The Jerusalem artichoke, also called sunroot, sunchoke, earth apple or topinambour, is a
species of sunflower native to eastern North America, and found from eastern Canada and
Maine west to North Dakota, and south to northern Florida and Texas. It is also cultivated widely
across the temperate zone for its tuber, which is used as a root vegetable.
Description It is a herbaceous perennial plant growing
to 1.5–3 m tall with opposite leaves on the upper part of the stem but alternate below.
The leaves have a rough, hairy texture and the larger leaves on the lower stem are broad
ovoid-acute and can be up to 30 cm long, and the higher leaves smaller and narrower.
The flowers are yellow and produced in capitate flowerheads, which are 5–10 cm in diameter,
with 10–20 ray florets. The tubers are elongated and uneven, typically
7.5–10 cm long and 3–5 cm thick, and vaguely resembling ginger root in appearance,
with a crisp texture when raw. They vary in colour from pale brown to white, red, or purple.
The artichoke contains about 10% protein, no oil, and a surprising lack of starch. However,
it is rich in the carbohydrate inulin, which is a polymer of the monosaccharide fructose.
Tubers stored for any length of time will convert their inulin into its component fructose.
Jerusalem artichokes have an underlying sweet taste because of the fructose, which is about
one and a half times sweeter than sucrose. Jerusalem artichokes have also been promoted
as a healthy choice for type 2 diabetics, because fructose is better tolerated by people
who are type 2 diabetic. It has also been reported as a folk remedy for diabetes. Temperature
variances have been shown to affect the amount of inulin the Jerusalem artichoke can produce.
When not in tropical regions, it has been shown to make less inulin than when it is
in a warmer region. Etymology
Despite its name, the Jerusalem artichoke has no relation to Jerusalem, and it is not
a type of artichoke, though both are members of the daisy family. The origin of the name
is uncertain. Italian settlers in the USA called the plant girasole, the Italian word
for sunflower, because of its resemblance to the garden sunflower. Over time, the name
girasole may have been changed to Jerusalem. The English later corrupted girasole artichoke
to Jerusalem artichoke. Another explanation for the name is that the Pilgrims, when they
came to the New World, named the plant with regard to the “New Jerusalem” they believed
they were creating in the wilderness. There have also been various other names applied
to the plant, such as the French or Canada potato, topinambour, and lambchoke. Sunchoke,
a name by which it is still known today, was invented in the 1960s by Frieda Caplan, a
produce wholesaler who was trying to revive the plant’s appeal.
The artichoke part of the Jerusalem artichoke's name comes from the taste of its edible tuber.
Samuel de Champlain, the French explorer, sent the first samples of the plant to France,
noting its taste was similar to an artichoke. Handbuch des speziellen Gemüsebaus attributes
the name "topinambur" to a 17th-century coincidence at the Vatican when a sample of the tuber
from Canada was on display, as having helped French Canadian settlers to survive the Winter;
at the same time a member of the Brazilian coastal tribe, the Tupinambá, was also visiting.
The New World connection evidently resulted in the name for Jerusalem artichoke now used
in French, German, Italian, Romanian, Russian, and Spanish.
History Jerusalem artichokes were first cultivated
by the Native Americans long before the arrival of the Europeans; this extensive cultivation
obscures the exact native range of the species. The French explorer Samuel de Champlain found
domestically grown plants at Cape Cod in 1605. He then brought the plant back with him to
France. By the mid-1600s, the Jerusalem artichoke had become a very common vegetable for human
consumption in Europe and the Americas and was also used for livestock feed in Europe
and colonial America. The French in particular were especially fond of the vegetable, which
reached its peak popularity at the turn of the 19th century. The Jerusalem artichoke
was titled 'best soup vegetable' in the 2002 Nice Festival for the Heritage of the French
Cuisine. Cultivation and uses
Unlike most tubers, but in common with other members of the Asteraceae, the tubers store
the carbohydrate inulin instead of starch. For this reason, Jerusalem artichoke tubers
are an important source of inulin used as a dietary fiber in food manufacturing.
Crop yields are high, typically 16–20 tonnes/ha for tubers, and 18–28 tonnes/ha green weight
for foliage. Jerusalem artichoke also has potential for production of ethanol fuel,
using inulin-adapted strains of yeast for fermentation.
Jerusalem artichokes are easy to cultivate, which tempts gardeners to simply leave them
completely alone to grow. However, the quality of the edible tubers degrades unless the plants
are dug up and replanted in fertile soil. This can be a chore, as even a small piece
of tuber will grow if left in the ground, making the hardy plant a potential weed. In
fact, the plant can be pernicious. It can ruin gardens by smothering or overshadowing
nearby plants and can overtake huge areas if left untamed. Commercial fields growing
sunchoke which then change to other vegetables or crops often must be treated with glyphosate
to stop the spread of the sunchokes. Each sunchoke root can make an additional 75 to
as many as 200 tubers by fall end.
The tubers are sometimes used as a substitute for potatoes: they have a similar consistency,
and in their raw form have a similar texture, but a sweeter, nuttier flavor; raw and sliced
thinly, they are fit for a salad. The carbohydrates give the tubers a tendency to become soft
and mushy if boiled, but they retain their texture better when steamed. The inulin cannot
be broken down by the human digestive system, but is metabolized by bacteria in the colon.
This can cause flatulence and, in some cases, gastric pain. Gerard's Herbal, printed in
1621, quotes the English planter John Goodyer on Jerusalem artichokes:
"which way soever they be dressed and eaten, they stir and cause a filthy loathsome stinking
wind within the body, thereby causing the belly to be pained and tormented, and are
a meat more fit for swine than men."
Jerusalem artichokes have 650 mg potassium per 1 cup serving. They are also high in iron,
and contain 10-12% of the US RDA of fiber, niacin, thiamine, phosphorus and copper.
Jerusalem artichokes can be used as animal feed, but they must be washed before being
fed to most animals. However pigs can forage and safely eat them directly from the ground.
The stalks and leaves can be harvested and used for silage, though cutting the tops greatly
reduces the harvest of the roots.
Liquor In Baden-Württemberg, Germany, over 90% of
the Jerusalem artichoke crop is used to produce a spirit called "Topinambur (de)", "Topi"
or "Rossler". By the end of the 19th-century, Jerusalem artichokes were being used in Baden
to make a spirit called "Jerusalem Artichoke Brandy", "Jerusalem Artichoke", "Topi", "Erdäpfler",
"Rossler", or "Borbel". Jerusalem artichoke brandy smells fruity and
has a slight nutty-sweet flavour. It is characterised by an intense, pleasing, earthy note. The
tubers are washed and dried in an oven before being fermented and distilled. It can be further
refined to make "Red Rossler" by adding common tormentil, and other ingredients such as currants,
to produce a somewhat bitter and astringent decoction. It is used as digestif, as well
as a remedy for diarrhea or abdominal pain. Pyramid scheme
In the 1980s, the Jerusalem artichoke also gained some notoriety when its seeds were
planted by midwestern US farmers at the prodding of an agricultural pyramid scheme. There was
little market for the tuber in that part of the US at the time, but farmers were assured
it would soon appear on the commodities market. The only profits were realized by the initial
distributors and the first few levels of farmers. As a result, many of the farms that had planted
large quantities of the crop were ruined. Synonyms
Helianthus tuberosus L., Sp. Pl. 2: 905. 1753.Helianthus tomentosus Michx., Fl. bor.-amer. 2:141. 1803.
Heliantus tuberosus var. subcanescens A. Gray, Syn. Fl. N. Amer.1(2): 280. 1884.
Helianthus subcanescens E. Wats., Pap. Michigan Acad. Sci. 9: 430. 1929.
References
External links Helianthus tuberosus – Plants for a Future
database Jerusalem artichoke – Ohio Perennial & Biennial
Weed Guide Complete nutritional info.
Alternative Field Crops Manual: Jerusalem Artichoke