh when in season, and dried the vegetable for use in winter. EmperorAugustus coined the expression "faster than cooking asparagus" for quick action.[Note 2][40][41]
A recipe for cooking asparagus is given in one of the oldest surviving collections of recipes (Apicius's 1st century ADDe re coquinaria, Book III). In the second century AD, the Greek physicianGalen, highly respected within Roman society, mentioned asparagus as a beneficial herb, but as dominance of the Roman empire waned, asparagus' medicinal value drew little attention[42][Note 1]untilal-Nafzawi'sThe Perfumed Garden.
By 1469, asparagus was cultivated in French monasteries. Asparagus appears to have been little noticed in England until 1538,[Note 1] and in Germany until 1542.[41][better source needed]
Asparagus was brought to North America by European settlers at least as early as 1655. Adriaen van der Donck, a Dutch immigrant to New Netherland, mentions asparagus in his description of Dutch farming practices in the New World.[43] Asparagus was grown by British immigrants as well; in 1685, one of William Penn's advertisements for Pennsylvania included asparagus in a long list of crops that grew well in the American climate.[44]
Thepoints d'amour ("love tips") were served as a delicacy toMadame de Pompadour (1721–1764).[45]
asparagus... affects the urine with afoetid smell (especially if cut when they are white) and therefore have been suspected by some physicians as not friendly to the kidneys; when they are older, and begin to ramify, they lose this quality; but then they are not so agreeable.
Subjectively, the first two are the most pungent, while the last two (sulfur-oxidized) give a sweet aroma. A mixture of these compounds form a "reconstituted asparagus urine" odor. This was first investigated in 1891 byMarceli Nencki, who attributed the smell tomethanethiol.[56] These compounds originate in the asparagus asasparagusic acid and its derivatives, as these are the only sulfur-containing compounds unique to asparagus. As these are more present in young asparagus, this accords with the observation that the smell is more pronounced after eating young asparagus. The biological mechanism for the production of these compounds is less clear.[57]
The onset of the asparagus urine smell is remarkably rapid while the decline is slower. The smell has been reported to be detectable 15 to 30 minutes after ingestion[58][59] and subsides with ahalf-life of approximately four hours.[60]Asparagus has been eaten and cultivated for at least two millennia but the association between odorous urine and asparagus consumption was not observed until the late 17th century when sulfur-rich fertilisers became common in agriculture.[61] Small-scale studies noted that the "asparagus urine" odour was not produced by all individuals and estimates as to the proportion of the population who are excretors (reporting a noticeable asparagus urine odour after eating asparagus) has ranged from about 40%[62] to as high as 79%.[63][60] When excretors are exposed to urine of people who do not report odour in their urine after asparagus consumption, however, the characteristic asparagus urine odour is usually reported.[61] More recent work has found that a small proportion of individuals do not produce asparagus urine, and amongst those who do, some cannot detect the odour due to asingle-nucleotide polymorphism within a cluster ofolfactory receptors.[64]
Debate exists about the universality of producing the sulfurous smell, as well as the ability to detect it. Originally, this was thought to be because some people digested asparagus differently from others, so some excreted odorous urine after eating asparagus, and others did not. In the 1980s, three studies from France,[65] China, and Israel published results showing that producing odorous urine from asparagus was a common human characteristic. The Israeli study found that from their 307 subjects, all of those who could smell "asparagus urine" could detect it in the urine of anyone who had eaten asparagus, even if the person who produced it could not detect it.[66] A 2010 study[67] found variations in both production of odorous urine and the ability to detect the odor, but that these were not tightly related. Most people are thought to produce the odorous compounds after eating asparagus, but the differing abilities of various individuals to detect the odor at increasing dilutions suggests a genetically determined specific sensitivity.[68][69][70]
In 2010, the company23andMe published agenome-wide association study on whether participants have "ever noticed a peculiar odor when [they] pee after eating asparagus".[71] This study pinpointed asingle-nucleotide polymorphism (SNP) in a cluster of olfactory genes associated with the ability to detect the odor. While this SNP did not explain all of the difference in detection between people, it provides support for the theory that genetic differences occur in olfactory receptors that lead people to be unable to smell these odorous compounds.
The green crop is significant enough in California'sSacramento–San Joaquin River Delta region that the city ofStockton holds a festival every year to celebrate it.Oceana County, Michigan, the self-proclaimed "asparagus capital of the world", hosts an annual festival.[72] TheVale of Evesham inWorcestershire (another "asparagus capital"[73]) celebrates the annual British Asparagus Festival, with auctions of the best crop, an "Asparagus Run" modelled on the Beaujolais Run, and a weekend "Asparafest" music festival.[74]
Many German cities hold an annualSpargelfest (asparagus festival) celebrating the harvest of white asparagus.Schwetzingen claims to be the "Asparagus Capital of the World".[75]
Three types of asparagus are on display, with white asparagus at the back and green asparagus in the middle. The plant at the front isOrnithogalum pyrenaicum, commonly called wild asparagus, and sometimesBath asparagus orPrussian asparagus.
^abcIn the eleventh century AD the word "sparagus" appeared in an English text. See Brunning (June 2010), p. 6. – Brunning uses the term "in print", though no printing technique was used in England at the time. In the same sentence, she states thatpeasants often called it "sparrow grass", and further on mentions a 1667 diary in which Samuel Pepys bought a bundle of "sparrow grass" in Fenchurch Street, London.
^Latinvelocius quam asparagi conquantur (orcelerius quam asparagi cocuntur), ascribed to Augustus bySuetonius (The Lives of the Twelve Caesars, Book 2(Augustus), para. 87). SeeList of Latin phrases (V).
^Diderot, D. (2009) [1772]."Asparagus".The Encyclopedia of Diderot & d'Alembert. Retrieved1 April 2015 – via Collaborative Translation Project, University of Michigan.
^Ewart Evans, George "Ask the Fellows who Cut the Hay"
^Plants of the World Online. (n.d.)."Asparagus officinalis L." Royal Botanic Gardens, Kew. Retrieved31 May 2018.
^Euro+Med Plantbase Project."Asparagus officinalis". Botanic Garden and Botanical Museum Berlin-Dahlem. Archived fromthe original on 11 August 2011. Retrieved19 May 2010.
^Jules Gouffé; Etienne Antoine; Eugène Ronjat (5 August 2016).""Chapitre XVI Légumes 71.Légumes"".Le Livre de cuisine: Comprenant la cuisine de ménage et la grande cuisine, 1893 (in French). BnF collection ebooks.ISBN978-2-346-01376-0. Retrieved28 April 2020. (Asperge is French for asparagus.)
^Waring RH, Mitchell SC, Fenwick GR (1987). "The chemical nature of the urinary odour produced by man after asparagus ingestion".Xenobiotica.17 (11):1363–1371.doi:10.3109/00498258709047166.PMID3433805.
^abvan Hasselt, J. G. C.; Elassaiss-Schaap, J.; Ramamoorthy, A.; Sadler, B. M.; Kasichayanula, S.; Edwards, Y.; van der Graaf, P. H.; Zhang, L.; Wagner, J. A. (2016)."The proof is in the pee: Population asparagus urinary odor kinetics".PAGE: Abstracts of the Annual Meeting of the Population Approach Group in Europe.25.ISSN1871-6032. Retrieved7 July 2016.
